Journal of Powder Materials

[Korean]
Effect of Fe and Cr on ω Phase Formation in Metastable β-Ti Alloy: Sun-Young Park, Young-Bum Chun; J Powder Mater. 2025;32(4):354-360. Published online August 29, 2025; DOI: https://doi.org/10.4150/jpm.2025.00220

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Abstract PDF: This study investigated the effects of Fe and Cr contents on ω phase formation and transformation during solution treatment and the subsequent aging process, for which four model alloys with varying Fe and Cr contents but keeping Mo equivalent of ~ 12.6 were prepared by plasma arc melting and fabricated into plates by hot forging followed by hot-rolling. The atherrmal ω phase was observed in all Ti alloys after solution treatment followed by water quenching through XRD and TEM analysis. The largest volume fraction of athermal ω phase is formed in Ti alloy with only Fe 4 wt.% among all Ti alloys, leading to the highest Vickers value due to hardening effect ω phase. It was found that not only Mo equivalent but also each characteristic of β stabilizing elements should be considered to understand a microstructure evolution and mechanical properties.

[English]
Cost-effective Fabrication of Near β-Ti Alloy via L-PBF: Process Optimization of In-situ Alloying Ti-3Fe: Sehun Kim, Ukju Gim, Taehu Kang, Jongik Lee, Sanghee Jeong, Jimin Han, Bin Lee; J Powder Mater. 2025;32(4):288-298. Published online August 29, 2025; DOI: https://doi.org/10.4150/jpm.2025.00213

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Abstract PDF: This study presents a cost-effective approach to fabricating near β-Ti alloys via in-situ alloying during laser powder bed fusion (L-PBF). A blend of non-spherical pure Ti, 3 wt.% Fe, and 0.1 wt.% SiO2 nanoparticles was used to induce β-phase stabilization and improve flowability. Twenty-five process conditions were evaluated across a volumetric energy density range of 31.75-214.30 J/mm3, achieving a maximum relative density of 99.21% at 89.29 J/mm3. X-ray diffraction analysis revealed that the β-Ti phase was partially retained at room temperature, accompanied by lattice contraction in the α’-Ti structure, indicating successful Fe incorporation. Elemental mapping confirmed that the Fe distribution was homogeneous, without significant segregation. Compared to pure Ti, the Ti-3Fe sample exhibited a 49.2% increase in Vickers hardness and notable improvements in yield and ultimate tensile strengths. These results demonstrate the feasibility of in-situ alloying with low-cost elemental powders to produce high-performance near β-Ti alloys using L-PBF.

[Korean]
The Recycling Process and Powderization Technology of Stellite 6 Scrap: A Thermodynamic and Heat Transfer Analysis: YongKwan Lee, Hyun-chul Kim, Myungsuk Kim, Soong Ju Oh, Kyoungtae Park, JaeJin Sim; J Powder Mater. 2025;32(4):330-343. Published online August 29, 2025; DOI: https://doi.org/10.4150/jpm.2025.00136

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Abstract PDF: Co-Cr alloys are widely used in cutting tools and turbine components due to their high strength and resistance against wear and corrosion. However, scrap generated during hardfacing is often discarded due to impurities and oxidation, and research on its recycling remains limited. This study aimed to optimize the recycling process of Stellite 6 scrap to reduce waste and minimize costs while maintaining material quality. Melting, casting, and powdering processes were designed using HSC Chemistry, FactSage, and COMSOL Multiphysics, with optimization of key parameters such as the crucible material and temperature control. The recycled alloy and powder were analyzed using X-ray fluorescence analysis, inductively coupled plasma optical emission spectroscopy, and X-ray diffractometry, showing mechanical and chemical properties comparable to commercial Stellite 6. The Co and Cr contents were maintained, with a slight increase in Fe. These findings demonstrate the potential for producing high-quality recycled Stellite 6 materials, contributing to the sustainable utilization of metal resources in high-performance applications.

[English]
Laser Processing of an Al_0.1CoCrFeNi High Entropy Alloy + Cu Composite Powders via Laser Powder Bed Fusion: Kwangtae Son, Ji-Woon Lee, Soon-Jik Hong, Somayeh Pasebani; J Powder Mater. 2025;32(4):277-287. Published online August 29, 2025; DOI: https://doi.org/10.4150/jpm.2025.00101

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Abstract PDF: This study examined process–structure relationships in laser powder bed fusion of Al₀.₁CoCrFeNi + Cu composites, focusing on densification, elemental distribution, and solidification cracking. Mechanically mixed Al₀.₁CoCrFeNi and Cu powders were processed across a range of laser powers (100–250 W) and scan speeds (200–800 mm/s). Increased volumetric energy density (VED) improved densification, with a plateau near 200 J/mm³ yielding ~96% relative density; however, this value was still below application-grade thresholds. At low VED, insufficient thermal input and short melt pool residence times promoted Cu segregation, while higher VED facilitated improved elemental mixing. Elemental mapping showed partial co-segregation of Ni with Cu at low energies. Solidification cracks were observed across all processing conditions. In high VED regimes, cracking exhibited a minimal correlation with segregation behavior and was primarily attributed to steep thermal gradients, solidification shrinkage, and residual stress accumulation. In contrast, at low VED, pronounced Cu segregation appeared to exacerbate cracking through localized thermal and mechanical mismatch.

[Korean]
The Manufacturing Process of Clean Ni-Cr-Co-Based Superalloy Powder Using a Plasma Rotating Electrode: Kyu-Sik Kim, Dae Woong Kim, Yeontae Kim, Jung Hyo Park; J Powder Mater. 2025;32(3):222-231. Published online June 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00171

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Abstract PDF: Ni-based superalloys are widely used for critical components in aerospace, defense, industrial power generation systems, and other applications. Clean superalloy powders and manufacturing processes, such as compaction and hot isostatic pressing, are essential for producing superalloy discs used in turbine engines, which operate under cyclic rotating loads and high-temperature conditions. In this study, the plasma rotating electrode process (PREP), one of the most promising methods for producing clean metallic powders, is employed to fabricate Ni-based superalloy powders. PREP leads to a larger powder size and narrower distribution compared to powders produced by vacuum induction melt gas atomization. An important finding is that highly spheroidized powders almost free of satellites, fractured, and deformed particles can be obtained by PREP, with significantly low oxygen content (approximately 50 ppm). Additionally, large grain size and surface inclusions should be further controlled during the PREP process to produce high-quality powder metallurgy parts.

[English]
Thermodynamic and Electronic Descriptor-Driven Machine Learning for Phase Prediction in High-Entropy Alloys: Experimental Validation: Nguyen Lam Khoa, Nguyen Duy Khanh, Hoang Thi Ngoc Quyen, Nguyen Thi Hoang Oanh, , Le Hong Thang, Nguyen Hoa Khiem, Nguyen Hoang Viet; J Powder Mater. 2025;32(3):191-201. Published online June 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00143

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Abstract PDF

High-entropy alloys (HEAs) exhibit complex phase formation behavior, challenging conventional predictive methods. This study presents a machine learning (ML) framework for phase prediction in HEAs, using a curated dataset of 648 experimentally characterized compositions and features derived from thermodynamic and electronic descriptors. Three classifiers—random forest, gradient boosting, and CatBoost—were trained and validated through cross-validation and testing. Gradient boosting achieved the highest accuracy, and valence electron concentration (VEC), atomic size mismatch (δ), and enthalpy of mixing (ΔHmix) were identified as the most influential features. The model predictions were experimentally verified using a non-equiatomic Al₃₀Cu₁₇.₅Fe₁₇.₅Cr₁₇.₅Mn₁₇.₅ alloy and the equiatomic Cantor alloy (CoCrFeMnNi), both of which showed strong agreement with predicted phase structures. The results demonstrate that combining physically informed feature engineering with ML enables accurate and generalizable phase prediction, supporting accelerated HEA design.

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Preparation and Arc Erosion Behavior of Cu-Based Contact Materials Reinforced with High Entropy Particles CuCrNiCoFe
Jiacheng Tong, Jun Wang, Huimin Zhang, Haoran Liu, Youchang Sun, Zhiguo Li, Wenyi Zhang, Zhe Wang, Yanli Chang, Zhao Yuan, Henry Hu
Metallurgical and Materials Transactions B.2025; 56(5): 5948. CrossRef
Recent progresses on high entropy alloy development using machine learning: A review
Abhishek Kumar, Nilay Krishna Mukhopadhyay, Thakur Prasad Yadav
Computational Materials Today.2025; 8: 100038. CrossRef

[Korean]
Effect of Support Structure on Residual Stress Distribution in Ti-6Al-4V Alloy Fabricated by Laser Powder Bed Fusion: Seungyeon Lee, Haeum Park, Min Jae Baek, Dong Jun Lee, Jae Wung Bae, Ji-Hun Yu, Jeong Min Park; J Powder Mater. 2025;32(3):244-253. Published online June 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00087

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Abstract PDF: Ti-6Al-4V alloy is widely utilized in aerospace and medical sectors due to its high specific strength, corrosion resistance, and biocompatibility. However, its low machinability makes it difficult to manufacture complex-shaped products. Advancements in additive manufacturing have focused on producing high-performance, complex components using the laser powder bed fusion (LPBF) process, which is a specialized technique for customized geometries. The LPBF process exposes materials to extreme thermal conditions and rapid cooling rates, leading to residual stresses within the parts. These stresses are intensified by variations in the thermal history across regions of the component. These variations result in differences in microstructure and mechanical properties, causing distortion. Although support structure design has been researched to minimize residual stress, few studies have conducted quantitative analyses of stress variations due to different support designs. This study investigated changes in the residual stress and mechanical properties of Ti-6Al-4V alloy fabricated using LPBF, focusing on support structure design.

