Effect of milling time on microstructure and mechanical properties of TiC-CoCrFeNi composites prepared by hot pressing sintering

TiC-CoCrFeNi composite was fabricated by mechanical alloying and consequently vacuum hot pressing sintering, and the effects of milling time on the microstructure and mechanical properties of the composite was investigated. The results show that a single-phase solid solution with fcc structure is obtained after milled for 10h of Co, Cr, Fe and Ni powders. TiC and Cr-7 C(3 )structured carbides are formed and dispersed in the CoCrFeNi solid solution after hot pressing sintered at 1200 degrees C for 1h. Milling time has a significant effect on the size and amount of TiC and Cr7C3 structured carbides, which can affect the mechanical properties of the composite. When the milling time reaches 10h, the hardness and yield strength of the composite reach the maximum values of 671HV and 1440MPa, respectively, which is probably attributed to the dramatically increasing of nano-sized TiC in sintered bodies.