This study explores the use of Powder Bed Fusion–Laser Beam (PBF-LB), an advanced additive manufacturing technique, for producing biodegradable magnesium (Mg) alloy implants intended for bone repair. While Mg alloys are already used in medical devices like bone screws, PBF-LB could enable the fabrication of patient-specific implants with intricate structures, potentially improving bone healing, especially in large defects. However, challenges such as oxide formation during powder production and the PBF-LB process itself complicate the printability of Mg alloys. Although achieving suitable mechanical properties is generally possible, controlling the degradation rate of these implants remains a significant hurdle for clinical application. The research examines three Mg alloys and employs a range of characterization methods, including optical and electron microscopy, mechanical testing , and corrosion assessments. It also utilizes computational fluid dynamics (CFD) modeling to investigate the effects of fluid flow and thermal history on microstructure development. Results indicate that printability varies significantly among the alloys, with WE43 achieving the highest densities (up to 99.5%). The microstructure, especially the presence of columnar dendrites and secondary phase precipitation, is crucial for sample quality. In WE43, two sub-grain structures-equiaxed dendrites and cellular grains-were identified, their formation influenced by melting modes and fluid flow as shown by CFD modeling. These microstructural features impact material properties: dendritic structures enhance mechanical strength but compromise corrosion resistance. Implant design, including strut-based lattices and triply periodic minimal surfaces (TPMS), also affects degradation and mechanical performance. However, all additively manufactured Mg alloys showed higher degradation rates than conventionally produced ones. The study concludes that PBF-LB allows for tailoring material properties through microstructural and geometric design, but further research is needed to address micro-galvanic corrosion and localized degradation in complex structures. Future work will focus on post-processing methods, such as hot isostatic pressing (HIP), to further optimize the clinical performance of these biodegradable implants.

INTRODUCTION: Periarticular fractures with bone defects like tibial plateau fracture are common and complicated diseases. The existing autogenous, artificial, and allogeneic bones are insufficient in anatomical shape matching and overall support capacity. Additive manufacturing of magnesium(Mg) alloy with lattice structures provides the feasibility of realizing bone defect prostheses with personalized and biodegradable functions. This study aimed to systematically evaluate the additive manufacturing mg alloy prostheses in addressing periarticular bone defect repair(tibial plateau fracture). METHODS: (1) WE43 powder was composed of 3.87 % Y, 2.24 % Nd, 1.16 % Gd, 0.39 % Zr, and balance Mg. A compact L-PBF machine (BLT S210, China) was used to additively manufacture WE43 porous scaffolds.Improving corrosion resistance of additively manufactured WE43 alloy by high-temperature oxidation(HTO)1. (2) We conducted a prospective study on patients with periarticular fractures(tibial plateau fracture and bone defects)treated at the Peking University Third Hospital between June 2022 and May 2025. Sixty patients(Thirty patients for each group) with periarticular fractures and bone defects were enrolled in the study, and Mg alloy prostheses were used for internal support combined with steel plate fixation to repair the fracture and bone defects.Hematological examinations were performed in the early postoperative period, X-ray examinations were performed in the long-term postoperative follow-up. Postoperative complications, including infection, failure of internal fixation and malunion, were recorded during the follow-up. The visual analogue scale (VAS) was used to evaluate postoperative pain perceived by the patients, and the the Hospital for Special Surgery Knee Score(HHS) was used to evaluate their postoperative function. RESULTS: HTO can enhance the corrosion resistance of additive manufacture mg alloy prostheses. In the study of 30 patients with tibial plateau fracture and bone defects, all patients achieved bone healing with an average healing time of 3 months. Hydrogen can be seen in the X ray to precipitate in soft tissues from the 1months, and hydrogen can be absorbed after about 2 months. The Mg alloy prostheses can maintain a support time of over 6 months. All patients achieved good fracture alignment and bone defect repair, and imaging examination showed that the Mg prosthesis degraded gradually with fully bone defect repair in the one year.

Additively manufactured (AM) biodegradable zinc alloys hold huge potential as promising candidates for bone defect and fracture repair, thanks to their suitable biodegradation rates and acceptable biocompatibility. However, the mechanical properties of AM zinc alloys developed so far, ductility in particular, fall short of the requirements for bone substitution. Here, we present Zn-1Mn and Zn-1Mn-0.4Mg alloy implants with unique microstructures, fabricated using laser powder bed fusion (LPBF). Notably, the LPBF Zn-Mn-Mg alloy exhibited an extraordinary balance of strength and ductility, with an ultimate tensile strength of 289 MPa, yield strength of 213.5 MPa, and elongation over 20 %, outperforming all previously reported AM zinc alloys. The simultaneously enhanced strength and ductility of the ternary alloy were attributed to the strong grain-refining effect of the Mg2Zn11 second phase and the synthetic strengthening caused by the dispersion of the MnZn13 and Mg2Zn11 second phases inside the grains and at the grain boundaries. In addition, both alloys had similar rates of in vitro biodegradation (∼0.15 mm/year), properly aligned with the bone remodeling process, while also demonstrating favorable biocompatibility and upregulating multiple osteogenic markers. The Zn-Mn-Mg alloy showed even better osteogenic potential than the Zn-Mn alloy, owing to the addition of Mg. The combined attributes of the LPBF Zn-Mn-Mg ternary alloy indicated huge potential for its use as a bone repair material, especially for load-bearing bone fixation.