[Korean]
Fabrication and Alloying Behavior of Ultra-Lightweight AlTiCrVMg High-Entropy Alloy via Al-Mg Mutual Solubility and Sintering Control: Eunhyo Song, Hansung Lee, Byungmin Ahn; J Powder Mater. 2025;32(3):254-261. Published online June 12, 2025; DOI: https://doi.org/10.4150/jpm.2025.00059

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Abstract PDF: High-entropy alloys (HEAs) incorporating low-melting-point elements (Mg and Al) and high-melting-point elements (Ti, Cr, and V) were fabricated via mechanical alloying and spark plasma sintering. Sintering temperatures were varied to investigate phase behavior and microstructural evolution. X-ray diffraction was used to identify phase structures, scanning electron microscopy to analyze microstructures, X-ray fluorescence to determine elemental composition, and a gas pycnometer to measure density. Micro-Vickers hardness testing was conducted to evaluate mechanical properties. Mechanical-alloyed HEAs exhibited a body-centered cubic (BCC) phase and lamellar structures with element-enriched regions. Sintering introduced additional BCC and Laves phases, while higher temperatures promoted Mg liquid-phase sintering, increasing density and hardness. This study highlights the effects of sintering on HEAs containing elements with differing melting points to optimize their properties.

[Korean]
Effect of Building Orientation on Tensile Properties of Hastelloy X alloy Manufactured by Laser Powder Bed Fusion: Seong-June Youn, GooWon Noh, Seok Su Sohn, Young-Sang Na, Young-Kyun Kim; J Powder Mater. 2025;32(2):131-137. Published online April 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00080

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Abstract PDF: In this study, the effect of build orientation on the mechanical properties of Hastelloy X fabricated by laser powder bed fusion (LPBF) process was investigated. Initial microstructural analysis revealed an equiaxed grain structure with random crystallographic orientation and annealing twins. Intragranular precipitates identified as Cr-rich M23C6 and Mo-rich M6C carbides were observed, along with a dense dislocation network and localized dislocation accumulation around the carbides. Mechanical testing showed negligible variation in yield strength with respect to build orientation; however, both ultimate tensile strength and elongation exhibited a clear increasing trend with higher build angles. Notably, the specimen built at 90° exhibited approximately 22% higher tensile strength and more than twice the elongation compared to the 0° specimen.

[English]
A Review of Recent Developments in CoCrFeMnNi High-Entropy Alloys Processed by Powder Metallurgy: Cheenepalli Nagarjuna, Sheetal Kumar Dewangan, Hansung Lee, Eunhyo Song, K. Raja Rao, Byungmin Ahn; J Powder Mater. 2025;32(2):145-164. Published online April 30, 2025; DOI: https://doi.org/10.4150/jpm.2024.00430

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Abstract PDF

In recent years, high-entropy alloys (HEAs) have attracted considerable attention in materials engineering due to their unique phase stability and mechanical properties compared to conventional alloys. Since the inception of HEAs, CoCrFeMnNi alloys have been widely investigated due to their outstanding strength and fracture toughness at cryogenic temperatures. However, their lower yield strength at room temperature limits their structural applications. The mechanical properties of HEAs are greatly influenced by their processing methods and microstructural features. Unlike traditional melting techniques, powder metallurgy (PM) provides a unique opportunity to produce HEAs with nanocrystalline structures and uniform compositions. The current review explores recent advances in optimizing the microstructural characteristics in CoCrFeMnNi HEAs by using PM techniques to improve mechanical performance. The most promising strategies include grain refinement, dispersion strengthening, and the development of heterogeneous microstructures (e.g., harmonic, bimodal, and multi-metal lamellar structures). Thermomechanical treatments along with additive manufacturing techniques are also summarized. Additionally, the review addresses current challenges and suggests future research directions for designing advanced HEAs through PM techniques.

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Thermodynamic and Electronic Descriptor-Driven Machine Learning for Phase Prediction in High-Entropy Alloys: Experimental Validation
Nguyen Lam Khoa, Nguyen Duy Khanh, Hoang Thi Ngoc Quyen, Nguyen Thi Hoang, Oanh, Le Hong Thang, Nguyen Hoa Khiem, Nguyen Hoang Viet
Journal of Powder Materials.2025; 32(3): 191. CrossRef

[English]
Advances in Powder Metallurgy for High-Entropy Alloys: Sheetal Kumar Dewangan, Cheenepalli Nagarjuna, Hansung Lee, K. Raja Rao, Man Mohan, Reliance Jain, Byungmin Ahn; J Powder Mater. 2024;31(6):480-492. Published online December 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00297

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High-entropy alloys (HEAs) represent a revolutionary class of materials characterized by their multi-principal element compositions and exceptional mechanical properties. Powder metallurgy, a versatile and cost-effective manufacturing process, offers significant advantages for the development of HEAs, including precise control over their composition, microstructure, and mechanical properties. This review explores innovative approaches integrating powder metallurgy techniques in the synthesis and optimization of HEAs. Key advances in powder production, sintering methods, and additive manufacturing are examined, highlighting their roles in improving the performance, advancement, and applicability of HEAs. The review also discusses the mechanical properties, potential industrial applications, and future trends in the field, providing a comprehensive overview of the current state and future prospects of HEA development using powder metallurgy.

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Fabrication and Alloying Behavior of Ultra-Lightweight AlTiCrVMg High-Entropy Alloy via Al-Mg Mutual Solubility and Sintering Control
Eunhyo Song, Hansung Lee, Byungmin Ahn
Journal of Powder Materials.2025; 32(3): 254. CrossRef
Thermodynamic and Electronic Descriptor-Driven Machine Learning for Phase Prediction in High-Entropy Alloys: Experimental Validation
Nguyen Lam Khoa, Nguyen Duy Khanh, Hoang Thi Ngoc Quyen, Nguyen Thi Hoang, Oanh, Le Hong Thang, Nguyen Hoa Khiem, Nguyen Hoang Viet
Journal of Powder Materials.2025; 32(3): 191. CrossRef

[English]
Effect of Calcium Addition on the High-Temperature Recovery of Nd and Dy from Nd-Fe-B Scrap Using Mg-Based Extractants: Hyoseop Kim; J Powder Mater. 2024;31(6):493-499. Published online December 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00283

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Abstract PDF: This study investigated whether calcium (Ca) addition improved the recovery of neodymium (Nd) and dysprosium (Dy) from Nd-Fe-B magnet scrap using magnesium (Mg)-based liquid metal extraction (LME). Traditional LME processes are limited to temperatures up to 850 °C due to oxidation issues, reducing the efficiency of rare earth element (REE) recovery, especially for Dy. By adding 10 wt.% Ca to Mg and increasing the processing temperature to 1,000 °C, we achieved nearly 100% Nd and approximately 38% Dy recovery, compared to 91% and 28%, respectively, with pure Mg at 850 °C. However, excessive Ca addition (20 wt.%) decreased the recovery efficiency due to the formation of stable intermetallic compounds. These results highlight the critical role of Ca in optimizing REE recycling from Nd-Fe-B magnet scrap.

[English]
Hot-Cracking Behaviors in (CoNi)₈₅Mo₁₅ Medium-Entropy Alloys Manufactured via Powder Bed Fusion: Seungjin Nam, Heechan Jung, Haeum Park, Chahee Jung, Jeong Min Park, Hyoung Seop Kim, Seok Su Sohn; J Powder Mater. 2024;31(6):537-545. Published online December 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00262

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Additive manufacturing makes it possible to improve the mechanical properties of alloys through segregation engineering of specific alloying elements into the dislocation cell structure. In this study, we investigated the mechanical and microstructural characteristics of CoNi-based medium-entropy alloys (MEAs), including the refractory alloying element Mo with a large atomic radius, manufactured via laser-powder bed fusion (L-PBF). In an analysis of the printability depending on the processing parameters, we achieved a high compressive yield strength up to 653 MPa in L-PBF for (CoNi)85Mo15 MEAs. However, severe residual stress remained at high-angle grain boundaries, and a brittle µ phase was precipitated at Mo-segregated dislocation cells. These resulted in hot-cracking behaviors in (CoNi)85Mo15 MEAs during L-PBF. These findings highlight the need for further research to adjust the Mo content and processing techniques to mitigate cracking behaviors in L-PBF-manufactured (CoNi)85Mo15 MEAs.

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Effect of Support Structure on Residual Stress Distribution in Ti-6Al-4V Alloy Fabricated by Laser Powder Bed Fusion
Seungyeon Lee, Haeum Park, Min Jae Baek, Dong Jun Lee, Jae Wung Bae, Ji-Hun Yu, Jeong Min Park
Journal of Powder Materials.2025; 32(3): 244. CrossRef

[English]
Comparative Review of the Microstructural and Mechanical Properties of Ti-6Al-4V Fabricated via Wrought and Powder Metallurgy Processes: Raj Narayan Hajra, Gargi Roy, An Seong Min, Hyunseok Lee, Jeoung Han Kim; J Powder Mater. 2024;31(5):365-373. Published online October 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00213

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This review examines the microstructural and mechanical properties of a Ti-6Al-4V alloy produced by wrought processing and powder metallurgy (PM), specifically laser powder bed fusion (LPBF) and hot isostatic pressing. Wrought methods, such as forging and rolling, create equiaxed alpha (α) and beta (β) grain structures with balanced properties, which are ideal for fatigue resistance. In contrast, PM methods, particularly LPBF, often yield a martensitic α′ structure with high microhardness, enabling complex geometries but requiring post-processing to improve its properties and reduce stress. The study evaluated the effects of processing parameters on grain size, phase distribution, and material characteristics, guiding the choice of fabrication techniques for optimizing Ti-6Al-4V performance in aerospace, biomedical, and automotive applications. The analysis emphasizes tailored processing to meet advanced engineering demands.

