Sreenivas Raguraman

Magnesium–aluminum (Mg–Al) alloys are promising candidates for biodegradable implants, offering a favorable balance of mechanical strength and corrosion resistance. However, the release and systemic fate of aluminum (Al) during alloy degradation remain poorly understood, especially in relation to their microstructure. In this study, we investigate the role of β-Mg17Al12 precipitates in governing Al release from Mg–9Al alloys under both in-vitro and in-vivo conditions. In-vitro immersion testing revealed that peak‑aged (PA) samples, containing a high density of β-Mg17Al12 precipitates, exhibited accelerated pitting corrosion and higher total Al release compared to solution‑treated (ST) samples. In contrast, in-vivo subcutaneous implantation demonstrated the opposite trend regarding Al release with ST implants yielding higher systemic Al ion levels, whereas PA implants retained more particulate β-Mg17Al12 and corrosion products at the implantation site. This behavior is attributed to differences in Al speciation and mobilization, with Al from ST alloys releasing primarily in solute form and Al from PA alloys predominantly present as highly elongated precipitate fragments that remained localized and resisted systemic transport. These findings underscore that microstructure influences not only corrosion kinetics but also the bioavailability and physiological distribution of Al degradation products. This work provides a framework for designing Mg‑based alloys that balance mechanical performance with favorable physiological clearance, advancing the development of safe and effective biodegradable implants.

Despite transformative advances in materials discovery, real-world performance still hinges on an often-overlooked variable: processing. To bridge the gap between discovery and deployment, processing must be elevated from an afterthought to a central pillar in design frameworks, data generation and machine learning.

Magnesium alloys are emerging as promising alternatives to traditional orthopedic implant materials thanks to their biodegradability, biocompatibility, and impressive mechanical characteristics. However, their rapid in-vivo degradation presents challenges, notably in upholding mechanical integrity over time. This study investigates the impact of high-temperature thermal processing on the mechanical and degradation attributes of a lean Mg-Zn-Ca-Mn alloy, ZX10. Utilizing rapid, cost-efficient characterization methods like X-ray diffraction and optical microscopy, we swiftly examine microstructural changes post-thermal treatment. Employing Pearson correlation coefficient analysis, we unveil the relationship between microstructural properties and critical targets (properties): hardness and corrosion resistance. Additionally, leveraging the least absolute shrinkage and selection operator (LASSO), we pinpoint the dominant microstructural factors among closely correlated variables. Our findings underscore the significant role of grain size refinement in strengthening and the predominance of the ternary Ca2Mg6Zn3 phase in corrosion behavior. This suggests that achieving an optimal blend of strength and corrosion resistance is attainable through fine grains and reduced concentration of ternary phases. This thorough investigation furnishes valuable insights into the intricate interplay of processing, structure, and properties in magnesium alloys, thereby advancing the development of superior biodegradable implant materials.

Magnesium alloys are increasingly recognized as promising materials for biodegradable implants due to their low density, biocompatibility, and favorable mechanical properties. However, achieving a balance between mechanical strength and bio-corrosion resistance remains a critical challenge. This study systematically investigates the effects of three thermomechanical processing routes—extrusion (EXT), Equal Channel Angular Pressing (ECAP), and ECAP followed by annealing at 150oC for 10 h (ECAP-A)—on the ZX10 magnesium alloy. EXT produced coarse grains and moderate mechanical and corrosion performance. ECAP refined the grain structure and reduced the Mg2Ca phase, leading to an 80 % increase in hardness, improved yield strength, and enhanced ductility, but at the cost of a doubled corrosion rate due to high dislocation density. ECAP-A mitigated this drawback, reducing the corrosion rate to 1.50 mm/year while maintaining a high yield strength ( \textgreater 200 MPa). This improvement was driven by a uniform distribution of the Ca2Mg6Zn3 phase, further dissolution of the Mg2Ca phase, and reduced dislocation density. These findings establish ECAP-A as an effective strategy to simultaneously optimize strength and bio-corrosion resistance, advancing the ZX10 magnesium alloy as a promising material for biodegradable implants.