Development of manufacturing method of the MAP21 magnesium alloy prepared by selective laser melting (SLM).

Magnesium alloys are well known for their biocompatibility and biodegradable properties [9], [27] owing to the fact that magnesium is a mineral crucial for human body, especially for bone tissue. There are studies [17] on using WE43 additively manufactured magnesium scaffolds for full bone and soft tissue regeneration. Moreover, magnesium implants in bones were investigated as having higher bone-implant interface strength than titanium ones [3]. In this paper, the results of the studies on MAP21 magnesium powder selective laser melting process optimization as a starting point for further bioapplications are presented. MAP21 magnesium alloy owing to its high mechanical properties, excellent vibration damping characteristic and good creep resistance is a promising material to be tested for scaffold structures. The study for the first time shows successful SLM manufacturing of dense samples made of MAP21 alloy. Using an algorithm based on design of experiment (DoE) method [21], the SLM process parameters were designated. The porosity was investigated as a SLM process optimization parameter. High density of produced sample, up to 99%, was achieved. Microstructure and oxidation level after selective laser melting (SLM) manufacturing were characterized. Fine grain microstructure and three kinds of precipitations were found Nd (Gd, Zr, Mg), Mg (Nd, Gd, Zr) and Mg (Zr, Nd, Gd, Zn)). In order to determine the mechanical properties of MAP21 alloy processed with SLM technology, static tensile tests and microhardness tests were conducted, resulting in mechanical properties (Rm = 167 MPa, E = 38.6 GPa, 63-74 HB) comparable with as-cast alloy. A discussion was held on further research opportunities for biomedical use of SLM-ed MAP21 alloy.