Microstructure evolution and mechanical properties of Mg-Zn-Zr alloys during high strain rate triaxial-forging

作者：Wu Yuanzhi^*; Yan Hongge; Zhu Suqin; Chen Jihua; Liu Anmin; Liu Xianlan

来源：Chinese Journal of Materials Research, 2014, 28(2): 144-152.

• Dynamic recrystallization (DRX)
• High strain rates
• Metallic material
• Micro-structure evolutions
• Mixed microstructures
• Pneumatic power
• Strength and elongations
• Ultimate tensile strength

High strain rate triaxial-forging (HSRTF) was successfully conducted on three Mg-Zn-Zr alloys by using a pneumatic power hammer. The microstructure evolution and mechanical properties of the forged alloys were investigated. The results show that HSRTF significantly refined the grains due to dynamic recrystallization (DRX). A novel microstructure was obtained, which was mixed by honeycombelike coarse DRX grains and island-like ultrafine DRX grains. The two features of the mixed microstructure were caused by different DRX mechanisms, i.e., rotation DRX at the initial grain boundaries and twin-induced DRX in the interior of the initial grains. The mechanical properties were dramatically improved, resulting from the severe grain refinement and weakening of the basal texture due to HSRTF. For ZK21 and ZK60 alloys, after HSRTF with an accumulative strain ΣΔΕ=2.64, excellent tensile properties were achieved with an ultimate tensile strength, yield strength and elongation of 341.6 MPa, 270.7 MPa, 25.1% and 330.2 MPa, 232.3 MPa, 24.8%, respectively.

• 出版日期2014