Journal of Powder Materials

[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]
The Effect of Aluminum Powder Size on the Structure and Mechanical Properties of Foam: Seunghyeok Choi, Sungjin Kim, Tae-Young Ahn, Yu-Song Choi, Jae-Gil Jung, Seung Bae Son, Seok-Jae Lee; J Powder Mater. 2025;32(3):232-243. Published online June 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00157

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Abstract PDF: In this study, we analyzed the structural and mechanical properties of aluminum foams fabricated using aluminum powders of varying sizes and mixtures. The effects of sintering and pore structure at each size on the integrity and mechanical properties of the foams were investigated. Structural characteristics were examined using scanning electron microscopy and micro–computed tomography, while mechanical properties were evaluated through compression testing. The experimental results demonstrated that smaller powder sizes improved foam integrity, reduced porosity and pore size, and resulted in thinner cell walls. In combination, these effects increased compressive strength as the powder size decreased. The findings of this study contribute to the understanding and improvement of the mechanical properties of aluminum foams and highlight their potential for use in a wide range of applications.

[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]
Ultra-Low-Temperature (4.2 K) Tensile Properties and Deformation Mechanism of Stainless Steel 304L Manufactured by Laser Powder Bed Fusion: Seung-Min Jeon, Young-Sang Na, Young-Kyun Kim; J Powder Mater. 2025;32(2):95-103. Published online April 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00066

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Abstract PDF: This study investigated the ultra-low-temperature (4.2 K) tensile properties and deformation mechanisms of stainless steel 304L manufactured via laser powder bed fusion (LPBF). The tensile properties of LPBF 304L were compared to those of conventional 304L to assess its suitability for cryogenic applications. The results revealed that LPBF 304L exhibited a significantly higher yield strength but lower ultimate tensile strength and elongation than conventional 304L at 4.2 K. The temperature dependence of the yield strength also favored LPBF 304L. Microstructural analysis demonstrated that LPBF 304L features a high density of dislocation cells and nano-inclusions, contributing to its greater strength. Furthermore, strain-induced martensitic transformation was observed as a key deformation mechanism at cryogenic temperatures, where austenite transformed into both hexagonal-closed packed (HCP) and body-centered cubic (BCC) martensite. Notably, BCC martensite nucleation occurred within a single HCP band. These findings provide critical insights into the mechanical behavior of LPBF 304L at cryogenic temperatures and its potential for applications in extreme environments.

[English]
Stretch-Flangeability of Laser Powder Bed Fusion-Processed 316L Stainless Steel: Rae Eon Kim, Yeon Taek Choi, Sang Guk Jeong, Do Won Lee, Hyoung Seop Kim; J Powder Mater. 2025;32(2):87-94. Published online April 30, 2025; DOI: https://doi.org/10.4150/jpm.2025.00017

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Abstract PDF Supplementary Material: Metal additive manufacturing (AM) facilitates the production of complex geometries with enhanced functionality. Among various AM techniques, laser powder bed fusion (LPBF) is distinguished by its precision and exceptional mechanical properties achieved via laser fusion deposition. Recent advancements in AM have focused on combining LPBF with post-processing methods such as cold rolling, high-pressure torsion, and forming processes. Therefore, understanding the forming behavior of LPBF-processed materials is essential for industrial adoption. This study investigates the stretch-flangeability of LPBF-fabricated 316L stainless steel, emphasizing its anisotropic microstructure and mechanical properties. Hole expansion tests were employed to assess stretch-flangeability in comparison to wrought 316L stainless steel. The results demonstrate that LPBF-processed samples exhibit significant anisotropic behavior, demonstrating the influence of microstructural evolution on formability. These findings contribute valuable insights into optimizing LPBF materials for industrial forming applications.

