Microstructure, mechanical properties, corrosion resistance and cytocompatibility of WE43 Mg alloy scaffolds fabricated by laser powder bed fusion for biomedical applications

TY - JOUR

T1 - Microstructure, mechanical properties, corrosion resistance and cytocompatibility of WE43 Mg alloy scaffolds fabricated by laser powder bed fusion for biomedical applications

AU - Li, Muzi

AU - Benn, Felix

AU - Derra, Thomas

AU - Kröger, Nadja

AU - Zinser, Max

AU - Smeets, Ralf

AU - Molina-Aldareguia, Jon M

AU - Kopp, Alexander

AU - LLorca, Javier

N1 - Copyright © 2020 Elsevier B.V. All rights reserved.

PY - 2021/2

Y1 - 2021/2

N2 - Open-porous scaffolds of WE43 Mg alloy with a body-center cubic cell pattern were manufactured by laser powder bed fusion with different strut diameters. The geometry of the unit cells was adequately reproduced during additive manufacturing and the porosity within the struts was minimized. The microstructure of the scaffolds was modified by means of thermal solution and ageing heat treatments and was analysed in detail by means of X-ray microtomography, optical, scanning and transmission electron microscopy. Moreover, the corrosion rates and the mechanical properties of the scaffolds were measured as a function of the strut diameter and metallurgical condition. The microstructure of the as-printed scaffolds contained a mixture of Y-rich oxide particles and Rare Earth-rich intermetallic precipitates. The latter could be modified by heat treatments. The lowest corrosion rates of 2-3 mm/year were found in the as-printed and solution treated scaffolds and they could be reduced to ~0.1 mm/year by surface treatments using plasma electrolytic oxidation. The mechanical properties of the scaffolds improved with the strut diameter: the yield strength increased from 8 to 40 MPa and the elastic modulus improved from 0.2 to 0.8 GPa when the strut diameter increased from 275 μm to 800 μm. Nevertheless, the strength of the scaffolds without plasma electrolytic oxidation treatment decreased rapidly when immersed in simulated body fluid. In vitro bicompatibility tests showed surface treatments by plasma electrolytic oxidation were necessary to ensure cell proliferation in scaffolds with high surface-to-volume ratio.

AB - Open-porous scaffolds of WE43 Mg alloy with a body-center cubic cell pattern were manufactured by laser powder bed fusion with different strut diameters. The geometry of the unit cells was adequately reproduced during additive manufacturing and the porosity within the struts was minimized. The microstructure of the scaffolds was modified by means of thermal solution and ageing heat treatments and was analysed in detail by means of X-ray microtomography, optical, scanning and transmission electron microscopy. Moreover, the corrosion rates and the mechanical properties of the scaffolds were measured as a function of the strut diameter and metallurgical condition. The microstructure of the as-printed scaffolds contained a mixture of Y-rich oxide particles and Rare Earth-rich intermetallic precipitates. The latter could be modified by heat treatments. The lowest corrosion rates of 2-3 mm/year were found in the as-printed and solution treated scaffolds and they could be reduced to ~0.1 mm/year by surface treatments using plasma electrolytic oxidation. The mechanical properties of the scaffolds improved with the strut diameter: the yield strength increased from 8 to 40 MPa and the elastic modulus improved from 0.2 to 0.8 GPa when the strut diameter increased from 275 μm to 800 μm. Nevertheless, the strength of the scaffolds without plasma electrolytic oxidation treatment decreased rapidly when immersed in simulated body fluid. In vitro bicompatibility tests showed surface treatments by plasma electrolytic oxidation were necessary to ensure cell proliferation in scaffolds with high surface-to-volume ratio.

U2 - 10.1016/j.msec.2020.111623

DO - 10.1016/j.msec.2020.111623

M3 - SCORING: Journal article

C2 - 33321665

VL - 119

JO - MAT SCI ENG C-MATER

JF - MAT SCI ENG C-MATER

SN - 0928-4931

M1 - 111623

ER -