High-throughput screening of process parameters and composition in laser additive manufacturing via in-situ X-ray imaging

Additive manufacturing (AM) of dissimilar metals enables localized weight reduction, enhanced properties, and distinct performance requirements in components, leveraging the diverse physical properties of materials. However, elemental segregation and defects adversely impact properties. This study used in-situ X-ray imaging to monitor melt flow during laser-based AM of AlSi7Mg/CuCrZr powders with varying ratios. Two distinct flow patterns were observed: (1) localized Cu-enrichment accompanied by counterclockwise melt flow direction, resulting in non-uniform mixing, and (2) Marangoni-driven uniform mixing. A solidification model was proposed to reflect melt-pool solidification under local equilibrium and solute trapping conditions, relating to the melt flow velocity. A high net linear energy input (ΔQ > 0, indicating a high heat input and a low powder feed rate) promotes uniform mixing and enhances flow velocity. Local equilibrium occurs when the flow rate exceeds 0.05 m s^-1, reducing crack sensitivity. In-situ X-ray imaging, combined with the proposed solidification model, enabled high-throughput screening of parameters in laser-based AM of dissimilar metals.