Fatigue Lifetime Improvement of Aluminum Alloys

Today, aluminum alloys are being considered as substitutes for many automotive parts made from steels because of the growing interest in producing lightweight vehicles. Consequently, it is crucial to understand the fatigue lifetime—the property itself and its behavior—of aluminum alloys, and to clarify its capacities at both room temperature and 1001 elevated temperatures. In particular, the aluminum alloys in the AA5xxx (non-precipitation-hardenable) and AA6xxx (precipitation-hardenable) series are very similar to those found in automotive industries, and are both frequently mentioned and the focus of studies. The satisfactory fatigue lifetime and the improved strength of aluminum alloys make them a strong candidate for automotive industries. This article focuses upon the fatigue property and behavior of aluminum alloys at room temperature and elevated temperatures. Then, the focus will shift to the concept of mechanical surface treatment, the so-called deep-rolling process, which can be used to improve the fatigue lifetime of aluminum alloys. The effects of a mechanical surface treatment on the fatigue properties and behavior of the aluminum alloys AA5083 and AA6110, and the residual stress stability at room temperature and elevated temperatures has been discussed. Moreover, modified deep-rolling processes, i.e., deep-rolling followed by an appropriate annealing process and high-temperature deep-rolling, have been elaborated upon in this article.