T. Griemsmann
R. Bernhard
J. Hermsdorf
S. Kaierle

Advances in laser-based powder bed fusion of WE43 magnesium alloy

22. Juni
Type: Konferenzbeitrag
Laser-based powder bed fusion is a predestinated technique to even expand the applicability of magnesium and its alloys for topology optimized lightweight constructions and in biomedical engineering for patient specific resorbable implants. Despite these outranging possibilities laser-based powder bed fusion of magnesium alloys is still in the research stage and is not used in industrial processes. The main reasons for this circumstance, such as poor reproducibility, low production speeds and safety issues, are addressed in this investigation. In order to increase the production speed by a factor of 2.3 (up to 0.96 mm3/s) and to reduce follow up processes, a test design with a focus on production times and an empirical model for adjusting the surface roughness are developed. A stabilized process is achieved through modifying the gas nozzles of an industrial powder bed machine and thus raise the gas volume flow. In this manner the high amount of process emissions during laser melting of magnesium alloys can be removed from the working chamber and kept from the optics. Mechanical properties are determined through tensile and hardness tests. A tensile strength of 367,6 ± 20,1 MPa and a yield strength of 348,1 ± 19,0 MPa are achieved. In addition, safety instructions for critical work, such as the removal of a full filter from the gas circulation, are given. The results are applied to design and manufacture a topology optimized lightweight bracket as a demonstration workpiece. The weight of the bracket is reduced approximately 57 \% compared to the original aluminum part.