Offsetting strength-ductility tradeoff in Mg-Sn-Zn-Zr alloy by a novel differential-thermal ECAP process

Equal-channel angular pressing (ECAP) technique is a promising method to enhance the properties of Mg alloys. Herein, a novel differential-thermal ECAP process (DTECAP) with pre-aging treatment (T6) was developed to simultaneously improve strength and ductility of Mg-Sn-Zn-Zr (TZK) alloys. After T6-DTECAP, the TZK alloy exhibited high ultimate tensile strength (UTS) of-323 MPa and excellent elongation (El.) of-28.7%, showing superior balance of strength and ductility. Examination microstructures of TZK alloys revealed that the excellent comprehensive properties were mainly associated with the activation of {10-12} tension twin variants and non basal slips. Moreover, the grain refinement, fine second phases, and transition of strong ED texture to fiber (10-10) 11-20 texture along TD were also beneficial for the enhanced properties. This work aims to provide a novel insight for the development of high-performance Mg alloys using T6-DTECAP processing.

Automated summary

A novel differential-thermal ECAP process (DTECAP) combined with pre-aging treatment (T6) was developed to enhance the strength and ductility of Mg-Sn-Zn-Zr (TZK) alloys, achieving a superior balance of comprehensive properties. The excellent properties were attributed to the activation of {10-12} tension twin variants and non basal slips, as well as the benefits of grain refinement and texture transition. This work provides new insights for the development of high-performance Mg alloys using T6-DTECAP processing.