时效析出相在强变形过程中的室温回归现象  

Investigation on Retrogressive Phenomenon of Aged Precipitates Caused by Severe Plastic Deformation in Al-Zn-Mg-Cu Alloy

作　　者：许晓嫦[1] 刘志义[1] 谭曼玲[2] 刘跃军[2] 吴纯[1] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]株洲工学院,湖南株洲412008

出　　处：《材料热处理学报》2004年第6期71-75,共5页Transactions of Materials and Heat Treatment

基　　金：湖南省自然科学基金资助项目 (0 3JJY30 74)

摘　　要：利用透射电镜和硬度测量实验手段 ,研究了多相Al Zn Mg Cu合金在强烈塑性变形中的组织和性能变化 ,特别是析出相的改变。结果发现 :强烈塑性变形加工可引起析出相变形、碎化 ,然后溶入基体形成过饱和固溶体。这种合金在重新时效处理时可再次沉淀析出。提出了析出相回溶现象的“畸变自由能”观点。认为因晶格畸变导致析出相自由能显著升高 ,当高于基体相的自由能时 ,便会发生析出相室温溶解的自发过程 ,称此过程为应变回归以区别于由热处理时加热引起的回归。The evolution of microstructure and properties of Al-Zn-Mg-Cu alloy in the process of heavy plastic deformation were studied by transmission electron microscopy and hardness measurement. It is found that the precipitates are deformed, fragmented, and followed by dissolution into the matrix to form super-saturated solid solution in severe plastic deformation process. This solid solution will decompose again during re-aging. The distorted free energy hypothesis is proposed in order to interpret the re-dissolution and re-precipitation of the precipitates. This process is termed strain induced retrogression to differentiate from thermally induced retrogression by heat treatment.

关 键 词：强烈塑性变形 AL-ZN-MG-CU合金 回归 时效 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG113[金属学及工艺—金属材料]