TC4钛合金绝热剪切带的微观组织及织构

Microstructure and texture of adiabatic shear band in TC4 titanium alloy

应用电子背散射衍射技术(EBSD)研究TC4钛合金绝热剪切带(ASB)的微观组织及其织构演化。原为等轴组织的小圆柱试样用Gleeble-3500热模拟试验机以相对低的应变速率热压缩获得ASB。结果表明,试样组织由基体、过渡区和ASB组成。基体为等轴α晶粒和晶粒间的β相;过渡区为内部包含亚晶的1~4μm宽的拉长组织;试样中心ASB由0.2~0.7μm的再结晶晶粒组成;接近试样边缘ASB存在剧烈拉长的条状组织、大量的亚晶和再结晶晶粒。极图表明,基体具有较强的{0001}【1010】织构;过渡区包含{1010}【1120】和{1122}【1123】织构;中心ASB没有取向集中;接近试样边缘ASB为{1120}【1010】织构。

Microstructure and texture evolution of adiabatic shear band ( ASB ) in TC4 titanium alloy were studied by electron back-scattered diffraction (EBSD).The ASB under investigation was induced in cylindrical sample of TC4 titanium alloy with equiaxed microstructure by hot compression with a relatively low strain rate.The structure of the sample after deformation consists of matrix, transition zone and ASB.The matrix contains equaxiedαgrains and intergranular β.In the transition zone severely elongated grains about 1-4μm in width and some subgrains in the elongated grains were observed.In the centre of ASB the equiaxed newly formed grains by recrystallization with sizes of 0.2-0.7μm were found. ASB close to the surface has highly elongated grains , large numbers of subgrains and recrystallized grains .Pole figure results indicate that matrix has strong {0001}<1010>texture;the transition zone consists of strong {1010}<1120>texture and {1122}<1123>texture;the centre of ASB shows nearly no orientation focus;ASB close to the surface exhibits an emergence of {1120}<1010>texture.