A high-performance β-stabilized Ti-43Al-9V-0.2Y alloy sheet with a nano-scaled antiphase domain

A novel beta-stabilized Ti-43Al-9V-0.2Y alloy sheet with a nano-scaled antiphase domain (APD) microstructure and excellent performance was fabricated via hot-pack rolling in the (alpha + gamma) phase region (1260 degrees C). Owing to the temperature drop and reheat associated with multi-pass rolling, heterogeneous and regular APD-mixed lamellar structures formed with the occurrence of alpha -> beta + gamma and alpha -> alpha(2) + gamma phase transformations. The antiphase boundary (APB) between two nano-scaled APD structures (average size: similar to 15 nm) is identified as a type of atomic shift, which is induced by the disorder-order transformation in the alpha(2) phase. Moreover, compared with the corresponding as-forged alloy and other hot-working beta-stabilized TiAl alloys, the current alloy sheet exhibited higher strength both at room and elevated temperatures. The improvement in the tensile properties is attributed mainly to the duplex microstructure consisting of fine nano-scaled APD/lamella mixed structures. (C) 2017 Elsevier B.V. All rights reserved.