【摘要】 采用压缩的方法对Ti75合金超塑变形时力学行为和组织演变进行了研究。结果表明,在800℃,5×10-4s-1以及850℃,1×10-1s-1的条件下,m值大于0.3,而900℃时,m值降低;在超塑变形初期由于动态再结晶和β相的扩散,实现板条组织的等轴化、细晶化、均匀化,使α晶粒得以进行滑动和转动,晶界运动成为主要变形机制;晶间β相对α晶粒的转动和滑动起着调节作用;而位错运动既是变形机制,又是晶界滑动的调节机制。更多还原

【Abstract】 The superplasticity and microstructure evolution of Ti75alloy in a comp ression testing were studied.The re sult showed that the strain rate sensitivities,m,was more than 0.3at 800℃,5×10 -4 s -1 and 850℃,1×10 -1 s -1 ,but m value reduced at 900℃.Dynamic re-crystallization and diffusion ofβphase made the lath-like grain becom e equiaxed,refined and homogeneous,which created a better condition for grain sliding and rotation.In th e whole deformation process,diffusion and dislocation movement act as b oth deformation mechanisms and assommodation ones for boundary sliding.更多还原