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研究了Ｔｉ－４４．９Ａｌ（ａｔ－％）合金和Ｔｉ－４４．３Ａｌ－３Ｃｒ（ａｔ－％）合金的室温拉伸断裂过程。结果表明，Ｃｒ提高了合金的塑性。塑性的提高与含Ｃｒ合金含有更多的γ－ＴｉＡｌ相和形成由细晶γ和α＿２＋γ细晶组成的双重组织有关。Ｃｒ促使块状α＿２和β２相的形成，对阻碍γ相上的长程滑移有明显的作用。进一步细化铸态晶粒或制备具有片状α＿２＋γ组织的单晶合金是发展铸造α＿２＋γ合金的目标。
Room temperature tensile fracture of Ti-44.9Al (at-%) alloy and Ti-44.3Al-3Cr (at-%) alloy was investigated. The results show that Cr improves the ductility of the alloy. The increase in ductility is related to the inclusion of more γ-TiAl phases in Cr-containing alloys and to the formation of double weaves consisting of fine-grained γ and α_2 + γ fine crystals. Cr promotes the formation of massive α_2 and β2 phases, and has a significant effect on preventing the long-range slip on γ phase. Further refinement of as-cast grains or preparation of single crystal alloys with lamellar α_2 + γ organization is the goal of developing α_2 + γ alloys.