Effect of laser scanning angle and atmospheric oxygen on mechanical properties and microstructural morphology of selective laser-sintered aluminum-filled polyamide monolayers

Abstract

The process parameters on selective laser sintering (SLS) have a strong effect on part quality. To better understand SLS of composite materials, this study focuses on the influence of laser scan angle and oxygen gas interaction on the mechanical properties, morphology, and joining mechanisms of laser-sintered aluminum- filled polyamide-12 single-layer specimens at room temperature. The results show that the strength and ductility increase with a higher laser scan angle (e.g., near 60°), and the oxygen concentration in the chamber shows a small effect on the elongation. No changes in the morphology and internal structure of the specimens were observed under a different set of process parameters. Additionally, two failure mechanisms were observed; a ductile failure that occurs when particles are well-blended where the metallic particles work effectively hindering crack propagations, and a brittle failure when local amounts of metallic particles are low.