中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 29 No. 8 August 2019 |
（1. School of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Hunan Provincial Key Laboratory of Spray Deposition Technology & Application, Hunan University, Changsha 410082, China）
Abstract:Effects of the sole and the combined addition of Ca and Sr on microstructure and mechanical properties of as-cast and as-rolled Mg-5Zn alloys were carefully investigated by OM, SEM, hot-compression testing and tensile testing. Ca is more effective than Sr in the microstructural refinement of as-cast alloys. High-strain-rate rolling (HSRR) produces more deformed twins and thus provides more nucleation sites for dynamic recrystallization (DRX). The addition of Ca and Sr can promote dynamic precipitation during HSRR, the precipitation process would consume the storage energy and thus increases the critical strain value of DRX, resulting in the retarded DRX effect by the addition of Ca and/or Sr. The as-rolled Mg-5Zn-0.4Ca-0.2Sr alloy exhibits a good combination of strength and ductility, with the ultimate tensile strength of 317 MPa, the yield strength of 235 MPa and the elongation to rupture of 24%.
Key words: magnesium alloys; high-strain-rate rolling; dynamic recrystallization; mechanical properties