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Removal of Organic and Inorganic Contaminants from Titanium Turning Scrap via Alkali and Acid Two-Step Cleaning
Seong Min An, Raj Narayan Hajra, Chan Hee Park, Jin-Ho Yoon, Jinsung Rho, Chang-Min Yoon, Jeoung Han Kim
MATERIALS TRANSACTIONS.2025; 66(7): 855. CrossRef
Effect of oxygen content in feedstock powders on microstructure and mechanical properties of ELI Ti-6Al-4V fabricated via laser powder bed fusion
Woo Hyeok Kim, Sang Woo Kim, Raj Narayan Hajra, Gargi Roy, Jeoung Han Kim
Powder Metallurgy.2025; 68(4): 307. CrossRef

[Korean]
Effect of Sintering Conditions on the Microstructure of an FeCrMnNiCo High-Entropy Alloy: Seonghyun Park, Sang-Hwa Lee, Junho Lee, Seok-Jae Lee, Jae-Gil Jung; J Powder Mater. 2024;31(5):406-413. Published online October 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00185

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We investigated the microstructure of an FeCrMnNiCo alloy fabricated by spark plasma sintering under different sintering temperatures (1000–1100°C) and times (1–600 s). All sintered alloys consisted of a single face-centered cubic phase. As the sintering time or temperature increased, the grains of the sintered alloys became partially coarse. The formation of Cr7C3 carbide occurred on the surface of the sintered alloys due to carbon diffusion from the graphite crucible. The depth of the layer containing Cr7C3 carbides increased to ~110 μm under severe sintering conditions (1100°C, 60 s). A molten zone was observed on the surface of the alloys sintered at higher temperatures (>1060°C) due to severe carbon diffusion that reduced the melting point of the alloy. The porosity of the sintered alloys decreased with increasing time at 1000°C, but increased at higher temperatures above 1060°C due to melting-induced porosity formation.

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Fabrication and Alloying Behavior of Ultra-Lightweight AlTiCrVMg High-Entropy Alloy via Al-Mg Mutual Solubility and Sintering Control
Eunhyo Song, Hansung Lee, Byungmin Ahn
Journal of Powder Materials.2025; 32(3): 254. CrossRef
Microstructure and mechanical properties of oxide-dispersion-strengthened CrMnFeCoNiC0.2O0.2 high-entropy alloy fabricated by mechanical alloying and spark plasma sintering
Sang-Hwa Lee, Seonghyun Park, Ka Ram Lim, Seok-Jae Lee, Jae-Gil Jung
Materials Science and Engineering: A.2025; 947: 149284. CrossRef

[Korean]
The Use of TiH₂ to Refine Y₂Ti₂O7 in a Nano Mo-ODS Alloy: Yuncheol Ha, Chun Woong Park, Won Hee Lee, Jongmin Byun, Young Do Kim; J Powder Mater. 2024;31(5):399-405. Published online October 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00178

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Abstract PDF: Mo-ODS alloys have excellent mechanical properties, including an improved recrystallization temperature, greater strength due to dispersed oxides, and the ability to suppress grain growth at high temperatures. In ODS alloys, the dispersed Y2O3 and added Ti form Y-Ti-O complex oxides, producing finer particles than those in the initial Y2O3. The complex oxides increase high-temperature stability and improve the mechanical properties of the alloy. In particular, the use of TiH2 powder, which is more brittle than conventional Ti, can enable the distribution of finer oxides than is possible with conventional Ti powder during milling. Moreover, dehydrogenation leads to a more refined powder size in the reduction process. This study investigated the refinement of Y2Ti2O7 in a nano Mo-ODS alloy using TiH2. The alloy compositions were determined to be Mo-0.5Ti-0.5Y2O3 and Mo-1.0Ti-0.5Y2O3. The nano Mo-ODS alloys were fabricated using Ti and TiH2 to explore the effects of adding different forms of Ti. The sintered specimens were analyzed through X-ray diffraction for phase analysis, and the microstructure of the alloys was analyzed using scanning electron microscopy and transmission electron microscopy. Vickers hardness tests were conducted to determine the effect of the form of Ti added on the mechanical properties, and it was found that using TiH2 effectively improved the mechanical properties.

[Korean]
High-Hardness Cemented Carbide With Nickel-Tungsten Alloy Binder: Hanjung Kwon; J Powder Mater. 2024;31(4):318-323. Published online August 30, 2024; DOI: https://doi.org/10.4150/jpm.2024.00227

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Abstract PDF: Cemented carbide for cutting tools, which is composed of carbide as a hard phase and metallic component as a metallic phase, mainly uses cobalt as the metallic phase due to the excellent mechanical properties of cobalt. However, as the demand for machining difficult-to-machine materials such as titanium and carbon fiber-reinforced plastics has recently increased, the development of high-hardness cemented carbide is necessary and the replacement of cobalt metal with a high-hardness alloy is required. In this study, we would like to introduce high-hardness cemented carbide fabricated using nickel-tungsten alloy as the metallic phase. First, nickel-tungsten alloy powder of the composition for formation of intermetallic compound confirmed through thermodynamic calculations was synthesized, and cemented carbide was prepared through the sintering process of tungsten carbide and the synthesized alloy powder. Through evaluating the mechanical properties of high-hardness cemented carbide with the nickel-tungsten alloy binder, the possibility of producing high-hardness cemented carbide by using the alloys with high-hardness was confirmed.

[English]
Characterization of the Manufacturing Process and Mechanical Properties of CoCrFeMnNi High-Entropy Alloys via Metal Injection Molding and Hot Isostatic Pressing: Eun Seong Kim, Jae Man Park, Do Won Lee, Hyojeong Ha, Jungho Choe, Jaemin Wang, Seong Jin Park, Byeong-Joo Lee, Hyoung Seop Kim; J Powder Mater. 2024;31(3):243-254. Published online June 27, 2024; DOI: https://doi.org/10.4150/jpm.2024.00059

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Abstract PDF: High-entropy alloys (HEAs) have been reported to have better properties than conventional materials; however, they are more expensive due to the high cost of their main components. Therefore, research is needed to reduce manufacturing costs. In this study, CoCrFeMnNi HEAs were prepared using metal injection molding (MIM), which is a powder metallurgy process that involves less material waste than machining process. Although the MIM-processed samples were in the face-centered cubic (FCC) phase, porosity remained after sintering at 1200°C, 1250°C, and 1275°C. In this study, the hot isostatic pressing (HIP) process, which considers both temperature (1150°C) and pressure (150 MPa), was adopted to improve the quality of the MIM samples. Although the hardness of the HIP-treated samples decreased slightly and the Mn composition was significantly reduced, the process effectively eliminated many pores that remained after the 1275°C MIM process. The HIP process can improve the quality of the alloy.

[Korean]
TiO₂ Thin Film Coating on an Nb-Si–Based Superalloy via Atomic Layer Deposition: Ji Young Park, Su Min Eun, Jongmin Byun, Byung Joon Choi; J Powder Mater. 2024;31(3):255-262. Published online June 27, 2024; DOI: https://doi.org/10.4150/jpm.2024.00052

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Abstract PDF: Nano-oxide dispersion–strengthened (ODS) superalloys have attracted attention because of their outstanding mechanical reinforcement mechanism. Dispersed oxides increase the material’s strength by preventing grain growth and recrystallization, as well as increasing creep resistance. In this research, atomic layer deposition (ALD) was applied to synthesize an ODS alloy. It is useful to coat conformal thin films even on complex matrix shapes, such as nanorods or powders. We coated an Nb-Si–based superalloy with TiO2 thin film by using rotary-reactor type thermal ALD. TiO2 was grown by controlling the deposition recipe, reactor temperature, N2 flow rate, and rotor speed. We could confirm the formation of uniform TiO2 film on the surface of the superalloy. This process was successfully applied to the synthesis of an ODS alloy, which could be a new field of ALD applications.

[English]
Data-driven Approach to Explore the Contribution of Process Parameters for Laser Powder Bed Fusion of a Ti-6Al-4V Alloy: Jeong Min Park, Jaimyun Jung, Seungyeon Lee, Haeum Park, Yeon Woo Kim, Ji-Hun Yu; J Powder Mater. 2024;31(2):137-145. Published online April 30, 2024; DOI: https://doi.org/10.4150/jpm.2024.00038

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Abstract PDF

In order to predict the process window of laser powder bed fusion (LPBF) for printing metallic components, the calculation of volumetric energy density (VED) has been widely calculated for controlling process parameters. However, because it is assumed that the process parameters contribute equally to heat input, the VED still has limitation for predicting the process window of LPBF-processed materials. In this study, an explainable machine learning (xML) approach was adopted to predict and understand the contribution of each process parameter to defect evolution in Ti alloys in the LPBF process. Various ML models were trained, and the Shapley additive explanation method was adopted to quantify the importance of each process parameter. This study can offer effective guidelines for fine-tuning process parameters to fabricate high-quality products using LPBF.

