Effect of Humidity on Fatigue Strength of Squeeze Cast Al Alloy
Fatigue properties of a squeeze cast Al-Si-Mg alloy were examined under rotating bending and the effect of humidity on the crack initiation and propagation behavior was investigated in controlled humidity. The fatigue strength was decreased in high humidity (RH85%) in comparison with the one in low humidity (RH25%). Cracks initiated at the early stage of fatigue life from slip bands and eutectic Si particles in many cases and partially casting defects, and most of fatigue life was occupied by the growth life of a small crack regardless of humidity. The propagation of a crack were promoted by humidity, especially the growth rate of a crack larger than about 100 µm, which propagated in tensile mode, was strongly accelerated.
H.S. Lee, I.S. Yoon and M.H. Aliabadi
Y. Sofuku et al., "Effect of Humidity on Fatigue Strength of Squeeze Cast Al Alloy", Key Engineering Materials, Vols. 385-387, pp. 397-400, 2008