Zinc alloys have emerged as promising candidates for biodegradable vascular stents due to their moderate degradation rate. However, developing zinc-based materials with high strength, ductility, and long-term mechanical stability remains critical for advancing their clinical translation. Based on our previously developed anti-aging Zn-Cu alloys, this study introduces trace amounts of lithium (Li) to fabricate a novel Zn-Cu-Li ternary alloy, as well as its thin-walled tubes and stents. The microstructure, mechanical properties, and degradation behaviour are systematically investigated. The results show that the introduced trace Li exists as a solute in the η-Zn matrix and ε-CuZn4 phase, and contributes to the refinement of grains and the increase of volume fraction for ε-CuZn4 phase. Trace Li alloying could significantly enhance the mechanical properties of zinc alloys. The Zn-2Cu-0.1Li alloy thin-walled tubes and stents exhibit excellent mechanical performance, meeting the clinical requirements.

Data on shelf-stability of Mg alloys for medical applications is limited. This paper highlights findings from an in-progress 5-year study, initiated in May 2022, which examines mechanical change in three medical Mg alloys in various sizes and conditions relevant to medical devices.

INTRODUCTION: The interest in zinc alloys as bioabsorbable metals gradually increased since it was discovered that pure zinc possesses the optimal corrosion rate for bioabsorbable cardiovascular stents. One of the main disadvantages of pure zinc is its insufficient mechanical properties. A wide range of potential zinc alloy systems were considered, mainly binary and ternary alloys. One of the most examined alloying elements is Mg, e.g. [1]. It forms a eutectic mixture of Zn α and Mg2Zn11 intermetallic phase. The presence of an intermetallic phase prevents the recrystallization process in Zn-Mg alloys. However, the larger content of Mg2Zn11 is not beneficial for the ductility of the material and the uniformity of corrosion properties. Thus, in order to ensure not only high mechanical properties but also optimal corrosion rate and homogenous degradation, some modification of Zn-Mg alloys needs to be applied. For the proposed investigation, the ZnMgMn ternary alloys were chosen. METHODS: Materials for investigations were prepared by gravity casting in an argon atmosphere from pure zinc with various magnesium and manganese contents (from 0.1 to 0.5% wt. for both) and then deformed using hot extrusion and hydrostatic extrusion. The deformed material was subjected to a microstructure investigation using XRD (X-ray Diffraction), SEM (scanning electron microscope), and TEM (transmission electron microscope). Mechanical properties using static tensile tests and microhardness measurements were analyzed. RESULTS: The UTS and YS obtained for materials were the highest for ternary alloys with 0.5 % Mg and 0.5 % M, reaching 458 MPa and 449 MPa, respectively. However, the elongation E was below 1%. After hydrostatic extrusion, the same alloy reached E=22 % elongation with slightly decreasing UTS and YS levels down to 437 MPa and 338 MPa, respectively. Detailed microstructure investigation showed significant grain refinement for hot and hydrostatic extrusion for ternary alloys with the highest amount of magnesium and manganese addition, especially after hydrostatic extrusion. The average grain size was about 700 nm. Additionally, the grain refinement of intermetallic phases Mg2Zn11 and MnZn13 were noticed after hydrostatic extrusion. There is also a change in the texture of the materials after hydrostatic extrusion. DISCUSSION & CONCLUSIONS: Alloying with magnesium and manganese is beneficial for improving the mechanical properties of zinc-based alloys. Additionally, applying hydrostatic extrusion is advantageous for the plasticity of those alloys. Modulation of different content of both alloying elements and deformation process parameters influences the final properties and opens the possibility of satisfying demands for particular applications. Further studies will focus on the uniformity of corrosion properties to ensure homogeneous degradation. REFERENCES: 1 Pachla W et. al, Structural and mechanical aspects of hypoeutectic Zn-Mg alloys for biodegradable vascular stent applications, Bioactive Materials 6, 1, 26-44, (2021). ACKNOWLEDGEMENTS: This work was supported by the National Science Centre Polish UMO-2023/51/B/ST11/02814

