The Influence of Air Humidity on Fatigue Properties of an AA2524－T34 Aluminum Alloy
Self-aligning four-point bend fatigue tests were conducted to investigate the influence of humid air on the fatigue behavior of an AA2524-T34 Al alloy. Test specimens of the alloy along the rolling direction was cycled at room temperature and frequency of 15 Hz, tension-tension loading(R = 0.1), in 15% relative humidity (RH) and 95% RH up to 107 cycles to failure. The S-N data shows continuous reduction tendency. It was found that with the increase of test relative humidity, the fatigue properties of the alloy is decreased, the fatigue limit in 95% RH was nearly 20% reduction of that in 15% RH, only 67% of its yield strength. Meanwhile, the S-N data is much more scattered than it in lower relative humidity. In 15% and 95% RH, cracks were initiated predominantly at coarse particles but partly at grain boundaries on the surface in 95%RH. SEM results show the characteristics of intergranular fracture in high humidity circumstance.
T. Li et al., "The Influence of Air Humidity on Fatigue Properties of an AA2524－T34 Aluminum Alloy", Advanced Materials Research, Vol. 213, pp. 311-314, 2011