Laser beam powder bed fused AlSi10Mg: An overview on the effect of post-processing on the microstructure and mechanical properties
Erfan Maleki, Alireza Bidar, Keivan Rahmdel, Shuai Shao, Nima Shamsaei
Abstract
Laser beam powder bed fusion (LB-PBF) has emerged as one of the most widely used additive manufacturing (AM) processes, recognized for its ability to produce complex geometries. Among LB-PBF metals, AlSi10Mg has received substantial attention due to its printability, high strength-to-weight ratio, acceptable mechanical properties, and widespread applications in various industries such as space and aviation. However, inherent characteristics associated with LB-PBF, such as layer-by-layer manufacturing, rapid cooling rates, and thermal gradients, cause inhomogeneous microstructures, residual stresses (RS), porosity, and rough surface finishes, which all can detrimentally affect mechanical performance. To address these challenges, various post-processing methods, including heat treatment (HT), hot isostatic pressing (HIP), and surface post-treatment (SPT) techniques, have been developed and studied. This article provides an overview on the effects of post-processing methods on the microstructure, surface texture, porosity, RS, hardness, tensile properties, and fatigue behavior of LB-PBF AlSi10Mg. HTs modify strength and ductility by adjusting microstructure and relieving RS. HIP effectively reduces porosity, which increases the material density and enhances fatigue performance. SPT generally enhances mechanical properties due to combined effects of grain refinement in surface layer, improved surface hardness, induced compressive residual stresses (CRS), and sub-surface pore closure. Studies highlight that hybrid treatments, such as the combination of HTs and SPTs, result in more pronounced enhancement of mechanical performance, especially fatigue behavior compared to single-step post-processing methods. Although these improvements are promising, some challenges related to cost, post-process optimization, and scalability still exist. This overview discusses various post-processing strategies and provides descriptions of their effects to assist with the optimization and adoption in critical applications.