多级时效对Al-Mg-Si(Cu)合金力学性能和显微结构的影响  

Effects of multi-step aging on mechanical property and microstructure of Al-Mg-Si-(Cu) alloy

作　　者：王时豪[1] 陈江华[1] 刘春辉[1] 桑益[1] 王漪雯[1] 龙慧池[1] 

机构地区：[1]湖南大学材料科学与工程学院高分辨电镜中心,湖南长沙410082

出　　处：《电子显微学报》2012年第5期420-426,共7页Journal of Chinese Electron Microscopy Society

基　　金：国家重点基础研究发展计划资助项目(2009CB623704);国家自然科学基金资助项目(51171063);湖南省高校科技创新团队项目;湖南省研究生科研创新项目;Gatan中国博士生奖学金

摘　　要：本文通过透射电镜观察、差示扫描量热分析(DSC)和硬度测试等方法研究了6061铝合金在多级时效处理过程中力学性能和显微结构演变的规律。其中,T6I6热处理为先进行固溶处理,淬火后进行180℃预时效,然后在65℃中断时效,最后在180℃再次时效,120/T6I6热处理则将预时效温度改为120℃。结果表明,T6I6热处理不会明显提高合金的峰值硬度,合金强度与析出相类型、尺寸和分布有关系。120℃预时效后中断时效时继续形成GP区或β″前驱相,而180℃预时效后中断时效对显微结构的影响较小。120/T6I6的中断时效过程析出的主要是尺寸较小的GP区或β″前驱相,它们在再时效阶段不能成为析出相的形核点。T6I6在中断时效前GP区和β″前驱相基本全部析出。T6I6热处理和120/T6I6热处理均没有使峰值硬度明显增加,而且120/T6I6会拖延峰值时间。The relationship between property and microstructure of 6061 alloy treated by multi-step aging were studied by means of transmission electron microscopy（TEM）,differential scanning calorimetry（DSC）,and hardness testing.The so-called T6I6 temper involves partially aging the alloy at a typical T6 temperature（the pre-aging stage）,then holding at 65 ℃ to facilitate further hardening（the secondary aging stage）,and finally,aging to peak properties at initial aging temperature（the re-aging stage）.120/T6I6 temper is the same with T6I6 except the pre-aging temperature（120 ℃）.It was found that an obvious increase of peak hardness as reported in the literature was not achieved by the T6I6 aging treatment.There was a continuous precipitation of GP zones during interrupted aging after pre-aging at 120 ℃,while only a slight change in microstructure was observed during the interrupted aging for the conventional T6I6 temper.The precipitates formed during interrupted aging in 120/T6I6 were mainly GP zones which were not large enough to act as precursors of β″ with enhanced strengthening potential.GP zones and β″ precursors were fully precipitated during pre-aging in T6I6.Neither T6I6 nor 120/T6I6 treatments increased the strength of peak aging.Moreover,120/T6I6 would delay the peak aging time.

关 键 词：Al-Mg-Si-(Cu)合金 时效 析出相 透射电镜 

分 类 号：TG156.92[金属学及工艺—热处理]