A dual-material model has been developed for wire-arc additive manufacturing (WAAM), focusing on strategies to embed secondary material elements uniformly in the surface layers of engineering parts. The embedment should distribute within the top surface layer of a component in a controlled manner, while enabling the fulfilment of specified minimum spacing requirement between any two adjacent elements. To optimize the locations of embedded elements, a new surface sub-sampling algorithm has been developed, for sampling the points that are uniformly distributed according to the specified requirements. The research workflow involves processing of the input 3D model, surface decomposition, a hexagon-based surface sub-sampling, and the generation of the dual-material model. The model is validated first using different prototypical geometries, and then tested using several real engineering parts. Finally, the WAAM toolpath is generated by slicing the dual-material model and converting the resultant 3D printing toolpath into robotic welding path code.

Utilizing electric arc as the heat source and metal wire as feedstock, WAAM is a promising metal additive manufacturing technology capable of fabricating large-scale components with high buy-to-fly ratio and with exceptional deposition rate, However, the high heat input associated with the welding process can result in high thermal and residual stresses, leading to cracking of the deposited parts;​ especially, cracking susceptibility is extremely high while depositing brittle materials. The proposed model can enhance structural integrity and, at the same time, ensure functionality of the additively manufactured parts by embedding brittle elements of suitable sizes into a ductile material matrix.