ZK60 based alloys with high-strength and high-ductility: A review

Wrought magnesium alloys with high-strength and high-ductility property have been attracting more and more interest in automotive and aerospace industries, and the conventional Mg-Zn based alloys are widely accepted as the representative one. Development of Mg-Zn based alloys with rare earth (RE) element additions and with modified preparation processes domains the evolution of their potential structural applications. Nonetheless, their highest tensile yield strength (TYS) is still in the order of 400 MPa, clearly lower than that of the Mg-RE based alloys, in the order of 500 MPa, much less compared with the high-strength aluminum alloys and titanium alloys. According to many previous investigations, two relatively efficient methods to improve mechanical properties of ZK based alloys were revealed as: alloying by RE and optimizing wrought processes. However, comprehensive combinative investigation was hitherto not conducted to date. Thus, it is imperative in the next work to further improve the yield strength to the order of 500 MPa or much higher, and simultaneously modify the tension-compression strength asymmetry of the ZK series alloys. Maybe, developing novel wrought processes for ZK60 (+ RE) alloys or exploring appropriate pre-dealing treatments before or after the wrought processes might be an important approach to accomplish a much higher level of balance of high-strength and high-ductility.