Environmental embrittlement of Ti-48Al alloys

Abstract
The tensile behaviour of two TiAl₄₈ alloys, namely Ti₄₇Al₄₈Cr₂Nb₂B₁ and Ti₅₂Al₄₈, was studied with respect to the gaseous environment. The samples were annealed to give them a duplex microstructure, consisting of equiaxed γ-TiAl grains and lamellar α/γ² grains. They were tensile tested at room temperature in pure argon gas or in water vapour saturated argon gas. Elongation was found rather low in the dry gas. It was reduced still further in moisture with respect to dry argon even in the case of Ti₄₇Al₄₈Cr₂Nb₂B₁ where additions, such as Cr, were thought to lessen the environmental embrittlement.