The phase evolution, mechanical behavior, and microstructural instability of a fully-lamellar Ti–46Al(at.%) alloy

Abstract

A Ti–46Al(at.%) polysynthetically twinned alloy, which contained a characteristic lamellar spacing of λ=1.3 μm, was converted to a polycrystalline fully-lamellar microstructure with λ=19.9 nm using an α-phase solution treatment followed by α 2+ γ aging. Tensile experiments, performed on microsamples extracted from within single grains of the polycrystalline material, illustrated that ultrafine lamellae led to exceptional tensile strength. However, the ultrafine lamellae were not stable at elevated temperatures and the ultrafine material was found to have relatively poor creep resistance.