全层片状TiAl基合金断裂过程的原位观察

In Situ Observation of Fracture Process for Ti Al- base Alloy with Fully Lamellar Microstructure

利用 SEM拉伸台 ,研究了 Ti- 33Al- 3Cr- 0 .5 Mo (wt% )合金的室温拉伸断裂动态过程。试验结果表明 ,具有全层片状显微组织的 Ti Al合金室温断裂韧性较高 ,归因于合金拉伸过程中裂纹尖端发生分叉致使应力松弛而使裂纹钝化 ;在变形过程中 ,主裂纹尖端附近的微裂纹之间形成剪切韧带 ,剪切韧带韧化是 Ti Al合金的一种韧化机理。断口分析表明 ,Ti Al合金的断裂方式为跨层片断裂和α2 /γ层片相界面解理的混和形式。

In situ observation of the tensile fracture process for Ti- 33Al- 3Cr- 0 .5Mo ( wt% ) alloy with fully microstructure was conducted in this work.Fully lamellar Ti Al alloy ex- hibits high fracture toughness.The crack bifurcation results in crack- tip blunting during tensile process.The formation of shear ligaments by mismatched crack planes might lead to an enhance- ment in the fracture toughness.The fractograghic analyses show that the translamellar fracture and cleavage of interfaces are the two dominant fracture modes.