Additive manufacturing of CrC-enriched WC-Co hybrid carbide with laser based - Powder bed fusion

Hard composite systems such as WC-Co have a wide range of applications in the areas of high wear resistance and stress. Additive processing using laser based - powder bed fusion (PBF-LB) offers the potential to produce highly complex structures from such material systems. However, processing of WC-Co using the PBF-LB process poses several challenges, which is why efforts are being made to qualify comparable, potentially easier-to-process material systems. One of these material systems is the novel hybrid carbide WC-Cr ₃C ₂-CoCr, which was originally developed for the electron beam based - powder bed fusion (PBF-EB). The aim of this study is to qualify this material system for the PBF-LB process. For this, samples are manufactured with varying process parameters and preheating of the base plate up to 800 °C and examined for their mechanical and microstructural properties. In addition, the effect of a downstream hot isostatic pressing (HIP) process is investigated. The results indicate that the material system requires significantly lower energy inputs compared to WC-Co to achieve low-porosity and crack-free specimens. The low variance of these values in the tested parameter range shows a low sensitivity of the target properties to the parameter changes, which makes processing with PBF-LB significantly less complex compared to WC-Co. The mechanical properties achieved by PBF-LB are comparable or superior to those of PBF-EB within a wide process window and the microstructure can be further densified and homogenized by HIP.