Iron and its alloys are of great interest in the medical field, especially for use as temporary devices. Electroforming emerges as a promising bottom-up technology destinated for the manufacturing of such a kind of tiny devices. Alloying iron is a way to increase this element low degradation rate, for example with zinc that is more susceptible to the corrosion phenomenon. However, Fe-Zn electroforming also faces a challenge called anomalous codeposition: zinc preferentially deposits over iron, leading to alloys with low iron content. Overcoming this barrier is crucial to successfully permit the production of the material. The aim of the present of work was to electroform Fe-Zn alloys containing different amounts of zinc and to investigate their effect on the microstructure and electrochemical properties of the alloys. Results indicated the presence of a zinc-rich second phase, inducing the appearance of cracks. This led to a decrease in the value of the impedance modulus in the Fe-Zn alloys, indicating an inferior resistance against corrosion.

Osteosarcoma is the most common primary bone tumor. After tumor resection, recurrence and postoperative bone defects remain a critical challenge. It is urgent to develop biomaterials which can kill osteosarcoma and promote bone regeneration. In this study, we utilized laser powder bed fusion to fabricate biodegradable Zn-Li pscaffolds that supress tumors and promote osteogenesis.

Powder bed fusion–laser beam (PBF-LB) processing of Zn-Mg alloys has gained attention as a promising approach for fabricating biodegradable, patient-specific implants. Although alloying Zn with Mg contents ≤ 1 wt.% enhances tensile performance, natural ageing (NA) remains a persistent challenge. This is due to Zn’s low melting point, which enables significant atomic diffusion at low temperatures, resulting in an exceptionally low recrystallisation temperature and undesirable changes in mechanical properties over time. Studies on conventionally processed Zn-Mg alloys have reported increased tensile strength over time, accompanied by a significant reduction in ductility, attributed to Mg2Zn11 precipitation. To date, no comprehensive studies have examined the static recrystallisation (SRX) behaviour of pure Zn, or the NA characteristics of Zn-Mg alloys produced via PBF-LB. This work addresses that gap by evaluating the SRX and NA behaviour of PBF-LB processed pure Zn and Zn-1Mg (wt.%) at room temperature (RT) and body temperature (37 °C). Alloys were prepared by mechanical mixing of Zn and Mg powders. Constructs were fabricated using an Aconity Midi PBF-LB system with optimised process parameters, achieving > 99.5% relative density. The evolution of mechanical properties of samples aged at RT and 37 °C was assessed by microhardness measurements and compression testing over 90 days. These changes were correlated with microstructural observations obtained via SEM and EDS. Grain size distribution and precipitation behaviour were examined using EBSD and Rietveld refinement of XRD patterns. Statistical analysis was performed using SciPy in Python. The microhardness of pure Zn remained stable at RT but declined at 37 °C after 60 days. Zn-1Mg showed stable hardness at RT for 30 days yet dropped significantly by 60 days. Similarly, Zn-1Mg exhibited a continuous decline in hardness at 37 °C, with a pronounced drop by 60 days. This trend correlates with the substantial reduction in the MgZn2 phase fraction over time. In conclusion, PBF-LB Zn-Mg alloys show notable temperature-dependent natural ageing effects. Future works will focus on mitigating this issue through multi-component alloying and optimisation of printing parameters.

The demand for biomedical implants has increased recently, particularly for scaffolds to treat large bone defects or fractures and promote bone regeneration. Recent studies have focused on biodegradable ones (Mg, Zn, and Fe). Fe-based alloys exhibit superior mechanical properties but have a slower corrosion rate than Mg and Zn alloys. To overcome this challenge, different elements like Mn can be incorporated [1,2]. Also, non-conventional fabrication techniques, like 3D printing through Laser Powder Bed Fusion (LPBF) [3], lead to complex microstructural changes affecting the degradation rate, simultaneously allowing the fabrication of complex structures, and creating the wished microstructural features. Typically, LPBF employs pre-alloyed spherical powders (Ø = ~20 ÷ 55 μm), but these are generally produced costly through atomization. Nevertheless, optimizing the 3D-printing parameters for using elementary powder to cut down the powder production cost is an important aspect that is proposed to keep the wished (microstructural, mechanical) properties, reducing the powder fabrication steps. The present work deals with the optimization of the fabrication process of a Fe-12Mn-1.2C alloy, its characterization, and evaluation of the performances through a fabrication process based on quasi-elemental powders.

Magnesium alloys are candidates for orthopaedic applications, but there is a need for improving their corrosion resistance. Developing an additively manufactured alloy is time and resource consuming. The aim of this study was to predict the microstructure-temperature relationship for a MgCaZn alloy studying mainly the raw powder and use the CALPHAD method as input for a classical nucleation and growth theory (CNGT) simulation. The composition of the powder was confirmed through Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES) and compared to the results obtained with ToF-ERDA (Time-of-Flight Elastic Recoil Detection Analysis). X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were the main characterisation tools used for phase identification, Kissinger analysis and the creation of a continuous-heating-transformation diagram. This experimental data was used to validate the numerical model. The overall transitions and phases agreed with previous literature, with only significant differences in the obtained energies of activation.