Tensile Mechanical Properties and Deformation Mechanism of the Extruded ZM61 Magnesium Alloy at High Strain Rates

Herein, the ZM61 alloys extruded at the extrusion ratios of 39 and 84 are named as ZM61‐39 alloy and ZM61‐84 alloy, respectively. The tensile mechanical properties and microstructure of both ZM61‐39 and ZM61‐84 alloys deformed at room temperature and different high strain rates (100, 500, and 1000 s⁻¹) along extrusion direction (ED) are investigated. The results show that, with the increase of strain rate, the strength of ZM61‐39 alloy changes a little, while the strength of ZM61‐84 alloy gradually increases. The fracture strain of both ZM61‐39 and ZM61‐84 alloys decreases as strain rate increases. The strength of ZM61‐39 and ZM61‐84 alloys shows different trends with increasing strain rates, which is mainly attributed to their different deformation mechanisms. The tension twinning‐basal slip dominates the deformation of ZM61‐39 alloy at high strain rates. And the nonbasal slip is the main deformation mechanism of ZM61‐84 alloy at high strain rates. In addition, ZM61‐39 alloy exhibits lower strength and better ductility than ZM61‐84 alloy at same high strain rates, which is strongly affected by the grain size.