Journal of Powder Materials

Research Articles

[English]
Analysis of Sintering Behavior and Microstructure of Mo-Ta Alloy under Different Sintering Conditions: Byungheon Oh, Geon Kim, Jio Yoon, Dongju Lee; J Powder Mater. 2026;33(2):130-136. Published online April 30, 2026; DOI: https://doi.org/10.4150/jpm.2026.00080

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Abstract PDF: Molybdenum-tantalum (Mo-Ta) alloy sputtering targets are widely used in electronic applications owing to their excellent corrosion resistance, high thermal and electrical conductivity, and low electrical impedance. In this study, the sintering behavior and microstructural evolution of Mo-Ta alloys fabricated by spark plasma sintering (SPS) were investigated as a function of sintering temperature in the range of 1650-1800 °C. X-ray diffraction and microstructural analyses indicate that densification and alloying of the mixed Mo and Ta powders occur simultaneously during the SPS process. Increasing the sintering temperatures significantly enhances densification, and the compact sintered at 1750 °C achieves a relative density exceeding 99%, which is essential for high-quality sputtering target applications. The sintered alloys exhibit a clear temperature-dependent grain growth behavior together with a homogeneous microstructure and randomly oriented grains. These results demonstrate that appropriate control of sintering temperature enables the fabrication of dense and microstructurally uniform Mo-Ta alloys, providing valuable guidelines for optimizing sputtering target performance.

[English]
Effect of Bimodal WC Particle Size Distribution on the Mechanical Properties of WC–Mo₂C–Co Cemented Carbides: Jinwoo Seok, Jong Tae Kim, Juree Jung, Bin Lee, Junhee Han, Leeseung Kang; J Powder Mater. 2026;33(1):13-21. Published online February 28, 2026; DOI: https://doi.org/10.4150/jpm.2025.00500

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Abstract PDF: In this study, the influence of bimodal WC particle size design on the microstructure and mechanical properties of WC–27 wt.% Mo₂C–10 wt.% Co cemented carbides was systematically investigated. Bimodal hard-phase designs were realized by combining ultrafine WC (300 nm) and coarse WC (1.8 μm) at various ratios, followed by consolidation via spark plasma sintering (SPS). During sintering, Mo₂C preferentially dissolved into the Co-rich liquid phase due to its higher solubility than WC, forming a Co–Mo–C liquid. During sintering progresses, ultrafine WC selectively dissolved owing to its high interfacial energy, gradually transforming the liquid composition into a Co–Mo–W–C system. Owing to the short holding time and rapid cooling rate of SPS, the η-phase (M₆C) formed during sintering remained metastable. Meanwhile, selective dissolution–reprecipitation resulted in the formation of Mo₂C-based core–rim structures with W enrichment in the rim region as (Mo, W)₂C. As the fraction of ultrafine WC increased, the hardness increased from 1769 to 1997 kgf/mm2, whereas the fracture toughness exhibited an insignificant difference from 6.56 to 6.65 MPa•m¹ᐟ². Fracture behavior analysis revealed that crack deflection and crack bridging occurred at the Mo₂C core–rim interfaces, effectively suppressing straight crack propagation. These results demonstrate that the introduction of ultrafine WC plays a dominant role in enhancing mechanical performance, and that bimodal WC design combined with Mo₂C addition is a highly effective strategy for developing high-performance cemented carbides for machining

[Korean]
Optimization of Mechanical Properties in WC–Mo₂C–Co Cemented Carbides via Dual Hard-Phase Based Heterogeneous Microstructure Design: Jinwoo Seok, Jong Tae Kim, Juree Jung, SongYi Kim, Bin Lee, Junhee Han, Leeseung Kang; J Powder Mater. 2025;32(5):428-436. Published online October 31, 2025; DOI: https://doi.org/10.4150/jpm.2025.00297

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Abstract PDF

WC–Mo₂C–Co cemented carbides were fabricated to investigate the effects of Mo₂C addition on microstructure and mechanical properties. Dual hard-phase design using WC and Mo₂C was employed to optimize the balance between hardness and toughness. Spark plasma sintering (SPS) was conducted at various temperatures after ball milling, and 1300 °C for 5 min was identified as the optimized sintering condition, achieving complete densification and phase stability. The addition of Mo₂C refined the microstructure by suppressing abnormal WC grain growth through preferential dissolution of Mo₂C into the Co binder. Hardness increased up to 1769 Hv30 due to grain refinement and solid-solution strengthening, while promoted η-phase formation and reduced fracture toughness.The 27Mo₂C composition exhibited the most balanced combination of hardness and toughness. These results demonstrate that controlled Mo₂C addition enables dual hard-phase strengthening and microstructure optimization in WC–Mo₂C–Co carbides for advanced cutting and forming applications.

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Effect of Bimodal WC Particle Size Distribution on the Mechanical Properties of WC–Mo2C–Co Cemented Carbides
Jinwoo Seok, Jong Tae Kim, Juree Jung, Bin Lee, Junhee Han, Leeseung Kang
Journal of Powder Materials.2026; 33(1): 13. CrossRef

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