大变形量Al-Zn-Mg-Cu合金的热轧板再结晶行为  

Recrystallization behavior of hot-rolled Al-Zn-Mg-Cu alloy after great deformation

作　　者：林亮华[1] 刘志义[1] 韩向楠[1] 陈旭[1] 李尧[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2011年第10期2990-2995,共6页Journal of Central South University:Science and Technology

基　　金：国家重点基础研究发展计划("973"计划)项目(2005CB623705-04)

摘　　要：采用光学显微镜、维氏硬度计和透射电子显微镜研究Al-Zn-Mg-Cu合金大变形热轧板退火过程中的组织演变和力学性能变化,探讨再结晶形核和长大机制,并通过分析位错和储存能变化规律研究动态回复对再结晶的影响。研究结果表明:Al-Zn-Mg-Cu合金在390℃热轧变形时,其主要软化机理为动态回复;当变形至90%时,其组织由直径为0.3～0.6μm的位错胞和亚晶组成,这种回复时发生的多边形化促进了随后退火过程中静态再结晶的进行。根据硬度曲线和组织分析确定总变形量为90%的Al-Zn-Mg-Cu热轧板再结晶起始温度为400℃,完全再结晶温度为420℃;超过450℃时再结晶晶粒明显长大,再结晶形核机制以亚晶合并形核为主。Optical microscope,Vickers hardness tester and transmitted electron microscope were employed to study microstructure evolution and mechanical properties of hot-rolled Al-Zn-Mg-Cu alloy during annealing.Mechanism for nucleation and its growth of recrystalized grains were discussed.The influence of dynamic recovery on recrystallization behavior was also investigated by analyzing the change rule of the dislocation and stored energy.The results show that the softening mechanism deformed at 390 ℃ is dynamic recorery.When the deformation reaches 90%,the microstructure is comprised of dislocation cell structures and subgrains with diameter of 0.3？0.6 μm.Polygonization occurs during dynamic recovery accelerates recrystallization during subsequent annealing.Hardness measurements and microstructure evolution suggest that the start recrystallized temperature and full recrystallized temperature are 400 ℃ and 420 ℃,respectively.Recrystallized grain grows apparently when the temperature is higher than 450 ℃.The dominant mechanism for recrystallized nucleation is boundary merging mechanism.

关 键 词：AL-ZN-MG-CU合金 动态回复 再结晶 热轧 退火 

分 类 号：TG146.2[一般工业技术—材料科学与工程]