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用透射电镜及备有拉伸装置的Ｓ５７０扫描电镜，研究了Ｔｉ３ＡｌＮｂ（Ｔｉ２４Ａｌ１４Ｎｂ３Ｖ０．５Ｍｏ）（摩尔百分数）合金在不同热处理制度下的组织形貌以及试样的拉伸断裂过程。结果表明：合金在α２＋β两相区固溶１ｈ水冷处理，组织由α２相、Ｂ２相和ｏ相组成。初生α２相体积分数不同，合金试样拉伸断裂机制不同，初生α２相体积分数低时，变形主要在Ｂ２相，裂纹主要在Ｂ２相内形核，随着Ｂ２相的减少，合金塑性提高。初生α２相体积分数高时，变形主要在α２相，裂纹主要萌生于α２相内，随着Ｂ２相的增多，合金塑性提高。细小的随机分布的针状α２相对合金拉伸断裂行为有良好作用。随固溶温度升高，α２相中位错密度逐渐减少，Ｂ２相中位错密度逐渐增多
The microstructures of Ti3AlNb (Ti24Al14Nb3V0.5Mo) (mol%) alloy under different heat treatment conditions were studied by transmission electron microscopy and scanning electron microscopy (SEM) Like the tensile fracture process. The results show that the alloy is solution-treated in α2 + β phase for 1h and the microstructure consists of α2 phase, B2 phase and o phase. The volume fraction of primary α2 phase is different. The tensile fracture mechanism of alloy sample is different. When the volume fraction of primary α2 phase is low, the deformation is mainly in phase B2 and the crack nucleates mainly in phase B2. With the decrease of B2 phase, the plasticity of alloy increases. When the volume fraction of primary α2 phase is high, the deformation is mainly in α2 phase, and the cracks mainly occur in α2 phase. With the increase of B2 phase, the plasticity of the alloy increases. Small and random distribution of acicular α2 relative tensile fracture behavior has a good effect. With the increase of solution temperature, the dislocation density in α2 phase decreases and the dislocation density in B2 phase increases