Low cycle fatigue behavior of the extruded AZ80 magnesium alloy under different strain amplitudes and strain rates

Abstract

Low cycle fatigue behavior of extruded AZ80 magnesium alloy was investigated under uniaxial tension-compression at different strain amplitudes and strain rates. The results show that the extruded AZ80 magnesium alloy exhibits cyclic hardening at strain amplitudes ranging from 0.4% to 1.0%, the asymmetry of hysteresis loops becomes increasingly obvious when the strain amplitude increases. Higher strain rates correspond to higher stress amplitudes, high mean stresses and short fatigue life. {10–12} extension twins play a role in the cyclic deformation under higher strain amplitudes (0.8%, 1.0%). The relationship between total strain energy density and fatigue life can be described by the modified Morrow model. The effect of strain rate on the fatigue life can also be predicted by the model.

Keywords

• Low cycle fatigue
• Magnesium alloy
• Extruded AZ80
• Strain amplitude
• Strain rate