Cyclic deformation behavior and fatigue life prediction of an automotive cast aluminum alloy: A new method of determining intrinsic fatigue toughness

Abstract The aim of this study was to identify cyclic deformation behavior of a high‐pressure die‐cast Silafont®‐36 automotive cast aluminum alloy consisting of heterogeneous composite‐like microstructures of nearly circular eutectic silicon particles embedded in Al matrix, with particular attention to fatigue life prediction. The alloy exhibited superior fatigue resistance at higher strain amplitudes, where cyclic hardening occurred. The fatigue life of the alloy could be well predicted via a strain‐energy density based accumulative damage model using a new method proposed to calculate the intrinsic fatigue toughness. The predicted fatigue life was in good agreement with the experimental life, and also lay in‐between the results obtained via other methods. Fatigue crack initiation was observed to occur from the sample surface or near‐surface defects and crack propagation was characterized by fatigue striations along with tear ridges in the primary Al‐grains.