[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

[Korean]
Effect of Hatch Spacing on the Microstructure and Mechanical Properties of SA508 Gr.3 Steel Fabricated by Laser Powder Bed Fusion: Yuanjiu Huang, Ho Jin Ryu, Kee-Ahn Lee; J Powder Mater. 2025;32(1):50-58. Published online February 28, 2025; DOI: https://doi.org/10.4150/jpm.2024.00479

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This study investigated the effect of the hatch spacing parameter on the microstructure and mechanical properties of SA508 Gr.3 steel manufactured by laser powder bed fusion (L-PBF) for a nuclear pressure vessel. Materials were prepared with varying hatch spacing (0.04 mm [H4] and 0.06 mm [H6]). The H4 exhibited finer and more uniformly distributed grains, while the H6 showed less porosity and a lower defect fraction. The yield strength of the H4 material was higher than that of the H6 material, but there was a smaller difference between the materials in tensile strength. The measured elongation was 5.65% for the H4 material and 10.41% for the H6 material, showing a significantly higher value for H6. An explanation for this is that although the H4 material had a microstructure of small and uniform grains, it contained larger and more numerous pore defects than the H6 material, facilitating stress concentration and the initiation of microcracks.

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Extremely low temperature mechanical behavior of in-situ oxide containing 304L stainless steel fabricated by laser powder bed fusion
Kwangtae Son, Seung-Min Jeon, Brian K. Paul, Young-Sang Na, Kijoon Lee, Young-Kyun Kim
Journal of Materials Science & Technology.2025; 234: 319. CrossRef

[Korean]
Fabrication of Al₁₈B₄O₃₃ Spherical Powder with Increased Fluidity via Control of B₂O₃ Particle Size and Distribution: Kiho Song, Sang in Lee, Hyunseung Song, Changui Ahn; J Powder Mater. 2024;31(6):513-520. Published online December 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00304

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Abstract PDF: Ceramic materials have become essential due to their high durability, chemical stability, and excellent thermal stability in various advanced industries such as aerospace, automotive, and semiconductor. However, high-performance ceramic materials face limitations in commercialization due to the high cost of raw materials and complex manufacturing processes. Aluminum borate (Al₁₈B₄O₃₃) has emerged as a promising alternative due to its superior mechanical strength and thermal stability, despite its simple manufacturing process and low production cost. In this study, we propose a method for producing Al₁₈B₄O₃₃ spherical powder with increased uniformity and high flowability by controlling the particle size of B₂O₃. The content ratio of the manufactured Al18B4O33 spherical powder was Al2O3: B2O3 = 87:13, and it exhibited a 17% reduction in the Hausner ratio (1.04) and a 29% decrease in the angle of repose (23.9°) compared to pre-milling conditions, demonstrating excellent flowability.

[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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2 Citations

Abstract PDF

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]
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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1 Citations

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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

[Korean]
Inter-laminar Strength of NITE-SiC/SiC Composites With Various Fiber Reinforcing Architecture: Jong-il Kim; J Powder Mater. 2024;31(5):437-444. Published online October 31, 2024; DOI: https://doi.org/10.4150/jpm.2024.00248

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Abstract PDF: The mechanical performance of SiC/SiC composites is significantly influenced by the architecture of fiber reinforcement. Among the various fabrication methods, the nano-powder infiltration transition/eutectic (NITE) process is a promising technique that is capable of achieving a dense and stoichiometric SiC matrix. The reinforcement architecture, such as cross-ply (CP) or woven prepreg (WP), is determined during the preform stage of the NITE process, which is crucial in determining the mechanical properties of SiC/SiC composites. In this study, the tensile test and double notch shear (DNS) test were conducted using NITE-SiC/SiC composites to investigate the effect of the fiber reinforcing architecture on the fracture mechanism of SiC/SiC composites. The tensile strength and maximum shear strength of both CP and WP specimens were nearly identical. However, other mechanical properties, particularly those of CP specimens, exhibited significant variability. A comparison of fracture surfaces and load-displacement curve analyses from the DNS tests revealed that the cross points of the longitudinal or transverse fibers act as obstacles to both deformation and crack propagation. These obstacles were found to be more densely distributed in WP specimens than in CP specimens. The variability observed in the mechanical properties of CP specimens is likely due to size effects caused by the sparser distribution of these obstacles compared to the WP specimens.

[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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2 Citations

Abstract PDF

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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Citations to this article as recorded by

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

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