预变形和过时效对AA2195铝锂合金晶粒的细化  

Grain refinement of AA2195 Al-Li alloy by pre-deformation and overaging

作　　者：张新明[1] 刘颖维[1] 叶凌英[1] 唐建国[1] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083

出　　处：《中国有色金属学报》2009年第4期633-638,共6页The Chinese Journal of Nonferrous Metals

基　　金：国际科技合作重点资助项目(2006DFA53250);国家重点基础研究发展计划资助项目(2005CB623706)

摘　　要：通过金相和扫描电镜等分析手段,研究预变形和过时效对机械热处理细化AA2195铝锂合金晶粒的影响。结果表明:过时效前的预轧制变形所形成的应变区为第二相提供了均匀的形核位置,提高了第二相粒子的体积分数;与400℃单级过时效相比,预变形后采用300℃+400℃双级过时效可使第二相粒子间距由2.09μm增大到3.43μm,在轧制过程中有利于形成独立的高能应变区,为再结晶提供更多的形核位置,进一步细化、等轴化AA2195铝锂合金晶粒,最终晶粒尺寸由12.6μm细化至8.8μm,晶粒纵横比由1.61减小至1.27。The effects of pre-deformations and overaging on grain refinement of AA2195 Al-Li alloy in thermo-mechanical processing （TMP） were investigated by means of optical microscopy （OM） and scanning electron microscopy （SEM）. The results show that the pre-deformation prior to overaging leads to the formation of strained zones, which provide homogeneous nucleation sites for the second-phase particles, and increases the volume fraction of the second-phase particles that can stimulate nucleation. Compared with overaging at 400℃, two-step overaging at 300℃＋ 400℃ following pre-deformatiom results in that the spacing among the particles increases from 2.09μm to 3.43μm, and the further refinement and spheroidization of the recrystallization grains are obtained. The grain size decreases from 12.6μm to 8.80μm and the respect ratio decreases from 1.61 to 1.27.

关 键 词：AA2195铝锂合金 机械热处理 粒子激发形核 双级过时效 预变形 

分 类 号：TG166.3[金属学及工艺—热处理]