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Effect of Support Structure on Residual Stress Distribution in Ti-6Al-4V Alloy Fabricated by Laser Powder Bed Fusion
Seungyeon Lee, Haeum Park, Min Jae Baek, Dong Jun Lee, Jae Wung Bae, Ji-Hun Yu, Jeong Min Park
Journal of Powder Materials.2025; 32(3): 244. CrossRef
Automated segmentation and analysis of microscopy images of laser powder bed fusion melt tracks
Aagam Shah, Reimar Weissbach, David A. Griggs, A. John Hart, Elif Ertekin, Sameh Tawfick
Journal of Manufacturing Processes.2025; 154: 61. CrossRef
Coefficient of Thermal Expansion of AlSi10Mg, 316L Stainless Steel and Ti6Al4V Alloys Made with Laser Powder Bed Fusion
Selami Emanet, Edem Honu, Kekeli Agbewornu, Evelyn Quansah, Congyuan Zeng, Patrick Mensah
Materials.2025; 18(19): 4468. CrossRef
Adaptive slicing for increased productivity of metal laser powder bed fusion
Lars Vanmunster, Louca R. Goossens, Laurent Sergeant, Brecht Van Hooreweder, Bey Vrancken
Additive Manufacturing.2025; 112: 105000. CrossRef

[Korean]
Fabrication of Ti-Mo Core-shell Powder and Sintering Properties for Application as a Sputtering Target: Won Hee Lee, Chun Woong Park, Heeyeon Kim, Yuncheol Ha, Jongmin Byun, Young Do Kim; J Powder Mater. 2024;31(1):43-49. Published online February 28, 2024; DOI: https://doi.org/10.4150/KPMI.2024.31.1.43

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[Korean]
Development of High-strength, High-temperature Nb-Si-Ti Alloys through Mechanical Alloying: Jung-Joon Kim, Sang-Min Yoon, Deok-Hyun Han, Jongmin Byun, Young-Kyun Kim; J Powder Mater. 2024;31(1):30-36. Published online February 28, 2024; DOI: https://doi.org/10.4150/KPMI.2024.31.1.30

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Review of “Integrated Computer-Aided Process Engineering Session in the 17th International Symposium on Novel and Nano Materials (ISNNM, 14–18 November 2022)”
Yeon-Joo Lee, Pil-Ryung Cha, Hyoung-Seop Kim, Hyun-Joo Choi
MATERIALS TRANSACTIONS.2025; 66(1): 144. CrossRef

[English]
Cryogenic Tensile Behavior of Ferrous Medium-entropy Alloy Additively Manufactured by Laser Powder Bed Fusion: Seungyeon Lee, Kyung Tae Kim, Ji-Hun Yu, Hyoung Seop Kim, Jae Wung Bae, Jeong Min Park; J Powder Mater. 2024;31(1):8-15. Published online February 28, 2024; DOI: https://doi.org/10.4150/KPMI.2024.31.1.8

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Abstract PDF

The emergence of ferrous-medium entropy alloys (FeMEAs) with excellent tensile properties represents a potential direction for designing alloys based on metastable engineering. In this study, an FeMEA is successfully fabricated using laser powder bed fusion (LPBF), a metal additive manufacturing technology. Tensile tests are conducted on the LPBF-processed FeMEA at room temperature and cryogenic temperatures (77 K). At 77 K, the LPBF-processed FeMEA exhibits high yield strength and excellent ultimate tensile strength through active deformation-induced martensitic transformation. Furthermore, due to the low stability of the face-centered cubic (FCC) phase of the LPBF-processed FeMEA based on nano-scale solute heterogeneity, stress-induced martensitic transformation occurs, accompanied by the appearance of a yield point phenomenon during cryogenic tensile deformation. This study elucidates the origin of the yield point phenomenon and deformation behavior of the FeMEA at 77 K.

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Effect of Building Orientation on Tensile Properties of Hastelloy X alloy Manufactured by Laser Powder Bed Fusion
Seong-June Youn, GooWon Noh, Seok Su Sohn, Young-Sang Na, Young-Kyun Kim
Journal of Powder Materials.2025; 32(2): 130. CrossRef
Thermodynamic and Electronic Descriptor-Driven Machine Learning for Phase Prediction in High-Entropy Alloys: Experimental Validation
Nguyen Lam Khoa, Nguyen Duy Khanh, Hoang Thi Ngoc Quyen, Nguyen Thi Hoang, Oanh, Le Hong Thang, Nguyen Hoa Khiem, Nguyen Hoang Viet
Journal of Powder Materials.2025; 32(3): 191. CrossRef
Cryogenic tensile behavior of carbon-doped CoCrFeMnNi high-entropy alloys additively manufactured by laser powder bed fusion
Haeum Park, Hyeonseok Kwon, Kyung Tae Kim, Ji-Hun Yu, Jungho Choe, Hyokyung Sung, Hyoung Seop Kim, Jung Gi Kim, Jeong Min Park
Additive Manufacturing.2024; 86: 104223. CrossRef
Recent progress in high-entropy alloys for laser powder bed fusion: Design, processing, microstructure, and performance
Asker Jarlöv, Zhiguang Zhu, Weiming Ji, Shubo Gao, Zhiheng Hu, Priyanka Vivegananthan, Yujia Tian, Devesh Raju Kripalani, Haiyang Fan, Hang Li Seet, Changjun Han, Liming Tan, Feng Liu, Mui Ling Sharon Nai, Kun Zhou
Materials Science and Engineering: R: Reports.2024; 161: 100834. CrossRef

[Korean]
Thermal Stability and Weight Reduction of Al0.75V2.82CrZr Refractory High Entropy Alloy Prepared Via Mechanical Alloying: Minsu Kim, Hansung Lee, Byungmin Ahn; J Powder Mater. 2023;30(6):478-483. Published online December 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.6.478

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Abstract PDF

High-entropy alloys (HEAs) are characterized by having five or more main elements and forming simple solids without forming intermetallic compounds, owing to the high entropy effect. HEAs with these characteristics are being researched as structural materials for extreme environments. Conventional refractory alloys have excellent hightemperature strength and stability; however, problems occur when they are used extensively in a high-temperature environment, leading to reduced fatigue properties due to oxidation or a limited service life. In contrast, refractory entropy alloys, which provide refractory properties to entropy alloys, can address these issues and improve the hightemperature stability of the alloy through phase control when designed based on existing refractory alloy elements. Refractory high-entropy alloys require sufficient milling time while in the process of mechanical alloying because of the brittleness of the added elements. Consequently, the high-energy milling process must be optimized because of the possibility of contamination of the alloyed powder during prolonged milling. In this study, we investigated the hightemperature oxidation behavior of refractory high-entropy alloys while optimizing the milling time.

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Tailored high-temperature oxidation behavior and nanomechanical properties of Al0.75VCrZrNb lightweight refractory high-entropy alloys
Hansung Lee, Hwi Geun Yu, Reliance Jain, Man Mohan, Younggeon Lee, Sheetal Kumar Dewangan, Byungmin Ahn
International Journal of Refractory Metals and Hard Materials.2026; 135: 107507. CrossRef
Simultaneous enhancement of strength and ductility of Al matrix composites enabled by submicron-sized high-entropy alloy phases
Chahee Jung, Seungin Nam, Hansol Son, Juyeon Han, Jaewon Jeong, Hyokyung Sung, Hyoung Seop Kim, Seok Su Sohn, Hyunjoo Choi
Journal of Materials Research and Technology.2024; 33: 1470. CrossRef

[Korean]
Effect of Heat Treatment on Microstructure and Mechanical Properties of Al–Zn–Mg–Cu–Si Sintered Alloys with and Without High-energy Ball Milling: Junho Lee, Seonghyun Park, Sang-Hwa Lee, Seung Bae Son, Seok-Jae Lee, Jae-Gil Jung; J Powder Mater. 2023;30(6):470-477. Published online December 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.6.470

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Abstract PDF

The effects of annealing on the microstructure and mechanical properties of Al–Zn–Mg–Cu–Si alloys fabricated by high-energy ball milling (HEBM) and spark plasma sintering (SPS) were investigated. The HEBM-free sintered alloy primarily contained Mg₂Si, Q-AlCuMgSi, and Si phases. Meanwhile, the HEBM-sintered alloy contains Mg-free Si and θ-Al₂Cu phases due to the formation of MgO, which causes Mg depletion in the Al matrix. Annealing without and with HEBM at 500°C causes partial dissolution and coarsening of the Q-AlCuMgSi and Mg₂Si phases in the alloy and dissolution of the θ-Al₂Cu phase in the alloy, respectively. In both alloys, a thermally stable α-AlFeSi phase was formed after long-term heat treatment. The grain size of the sintered alloys with and without HEBM increased from 0.5 to 1.0 μm and from 2.9 to 6.3 μm, respectively. The hardness of the sintered alloy increases after annealing for 1 h but decreases significantly after 24 h of annealing. Extending the annealing time to 168 h improved the hardness of the alloy without HEBM but had little effect on the alloy with HEBM. The relationship between the microstructural factors and the hardness of the sintered and annealed alloys is discussed.

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Microstructural evolution and thermal stability of Al–Zn–Mg–Cu–Si–Zr alloy fabricated via spark plasma sintering
Junho Lee, Seonghyun Park, Sang-Hwa Lee, Seung Bae Son, Hanjung Kwon, Seok-Jae Lee, Jae-Gil Jung
Journal of Materials Research and Technology.2024; 31: 205. CrossRef

[Korean]
Combinatorial Experiment for Al-6061 and Al-12Si alloy Based on Directed Energy Deposition (DED) Process: Seoyeon Jeon, Suwon Park, Yongwook Song, Jiwon Park, Hyunyoung Park, Boram Lee, Hyunjoo Choi; J Powder Mater. 2023;30(6):463-469. Published online December 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.6.463

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4 Citations

Abstract PDF

Aluminum alloys, known for their high strength-to-weight ratios and impressive electrical and thermal conductivities, are extensively used in numerous engineering sectors, such as aerospace, automotive, and construction. Recently, significant efforts have been made to develop novel aluminum alloys specifically tailored for additive manufacturing. These new alloys aim to provide an optimal balance between mechanical properties and thermal/ electrical conductivities. In this study, nine combinatorial samples with various alloy compositions were fabricated using direct energy deposition (DED) additive manufacturing by adjusting the feeding speeds of Al6061 alloy and Al-12Si alloy powders. The effects of the alloying elements on the microstructure, electrical conductivity, and hardness were investigated. Generally, as the Si and Cu contents decreased, electrical conductivity increased and hardness decreased, exhibiting trade-off characteristics. However, electrical conductivity and hardness showed an optimal combination when the Si content was adjusted to below 4.5 wt%, which can sufficiently suppress the grain boundary segregation of the α- Si precipitates, and the Cu content was controlled to induce the formation of Al₂Cu precipitates.

