The Microstructure and Mechanical Properties of the WC-10CoCrFeMnNi/CoCrFeNi Cemented Carbide
摘要
To elucidate the differences between cemented carbides incorporating high-entropy alloys as binder phases and those utilizing conventional Co-based binders with a specific focus on the role of Mn elements, three distinct carbide compositions—WC-10CoCrFeMnNi, WC-10CoCrFeNi, and WC-10Co—were fabricated via mechanical alloying followed by spark plasma sintering. The results reveal that complete alloying of metal powders during HEA synthesis was achieved only after 80 hours of ball milling accompanied by a significant reduction in powder particle size post-milling. Phase composition analysis of the sintered carbides indicated that the WC-10CoCrFeMnNi variant consisted of WC phase FeCoNi solid solution MnCr2O4 and MnO phases, whereas the WC-10CoCrFeNi composition contained WC phase FeCoNi solid solution and Cr5O12 phase. Notably, the WC-10CoCrFeMnNi carbide exhibited the highest lattice distortion of 6.54% in the (1011) WC crystal plane. Mechanical property characterization demonstrated that the WC-10CoCrFeNi carbide outperformed the WC-Co reference in terms of transverse fracture strength and wear resistance with measured values of 2052 MPa, 0.54 and 1.716 × 10−4 mm3/N m. Furthermore, its Vickers hardness was determined to be 1413 HV30 with a fracture toughness of 10.50 MPa m1/2, which was comparable to that of WC-10Co. These results collectively indicate that the CoCrFeNi high-entropy alloy holds significant promise as a binder phase for cemented carbides.