中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 6 June 2020 |
（1. School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China;
2. Key Laboratory of Magnesium Alloys and the Processing Technology of Liaoning Province, Shenyang 110870, China）
Abstract:As-cast Mg-6Zn-xCu-0.6Zr (x=0, 0.5, 1.0, wt.%) alloys were fabricated by permanent mold casting; then, the alloys were subjected to homogenization heat treatment and extrusion-shearing (ES) process. The microstructure and mechanical properties of the alloys were evaluated by OM, SEM/EDS, XRD, TEM, EBSD and tensile tests. The results show that the hard MgZnCu phase in Cu-added alloy can strengthen particle-stimulated nucleation (PSN) effect and hinder the migration of dynamic recrystallization (DRX) grain boundary at an elevated temperature during ES. The ZK60+0.5Cu alloy shows an optimal tensile strength–ductility combination (UTS of 396 MPa, YS of 313 MPa, and δ=20.3%) owing to strong grain boundary strengthening and improvement of Schmid factor for {0001} basal slip. The aggregation of microvoids around the MgZnCu phase mainly accounts for the lower tensile elongation of ZK60+1.0Cu alloy compared with ZK60 alloy.
Key words: Mg-Zn-Cu-Zr alloy; extrusion-shearing process; microstructure characterization; mechanical properties; texture evolution; strengthening mechanism
