Extraordinary mechanical properties of AZ61 alloy processed by ECAP with 160° channel angle and EPT

Abstract

AZ61 Mg alloy with homogeneous refined microstructure and exceptional mechanical properties was obtained by the combined technology of equal-channel angular pressing (ECAP) and electropulsing treatment (EPT) in this paper. Based on an ECAP die with an intersection angle of 160, the lower temperature is particularly adapted for AZ61 alloy to be deformed, in which accompanied by high accumulated defects density. The recrystallization of EPTed samples during different stages indicated that the recrystallization behavior of the deformed Mg alloy was mainly affected by the processing time and duration of EPT. Compared to those of the as-received samples, the average grain size of the EPTed samples was refined from 89 µm to 1.0 µm, accordingly the yields stress (YS) and ultimate tensile strength (UTS) were increased from 100 MPa and 260 MPa to 330 MPa and 448 MPa, respectively. The mechanisms of microstructure transformation and the reinforced mechanical properties were analyzed based on the strain of single ECAP, cumulative storage energy and the athermal effect of EPT.

Keywords

• AZ61 Mg alloy
• Equal channel angular pressing
• Electropulsing treatment
• Recrystallization
• Mechanical properties