Towards manufacturing intra-layer multi-material mould tools with vertical interfaces using laser-based powder bed fusion

Additively manufactured mould tools offer advantages compared to conventional tools, including cooling performance and cost savings. Certain moulds require inserts with high aspect ratio (>3) where using traditional tool steel, with low thermal conductivity, is insufficient for cooling. This necessitates the manual addition of high thermal conductivity pins, such as copper. Recent advances in selective powder deposition enable the fabrication of multi-material components with multi-material interface perpendicular to the build plate (vertical interface). This work investigates, for the first time, the manufacturability of tool steel and CuCrZr multi-material components with vertical interfaces. EDS and EBSD across multiple vertical interfaces revealed that metallurgically sound interfaces were obtained with porosity along the intermixed zone, attributed to using one set of parameters per material, without correction. Anisotropy in the intermixing zone was observed along the recoating direction (1.5 mm) compared to the other direction (0.5 mm), leading to increased porosity. This study establishes the manufacturability of multi-material tools and paves the way for adapting multi-material dosing and LPBF process parameters to manufacture defect-free interfaces.