对Ti-5Al-5Mo-5V-3Cr-1Zr合金在580℃进行不同时间（0，5，15，60 min）的时效处理，研究了α相的析出行为及其对合金拉伸断裂机制的影响。结果表明：随着时效时间的延长，从试验合金基体β相中先后析出三角形或V字形、树枝状和集束状形貌的α相；不同形貌α相与β相均保持Burgers取向关系；在拉伸变形过程中，三角形形貌α相组织中的位错集中在大尺寸条状α相中，裂纹沿优先变形的α相萌生；树枝状形貌α相组织中的位错集中在相互平行的条状α相中，裂纹沿主干α相萌生而形成准解理面；集束状形貌α相组织中的位错在条状α相间的β相中激活，裂纹沿高角度β/β相界面萌生而形成光滑解理面。

Ti-5Al-5Mo-5V-3Cr-1Zr alloy was treated by to aging at 580℃ for different times (0, 5, 15, 60 min), and then α phase precipitation behavior and its effect on the tensile fracture mechanism of the alloy were studied. The results show that α phases with triangle or V shaped, dendritic and cluster morphology successively precipitated in matrix β phase of test alloy with the increase of aging time. The orientation relationship between α phase with different morphology and β phase obeyed the Burgers rule. During the tensile deformation, the dislocations in the structure with triangular morphology α phase were concentrated in the large-sized strip α phase, and the cracks initiated along the preferentially deformed α phase. The dislocations in the structure with dendritic morphology α phase were concentrated in parallel strip α phase; the cracks initiated along the trunk α phase, and then the quasi-cleavage plane was formed. The dislocations in the structure with cluster morphology α phase were activated in β phase between strip α phase; the crack initiated along the high angle β/β phase interface, and then the smooth quasi-cleavage plane was formed.