Bioresorbable magnesium (Mg) alloy is known as revolutionary biomedical metal for orthopedic implants, despite the challenge of its too rapid degradation. In this study, laser powder bed fusion (LPBF) was employed to prepare amorphous Mg-Zn-Ca for biomedical application. By optimizing laser power and scanning speed, a near-fully dense part with a heterogeneous microstructure was achieved, consisting primarily of an amorphous matrix (>80%) with embedded nanocrystalline phases. Specifically, the molten pool zone exhibited a predominantly amorphous structure due to its cooling rate exceeding the critical value required for amorphous formation in Mg-Zn-Ca system. In contrast, the heat-affected zone underwent structural relaxation and initiated a partial crystallization. The amorphous/crystalline Mg-Zn-Ca owned relatively few of intermetallic or grain boundaries, leading to the formation of relatively dense and continuous Zn-rich protective layer, and effectively delayed the degradation of Mg matrix. Besides, it also demonstrated a favorable cytocompatibility, osteogenic capacity, and notable antibacterial efficacy. This work highlighted the promising potential of LPBF-processed amorphous/crystalline Mg-Zn-Ca as biodegradable bone implant with improved overall performance.

Laser powder bed fusion (LPBF) has revolutionized modern manufacturing by enabling high design freedom, rapid prototyping, and tailored mechanical properties. However, optimizing process parameters remains challenging due to the trial-and-error approaches required to capture subtle parameter-microstructure relationships. This study employed a multi-physics computational framework to investigate the melting and solidification dynamics of magnesium alloy. By integrating the discrete element method for powder bed generation, finite volume method with volume of fluid for melt pool behavior, and phase-field method for microstructural evolution, the critical physical phenomena, including powder melting, molten pool flow, and directional solidification were simulated. The effects of laser power and scanning speed on temperature distribution, melt pool geometry, and dendritic morphology were systematically analyzed. It was revealed that increasing laser power expanded melt pool dimensions and promoted columnar dendritic growth, while high scanning speeds reduced melt pool stability and refined dendritic structures. Furthermore, Marangoni convection and thermal gradients governed solute redistribution, with excessive energy input risking defects such as porosity and elemental evaporation. These insights establish quantitative correlations between process parameters, thermal history, and microstructural characteristics, providing a validated roadmap for LPBF-processed magnesium alloy with tailored performance.

Magnesium (Mg) alloys have gained recognition as revolutionary biomaterials, owing to their inherent degradability, favorable biocompatibility and mechanical properties. Additive manufacturing (AM) provides high design flexibility and enables the creation of implants with personalized complex shapes and internal porous structures tailored to individual anatomical and functional needs. Particularly, laser powder bed fusion (LPBF), one prevalent AM technique, utilizes a fine laser beam as heat source and results in tiny molten pool with extremely fast cooling rate, which effectively restricts grain growth, inter-metallic precipitation and macroscopic segregation, thus facilitating the fabrication of high-performance metal parts. This review critically assesses the significance of biodegradable Mg alloys and investigates the feasibility of utilizing LPBF for Mg alloys applications in biomedical field. Detailed discussions on LPBF-processed biomedical Mg alloys parts cover process parameters, microstructure, metallurgical defects, and properties like mechanical performance, corrosion behavior, and biological response in both as-built and post-processed states. Additionally, suggestions for advancing knowledge in LPBF of biodegradable Mg alloys for biomedical applications are highlighted to propel further research and development in this field.

Biomedical magnesium (Mg) alloys have garnered significant attention because of their unique biodegradability, favorable biocompatibility, and suitable mechanical properties. The incorporation of rare earth (RE) elements, with their distinct physical and chemical properties, has greatly contributed to enhancing the mechanical performance, degradation behavior, and biological performance of biomedical Mg alloys. Currently, a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents, achieving substantial and encouraging research progress. In this work, a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided. The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed. Particularly, the degradation behavior and mechanical properties, including their underlying action are studied in-depth. Furthermore, the preparation techniques and current application status of RE-Mg alloys are reviewed. Finally, we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.

Magnesium (Mg) alloys are considered to be a new generation of revolutionary medical metals. Laser-beam powder bed fusion (PBF-LB) is suitable for fabricating metal implants with personalized and complicated structures. However, the as-built part usually exhibits undesirable microstructure and unsatisfactory performance. In this work, WE43 parts were firstly fabricated by PBF-LB and then subjected to heat treatment. Although a high densification rate of 99.91% was achieved using suitable processes, the as-built parts exhibited anisotropic and layered microstructure with heterogeneously precipitated Nd-rich intermetallic. After heat treatment, fine and nano-scaled Mg₂₄Y₅ particles were precipitated. Meanwhile, the α-Mg grains underwent recrystallization and turned coarsened slightly, which effectively weakened the texture intensity and reduced the anisotropy. As a consequence, the yield strength and ultimate tensile strength were significantly improved to (250.2 ± 3.5) MPa and (312 ± 3.7) MPa, respectively, while the elongation was still maintained at a high level of 15.2%. Furthermore, the homogenized microstructure reduced the tendency of localized corrosion and favored the development of uniform passivation film. Thus, the degradation rate of WE43 parts was decreased by an order of magnitude. Besides, in-vitro cell experiments proved their favorable biocompatibility.