Prediction of Cracking Locations in Part-Scale Process Simulation of Wire-and-Arc Additive Manufacturing

Wire-and-arc additive manufacturing (known in the standard as direct energy deposition with an arc source, DED-Arc) is a cost-effective and high-productivity technology for aerospace, automotive, and maritime applications. However, its application to light-weighting of structural components which are made of higher strength aluminum alloys is hindered by a lack of microstructure control and the presence of solidification cracking. These are two issues that are inherited from its immediate predecessor technology, welding. Using an integrated computational materials engineering approach, a thermo-mechanical finite element model is coupled with a microstructure and cracking prediction framework. The model successfully predicts thermal field evolution, microstructural features, and regions prone to solidification cracking. When validated against experimental DED-Arc builds, it accurately identifies subsurface cracks with high spatial specificity. Key findings indicate that grain refinement significantly reduces cracking, and that toolpath control and part design play crucial roles in mitigating defects in thin-walled structures. This work advances predictive modeling for DED-Arc and provides guidelines for improving manufacturability through microstructural engineering.