In this study, the initial microstructure dependency of flow localization behavior was investigated for Ti–6Al–4V alloys with equiaxed, duplex, basket-weave and widmannstatten microstructures. The flow localization behavior was conducted using micro-compression hot deformation tests and the microstructures were characterized by Electron backscatter diffraction (EBSD). The results reveal that initiation of micro shear bands in basket-weave is driven through the absorption of dislocations to colony boundaries, whereas it is implemented via the pinch-off of α lamellae in widmannstatten. A semi-quantitative result based on EBSD observations indicates that the high globularization rate of micro shear bands in basket-weave are found in α lamellae with soft orientation where the c-axis of crystal is tilted of 15–75° from the compression axis or the geometric orientation of lamellae is perpendicular to the shear direction. However, the globularization of widmannstatten is no longer subject to the effects of geometric or crystal orientation, suggesting that there is a noteworthy coupling size effects. In addition, accompanying with the microstructure change from duplex through basket-weave to widmannstatten, the decrease of interlamellar spacing for α lamellae increases the strength of materials through Hall-Petch. At the same time, the decrease of interlamellar spacing promotes slip transmission via the proposed mechanisms of boundary absorption and pinch-off, resulting in easier flow softening, earlier flow localization, more intense shear deformation, narrower and sharper shear bands.

在这项研究中，研究了具有等轴，双相，网状组织和魏德斯坦施坦组织的Ti-6Al-4V合金流动局部化行为的初始微观结构依赖性。使用微压缩热变形测试进行了流动局部化行为，并通过电子背散射衍射（EBSD）表征了微观结构。结果表明，篮状组织中微剪切带的萌发是通过位错吸收到菌落边界来驱动的，而这是通过在widmannstatten中夹断α薄片来实现的。基于EBSD观测值的半定量结果表明，篮状编织中微剪切带的高球化率位于具有软取向的α层中，其中晶体的c轴从压缩轴倾斜15-75°或薄片的几何取向垂直于剪切方向。但是，widmannstatten的球状化不再受几何或晶体取向的影响，这表明存在显着的耦合尺寸效应。此外，伴随着从双相结构到篮状组织到魏德曼斯坦的微观结构变化，α薄片的层间间距的减小增加了通过Hall-Petch处理的材料的强度。同时，