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Powder bed fusion – laser beam (PBF-LB) of Mg alloys provides new possibilities for the production of complex structures with optimized designs, both for weight reduction in aerospace applications, as well as for patient-specific implants in orthopedic applications. However, even though numerous studies have been carried out on the topic, the influence of the individual PBF-LB process parameters on the microstructure and resulting material properties of Mg alloys remains ambiguous. Thus, this study aims to investigate the influence of laser power on the surface roughness, microstructure and resulting key material properties, namely corrosion resistance and mechanical performance. Samples were produced by PBF-LB from gas atomized Mg-4%Y-3%Nd-0.5%Zr (WE43) alloy powder, using three different laser powers: 60 W, 80 W, and 90 W. Contrary to expectation, the 90 W samples exhibited the highest degradation rate, while 60 W samples had the lowest, despite the latter having highest surface roughness and large internal pores. The higher degradation rate for the 90 W samples was instead found to stem from the near-surface microstructure. The higher energy input and subsequently reduced grain size, resulted in an increased amount of second phase precipitates than for the 60 W samples, thereby increasing the tendency for pitting via microgalvanic corrosion. For the tensile strength and elongation at break, the opposite trend was observed. Here, a reduction in grain size and an increase in precipitates for the 90 W samples were found to be beneficial. In conclusion, a definite influence of laser power on the formation of microstructure was observed, ultimately impacting the resulting corrosion and tensile properties of WE43. Future work should investigate the influence of other PBF-LB process parameters, with the aim of establishing an optimum balance between corrosion resistance and mechanical properties.

The present work explored the potential of customizing the final part texture and mechanical properties of a biodegradable magnesium alloy (WE43, composition Mg-4 wt%Y-3 wt%Nd-0.5 wt%Zr) manufactured by laser beam powder bed fusion (PBF-LB). This was done by printing samples using two sets of laser scan strategies (670 and 900 rotation between consecutively scanned layers) and build directions (horizontal and vertically printed samples). Samples were characterized for density and microstructure, followed by in-depth texture analysis using both lab-based techniques and neutron diffraction measurements. The mechanical performance was evaluated through tensile testing. The findings in this work show that strong basal texture was generated in the build direction. This allowed for altering the mechanical strength of WE43, whereby horizontally built samples showed increased strength and Young's modulus under tensile loading in a direction normal to the basal texture. Laser scan strategy influences the overall texture, however with limited effect on the resulting mechanical properties for the two scan strategies under study. This study demonstrates the importance of sample design and build strategy for the resulting texture and final material properties.