中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 29 No. 8 August 2019 |
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Beijing Institute of Aerospace Systems Engineering, Beijing 100076, China;
3. Key Laboratory of Nonferrous Materials Science and Engineering of Ministry of Education, Central South University, Changsha 410083, China;
4. Light Alloy Research Institute, Central South University, Changsha 410083, China）
Abstract:The effect of cold rolling reduction (50%-90%) on the grain structures of solutionized 1445 Al-Li alloy sheet at 525-575 °C was investigated through electron backscatter diffraction (EBSD). Although the solutionization temperature is elevated to 575 °C, the sheet is not completely recrystallized. The main recrystallization model is subgrain coalescence and growth, and the non-recrystallization is due to the formed nano-sized Al3(Sc,Zr) dispersoids, which pin the grain boundaries, subgrain boundaries and dislocations. With increasing the cold rolling reduction, the fraction and size of the recrystallized grains in the sheet solutionized at 525 °C are decreased, but the fraction of the subgrains is increased, leading to a decrease in the fraction of the deformed structures. Meanwhile, the number fraction of high-angle boundaries (HABs) is increased. Due to the decreased fraction of the deformed structures and increased fraction of the HABs, the T8-aged 1445 Al-Li alloy sheet displays a decrease trend in the strength and heterogeneity with increasing the cold rolling reduction. At higher solutionization temperature of 575 °C, the fraction of the recrystallized grains and their size are obviously increased.
Key words: Al-Li alloy; grain structure; recrystallization; strength; cold rolling reduction
