Microstructure, mechanical properties and deformation behavior of new V-free low-cost Ti-6Al-xFe-yCr alloys

Abstract

A variety of low-cost V-free near-β titanium alloys, Ti-6Al-xFe-yCr(x = 1, 2 and y = 9, 12 wt%), were designed and fabricated to research the influence of Fe and Cr content on the phase composition, microstructure and properties of the alloy. The Ti-6Al-xFe-yCr alloy is less costly to prepare than the commonly used Ti-6Al-4V alloy, which exhibited a typical near-β microstructure. When the Fe content was 2 wt% and the Cr content was 12 wt%, the resulting alloy’s microstructure exhibited a great amount of β phase and a small quantity of α phase, which suggested the addition of Fe and Cr was an effective method to restrain α phase formation, thereby making efforts to stabilize β phase. To study the hot workability of the Ti-6Al-2Fe-12Cr titanium alloy, the thermal compress deformation behavior was studied at the strain rate ranging from 0.001 s−1 to 5 s−1, in the temperature variation of 800 °C up to 950 °C. The results showed that the thermal deformation behavior of the Ti-6Al-2Fe-12Cr alloy was susceptible to the deformation temperature and strain rate. The peak flow stress reduced as experimental temperature increment and the strain rate decrement. A constitutive model of the Ti-6Al-2Fe-12Cr alloy during thermal deformation was obtained based on the Arrhenius equation.