Microstructure evolution of a Ti–Al–Sn–Zr based alloy during the hot compression deformation

Abstract

The Ti–Al–Sn–Zr based alloy was fabricated and its deformation behavior was investigated with increasing of temperature and strain rate. Microstructure and phase of the as-fabricated, heat treated and deformed alloy was characterized by OM, XRD and TEM. The results exhibited that the addition of Mo, Nb and Ta promoted the precipitate of β phase at relative low heat treatment temperature. And the β phase has relative good phase interface with the αphase. During the compression test, the compressive strength of the alloy dropped with the strain rate decreasing and the testing temperature rising. When the compression deformation was preformed above α phase transformation temperature, the high strain rate would promote the phase transformation. When the alloy was compressed with strain rate of 1 s–1, it almost had the similar compressive strengths at 960 °C and 940 °C. Moreover, the same phenomenon appeared when the compression was carried out at 960 °C and 980 °C with stain rate of 0.01 s–1. Such a phenomenon should be ascribed to the existence of high amount of β phase which could contribute to the strength.