Fatigue Crack Propagation in Die-Cast AZ91D Magnesium Alloy

Abstract

We studied the effects of heat treatments and environmental and experimental conditions on the fatigue crack propagation behavior of AZ91D magnesium alloy. Fatigue crack propagation rate (FCPR) is reduced by solution treatment but accelerated by aging. FCPR is higher in air than in argon. FCPR increases with decreasing test stress frequency. The minimum stress intensity factor range increases with decreasing load ratio (Pmin⁄Pmax). FCPR of this magnesium alloy is sensitive to oxygen, because of the formation of brittle oxide films on the fresh fatigued surface.