Effect of heat treatment on mechanical properties and SCC of 7056 and 7095 aluminum alloys

被引：0

作者：

Wei S.-L. ^{[1
,2
]}

Feng Y. ^{[1
,2
]}

Wang R.-C. ^{[1
,2
]}

Ren J. ^{[1
,2
]}

Peng C.-Q. ^{[1
,2
]}

Zhang H. ^{[3
]}

Xu C.-T. ^{[3
]}

Wu Y. ^{[3
]}

机构：

[1] School of Materials Science and Engineering, Central South University, Changsha

[2] Key Laboratory of Electronic Packaging and Advanced Functional Materials, Central South University

[3] The 38th Institute of China Electronics Technology Group Corporation, Hefei

来源：

Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | 2020年 / 30卷 / 08期

关键词：

7xxx series aluminum alloy; Aging precipitation; Fracture toughness; Stress corrosion cracking;

D O I：

10.11817/j.ysxb.1004.0609.2020-39633

中图分类号：

学科分类号：

摘要：

The microstructure, mechanical properties and stress corrosion cracking sensitivity of 7056 and 7095 alloys with peak aging and over aging treatments were studied by SEM, EBSD, TEM, slow strain rate tensile tests and fracture toughness tests. The results show that both alloys have obvious recrystallization after solid solution and the recrystallization degree of 7095 alloy is higher than 7056 alloy. After peak aging, fine precipitates with small size and high density in both alloys. 7056 alloy has smaller size (3.5 nm) and higher density than 7095 alloy, thus showing higher strength (643 MPa). After overaging, the precipitates of the two alloys obviously coarsen, leading to deteriorative strength. The 7095 alloy have lots of coarsening η phase after overaging, thus the strength of the 7095 alloy decreased 8.5%. The fracture toughness values of 7056 and 7095 alloys after peak aging are 26.8 MPa•m1/2 and 28.2 MPa•m1/2, respectively, and increase to 29.6 MPa•m1/2 and 34.7 MPa•m1/2, respectively, after overaging. The large fracture toughness of overaged 7095 alloy is due to the decrease of the strength difference between the grain and the grain boundary. The combined action of the precipitate free zones and the coarsening and discontinuous grain boundary precipitates is another reason. The continuous precipitates in the grain boundary in the two peak aging alloys result in high stress corrosion cracking (SCC) sensitivity. After overaging, the grain boundary precipitates (GBPs) in the two alloys turn to discontinuous distribution and obviously coarsen, decreasing the SCC sensitivity. © 2020, Science Press. All right reserved.

引用

页码：1739 / 1749

页数：10

共 31 条

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