Multiaxial fatigue behavior of low-temperature closed-die forged ZK60 extrusion under proportional and non-proportional loading

Uniaxial and multiaxial fatigue characteristics of as-extruded and extruded-then-forged ZK60 magnesium alloys were examined to understand the influence of low-temperature forging on its deformation mechanics. Upon forging, basal texture weakening and grain refinement occurred in ZK60 extrusion. Based on uniaxial results, forging process led to improvements in quasi-static tensile strength and axial cyclic response in high-cycle fatigue regime, whereas shear responses remained unaffected. Biaxial non-proportional tests demonstrated that changing phase angle shift between axial and torsional waveforms had no effect on cyclic axial response, contrary to the shear response. Lastly, critical-plane and energy-based life prediction models were assessed.

Automated summary

This study examined the uniaxial and multiaxial fatigue characteristics of ZK60 magnesium alloys that were as-extruded and extruded-then-forged, in order to understand the influence of low-temperature forging on its deformation mechanics. The results showed that the forging process improved the quasi-static tensile strength and axial cyclic response of the alloy in the high-cycle fatigue regime, while the shear response remained unaffected.