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Development of Aluminum Alloys for Additive Manufacturing Using Machine Learning
Sungbin An, Juyeon Han, Seoyeon Jeon, Dowon Kim, Jae Bok Seol, Hyunjoo Choi
Journal of Powder Materials.2025; 32(3): 202. CrossRef
Trends in Materials Modeling and Computation for Metal Additive Manufacturing
Seoyeon Jeon, Hyunjoo Choi
journal of Korean Powder Metallurgy Institute.2024; 31(3): 213. CrossRef
The Challenges and Advances in Recycling/Re-Using Powder for Metal 3D Printing: A Comprehensive Review
Alex Lanzutti, Elia Marin
Metals.2024; 14(8): 886. CrossRef
Microstructural Effects on the Mechanical Properties of Ti-6Al-4V Fabricated by Direct Energy Deposition
Juho Kim, Seoyeon Jeon, Hwajin Park, Taeyoel Kim, Hyunjoo Choi
Journal of Powder Materials.2024; 31(4): 302. CrossRef

[Korean]
Alloy Design and Powder Manufacturing of Al-Cu-Si alloy for Low-Temperature Aluminum Brazing: Heeyeon Kim, Chun Woong Park, Won Hee Lee, Young Do Kim; J Powder Mater. 2023;30(4):339-345. Published online August 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.4.339

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Abstract PDF: This study investigates the melting point and brazing properties of the aluminum (Al)-copper (Cu)-silicon (Si)-tin (Sn) alloy fabricated for low-temperature brazing based on the alloy design. Specifically, the Al-20Cu-10Si-Sn alloy is examined and confirmed to possess a melting point of approximately 520°C. Analysis of the melting point of the alloy based on composition reveals that the melting temperature tends to decrease with increasing Cu and Si content, along with a corresponding decrease as the Sn content rises. This study verifies that the Al-20Cu-10Si-5Sn alloy exhibits high liquidity and favorable mechanical properties for brazing through the joint gap filling test and Vickers hardness measurements. Additionally, a powder fabricated using the Al-20Cu-10Si-5Sn alloy demonstrates a melting point of around 515°C following melting point analysis. Consequently, it is deemed highly suitable for use as a low-temperature Al brazing material.

[Korean]
Exploration of Aluminum Alloy using Multi-feeder 3D Additive Manufacturing-based Combinatorial Experiment: Suwon Park, Yongwook Song, Jiyoon Yeo, Songyun Han, Hyunjoo Choi; J Powder Mater. 2023;30(3):255-261. Published online June 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.3.255

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3 Citations

Abstract PDF

Aluminum alloys are widely utilized in diverse industries, such as automobiles, aerospace, and architecture, owing to their high specific strength and resistance to oxidation. However, to meet the increasing demands of the industry, it is necessary to design new aluminum alloys with excellent properties. Thus, a new method is required to efficiently test additively manufactured aluminum alloys with various compositions within a short period during the alloy design process. In this study, a combinatory approach using a direct energy deposition system for metal 3D printing process with a dual feeder was employed. Two types of aluminum alloy powders, namely Al6061 and Al-12Cu, were utilized for the combinatory test conducted through 3D printing. Twelve types of Al-Si-Cu-Mg alloys were manufactured during this combinatory test, and the relationship between their microstructures and properties was investigated.

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Citations to this article as recorded by

Trends in Materials Modeling and Computation for Metal Additive Manufacturing
Seoyeon Jeon, Hyunjoo Choi
journal of Korean Powder Metallurgy Institute.2024; 31(3): 213. CrossRef
Microstructural Effects on the Mechanical Properties of Ti-6Al-4V Fabricated by Direct Energy Deposition
Juho Kim, Seoyeon Jeon, Hwajin Park, Taeyoel Kim, Hyunjoo Choi
Journal of Powder Materials.2024; 31(4): 302. CrossRef
Combinatorial Experiment for Al-6061 and Al-12Si alloy Based on Directed Energy Deposition (DED) Process
Seoyeon Jeon, Suwon Park, Yongwook Song, Jiwon Park, Hyunyoung Park, Boram Lee, Hyunjoo Choi
journal of Korean Powder Metallurgy Institute.2023; 30(6): 463. CrossRef

[Korean]
Analysis of the Effects of Process Variables and Alloy Composition on the Relative density and Mechanical Properties of 3D Printed Aluminum Alloys: Suwon Park, Jiyoon Yeo, Songyun Han, Hyunjoo Choi; J Powder Mater. 2023;30(3):223-232. Published online June 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.3.223

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Abstract PDF

Metal additive manufacturing (AM) has transformed conventional manufacturing processes by offering unprecedented opportunities for design innovation, reduced lead times, and cost-effective production. Aluminum alloy, a material used in metal 3D printing, is a representative lightweight structural material known for its high specific strength and corrosion resistance. Consequently, there is an increasing demand for 3D printed aluminum alloy components across industries, including aerospace, transportation, and consumer goods. To meet this demand, research on alloys and process conditions that satisfy the specific requirement of each industry is necessary. However, 3D printing processes exhibit different behaviors of alloy elements owing to rapid thermal dynamics, making it challenging to predict the microstructure and properties. In this study, we gathered published data on the relationship between alloy composition, processing conditions, and properties. Furthermore, we conducted a sensitivity analysis on the effects of the process variables on the density and hardness of aluminum alloys used in additive manufacturing.

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Effect of Heat Treatment on Microstructure and Mechanical Properties of Al–Zn–Mg–Cu–Si Sintered Alloys with and Without High-energy Ball Milling
Junho Lee, Seonghyun Park, Sang-Hwa Lee, Seung Bae Son, Seok-Jae Lee, Jae-Gil Jung
journal of Korean Powder Metallurgy Institute.2023; 30(6): 470. CrossRef

[Korean]
Machine Learning-based Data Analysis for Designing High-strength Nb-based Superalloys: Eunho Ma, Suwon Park, Hyunjoo Choi, Byoungchul Hwang, Jongmin Byun; J Powder Mater. 2023;30(3):217-222. Published online June 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.3.217

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Abstract PDF: Machine learning-based data analysis approaches have been employed to overcome the limitations in accurately analyzing data and to predict the results of the design of Nb-based superalloys. In this study, a database containing the composition of the alloying elements and their room-temperature tensile strengths was prepared based on a previous study. After computing the correlation between the tensile strength at room temperature and the composition, a material science analysis was conducted on the elements with high correlation coefficients. These alloying elements were found to have a significant effect on the variation in the tensile strength of Nb-based alloys at room temperature. Through this process, a model was derived to predict the properties using four machine learning algorithms. The Bayesian ridge regression algorithm proved to be the optimal model when Y, Sc, W, Cr, Mo, Sn, and Ti were used as input features. This study demonstrates the successful application of machine learning techniques to effectively analyze data and predict outcomes, thereby providing valuable insights into the design of Nb-based superalloys.

[Korean]
Effect of Bulk Shape on Mechanical Properties of Ti-6Al-4V Alloy Manufactured by Laser Powder Bed Fusion: Haeum Park, Yeon Woo Kim, Seungyeon Lee, Kyung Tae Kim, Ji-Hun Yu, Jung Gi Kim, Jeong Min Park; J Powder Mater. 2023;30(2):140-145. Published online April 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.2.140

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Abstract PDF

Although the Ti–6Al–4V alloy has been used in the aircraft industry owing to its excellent mechanical properties and low density, the low formability of the alloy hinders broadening its applications. Recently, laser-powder bed fusion (L-PBF) has become a novel process for overcoming the limitations of the alloy (i.e., low formability), owing to the high degree of design freedom for the geometry of products having outstanding performance used in hightech applications. In this study, to investigate the effect of bulk shape on the microstructure and mechanical properties of L-PBFed Ti-6Al-4V alloys, two types of samples are fabricated using L-PBF: thick and thin samples. The thick sample exhibits lower strength and higher ductility than the thin sample owing to the larger grain size and lower residual dislocation density of the thick sample because of the heat input during the L-PBF process.

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Effect of Support Structure on Residual Stress Distribution in Ti-6Al-4V Alloy Fabricated by Laser Powder Bed Fusion
Seungyeon Lee, Haeum Park, Min Jae Baek, Dong Jun Lee, Jae Wung Bae, Ji-Hun Yu, Jeong Min Park
Journal of Powder Materials.2025; 32(3): 244. CrossRef
Cryogenic Tensile Behavior of Ferrous Medium-entropy Alloy Additively Manufactured by Laser Powder Bed Fusion
Seungyeon Lee, Kyung Tae Kim, Ji-Hun Yu, Hyoung Seop Kim, Jae Wung Bae, Jeong Min Park
journal of Korean Powder Metallurgy Institute.2024; 31(1): 8. CrossRef
Microstructural Evolution and Mechanical Properties of Ti-6Al-4V Alloy through Selective Laser Melting: Comprehensive Study on the Effect of Hot Isostatic Pressing (HIP)
Gargi Roy, Raj Narayan Hajra, Woo Hyeok Kim, Jongwon Lee, Sangwoo Kim, Jeoung Han Kim
journal of Korean Powder Metallurgy Institute.2024; 31(1): 1. CrossRef
Data-driven Approach to Explore the Contribution of Process Parameters for Laser Powder Bed Fusion of a Ti-6Al-4V Alloy
Jeong Min Park, Jaimyun Jung, Seungyeon Lee, Haeum Park, Yeon Woo Kim, Ji-Hun Yu
journal of Korean Powder Metallurgy Institute.2024; 31(2): 137. CrossRef
A Parametric Study on the L-PBF Process of an AlSi10Mg Alloy for High-Speed Productivity of Automotive Prototype Parts
Yeonha Chang, Hyomoon Joo, Wanghyun Yong, Yeongcheol Jo, Seongjin Kim, Hanjae Kim, Yeon Woo Kim, Kyung Tae Kim, Jeong Min Park
Journal of Powder Materials.2024; 31(5): 390. CrossRef
High-speed manufacturing-driven strength-ductility improvement of H13 tool steel fabricated by selective laser melting
Yeon Woo Kim, Haeum Park, Young Seong Eom, Dong Gill Ahn, Kyung Tae Kim, Ji-hun Yu, Yoon Suk Choi, Jeong Min Park
Powder Metallurgy.2023; 66(5): 582. CrossRef

[English]
Selective Laser Sintering of Co-Cr Alloy Powders and Sintered Products Properties: Dong-Wan Lee, Minh-Thuyet Nguyen, Jin-Chun Kim; J Powder Mater. 2023;30(1):7-12. Published online February 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.1.7

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Abstract PDF: Metal-additive manufacturing techniques, such as selective laser sintering (SLS), are increasingly utilized for new biomaterials, such as cobalt-chrome (Co-Cr). In this study, Co-Cr gas-atomized powders are used as charge materials for the SLS process. The aim is to understand the consolidation of Co-Cr alloy powder and characterization of samples sintered using SLS under various conditions. The results clearly suggest that besides the matrix phase, the second phase, which is attributed to pores and oxidation particles, is observed in the sintered specimens. The as-built samples exhibit completely different microstructural features compared with the casting or wrought products reported in the literature. The microstructure reveals melt pools, which represent the characteristics of the scanning direction, in particular, or of the SLS conditions, in general. It also exposes extremely fine grain sizes inside the melt pools, resulting in an enhancement in the hardness of the as-built products. Thus, the hardness values of the samples prepared by SLS under all parameter conditions used in this study are evidently higher than those of the casting products.

