(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 利用分离式Hopkinson压杆(SHPB)技术对钛合金TC16的帽形试样进行动态加载，采用光学显微镜和透射电镜技术观测TC16中绝热剪切带内的微观结构和相变情况。结果表明，剪切带的边缘由具有高位错密度的沿着剪切方向排列的宽度为0.2~0.5 μm的伸长组织构成，其与基体组织的形貌显著不同；剪切带中部由大量低位错密度的直径约为0.2 μm的再结晶等轴晶组成。衍射花样的标定表明α-Ti和α″相共存于剪切带中部，剪切带内发生了相变。绝热剪切变形过程中剪切带内的温度约为796 ℃。讨论了TC16中绝热剪切带内的相变规律和微观结构演化过程。
关键字: TC16合金；绝热剪切带；动态再结晶；相变
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:Abstract: Dynamic loading was carried out in the hat-shaped specimens of titanium alloy TC16 by split Hopkinson pressure bar (SHPB) technique. The microstructure and the phase transformation in the adiabatic shear band (ASB) produced in TC16 alloy were investigated by means of OM and TEM. The results show that the boundary of the shear band is composed of grains of 0.2−0.5 μm in width with high dislocation density elongated along the shear direction, whose pattern is obvious different from the matrix grains. The center of shear band consists of a number of recrystallized equiaxed grains with diameters of about 0.2 μm with low dislocation density. The results of SAD indicate that α-Ti and α″ grains coexist in the shear band and the phase transformation occurs in the shear band. The temperature in the shear band during the adiabatic shearing deformation is about 796 ℃. The phase transformation and the microstructure evolution process within ASB in TC16 alloy were explained.
Key words: TC16 alloy; adiabatic shear band; dynamic recrystallization; phase transformation
