预时效对7475铝合金微观组织和力学性能的影响  

Effect of pre-aging on microstructure and mechanical properties of 7475 aluminum alloy

作　　者：陈志龙 李茂华 杨延清[2] 唐昌平 徐伊雯 袁紫鹏 CHEN Zhi-long;LI Mao-hua;YANG Yan-qing;TANG Chang-ping;XU Yi-wen;YUAN Zi-peng(School of Materials Science and Engineering,Hunan University of Science and Technology,Xiangtan 411201,China;School of Materials Science and Engineering,Northwestern Polytechnical University,Xi′an 710072,China)

机构地区：[1]湖南科技大学材料科学与工程学院,湖南湘潭411201 [2]西北工业大学材料学院,陕西西安710072

出　　处：《塑性工程学报》2022年第11期240-247,共8页Journal of Plasticity Engineering

基　　金：国家自然科学基金资助项目(52075167)。

摘　　要：采用透射电镜和万能材料试验机研究了双级时效处理中预时效对7475铝合金微观组织和力学性能的影响。结果表明,最佳的预时效工艺为120℃/5 h,再经165℃/18 h终时效处理后其力学性能最优,此时抗拉强度、屈服强度和伸长率分别为489 MPa、441 MPa和12.3%。基体析出相数量多,尺寸细小,且均匀弥散。晶界析出相呈断续分布,晶界无析出带较窄。当预时效温度为115℃时,随预时效时间延长,强度单调增加。当预时效温度大于120℃时,随预时效时间延长,强度先升后降。The effects of pre-aging on the microstructure and mechanical properties of 7475 aluminum alloy during two-stage aging treatment were studied by transmission electron microscopy(TEM)and universal material testing machine.The results show that the optimal pre-aging process is 120℃/5 h,the mechanical properties are the best after final aging treatment of 165℃/18 h,and the tensile strength,yield strength and elongation are 489 MPa,441 MPa and 12.3%,respectively.The matrix precipitates(MPt)are numerous and the sizes are slight and uniformly dispersed.The grain boundary precipitates(GBP)are discontinuous,and precipitation free zone(PFZ)in grain boundaries is narrower.When the pre-aging temperature is 115℃,with the extension of pre-aging time,the strength monotonously increases.When the pre-aging temperature is higher than 120℃,with the extension of pre-aging time,the strength increases at first and then decreases.

关 键 词：7475铝合金 双级时效 预时效 微观组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]