[English]
Investigation on Microstructure and Flowability of Gas Atomized Heat-resistant KHR45A Alloy Powders for Additive Manufacturing: Geonwoo Baek, Mohsen Saboktakin Rizi, Yeeun Lee, SungJae Jo, Joo-Hyun Choi, Soon-Jik Hong; J Powder Mater. 2023;30(1):13-21. Published online February 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.1.13

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2 Citations

Abstract PDF

In additive manufacturing, the flowability of feedstock particles determines the quality of the parts that are affected by different parameters, including the chemistry and morphology of the powders and particle size distribution. In this study, the microstructures and flowabilities of gas-atomized heat-resistant alloys for additive manufacturing applications are investigated. A KHR45A alloy powder with a composition of Fe-30Cr-40Mn-1.8Nb (wt.%) is fabricated using gas atomization process. The microstructure and effect of powder chemistry and morphology on the flow behavior are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and revolution powder analysis. The results reveal the formation of spherical particles composed of single-phase FCC dendritic structures after gas atomization. SEM observations show variations in the microstructures of the powder particles with different size distributions. Elemental distribution maps, line scans, and high-resolution XPS results indicate the presence of a Si-rich oxide accompanied by Fe, Cr, and Nb metal oxides in the outer layer of the powders. The flowability behavior is found to be induced by the particle size distribution, which can be attributed to the interparticle interactions and friction of particles with different sizes.

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Engineering heterogeneous microstructure for enhancing mechanical properties of multicomponent alloys via powder metallurgy route
Min Woo Shin, Sung-Jae Jo, Sourabh Kumar Soni, Ji-Woon Lee, Jongun Moon, Hyoung Seop Kim, Soon-Jik Hong
Materials Science and Engineering: A.2025; 941: 148599. CrossRef
Al-based amorphous coatings by warm spraying: Numerical simulation and experimental validation
Deming Wang, Nianchu Wu, Peng Cao
Journal of Alloys and Compounds.2024; 1008: 176674. CrossRef

[English]
Fabrication of Equiatomic CoCrFeMnNi High-Entropy Alloy by Metal Injection Molding Process Using Coarse-Sized Powders: Eun Seong Kim, Jae Man Park, Ji Sun Lee, Jungho Choe, Soung Yeoul Ahn, Sang Guk Jeong, Do Won Lee, Seong Jin Park, Hyoung Seop Kim; J Powder Mater. 2023;30(1):1-6. Published online February 1, 2023; DOI: https://doi.org/10.4150/KPMI.2023.30.1.1

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3 Citations

Abstract PDF

High-entropy alloys (HEAs) are attracting attention because of their excellent properties and functions; however, they are relatively expensive compared with commercial alloys. Therefore, various efforts have been made to reduce the cost of raw materials. In this study, MIM is attempted using coarse equiatomic CoCrFeMnNi HEA powders. The mixing ratio (powder:binder) for HEA feedstock preparation is explored using torque rheometer. The block-shaped green parts are fabricated through a metal injection molding process using feedstock. The thermal debinding conditions are explored by thermogravimetric analysis, and solvent and thermal debinding are performed. It is densified under various sintering conditions considering the melting point of the HEA. The final product, which contains a small amount of non-FCC phase, is manufactured at a sintering temperature of 1250°C.

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Development of 3D interconnected nanoporous TiZrHfNbTaNi high-entropy alloy via liquid metal dealloying and subsequent synthesis of (TiZrHfNbTaNi)O high-entropy oxide
Jae Hyuk Lee, Soo Vin Ha, Jihye Seong, Akira Takeuchi, Ruirui Song, Hidemi Kato, Soo-Hyun Joo
Journal of Materials Research and Technology.2025; 35: 5204. CrossRef
Development of 3D interconnected heterogeneous high-entropy alloy composites with enhanced multifunctionality via liquid metal dealloying
Munsu Choi, Gang Hee Gu, Jongun Moon, Jae Wung Bae, Hidemi Kato, Seung Zeon Han, Hyoung Seop Kim, Yongseok Choi, Soo-Hyun Joo
Journal of Materials Research and Technology.2025; 37: 5672. CrossRef
Characterization of the Manufacturing Process and Mechanical Properties of CoCrFeMnNi High-Entropy Alloys via Metal Injection Molding and Hot Isostatic Pressing
Eun Seong Kim, Jae Man Park, Do Won Lee, Hyojeong Ha, Jungho Choe, Jaemin Wang, Seong Jin Park, Byeong-Joo Lee, Hyoung Seop Kim
journal of Korean Powder Metallurgy Institute.2024; 31(3): 243. CrossRef

[Korean]
Effect of Mo Addition on the Austenite Stability of Nanocrystalline Fe-7wt.%Mn Alloy Fabricated by Spark Plasma Sintering: Woochul Shin, Seung Bae Son, Jae-Gil Jung, Seok-Jae Lee; J Powder Mater. 2022;29(6):517-522. Published online December 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.6.517

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Abstract PDF: We investigate the austenite stability in nanocrystalline Fe-7%Mn-X%Mo (X = 0, 1, and 2) alloys fabricated by spark plasma sintering. Mo is known as a ferrite stabilizing element, whereas Mn is an austenite stabilizing element, and many studies have focused on the effect of Mn addition on austenite stability. Herein, the volume fraction of austenite in nanocrystalline Fe-7%Mn alloys with different Mo contents is measured using X-ray diffraction. Using a disk compressive test, austenite in Fe–Mn–Mo alloys is confirmed to transform into strain-induced martensite during plastic deformation by a disk d. The variation in austenite stability in response to the addition of Mo is quantitatively evaluated by comparing the k-parameters of the kinetic equation for the strain-induced martensite transformation.

[English]
Optimization of VIGA Process Parameters for Power Characteristics of Fe-Si-Al-P Soft Magnetic Alloy using Machine Learning: Sung-Min Kim, Eun-Ji Cha, Do-Hun Kwon, Sung-Uk Hong, Yeon-Joo Lee, Seok-Jae Lee, Kee-Ahn Lee, Hwi-Jun Kim; J Powder Mater. 2022;29(6):459-467. Published online December 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.6.459

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Abstract PDF: Soft magnetic powder materials are used throughout industries such as motors and power converters. When manufacturing Fe-based soft magnetic composites, the size and shape of the soft magnetic powder and the microstructure in the powder are closely related to the magnetic properties. In this study, Fe-Si-Al-P alloy powders were manufactured using various manufacturing process parameter sets, and the process parameters of the vacuum induction melt gas atomization process were set as melt temperature, atomization gas pressure, and gas flow rate. Process variable data that records are converted into 6 types of data for each powder recovery section. Process variable data that recorded minute changes were converted into 6 types of data and used as input variables. As output variables, a total of 6 types were designated by measuring the particle size, flowability, apparent density, and sphericity of the manufactured powders according to the process variable conditions. The sensitivity of the input and output variables was analyzed through the Pearson correlation coefficient, and a total of 6 powder characteristics were analyzed by artificial neural network model. The prediction results were compared with the results through linear regression analysis and response surface methodology, respectively.

[Korean]
Evaluation of Mechanical Properties and Microstructure Depending on Sintering Heating Rate of IN 939W Alloy: Junhyub Jeon, Junho Lee, Namhyuk Seo, Seung Bae Son, Jae-Gil Jung, Seok-Jae Lee; J Powder Mater. 2022;29(5):399-410. Published online October 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.5.399

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Abstract PDF: Changes in the mechanical properties and microstructure of an IN 939 W alloy according to the sintering heating rate were evaluated. IN 939 W alloy samples were fabricated by spark plasma sintering. The phase fraction, number density, and mean radius of the IN 939W alloy were calculated using a thermodynamic calculation. A universal testing machine and micro-Vickers hardness tester were employed to confirm the mechanical properties of the IN 939W alloy. X-ray diffraction, optical microscopy, field-emission scanning electron microscopy, Cs-corrected-field emission transmission electron microscopy, and energy dispersive X-ray spectrometry were used to evaluate the microstructure of the alloy. The rapid sintering heating rate resulted in a slightly dispersed γ' phase and chromium oxide. It also suppressed the precipitation of the η phase. These helped to reinforce the mechanical properties.

