Laser additive manufacturing of Mg-based composite with improved degradation behaviour

Abstract

Magnesium (Mg) alloy shows great potential as bone implant owing to its favourable biocompatibility and degradability. In the present work, bioglass-reinforced Mg-based composite was manufactured via laser additive manufacturing. The results showed that too low a volumetric energy density (Ev) resulted in the appearance of open pores on the surface, which significantly deteriorated the densification behaviour. In contrast, too high an Ev caused the occurrence of the‘balling phenomenon’ with discontinuous surface, because of the excessive liquid formation and extended pool lifetime. Under a proper Ev of 185.19 J/mm3, favourable part with high densification rate was obtained. Meanwhile, the refined grains together with orderly dispersed reinforcing particles contributed to the enhanced mechanical properties. Significantly, the incorporated bioglass promoted the apatite deposition on Mg matrix, which served as an effective protection layer and reduced the degradation rate. Furthermore, it also improved the cell growth and differentiation, showing great potential in clinical bone repair.

Keywords

• laser additive manufacturing
• mg alloy
• bone implant
• forming quality
• degradation behaviour