Journal of Powder Materials

[Korean]
Aging Temperature Effect on the Microstructure and Mechanical Properties of Directed Energy Deposited Inconel 939 Alloy: Youngwoo Kim, Ye Chan Sung, Ho Seoung Kang, Jung Gi Kim; J Powder Mater. 2026;33(3):203-213. Published online June 30, 2026; DOI: https://doi.org/10.4150/jpm.2026.00115

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Abstract PDF: Directed energy deposition (DED) of Inconel 939 (IN939) alloy is useful for fabricating and repairing geometrically complex components used in gas turbine systems. Repeated laser scanning produces a non-equilibrium microstructure that can support high mechanical strength. However, because the microstructure of DED IN939 differs from that of conventionally manufactured IN939, it may evolve differently under the same post-heat-treatment conditions. Therefore, this study applied different aging temperatures to investigate the microstructural evolution and mechanical properties of DED IN939 alloys and to identify suitable post-heat-treatment conditions. Quantitative microstructural characterization showed that both the γ′ phase fraction and γ′ size increased as the first and second aging temperatures increased. Consistent with γ′ evolution under the different aging conditions, specimen strength was positively correlated with aging temperature, whereas elongation decreased because excessive γ′ formation and growth narrowed the γ′ channel width. Consequently, aging at 840 °C for 8 hours followed by aging at 740 °C for 8 hours provided the best combination of high strength and ductility in room-temperature tensile tests.

[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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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.

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Characterization of Hf, Pt-doped NiCoCrAlY powders fabricated via plasma rotating electrode process
Chengxi Wang, Bochun Zhang, Jiale Tian, Peng Song, Taihong Huang, Jilin Lei, Wei Deng, Vincent Ji
Powder Technology.2026; 480: 122628. CrossRef

[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.

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Interfacial Characterization of Al2O3-Coated p-Type Bi–Sb–Te Powders by Thermal and UV-assisted Atomic Layer Deposition
Jin Kyeong Shin, Yeongtae Choi, Byung Joon Choi
Journal of Powder Materials.2026; 33(3): 221. CrossRef
Engineering oxide-structured niobium composites via atomic layer deposition and spark plasma sintering
Ji Young Park, Seung-Hyeok Shin, Jongmin Byun, Byoungchul Hwang, Byung Joon Choi
Materials & Design.2026; 268: 116547. CrossRef

[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]
Analysis on Milling Behavior of Oxide Dispersion Strengthened Ni-based Atomizing Powder with Ni₅Y Intermetallic Phase: Chun Woong Park, Jong Min Byun, Won June Choi, Young Do Kim; J Korean Powder Metall Inst. 2019;26(2):101-106. Published online April 1, 2019; DOI: https://doi.org/10.4150/KPMI.2019.26.2.101

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Abstract PDF

Ni-based oxide dispersion strengthened (ODS) alloys have a higher usable temperature and better hightemperature mechanical properties than conventional superalloys. They are therefore being explored for applications in various fields such as those of aerospace and gas turbines. In general, ODS alloys are manufactured from alloy powders by mechanical alloying of element powders. However, our research team produces alloy powders in which the Ni₅Y intermetallic phase is formed by an atomizing process. In this study, mechanical alloying was performed using a planetary mill to analyze the milling behavior of Ni-based oxide dispersions strengthened alloy powder in which the Ni₅Y is the intermetallic phase. As the milling time increased, the Ni₅Y intermetallic phase was refined. These results are confirmed by SEM and EPMA analysis on microstructure. In addition, it is confirmed that as the milling increased, the mechanical properties of Ni-based ODS alloy powder improve due to grain refinement by plastic deformation.

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Efficient prediction of corrosion behavior in ternary Ni-based alloy systems: Theoretical calculations and experimental verification
Xuelian Xiao, Keke Chang, Kai Xu, Ming Lou, Liping Wang, Qunji Xue
Journal of Materials Science & Technology.2023; 167: 94. CrossRef
Effect of high-energy ball milling on the microstructure and mechanical properties of Ni-based ODS alloys fabricated using gas-atomized powder
Chun Woong Park, Won June Choi, Jongmin Byun, Young Do Kim
Journal of Materials Science.2022; 57(38): 18195. CrossRef

[Korean]
Analyses of Creep Properties of Ni-base Superalloy Powders as Cooling Rate after Solid Solution Heat Treatment: Chan Jun, Youngseon Lee, Byeong Beom Bae, Hong-Kyu Kim, Seong Suk Hong, Donghoon Kim, Jondo Yun, Eun Yoo Yoon; J Korean Powder Metall Inst. 2016;23(3):247-253. Published online June 1, 2016; DOI: https://doi.org/10.4150/KPMI.2016.23.3.247

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Abstract PDF: In this study, solid solution heat treatment of consolidated nickel-based superalloy powders is carried out by hot isotactic pressing. The effects of the cooling rate of salt quenching, and air cooling on the microstructures and the mechanical properties of the specimens are analyzed . The specimen that is air cooled shows the formation of serrated grain boundaries due to their obstruction by the carbide particles. Moreover, the specimen that is salt quenched shows higher strength than the one that is air cooled due to the presence of fine and close-packed tertiary gamma prime phase. The tensile elongation at high temperatures improves due to the presence of grain boundary serrations in the specimen that is air cooled. On the contrary, the specimen that is salt quenched and consists of unserrated grain boundaries shows better creep properties than the air cooled specimen with the serrated grain boundaries, due to the negative creep phenomenon.

[English]
Simulation and Experiment of Injection Molding Process for Superalloy Feedstock: Im Doo Jung, Youngmoo Kim, Seong Jin Park; J Korean Powder Metall Inst. 2015;22(1):1-5. Published online February 1, 2015; DOI: https://doi.org/10.4150/KPMI.2015.22.1.1

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Abstract PDF

Powder injection molding is an important manufacturing technology to mass produce superalloy components with complex shape. Injection molding step is particularly important for realizing a desired shape, which requires much time and efforts finding the optimum process condition. Therefore computer aided engineering can be very useful to find proper injection molding conditions. In this study, we have conducted a finite element method based simulation for the spiral mold test of superalloy feedstock and compared the results with experimental ones. Sensitivity analysis with both of simulation and experiment reveals that the melt temperature of superalloy feedstock is the most important factor for the full filling of mold cavity. The FEM based simulation matches well the experimental results. This study contributes to the optimization of superalloy powder injection molding process.

Citations

Citations to this article as recorded by

Powder Injection Molding Process in Industrial Fields
Joo Won OH, Chang Woo GAL, Daseul SHIN, Jae Man PARK, Woo Seok YANG, Seong Jin PARK
Journal of the Japan Society of Powder and Powder Metallurgy.2018; 65(9): 539. CrossRef
Effect of Diamond Particle Size on the Thermal Shock Property of High Pressure High Temperature Sintered Polycrystalline Diamond Compact
Ji-Won Kim, Min-Seok Baek, Hee-Sub Park, Jin-Hyeon Cho, Kee-Ahn Lee
Journal of Korean Powder Metallurgy Institute.2016; 23(5): 364. CrossRef

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