Effect of Zr, Mo and TiC on microstructure and high-temperature tensile strength of cast titanium matrix composites

Abstract

In this paper, five types of TiC particle reinforced titanium matrix composites (TiC-PTMCs) were fabricated by casting route in order to investigate the influence of Zr, Mo and TiC on microstructures and tensile strengths of TiC-PTMCs. The increase of Zr content promoted the precipitation of eutectic TiC and refined primary TiC, while increasing Mo content led to the refinement of α lath. The composites with high Zr and Mo contents and low TiC content showed superiority in ultimate tensile strength (UTS) below 650°C, whereas above 700°C, high UTS was obtained in the composites with high TiC content and low Mo content. Below 650°C, solid solution strengthening and fine grain strengthening of matrix make the largest contribution to the improvement of UTS. However, above 700°C, solid-solution strengthening of Zr and the load bearing effect of TiC play a dominant role in the enhancement of UTS. Accordingly, effective routes for improving UTSs of TiC-PTMCs in different temperature ranges are different.