双级时效对1420铝锂合金超塑性的影响  

Effect of two-stage ageing on superplasticity of 1420 Al-Li alloy

作　　者：张新明[1] 罗智辉 杜予 叶凌英[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：《材料热处理学报》2007年第4期55-58,共4页Transactions of Materials and Heat Treatment

基　　金：国家重大基础研究资助项目(2005CB623706);国际科技合作重点资助项目(2006DFA53250)

摘　　要：采用金相、透射电镜、高温拉伸等检测手段研究了双级时效对1420铝锂合金组织及超塑性的影响,结果表明：与单级时效相比,双级时效处理得到分布更均匀、体积分数更大的析出相粒子。双级时效经过轧制和再结晶退火后,得到的晶粒尺寸为8-12μm;500℃条件下8×10^-4s^-1超塑性伸长率达到860%。第一级低温时效先在基体形成较均匀的细小粒子,这些粒子不仅在晶界,也在晶内大量析出。在高温时效时,这些粒子长大形成分布均匀,体积分数大的析出相粒子。Effects of two-stage ageing on microstructure and superplasticity of 1420 Al-Li alloy were studied by means of OM, TEM and stretching at high temperature. The results demonstrate that second phase particles distributed more uniformly with a larger volume fraction can be observed after two-stage ageing （120℃ × 12h ＋ 300℃ × 36h） compared with single-ageing（300℃ × 48h）. After rolling and recrystallization annealing, ultra-fine grains with size of 8 - 12tim are obtained, and the superplastic elongation of the specimens reachs 860% at 8 × 10^-4 s^-1 and 500℃ . Uniform ultra-fine phase were precipitated in matrix at lower temperature, which not only on grain boundaries but within grains. When aged at high temperature, the precipitates become coarser and distribute more uniformly with a large volume fraction.

关 键 词：铝锂合金 双级时效 晶粒细化 超塑性 

分 类 号：TG115[金属学及工艺—物理冶金]