Work-Hardening/Softening Behavior and Temperature Evolution of AZ31B Magnesium Alloy During High Cycle Fatigue Process

The temperature evolution of AZ31B magnesium alloy in fatigue and tensile processes was measured with infrared imager. The work-hardening/softening behavior of the alloy during fatigue process was studied by conducting tensile tests on the fatigued AZ31B magnesium alloy samples. The results show that the temperature evolution process of the AZ31B magnesium alloy during fatigue was divided into five stages including initial temperature rising, temperature falling, temperature stabilizing, rapid temperature rising and natural temperature falling after fracture in sequence when the maximum stress during fatigue was higher than the fatigue strength of the alloy. The tensile strength of the fatigued sample increased and then decreased and then increased with the number of cycles increasing, due to the fact that the work-hardening and softening occurred in turn of the samples. With the increase of the cyclic maximum stress, the tensile strength of the fatigued sample increased because of the different work-hardening levels caused with the different stress levels during fatigue.