[Korean]
Effect of Iron Content on Microstructure and Mechanical Properties of Ti-Mo-Fe P/M Alloys: HyoWoon Hwang, YongJae Lee, JiHwan Park, Dong-Geun Lee; J Powder Mater. 2022;29(4):325-331. Published online August 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.4.325

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2 Citations

Abstract PDF

Beta-titanium alloys are used in many industries due to their increased elongation resulting from their BCC structure and low modulus of elasticity. However, there are many limitations to their use due to the high cost of betastabilizer elements. In this study, biocompatible Ti-Mo-Fe beta titanium alloys are designed by replacing costly betastabilizer elements (e.g., Nb, Zr, or Ta) with inexpensive Mo and Fe elements. Additionally, Ti-Mo-Fe alloys designed with different Fe contents are fabricated using powder metallurgy. Fe is a strong, biocompatible beta-stabilizer element and a low-cost alloying element. The mechanical properties of the Ti-Mo-Fe metastable beta titanium alloys are analyzed in relation to the microstructural changes. When the Fe content increases, the tensile strength and elongation decrease due to brittle fracture despite a decreasing pore fraction. It is confirmed that the hardness and tensile strength of Ti-5Mo-2Fe P/M improve to more than 360 Hv and 900 MPa, respectively.

Citations

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Fabrication of Ti-Mo Core-shell Powder and Sintering Properties for Application as a Sputtering Target
Won Hee Lee, Chun Woong Park, Heeyeon Kim, Yuncheol Ha, Jongmin Byun, Young Do Kim
journal of Korean Powder Metallurgy Institute.2024; 31(1): 43. CrossRef
Effect of Strain Rate on Deformation Behaviors of Ti-12.1Mo -1Fe Metastable Beta Alloy
In Kyeong Jin, Dong-Geun Lee
Korean Journal of Metals and Materials.2023; 61(10): 741. CrossRef

[Korean]
Evaluation of Microstructures and Mechanical Properties in Functionally Graded Materials (STS 316L and Low Alloy Steel) Produced by DED Processes: G. Shin, W. Choo, J. H. Yoon, S. Y. Yang, J. H. Kim; J Powder Mater. 2022;29(4):309-313. Published online August 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.4.309

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Abstract PDF: In this study, additive manufacturing of a functionally graded material (FGM) as an alternative to joining dissimilar metals is investigated using directed energy deposition (DED). FGM consists of five different layers, which are mixtures of austenitic stainless steel (type 316 L) and low-alloy steel (LAS, ferritic steel) at ratios of 100:0 (A layer), 75:25 (B layer), 50:50 (C layer), 25:75 (D layer), and 0:100 (E layer), respectively, in each deposition layer. The FGM samples are successfully fabricated without cracks or delamination using the DED method, and specimens are characterized using optical and scanning electron microscopy to monitor their microstructures. In layers C and D of the sample, the tensile strength is determined to be very high owing to the formation of ferrite and martensite structures. However, the elongation is high in layers A and B, which contain a large fraction of austenite.

[Korean]
3D-printing-based Combinatorial Experiment for Al-Si-Cu-Mg Alloys: Yongwook Song, Jungjoon Kim, Suwon Park, Hyunjoo Choi; J Powder Mater. 2022;29(3):233-239. Published online June 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.3.233

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Abstract PDF: Aluminum alloys are extensively employed in several industries, such as automobile, aerospace, and architecture, owing to their high specific strength and electrical and thermal conductivities. However, to meet the rising industrial demands, aluminum alloys must be designed with both excellent mechanical and thermal properties. Computer-aided alloy design is emerging as a technique for developing novel alloys to overcome these trade-off properties. Thus, the development of a new experimental method for designing alloys with high-throughput confirmation is gaining focus. A new approach that rapidly manufactures aluminum alloys with different compositions is required in the alloy design process. This study proposes a combined approach to rapidly investigate the relationship between the microstructure and properties of aluminum alloys using a direct energy deposition system with a dual-nozzle metal 3D printing process. Two types of aluminum alloy powders (Al-4.99Si-1.05Cu-0.47Mg and Al-7Mg) are employed for the 3D printing-based combined method. Nine types of Al-Si-Cu-Mg alloys are manufactured using the combined method, and the relationship between their microstructures and properties is examined.

[Korean]
Interfacial Reaction between Spark Plasma Sintered High-entropy Alloys and Cast Aluminum: Min-Sang Kim, Hansol Son, Cha Hee Jung, Juyeon Han, Jung Joon Kim, Young-Do Kim, Hyunjoo Choi, Se Hoon Kim; J Powder Mater. 2022;29(3):213-218. Published online June 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.3.213

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Abstract PDF

This study investigates the interfacial reaction between powder-metallurgy high-entropy alloys (HEAs) and cast aluminum. HEA pellets are produced by the spark plasma sintering of Al_0.5CoCrCu_0.5FeNi HEA powder. These sintered pellets are then placed in molten Al, and the phases formed at the interface between the HEA pellets and cast Al are analyzed. First, Kirkendall voids are observed due to the difference in the diffusion rates between the liquid Al and solid HEA phases. In addition, although Co, Fe, and Ni atoms, which have low mixing enthalpies with Al, diffuse toward Al, Cu atoms, which have a high mixing enthalpy with Al, tend to form Al–Cu intermetallic compounds. These results provide guidelines for designing Al matrix composites containing high-entropy phases.

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Simultaneous enhancement of strength and ductility of Al matrix composites enabled by submicron-sized high-entropy alloy phases
Chahee Jung, Seungin Nam, Hansol Son, Juyeon Han, Jaewon Jeong, Hyokyung Sung, Hyoung Seop Kim, Seok Su Sohn, Hyunjoo Choi
Journal of Materials Research and Technology.2024; 33: 1470. CrossRef

[Korean]
Microstructure and Mechanical Properties of CoCrFeMnNi-type High-entropy Alloy Fabricated by Selective Laser Melting: A Review: Jeong Min Park; J Powder Mater. 2022;29(2):132-151. Published online April 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.2.132

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Abstract PDF

The CoCrFeMnNi high-entropy alloy (HEA), which is the most widely known HEA with a single facecentered cubic structure, has attracted significant academic attention over the past decade owing to its outstanding multifunctional performance. Recent studies have suggested that CoCrFeMnNi-type HEAs exhibit excellent printability for selective laser melting (SLM) under a wide range of process conditions. Moreover, it has been suggested that SLM can not only provide great topological freedom of design but also exhibit excellent mechanical properties by overcoming the strength–ductility trade-off via producing a hierarchical heterogeneous microstructure. In this regard, the SLM-processed CoCrFeMnNi HEA has been extensively studied to comprehensively understand the mechanisms of microstructural evolution and resulting changes in mechanical properties. In this review, recent studies on CoCrFeMnNi-type HEAs produced using SLM are discussed with respect to process-induced microstructural evolution and the relationship between hierarchical heterogeneous microstructure and mechanical properties.

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Thermodynamic and Electronic Descriptor-Driven Machine Learning for Phase Prediction in High-Entropy Alloys: Experimental Validation
Nguyen Lam Khoa, Nguyen Duy Khanh, Hoang Thi Ngoc Quyen, Nguyen Thi Hoang, Oanh, Le Hong Thang, Nguyen Hoa Khiem, Nguyen Hoang Viet
Journal of Powder Materials.2025; 32(3): 191. CrossRef
Investigation of effects of process parameters on microstructure and fracture toughness of SLM CoCrFeMnNi
Joseph Agyapong, Diego Mateos, Aleksander Czekanski, Solomon Boakye-Yiadom
Journal of Alloys and Compounds.2024; 987: 173998. CrossRef
Cryogenic Tensile Behavior of Ferrous Medium-entropy Alloy Additively Manufactured by Laser Powder Bed Fusion
Seungyeon Lee, Kyung Tae Kim, Ji-Hun Yu, Hyoung Seop Kim, Jae Wung Bae, Jeong Min Park
journal of Korean Powder Metallurgy Institute.2024; 31(1): 8. CrossRef
Data-driven Approach to Explore the Contribution of Process Parameters for Laser Powder Bed Fusion of a Ti-6Al-4V Alloy
Jeong Min Park, Jaimyun Jung, Seungyeon Lee, Haeum Park, Yeon Woo Kim, Ji-Hun Yu
journal of Korean Powder Metallurgy Institute.2024; 31(2): 137. CrossRef
Cryogenic tensile behavior of carbon-doped CoCrFeMnNi high-entropy alloys additively manufactured by laser powder bed fusion
Haeum Park, Hyeonseok Kwon, Kyung Tae Kim, Ji-Hun Yu, Jungho Choe, Hyokyung Sung, Hyoung Seop Kim, Jung Gi Kim, Jeong Min Park
Additive Manufacturing.2024; 86: 104223. CrossRef
Microstructural evolution and high strain rate deformation response of SLM-printed CoCrFeMnNi after annealing and deep-cryogenic treatment
Joseph Agyapong, Aleksander Czekanski, Solomon Boakye Yiadom
Materials Characterization.2024; 218: 114506. CrossRef
High-speed manufacturing-driven strength-ductility improvement of H13 tool steel fabricated by selective laser melting
Yeon Woo Kim, Haeum Park, Young Seong Eom, Dong Gill Ahn, Kyung Tae Kim, Ji-hun Yu, Yoon Suk Choi, Jeong Min Park
Powder Metallurgy.2023; 66(5): 582. CrossRef

[Korean]
A Study on Powder Size Dependence of Additive Manufactured AlCrFeNi HEA on Its Microstructure and Mechanical Properties: Jong Woo Choi, Hae Jin Park, Gyeol Chan Kang, Min Seob Jung, Ki Tae Oh, Sung Hwan Hong, Hyun Gil Kim, Ki Buem Kim; J Powder Mater. 2022;29(1):22-27. Published online February 1, 2022; DOI: https://doi.org/10.4150/KPMI.2022.29.1.22

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Conventionally, metal materials are produced by subtractive manufacturing followed by melting. However, there has been an increasing interest in additive manufacturing, especially metal 3D printing technology, which is relatively inexpensive because of the absence of complicated processing steps. In this study, we focus on the effect of varying powder size on the synthesis quality, and suggest optimum process conditions for the preparation of AlCrFeNi high-entropy alloy powder. The SEM image of the as-fabricated specimens show countless, fine, as-synthesized powders. Furthermore, we have examined the phase and microstructure before and after 3D printing, and found that there are no noticeable changes in the phase or microstructure. However, it was determined that the larger the powder size, the better the Vickers hardness of the material. This study sheds light on the optimization of process conditions in the metal 3D printing field.