INTRODUCTION: Magnesium-lithium (Mg-Li) alloys are notable for their ultra lightweight and biocompatibility. The biodegradation of Mg implants reduces the need for secondary surgeries, while the similar elastic modulus to bone prevents stress shielding. Indeed, Mg alloys have been used in vascular stents and bone fixation implants. Additive manufacturing (AM) has also allowed for advancements in biomedical implant design, primarily due to fabrication of custom components. One disadvantage however, hindering the implementation of AM-fabricated Mg alloys is their limited ductility, given e.g., the propensity of texture formation during such processing. Mg-Li alloys can aid in this regard, due to the formation of BCC at Li contents above 11.7wt.%. Moreover, BCC Li-phases allow for improved corrosion resistance in Mg alloys by generating a passive Li2CO3 layer. Nevertheless, AM processing of Mg-Li alloys is vastly underreported. Hence, the aim of this study was to investigate the processability of binary Mg-Li alloys using AM, specifically through laser-powder bed fusion (L-PBF). Both a single- (alpha-Mg) phase and dual-phase (alpha-Mg + beta-Li) alloy were processed, and evaluated for mechanical properties and corrosion resistance.

Biodegradable metals, particularly zinc (Zn) and magnesium (Mg) alloys, offer significant potential for biomedical applications, especially as temporary implants that naturally degrade within the body. Recent advances in additive manufacturing (AM) have enabled the fabrication of patient-specific implants with complex geometries, further broadening their clinical applicability. This study investigates the influence of powder quality and laser process parameters on the surface quality and geometric accuracy of AM-produced Mg and Zn alloy parts in their as-built state.à For the experimental work, gas-atomized, pre-alloyed Zn0.5Mg, conventional WE43, and medical-grade WE43MEO powders were used. Specimens were manufactured using a modified Laser Powder Bed Fusion (LPBF) system from Aconity 3D GmbH, specifically adapted for low-melting, biodegradable alloys. The effect of powder quality was evaluated by comparing thin-walled lattice structures made from conventional and medical-grade powders. Additionally, the influence of laser parameters was studied using both solid and thin-walled structures, with 18 specimens produced across different volume energy densities and spot diameters. Overhang behavior was also analyzed by varying the inclination angle. Results showed that the use of medical-grade WE43MEO powder significantly improved geometric accuracy. The strut size in top-view planes decreased from 425.56 ± 17.38 µm (conventional WE43) to 387.11 ± 14.09 µm (WE43MEO), with even greater improvements observed in perpendicular planes (Fig. 1). For Zn0.5Mg, a volume energy density of 133.33 J/mm³ combined with an 80 µm spot diameter produced samples with high relative density, but low geometric accuracy for inclination angles below 45°. By increasing the energy density to 170 J/mm³ and the spot diameter to 100 µm, samples with inclination angles of 30° and above could be reliably fabricated. These findings highlight the critical importance of material selection and process parameter optimization in balancing geometric precision and structural integrity for biodegradable implants. While medical-grade powders improve dimensional control in Mg alloys, careful adjustment of laser parameters is essential for Zn alloys to achieve the desired combination of density and accuracy. The study underscores the potential of AM for producing patient-specific biodegradable implants but emphasizes the need for tailored process optimization based on material behavior.

Magnesium alloy WE43 shows strong potential for bone scaffolds due to its biocompatibility and controlled biodegradation. Additive manufacturing (AM) techniques, particularly laser powder bed fusion (L-PBF), enable the production of patient-specific porous lattice structures that can optimize mechanical support and promote bone ingrowth. While the static mechanical behavior of such scaffolds has been well studied, their dynamic response under high-strain-rate conditions, critical for real-world impacts like falls, remains underexplored. This study investigates the dynamic mechanical behavior of WE43 lattices using a Split-Hopkinson Pressure Bar (SHPB) setup combined with synchrotron X-ray phase-contrast imaging. Two types of lattice architectures were examined: strut-based (e.g., FCC) and Triply Periodic Minimal Surface (TPMS, e.g., Gyroid) designs, with relative densities ranging from 11% to 47%. Dynamic compression tests were performed at high strain rates, and real-time deformation was captured at the ESRF ID19 beamline using ultra-fast X-ray imaging. Micro-computed tomography was also employed to assess the manufacturing quality of the lattices. Results showed that TPMS lattices consistently outperformed strut-based ones, demonstrating up to twice the load-bearing capacity and 40–60% greater stiffness across all densities tested. Synchrotron imaging revealed that TPMS lattices deformed through progressive pore collapse and densification, while strut-based structures experienced brittle failure. TPMS designs also achieved more efficient energy absorption. Despite good overall density, some semi-melted powder residues were observed on the printed surfaces. These findings highlight the critical role of lattice architecture in the dynamic performance of biodegradable scaffolds. TPMS structures, with their smooth, continuous geometry, offer enhanced resistance to impact loading by avoiding stress concentrations and enabling controlled energy dissipation. This work lays important groundwork for designing next-generation, patient-specific magnesium alloy implants that better withstand dynamic physiological conditions during bone healing.

