Preparation of porous magnesium alloy scaffolds with high formation quality and dimensional accuracy through contour scan optimization in laser powder bed fusion

Abstract

Biodegradable magnesium-based scaffolds for bone tissue engineering are considered a promising treatment approach for repairing large bone defects. In this study, porous magnesium-neodymium-zinc-zirconium alloy (JDBM) scaffolds were fabricated using laser powder bed fusion (L-PBF) followed by dynamic electrochemical polishing. The effects of laser energy input and contour scan strategy on the formation quality of L-PBF scaffolds were systematically investigated. A novel scanning strategy, C64F84, combining low laser power for contour scans with high laser power for filling scans, was developed to achieve good fusion quality while controlling surface powder adhesion and dross defects. The printed specimens achieved a maximum relative density of 99.54%. The effects of electrochemical polishing on L-PBF scaffolds with different contour scan strategies were further evaluated. Electrochemical polishing effectively removed excess adhered powder and brought the scaffold porosity in line with the intended design value. The polished C64F84 scaffold exhibited higher dimensional accuracy, with smaller mean deviations, due to improved geometric consistency in the L-PBF process. Finite element analysis results were consistent with compression test data, confirming the high quality of the prepared C64F84 scaffolds. The yield strength (23.88 MPa) and elastic modulus (0.855 GPa) were comparable to those of cancellous bone, highlighting the medical potential of L-PBF-fabricated JDBM scaffolds.

Keywords

Magnesium alloy scaffolds / Laser powder bed fusion / Formation quality / Dimensional accuracy / Finite element analysis

Funding

This work was supported by the National Key Research and Development Program of China (No.2024YFB4610100, No.2024YFC2418602), the National Natural Science Foundation of China (No.52130104), Shanghai Jiao Tong University Medial-Engineering Cross Fund (YG2024LC05), the Scientific Research Foundation for Shenzhen high-level talents (No.RC2022-003), Guangdong Basic and Applied Basic Research Foundation (No.2022B1515120046), Sanming Project of Medicine in Shenzhen (No.SZSM202211038) and Shanghai Science and Technology Committee(23JC1402400).

Conflict of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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