【摘要】 研究了拉伸条件对温轧态Al-Li-Cu-Mg-Zr合金超塑变形行为的影响.结果表明:该合金在变形初期发生了界面取向差逐渐增大,从亚晶组织向再结晶组织变化的形变促使连续再结晶过程;应变速率越高,再结晶速度越快,再结晶晶粒越细;经高应变速率的第一阶段拉伸变形后,形成的细晶组织具有高的应变速率敏感性,同时在低应变速率的第二阶段拉伸变形中发生晶粒长大而具有高的应变硬化效果,两者的综合作用是两段速率拉伸获得高延伸率的根本原因。更多还原

【Abstract】 A much higher elongation of warm-rolled superplastic Al-Li-Cu-Mg-Zr alloy was made under two-stage strain rate tests comparing with the single ones.During initial stage of deformation, a deformation-induced continuous recrystallization which converted a subgrain structure into a recrystallized grain structure by a conitnuous increase in boundary misorientations had occurred. The higher the strain rate is, the faster the continuous recrystallization and the finer the recrystallized grains will be. The fine recrystallized grain structure formed duringthe first stage deformation is the essential condition for the material to have high strain rate hardening and strain hardening during the low second hardening superplastic deformation. The combination of strain rate hardening and strain hardening is the reason why the higher elongation may be obtained during two-stage superplastic deformation of the alloy.更多还原