Environmental effect of fatigue crack propagation of magnesium alloy

Fatigue crack propagation tests were carried out for a magnesium alloy in various kinds of environment. The presence of oxygen causes the production of oxide film on the fresh fracture surfaces made during the cyclic loading. Therefore, the fatigue crack behavior depends strongly upon the environment. The fatigue tests have been conducted in dry and wet argon gas as well as in air. The wet atmosphere, in particular, accelerated the fatigue crack propagation rate. The presence of the oxide film would restrict the deformation of the matrix beneath the hard film and promote hydrogen embrittlement in the wet condition.