Optimizing Laser Conditions and Controlling Microstructure/Properties of Laser Powder Bed Fused Al-Si Alloys

Abstract

In the laser beam powder bed fusion (PBF-LB) processes, laser parameters need to be customized for fabricating dense components. Al-Si alloys are representative Al alloys used for the PBF-LB processes. The Al-Si alloys fabricated by the PBF-LB processes exhibit characteristic microstructures and mechanical properties, which are affected by the laser parameters. This paper describes the effect of laser conditions on the relative density, microstructure, and mechanical properties of Al-12Si (mass%) alloy fabricated by the PBF-LB process. The first topic is a machine-learning-assisted exploration of laser parameters (laser power and scan speed) for fabricating dense Al-12Si alloy parts. Using a neural network model, the laser condition range for fabricating dense Al-12Si alloy parts is predicted. A methodology for accurately predicting the laser condition range for fabricating dense components is introduced. The second topic is controlling the microstructures and mechanical properties of the dense Al-12Si alloys. Variations in α-Al crystal grain size/orientation, the width of primary α-Al phase, and solute Si content in α-Al matrix with laser conditions are introduced. The changes in mechanical properties with laser conditions and correlation with microstructural features are also described.