Processing optimization in directed energy deposition of aluminium alloy powders

Aluminium alloys present significant challenges for metal additive manufacturing (AM) due to their susceptibility to solidification cracking and porosity. To address this, a comprehensive framework has been developed to optimize Directed Energy Deposition (DED) parameters, beginning with gas atomized Al6061 powders as a representative system. Single-track DED experiments are systematically performed across a matrix of laser powers and scan speeds, guided by a central composite design embedded within a response surface methodology framework. Melt pool geometries, including width, depth, and aspect ratio, are characterized to understand the primary process responses. Planned cross-sectional microstructural analysis will quantify Secondary Dendrite Arm Spacing as a metric for cooling rate assessment, thereby linking thermal conditions to microstructural refinement. Based on the identified optimal processing window, subsequent work will involve layer-wise printing trials with customized toolpath strategies to evaluate their influence on solidification cracking behaviour and internal defect distribution. By combining validated feedstock insights, quantitative microstructure–process mapping, and toolpath-driven thermal management strategies, this work aims to advance the tailored processing of aluminium alloys for structural and defect-sensitive additive manufacturing applications.