To study the effect of α phase morphology (equiaxed α (αE)/lamellar α (αL)) on the in situ tensile behavior of TC21 alloy, the slip band, dislocation, crack initiation, and propagation were analyzed by scanning electron microscopy (SEM) with in situ tensile stage and transmission electron microscopy (TEM). The results show that the slip bands first concentrate in the αE phases and easily truncate at the α/β phase boundaries, whereas the slip bands move across the α lamellae in the αL phase. Microcracks are easily generated in αE or α/β phase boundaries with large plastic deformation. When the quantity of αL is more than αE, the crack tip is more easily deflected at α phases or α clusters with different orientations, making the main crack propagation path more zigzag. When the volume fraction ratio of αE to αL is ~ 3:4, i.e., the volume fraction of αE is close to that of αL, TC21 alloy exhibits better strength and slower crack propagation rate.

中文翻译：

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不同α形貌（等轴/层状）TC21钛合金的原位变形行为

为了研究α相形貌（等轴α（αE）/层状α（αL））对TC21合金原位拉伸行为的影响，通过扫描电子显微镜（SEM）分析了滑移带、位错、裂纹萌生和扩展) 与原位拉伸阶段和透射电子显微镜 (TEM)。结果表明，滑带首先集中在αE相中，并在α/β相边界处容易截断，而滑带在αL相中穿过α薄片。在具有较大塑性变形的αE或α/β相界中容易产生微裂纹。当αL的量大于αE时，裂纹尖端更容易在不同取向的α相或α簇处偏转，使裂纹的主要传播路径更加曲折。当αE与αL的体积分数比为~3:4时，即，