On the cyclic hardening/softening behavior of a rare earth-containing magnesium alloy during strain-controlled fatigue

Abstract

The origin of cyclic hardening under low strain amplitude (with N = 25284 cycles to failure) followed by pseudo-plateau response under high strain amplitude (with N = 2671 cycles to failure) during fully reversal (R = −1) strain-controlled pull–push fatigue of Mg-8.2Gd-3.6Y-1.6Zn-0.5Zr (wt.%) at room temperature condition was explored. The (i) dislocations trapping between LPSO (long period stacking order) lamellas, (ii) substructure development, and (iii) deformation twinning and tangling/rearrangement of partials within twin band were known as the main factors contributing to the room temperature cyclic hardening response. The pseudo-plateau behavior and cyclic stabilization were also attributed to the co-formation of the veins structure in the vicinity of 18R LPSO and reversion of 14H LPSO at higher strain amplitudes.