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Fabrication and Alloying Behavior of Ultra-Lightweight AlTiCrVMg High-Entropy Alloy via Al-Mg Mutual Solubility and Sintering Control
Eunhyo Song, Hansung Lee, Byungmin Ahn
Journal of Powder Materials.2025; 32(3): 254. CrossRef

[Korean]
Porosity Prediction of the Coating Layer Based on Process Conditions of HVOF Thermal Spray Coating: Junhyub Jeon, Namhyuk Seo, Jong Jae Lee, Seung Bae Son, Seok-Jae Lee; J Korean Powder Metall Inst. 2021;28(6):478-482. Published online December 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.6.478

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Abstract PDF: The effect of the process conditions of high-velocity oxygen fuel (HVOF) thermal spray coating on the porosity of the coating layer is investigated. HVOF coating layers are formed by depositing amorphous FeMoCrBC powder. Oxygen pressure varies from 126 to 146 psi and kerosene pressure from 110 to 130 psi. The Microstructural analysis confirms its porosity. Data analysis is performed using experimental data. The oxygen pressure-kerosene pressure ratio is found to be a key contributor to the porosity. An empirical model is proposed using linear regression analysis. The proposed model is then validated using additional test data. We confirm that the oxygen pressure-kerosene pressure ratio exponentially increases porosity. We present a porosity prediction model relationship for the oxygen pressure-kerosene pressure ratio.

[Korean]
Evolution on Microstructures and Tensile Properties of 10Cr-1Mo ODS Steel with Different Lengths of Mechanical Alloying Process Times: Sanghoon Noh, Tae Kyu Kim; J Korean Powder Metall Inst. 2021;28(5):375-380. Published online October 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.5.375

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Abstract PDF: In this study, we investigate the effect of the duration of mechanical alloying on the microstructures and mechanical properties of ODS ferritic/martensitic steel. The Fe(bal.)-10Cr-1Mo pre-alloyed powder and Y₂O₃ powder are mechanically alloyed for the different mechanical alloying duration (0 to 40 h) and then constantly fabricated using a uniaxial hot pressing process. Upon increasing the mechanical alloying time, the average powder diameter and crystallite size increased dramatically. In the initial stages within 5 h of mechanical alloying, inhomogeneous grain morphology is observed along with coarsened carbide and oxide distributions; thus, precipitate phases are temporarily observed between the two powders because of insufficient collision energy to get fragmented. After 40 h of the MA process, however, fine martensitic grains and uniformly distributed oxide particles are observed. This led to a favorable tensile strength and elongation at room temperature and 650°C.

[Korean]
Austenite Stability and Mechanical Properties of Nanocrystalline FeNiCrMoMnSiC Alloy Fabricated by Spark Plasma Sintering: Jungbin Park, Junhyub Jeon, Namhyuk Seo, Gwanghun Kim, Seung Bae Son, Seok-Jae Lee; J Korean Powder Metall Inst. 2021;28(4):336-341. Published online August 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.4.336

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Abstract PDF

In this study, a nanocrystalline FeNiCrMoMnSiC alloy was fabricated, and its austenite stability, microstructure, and mechanical properties were investigated. A sintered FeNiCrMoMnSiC alloy sample with nanosized crystal was obtained by high-energy ball milling and spark plasma sintering. The sintering behavior was investigated by measuring the displacement according to the temperature of the sintered body. Through microstructural analysis, it was confirmed that a compact sintered body with few pores was produced, and cementite was formed. The stability of the austenite phase in the sintered samples was evaluated by X-ray diffraction analysis and electron backscatter diffraction. Results revealed a measured value of 51.6% and that the alloy had seven times more austenite stability than AISI 4340 wrought steel. The hardness of the sintered alloy was 60.4 HRC, which was up to 2.4 times higher than that of wrought steel.

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Microstructure and mechanical behavior of AISI 4340 steel fabricated via spark plasma sintering and post-heat treatment
Jungbin Park, Junhyub Jeon, Namhyuk Seo, Singon Kang, Seung Bae Son, Seok-Jae Lee, Jae-Gil Jung
Materials Science and Engineering: A.2023; 862: 144433. CrossRef

[Korean]
Improvement of Mechanical Properties of Nanocrystalline FeCrC Alloy via Strain-Induced Martensitic Transformation: Gwanghun Kim, Junhyub Jeon, Namhyuk Seo, Jungbin Park, Seung Bae Son, Seok-Jae Lee; J Korean Powder Metall Inst. 2021;28(3):246-252. Published online June 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.3.246

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Abstract PDF: The effect of sintering conditions on the austenite stability and strain-induced martensitic transformation of nanocrystalline FeCrC alloy is investigated. Nanocrystalline FeCrC alloys are successfully fabricated by spark plasma sintering with an extremely short densification time to obtain the theoretical density value and prevent grain growth. The nanocrystallite size in the sintered alloys contributes to increased austenite stability. The phase fraction of the FeCrC sintered alloy before and after deformation according to the sintering holding time is measured using X-ray diffraction and electron backscatter diffraction analysis. During compressive deformation, the volume fraction of strain-induced martensite resulting from austenite decomposition is increased. The transformation kinetics of the strain-induced martensite is evaluated using an empirical equation considering the austenite stability factor. The hardness of the S0W and S10W samples increase to 62.4-67.5 and 58.9-63.4 HRC before and after deformation. The hardness results confirmed that the mechanical properties are improved owing to the effects of grain refinement and strain-induced martensitic transformation in the nanocrystalline FeCrC alloy.

[Korean]
Effect of Sintering Condition on Tensile Strength of Fe-based Non-equiatomic High Entropy Alloy: Namhyuk Seo, Junhyub Jeon, Gwanghun Kim, Jungbin Park, Seung Bae Son, Seok-Jae Lee; J Korean Powder Metall Inst. 2021;28(3):221-226. Published online June 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.3.221

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Abstract PDF

We fabricate the non-equiatomic high-entropy alloy (NE-HEA) Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) using spark plasma sintering under various sintering conditions. Each elemental pure powder is milled by high-energy ball milling to prepare NE-HEA powder. The microstructure and mechanical properties of the sintered samples are investigated using various methods. We use the X-ray diffraction (XRD) method to investigate the microstructural characteristics. Quantitative phase analysis is performed by direct comparison of the XRD results. A tensile test is used to compare the mechanical properties of small samples. Next, electron backscatter diffraction analysis is performed to analyze the phase fraction, and the results are compared to those of XRD analysis. By combining different sintering durations and temperature conditions, we attempt to identify suitable spark plasma sintering conditions that yield mechanical properties comparable with previously reported values. The samples sintered at 900 and 1000°C with no holding time have a tensile strength of over 1000 MPa.

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Fabrication and Alloying Behavior of Ultra-Lightweight AlTiCrVMg High-Entropy Alloy via Al-Mg Mutual Solubility and Sintering Control
Eunhyo Song, Hansung Lee, Byungmin Ahn
Journal of Powder Materials.2025; 32(3): 254. CrossRef

[Korean]
Influence of Milling Conditions on the Microstructural Characteristics and Mechanical Properties of Non-equiatomic High Entropy Alloy: Namhyuk Seo, Junhyub Jeon, Gwanghoon Kim, Jungbin Park, Seung Bae Son, Seok-Jae Lee; J Korean Powder Metall Inst. 2021;28(2):103-109. Published online April 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.2.103

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Abstract PDF: High-entropy alloys have excellent mechanical properties under extreme environments, rendering them promising candidates for next-generation structural materials. It is desirable to develop non-equiatomic high-entropy alloys that do not require many expensive or heavy elements, contrary to the requirements of typical high-entropy alloys. In this study, a non-equiatomic high-entropy alloy powder Fe_49.5Mn₃₀Co₁₀Cr₁₀C_0.5 (at.%) is prepared by high energy ball milling and fabricated by spark plasma sintering. By combining different ball milling times and ball-topowder ratios, we attempt to find a proper mechanical alloying condition to achieve improved mechanical properties. The milled powder and sintered specimens are examined using X-ray diffraction to investigate the progress of mechanical alloying and microstructural changes. A miniature tensile specimen after sintering is used to investigate the mechanical properties. Furthermore, quantitative analysis of the microstructure is performed using electron backscatter diffraction.

[Korean]
Microstructure and Mechanical Property of Ti-Mn-Cu Alloys with Magnetic Pulsed Compaction: Ye Jun Yun, Chun Woong Park, Won June Choi, Jongmin Byun; J Korean Powder Metall Inst. 2021;28(1):20-24. Published online February 1, 2021; DOI: https://doi.org/10.4150/KPMI.2021.28.1.20

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Abstract PDF: Ti-based alloys are widely used in biomaterials owing to their excellent biocompatibility. In this study, Ti- Mn-Cu alloys are prepared by high-energy ball milling, magnetic pulsed compaction, and pressureless sintering. The microstructure and microhardness of the Ti-Mn-Cu alloys with variation of the Cu addition and compaction pressure are analyzed. The correlation between the composition, compaction pressure, and density is investigated by measuring the green density and sintered density for samples with different compositions, subjected to various compaction pressures. For all compositions, it is confirmed that the green density increases proportionally as the compaction pressure increases, but the sintered density decreases owing to gas formation from the pyrolysis of TiH₂ powders and reduction of oxides on the surface of the starting powders during the sintering process. In addition, an increase in the amount of Cu addition changes the volume fractions of the α-Ti and β-Ti phases, and the microstructure of the alloys with different compositions also changes. It is demonstrated that these changes in the phase volume fraction and microstructure are closely related to the mechanical properties of the Ti-Mn-Cu alloys.

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