Orientation control of a lamellar microstructure in a Ti−Al intermetallic compound by high-temperature compression in an alpha single-phase and/or in a two-phase region and the alpha re-heat treatment

Abstract

In order to control the spatial Ti−Al distribution of the α2+γ γ lamellar microstructure in Ti−Al alloys, processes consisting of a high-temperature deformation in an alpha single-phase region, and an annealing and deformation in the α2+γ ψ region were examined. The compression deformation temperatures and strain rates were from 1573 to 1623 K and from 1.0×10−4 to 5.0×10−3 s−1, respectively. Dynamic recrystallization occurred during the compressive deformation in the alpha single-phase region. The uniaxial compression resulted in the formation of a fiber texture. It was found that more than half of the lamellar microstructure can be arranged within 30 degrees from the specimen surface by these processes. It was also shown that the orientation control of the lamellar microstructure in a polycrystalline Ti−Al intermetallic compound is effective in improving the creep resistance of this material.