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

•A novel T6-DTECAP process was developed.•The T6-DTECAPed Mg alloys showed high UTS of ~323 MPa and excellent El. of ~28.7%.•The deformation mechanisms were mainly the activation of twinning and non-basal slip.•The good performance was associated with grain refinement, second phase and texture. 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) 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.