Microstructure and Fatigue Behaviour of AlSi10Mg Alloy Samples Fabricated by Selective Laser Melting

The review consolidates state-of-the-art research on the AlSi10Mg alloy, specifically focusing on the samples produced by selective laser melting (SLM). Currently, SLM is the most promising technique among the emerging additive-manufacturing (AM) technologies used for printing AlSi10Mg-alloy parts in industrial applications such as aerospace and automotive. The more specific goal of this study is to analyse how the fatigue behaviour of printed AlSi10Mg-alloy samples by SLM is influenced by printing parameters and post-processing treatments, in order to improve product quality under conditions of exposure to vibrations of different frequencies and intensities. It is important to note that the fatigue performance properties of the SLM-produced parts are evaluated according to the relative bulk and surface microstructures and defects’ criteria. The following printing parameters are analysed: laser power, layer thickness, scanning speeds, hatch distances, platform temperature, and printing orientation. Additionally, the review examines post-processing treatments enhancing fatigue resistance. These ones include heat treatment (age hardening and stress relief), friction stir processing, hot isostatic pressing, stream finishing process, and shot peening. The fatigue behaviour is compared for the as-printed and surface-modified samples. Furthermore, the impact of these treatments on the alloy microstructure, particularly, the distribution and morphology of the Si phases within the aluminium matrix, is critically discussed, as they influence fatigue.