Additive manufacturing of multi-material parts – Effect of heat treatment on thermal, electrical, and mechanical part properties of 316L/CuCrZr

Abstract

Recent advancements in multi-material powder bed fusion of metals using a laser beam (PBF-LB/M) facilitate manufacturing 3D parts with an arbitrary voxel-wise material distribution, using 316L and CuCrZr alloy in a single-step process. This combination leverages each material's distinct advantages for applications requiring high strength, corrosion resistance, and superior thermal and electrical conductivity. However, inherent anisotropy at the interface between these materials poses significant challenges, impacting the integrity of material interfaces and affecting the materials' properties. This research investigates the influence of three different build orientations (CuCrZr on 316L, 316L on CuCrZr, and CuCrZr next to 316L) on interface quality and part performance. Techniques like microscopy imaging, laser flash analysis, and eddy current measurements, alongside Vickers hardness tests, were employed. Aging at 500 °C for 1.5 hours increased CuCrZr's conductivity by 250% and doubled its hardness. Samples with 316L built on CuCrZr showed reduced thermal contact resistance, suggesting this configuration is preferable for efficient heat transfer. Moreover, 316L contamination reduced the microhardness of CuCrZr, impacting its precipitation hardening potential. These findings underscore the importance of strategic material selection and arrangement within the PBF-LB/M process and highlight the benefits and challenges of heat treatment and contamination.