LAUSR

Abstract The objective of the present study was to evaluate strain-controlled low cycle fatigue behavior of a high zinc-containing Mg-10Zn-5Al (wt.%) cast magnesium alloy in relation to the microstructure characterized via EBSD and XRD. The addition of Zn with a Zn/Al ratio of ∼2 suppressed the presence of β-Mg17Al12 phase, and the as-cast alloy consisted mainly of primary α-Mg and eutectic-like τ-Mg32(Al,Zn)49 phase in a characteristic network form. The alloy exhibited superior tensile properties compared with several commercial cast alloys. Unlike extruded magnesium alloys, the alloy exhibited almost symmetrical stress-strain hysteresis loops due to the presence of τ-Mg32(Al,Zn)49 phase and nearly random textures. Although slight cyclic softening occurred at higher strain amplitudes, cyclic stabilization basically remained. This was also reflected by the nearly overlapped cyclic and monotonic stress-strain curves. The fatigue life predicted via strain energy based approach was in good agreement with the experimental value. Fatigue crack initiated from the near-surface imperfections, and crack propagation was characterized by fatigue striation-like features along with tear ridges.