Influence of the sintering temperature on the microstructure, mechanical properties and densification characteristics of (TiB + TiC)/TC4 composite

A hybrid of TiB whiskers and TiC particles reinforced TC4 matrix composites were in situ synthesized by spark plasma sintering (SPS) using a TC4-0.6wt.% B4C powder mixture at temperatures range from 550 C to 1150 C. The effect of sintering temperature on microstructure, grain size, mechanical properties and densification process of the (TiB + TiC)/ TC4 matrix composites were investigated. The composite sintered at 1050 C has the highest tensile strength (1129.0 MPa), yield strength (1077.8 MPa) and plasticity (7.1%). The aspect ratio of TiB whiskers increases almost linearly below 1050 C and its highest value is 33.2. The grain size of TiC increases with the increase of sintering temperature, and rapid growth occurs in the range of 850 C to 950 C. The composite sintered body appears four shrinkage stages before applying sintering pressure. The corresponding peak temperatures are 663 C, 758 C, 840 C and 994 C, respectively.