Effect of temperature on high-cycle fatigue strength of Al-Cu T4 alloy

Abstract

In order to evaluate the effect of solute Cu atoms on the high-cycle fatigue properties, a naturally aged (T4) Al-Cu binary alloy is tested under different temperature conditions. The S-N diagram of the alloy tested in room temperature shows a distinct fatigue limit while those evaluated in high temperature do not. An eminent increase of crack growth resistance is observed particularly at lower stress amplitude and higher temperature, which is different from the room temperature behavior. In order to analyse the microscopic aspect of the temperature effect, the crack tip region is investigated by TEM observation.