Investigation of uniaxial low-cycle fatigue failure behavior of hot-rolled AZ91 magnesium alloy

► Uniaxial asymmetric cyclic stress-controlled fatigue behavior of AZ91Mg alloy was investigated. ► The fatigue life in the rolling direction is shorter than that in the transverse direction. ► A modified Basquin model was proposed to evaluate the fatigue life of the studied material. ► The effect of mean stress on the fatigue strength coefficient and exponent are considered. The uniaxial low-cycle fatigue behavior of hot-rolled AZ91 magnesium alloy was investigated by asymmetric cyclic stress-controlled experiments at room temperature. The effects of the sampling direction, peak stress and stress ratio on the fatigue life were discussed. The fatigue life increases with increasing the stress ratio or decreasing the peak stress. Due to the anisotropic property, the specimen in transverse direction shows superior fatigue resistance. Considering the effects of mean stress on the fatigue strength coefficient and fatigue strength exponent, a modified Basquin model was proposed and validated to evaluate the fatigue life of AZ91 magnesium alloy.