Synergic strategies to improve the PBF-LB/M processability of a cracking-sensitive alloy

Abstract

The Powder Bed Fusion-Laser Beam/Metals (PBF-LB/M) is a promising additive manufacturing process that can be used to directly produce functional components with a complex shape for a wide variety of applications. However, the layer-by-layer scanning and high cooling rates result in a high thermal gradient and thus, in thermally induced stresses. The stresses developed during the additive process could lead to undesirable cracking and delamination phenomena that can seriously affect the performance of the final component. The alloy composition can exacerbate crack and delamination formation, however, the need to expand the portfolio of high-strength materials processable for PBF-LB/M makes the resolution of these undesirable phenomena a primary challenge in the additive manufacturing field. This works aims to systematically investigate some strategies to make processable non-standard compositions. As no standard compositions, the promising pre-alloyed AlSi10Cu8Mg composition was chosen for the present work. Based on the results obtained from a condition of severe delamination, the synergetic use of appropriate process parameters and support structures can lead to crack-free and fully dense specimens also when platform heating is not allowed. The developed approach could also be applied to adapt other cracking-sensitive alloys for PBF-LB/M production.

Keywords

• Processability
• Cracking-sensitive alloy
• Aluminium alloys
• Residual stresses
• Support structures
• Process parameters