Study on strengthening mechanism and high temperature mechanical properties of TiC-Fe-HEA cemented carbide

Abstract

High entropy alloy (HEA) can be used as binder phase to improve the properties of cemented carbide due to its high hardness, high strength and high temperature softening resistance. TiC-Fe-AlCoCrFeNi cemented carbide was prepared by vacuum sintering, and the effect of AlCoCrFeNi high entropy alloy content on the microstructure, room temperature properties, friction and wear and high temperature hardness was studied. By analyzing the microstructure and properties of cemented carbide, it is found that adding HEA can refine grains and strengthen properties. With the increase of HEA content, the room temperature hardness, fracture toughness and flexural strength of cemented carbide all showed a trend of first increasing and then decreasing. When the HEA content was 7.5% (TiC 7.5 H), the room temperature properties of cemented carbide are the best, and the room temperature hardness, fracture toughness and flexural strength of 1610HV, 10.7 MPa·m1/2 and 945 MPa respectively. According to the high temperature hardness test, TiC 7.5 H cemented carbide has good high temperature properties, the hardness at 800 ℃ is 920HV, and it maintains 57.14% of the room temperature hardness. Through the analysis of friction and wear experiments, it is found that cemented carbide has three wear forms: abrasive wear, adhesive wear and oxidation wear, and TiC 7.5 H has the lowest friction coefficient and wear rate and the best wear resistance.