Effect of Humidity on Fatigue Properties of Shot-Peened High Strength Al Alloy

Author:  Q. Chen, N. Kawagoishi, K. Kariya, T. Nagano, Y. Kobayashi and T. Tsuji
Source:  Conf Proc 2014: ICSP-12 Goslar, Germany (pgs.476-481)
Doc ID:  2014123
Year of Publication:  2014
Abstract:  
Fatigue properties of a shot-peened high strength Al-Cu-Mg alloy, extruded 2017-T4, was investigated in relative humidity of 25% and 85% under rotating bending. Fatigue strength was increased by shot-peening in both humidity environments. Although fatigue strength was markedly decreased by high humidity in the non-peened specimen, there is no or little influence of humidity on fatigue strength in the shot-peened one. In the non-peened specimen, the macroscopic propagation mode of a crack changed from a shear mode to a tensile one with increasing in fatigue life in high humidity which is different from the tensile mode only in low humidity. On the other hand, the propagation in the shot-peened one was a tensile mode irrespective of humidity.