Single track deposition study of biodegradable Mg-rare earth alloy by micro laser metal wire deposition

The high reactivity of the material is one of the key issues in powder-based additive manufacturing of biodegradable Mg-alloys. In fact, the powder feedstock is highly inflammable and difficult to manage in laser powder-bed fusion and metal deposition. On the other hand, wire feedstock can provide an intrinsically safer solution for the purpose. However, the process should be developed for maintaining geometrical precision and deposition quality. In this work, micro laser metal wire deposition ( LMWD) of a biodegradable Mg-alloy with Dy as the main alloying element (Resoloy) is demonstrated. A flash-pumped Nd:YAG laser was used along with a custom-built wire feeder. Single-tracks were deposited and analysed for their geometrical attributes, microhardness, and deposition efficiency. The results were evaluated to determine the processability of the heat sensitive Mg-alloy with respect to an austenitic stainless steel with known processability. Despite a narrow processability window, single-track deposits were successfully produced. Micrometric feature resolution was maintained with crack and pore free deposits.