Additive manufacturing of biodegradable Zn-xWE43 porous scaffolds: Formation quality, microstructure and mechanical properties

Abstract

Zn is promising candidate material for biodegradable implants due to its acceptable biocompatibility and moderate degradation rate. However, the strength of pure Zn metal is regarded not enough. In this work, Zn-xWE43 porous scaffolds were fabricated by laser powder bed fusion (L-PBF) with different mass ratios of WE43: 2%, 5% and 8%. WE43 is a biodegradable Mg alloy with addition of Y and rare earth elements, and has been clinically verified. The formation quality, microstructure and mechanical properties were analyzed. L-PBF samples with high densification were achieved. Rapid cooling rate and the addition of WE43 together resulted to grain refinement. With increasing content of WE43, more Zn + Mg2Zn11 eutectics were precipitated, which increased tensile strength but decreased elongation. The formation of brittle MgZn2 deteriorated strength in Zn-8WE43. Zn-5WE43 showed the highest tensile strength of 335.4 MPa, but the elongation was only 1%. The compressive strength and Young's modulus of Zn-5WE43 porous scaffolds was 73.2 MPa and 2480 MPa, while 22.9 MPa and 950 MPa for pure Zn porous scaffolds respectively. The present results addressed the key technical issues and pointed out the future directions on additive manufacturing of Zn alloy porous scaffolds for biodegradable application.