Creep aging behavior of retrogression and re-aged 7150 aluminum alloy  

回归再时效7150铝合金的蠕变时效行为

作　　者：Qing WANG Li-hua ZHAN Yong-qian XU Chun-hui LIU Xing ZHAO Ling-zhi XU You-liang YANG Yi-xian CAI 王庆;湛利华;徐永谦;刘春辉;赵兴;徐凌志;杨有良;蔡一贤(中南大学机电工程学院,长沙410083;中南大学高性能复杂制造国家重点实验室,长沙410083;中南大学轻合金研究院,长沙410083)

机构地区：[1]School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China [2]State Key Laboratory of High-Performance Complex Manufacturing,Central South University,Changsha 410083,China [3]Light Alloy Research Institute of Central South University,Changsha 410083,China

出　　处：《Transactions of Nonferrous Metals Society of China》2020年第10期2599-2612,共14页中国有色金属学报（英文版）

基　　金：Project(2017YFB0306300)supported by the National Key Research and Development Program of China;Project(2017ZX04005001)supported by the National Science and Technology Major Project,China;Project(JCKY2014203A001)supported by National Defense Program of China;Projects(51905551,51675538,51601060)supported by the National Natural Science Foundation of China;Projects(Kfkt2018-03,zzYJKT2019-11)supported by State Key Laboratory of High-Performance Complex Manufacturing,China。

摘　　要：Creep aging behavior of retrogression and re-aged(RRAed)7150 aluminum alloy(AA7150)was systematically investigated using the creep aging experiments,mechanical properties tests,electrical conductivity tests and transmission electron microscope(TEM)observations.Creep aging results show that the steady-state creep mechanism of RRAed alloys is mainly dislocation climb(stress exponent≈5.8),which is insensitive to the grain interior and boundary precipitates.However,the total creep deformation increases over the re-aging time.In addition,the yield strength and tensile strength of the four RRAed samples are essentially the same after creep aging at 140℃ for 16 h,but the elongation decreases slightly with the re-aging time.What’s more,the retrogression and re-aging treatment are beneficial to increase the hardness and electrical conductivity of the creep-aged 7150 aluminum alloy.It can be concluded that the retrogression and re-aging treatment before creep aging forming process can improve the microstructure within grain and at grain boundary,forming efficiency and comprehensive performance of mechanical properties and electrical conductivity of 7150 aluminum alloy.通过蠕变时效实验、拉伸性能测试、电导率测试和透射电镜观察,系统研究回归再时效状态的7150铝合金的蠕变时效行为。蠕变时效实验结果表明,回归再时效状态7150铝合金的稳态蠕变主要是位错攀移机制(应力指数≈5.8),其稳态蠕变行为对晶内和晶界的析出相变化不敏感,但总的蠕变变形随着再时效时间的延长而增大。另外,在140℃蠕变时效16 h后,4种回归再时效样品的屈服强度和抗拉强度基本相同,但伸长率随着再时效时间的延长略有下降。而且回归再时效处理有利于提高7150铝合金的硬度和电导率。研究结果表明,蠕变时效前的回归再时效处理可以改善7150铝合金的晶内和晶界组织,提高合金的成形效率,改善合金的综合性能,包括力学性能和电导率。

关 键 词：creep aging forming creep behavior mechanical properties electrical conductivity aging precipitates Al−Zn−Mg−Cu alloy 

分 类 号：TG146.21[一般工业技术—材料科学与工程]