Effect of surface treatment on fatigue properties of Al–Li–Cu–Mg–Zr and Al–Zn–Mg–Cu–Zr plate

The effects of surface treatments on the fatigue lifetime of 8090 (Al–Li–Cu–Mg–Zr) and 7010 (Al–Zn–Mg–Cu–Zr) alloys have been assessed, using a rotating bend fatigue testing machine at a stress ratio R = −1. It was found that the fatigue performance of alloy 8090 was less susceptible to chromic/sulphuric pickling than alloy 7010 and shot peening was more beneficial for the lithium containing alloy. Excellent fatigue properties were also exhibited by alloy 8090 in the anodised condition. These observations are discussed in terms of the physical properties of the lithium bearing alloys and of their microstructure.MST/833