Fatigue performance of U-notched additively manufactured AlSi10Mg parts: The effects of chemical and thermal post-treatments

Abstract

In the current study, the effects of different post-processing methods, including heat treatment (HT) and electro-chemical polishing (ECP) as well as their combination on the surface texture, porosity, microstructure, mechanical properties, and rotating bending fatigue behavior of U-notched laser powder bed fused AlSi10Mg specimens were comprehensively investigated. In addition, to better understand the effects of the applied post-processing methods on the sensitivity of the notched specimen to surface and near-surface defects, finite element analysis was performed. Chemical treatment was found to be very influential on surface texture modification of the very narrow notched parts, for which the application of other treatments can be quite challenging. It was also found that the fatigue behavior of the notched specimens was more sensitive to the surface texture rather than to the near-surface defects. The hybrid treatment involving HT+ECP was the most effective for fatigue behavior improvement due to simultaneous homogenization of the microstructure, released tensile residual stresses, enhanced ductility and high surface texture modification.

Keywords

• Additive manufacturing (AM)
• AlSi10Mg
• Electro-chemical polishing (ECP)
• Finite element analysis, Notch
• Fatigue