Microstructure and mechanical behavior of WC-HEA cemented carbide at various scales: Molecular dynamics simulation and experimental study

D Wang and DB Li and ZW Ding and B Zhao and FK Shi and G Qi, CERAMICS INTERNATIONAL, 51, 32339-32354 (2025).

DOI: 10.1016/j.ceramint.2025.04.420

High-entropy alloys (HEAs) as WC matrix binders can significantly improve the mechanical properties of cemented carbide tool materials. To investigate the microstructural mechanisms governing these property changes in WC-CoCrNiFeCu cemented carbides, this study combined molecular dynamics (MD) nanoindentation simulations with spark plasma sintering (SPS) experiments. The simulations revealed that during plastic deformation, dislocations nucleate in HEA regions, inducing heterogeneous plastic deformation and a partial FCC -> BCC phase transformation. Increasing HEA content reduced system stability during indentation, enhancing plasticity while decreasing hardness and Young's modulus. Elevated temperature significantly lowered the alloy's load- bearing capacity, promoting stress-induced amorphization and stacking fault expansion. Experimentally, sintered materials developed a BCC structure, likely due to Cr enrichment, with intergranular fracture being the dominant failure mode. Optimal HEA content and sintering parameters yielded cemented carbide tool materials with excellent mechanical properties: hardness of 19.49 GPa, fracture toughness of 16.01 MPa m1/2, and flexural strength of 1.228 GPa. The close agreement between experimental and simulated hardness values validates the MD approach, which provides fundamental insights into the microstructural origins of mechanical property evolution in these materials.

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