Regulation of Ta element on the B2+γ like pearlitic microstructure and mechanical properties of Ti-46Al-2Cr-0.3Si alloy

Abstract

The β/B2 phase is recognized to impair the room temperature plasticity of TiAl alloys. To address this problem, a novel B2+γ like pearlitic microstructure (LPM) has been proposed to enhance performance. In this work, Ti-46Al-2Cr-0.3Si- x Ta ( x = 0, 0.5, 1, 2, and 4 at.%) alloys were prepared to elucidate the influence of LPM formation on microstructural evolution and mechanical properties. The results show that initial alloy is dominated by γ+α 2 lamellar colonies, whereas Ta addition promotes the precipitation of LPM within these lamellar colonies. The comprehensive properties increase first and then decrease with increasing Ta content. The room-temperature fracture stress and fracture strain of the Ti-46Al-2Cr-0.3Si-2Ta alloy are increased by 26.99% and 8.97%, respectively. It can be attributed to the synergistic effect of LPM formation and Ta-induced solid-solution strengthening.