| Abstract Scope |
Directed Energy Deposition (DED) has emerged as a powerful additive manufacturing technique for fabricating complex geometries in aerospace, automotive, and biomedical industries. The thermal history during deposition critically governs melt pool dynamics, microstructure, and mechanical properties, yet it remains challenging to fully capture through experimental measurements. In this study, a finite element numerical model is developed to examine melt pool evolution under both continuous and intermittent laser modes during DED of 316L stainless steel. Simulation results demonstrate that intermittent lasers produce smaller and more stable melt pools, faster cooling rates, and narrower heat-affected zones, which collectively favor the formation of refined microstructures. Continuous lasers, by contrast, sustain larger pools with prolonged heat transfer, promoting grain coarsening. Furthermore, the model reveals that intermittent laser pulses generate shock and stabilization effects that significantly modify temperature distribution, pressure, and velocity fields. These findings emphasize laser modulation as a promising route to control solidification and optimize DED performance. |