中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 33 No. 10 October 2023 |
（1. School of Mechanical Engineering, Nanjing Vocational University of Industry Technology, Nanjing 210023, China;
2. Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education), Shandong University, Jinan 250061, China;
3. School of Computer Science and Technology, Shandong Technology and Business University, Yantai 264005, China）
Abstract:The 7A99 Al alloy was subjected to peak aging (PA) and retrogression + re-aging (RRA), and the pre-rolling (R) was combined with RRA (RRRA) to balance the mechanical properties and corrosion resistance. The results show that the precipitates of PA-treated sample are mainly unstable η'''' phase with small size, while the coarse and stable η phase appears after RRA and RRRA. The grain boundary precipitates of PA-treated sample exhibit the smallest size and continuous distribution, while they show increased size, discontinuous distribution, and Cu enrichment after RRA and RRRA. The hardness and strength of RRRA-treated sample are higher than those of RRA-treated one, and they are even close to the values of PA-treated one. Moreover, the samples exhibit better corrosion resistance after RRA and RRRA than that after PA. These results indicate that the proposed RRRA method can enhance the corrosion resistance without a significant sacrifice on the mechanical strength.
Key words: 7A99 Al alloy; aging; pre-rolling; precipitates; mechanical properties; corrosion resistance
