Microstructure evolution, mechanical properties, and wear behavior of in-situ TiCx/TC4 composites

Abstract

In this work, In-situ TiCx/TC4 composites were fabricated using Ti3AlC2 as a precursor via vacuum hot-pressing sintering. The effect of Ti3AlC2 content on the microstructure, mechanical properties, and wear behavior of TC4 matrix composites was investigated. The results indicate that the TiCx phase formed from the reaction between Ti3AlC2 and Ti during sintering. The in-situ formation of the TiCx phase could refine the size of the prior β grain and alter the microstructures of the matrix from the Widmanstatten structure of neat TC4 to an equiaxed structure. The TC4 matrix composites with different amounts of Ti3AlC2 exhibited higher hardness, yield strength, and tensile strength than neat TC4. When the volume fraction of Ti3AlC2 was 2.5%, the yield strength and tensile strength of composites were 951.2 MPa and 1033 MPa, respectively, which increased by 16.5% and 9.4% compared to neat TC4, respectively. Moreover, the elongation of the composites was 12.8% with substantially maintained plasticity. The improvement of yield strength in the composites is attributed to grain refinement strengthening and load transfer strengthening. The wear behavior of in-situ TiCx/TC4 composites was enhanced significantly. Abrasive wear and adhesive wear are the dominant wear mechanism in the TiCx/TC4 composites.