INTRODUCTION: Addressing the challenge of balancing rapid degradation and insufficient bio-regenerative capabilities in biodegradable magnesium (Mg) alloys for bone repair is a significant endeavor. METHODS: In this study, we investigate the influence of Scandium (Sc) content on the microstructure, strength, degradation, cytotoxicity, angiogenesis, and osteogenesis of Mg-4Yttrium(Y)-xSc alloy system, and successfully develop a novel alloy Mg-4Y-2.25Sc (wt.%) that significantly inhibit degradation and promote bone regeneration. This achievement is contributed to the combination of the alloying and high-temperature oxidation (HTO) treatment, guided by a thermodynamic calculation model. RESULTS: The performance of our alloy notably surpasses that of the widely used biodegradable WE43 alloy. At the microstructural level, a thin and dense protective film of Y2O3/Sc2O3 is introduced to form a passivation effect. The synergetic release of Mg and Sc ions significantly promotes angiogenesis and osteogenesis. In vivo results verifies that Mg-4Y-2.25Sc implants promote osseointegration of implants during the bone healing cycle. DISCUSSION & CONCLUSIONS: In this study, an Mg-4Y-xSc (0.75, 1.50, 2.25, wt.%) ternary alloy system is proposed to achieve high degradation resistance and osteo/angiogenesis activity simultaneously through the Sc-enhanced growth of the oxidation layer. Under HTO treatment, compared with the protective oxide layers of Y2O3 and MgO, Sc2O3 migrates to the surface of Mg alloy, possessing higher thermodynamic stability. The Mg-4Y-xSc alloy system delivers Mg2+ and Sc3+, shaping the microenvironment for osteogenesis and vascularization, thereby promoting bone repair. Furthermore, the promotion mechanism of cell proliferation and adhesion, osteogenesis, and angiogenesis effects of the HTO combined Sc microalloying on the Mg-4Y-xSc alloy system are systematically evaluated. The novel Mg-4Y-Sc alloy system can be a promising candidate for next-generation high-performance Mg alloys for biodegradable applications.

This study explores the development of iron–manganese (Fe–Mn) alloy coatings enhanced with zinc for potential application in biodegradable metallic implants. While Fe–Mn alloys provide mechanical strength comparable to stainless steel, their clinical application is limited by a low corrosion rate and vulnerability to bacterial infections, particularly those caused by Staphylococcus species. To address these limitations, zinc was incorporated into the coatings for its antibacterial activity and its ability to modulate corrosion through electrochemical interactions. The coatings were fabricated using dual-target magnetron sputtering with Hadfield steel and zinc targets under varying power and temperature conditions. Surface and structural characterizations were performed using techniques such as SEM, EDS, AFM, XPS, and XRD, as well as electrochemical and antibacterial testing. The resulting coatings were homogeneous, smooth, and free of visible defects or porosity. Elemental analyses revealed a distinct distribution pattern: manganese was mainly located in the bulk of the coating, while zinc was enriched at the surface. Deposition parameters, especially temperature and power, were found to influence coating morphology and composition. These findings support the potential of Fe–Mn–Zn coatings as multifunctional surfaces for biodegradable implants, combining mechanical integrity with antibacterial protection.