Sreenivas Raguraman

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 offer immense potential as intelligent alternatives to traditional implant materials due to their inherent degradability, biocompatibility, and exceptional mechanical properties. However, their rapid deterioration hinders their practical applications, compromising their mechanical integrity. This study addresses this challenge by investigating the effects of thermo-mechanical processing, including extrusion, cECAP, rolling, and annealing, on the high-strength, dilute ZX10 Mg alloy. By subjecting the alloy to over thirty processing conditions, we identify an optimal combination of high-strength and low-corrosion rates. Simple characterization techniques like XRD, optical microscopy, and SEM were employed to rapidly evaluate the microstructural changes post-processing. The findings identify that grain boundary and strain hardening play pivotal roles in enhancing hardness, while factors such as texture, dislocation density, and precipitates impact corrosion significantly. This comprehensive investigation provides valuable insights into processing-structure–property relationships for Mg alloys, paving the way for developing superior biodegradable implant materials.

Biodegradable magnesium (Mg) alloys are gaining attention for biomedical implants due to their favorable mechanical properties and safe degradation within the human body. However, the rapid corrosion of Mg remains a challenge, necessitating a deeper understanding of its behavior in physiological environments. This study examines the in-vitro corrosion performance of a lean Mg-Zn-Ca alloy in various degradation media, including Hank’s Balanced Salt Solution (HBSS), Earle’s Balanced Salt Solution (EBSS) buffered with 5% CO2, and Dulbecco’s Modified Eagle Medium (DMEM) with 10% Fetal Bovine Serum (FBS) buffered with 5% CO2. Significant differences in corrosion rates were observed across media, with HBSS exhibiting the lowest rates and EBSS the highest. DMEM with 10% FBS and corrosion conditions that most closely resemble physiological environments produced intermediate corrosion rates. The effect of CO2 buffering in HBSS was also evaluated, demonstrating enhanced pH control below 7.5, which simulates physiological pH. Additionally, increasing the volume of HBSS, both with and without CO2 buffering, led to reduced corrosion rates and greater pH stabilization. These findings shed light on how testing conditions can impact corrosion rates and pH stability.

Medical application materials must meet multiple requirements, and the designed material must mimic the structure, shape. and support the formation of the replacing tissue. Magnesium (Mg) and Zinc alloys (Zn), as a “smart” biodegradable material and as “the green engineering material in the 21st century”, have become an outstanding implant material due to their natural degradability, smart biocompatibility, and desirable mechanical properties. Magnesium and Zinc are recognized as the next generation of cardiovascular stents and bioresorbable scaffolds. At the same time, improving the properties and corrosion resistance of these alloys is an urgent challenge. particularly to promote the application of magnesium alloys. A relatively fast deterioration rate of magnesium-based materials generally results in premature mechanical integrity compromise and local hydrogen build-up, resulting in restricted applicability. This review article aims to give a comprehensive comparison between Zn-based alloys and Mg-based alloys, focusing primarily on degradation and biocompatibility for cardiovascular applications. The recent clinical trials using these biodegradable metals have also been addressed.

Bone defects occur due to factors such as congenital anomaly, trauma, and osseous deficiency following resection of tumours. Biomaterials are required for bone augmentation of the lost bone architecture. Clinicians attempting to regenerate the tissue and restore its function and aesthetics because of trauma, pathology, or congenital defects face a substantial challenge. The concept of using metallic foam in bone tissue engineering is a key factor in the regeneration of critical size bone defects. Significant research efforts have been dedicated to the development of metallic foams for bone tissue engineering due to their suitable mechanical and biological properties. Although, at present, most of the studies are focused on non-load bearing materials, many materials are also being investigated for hard tissue repair. Several biocompatible metallic foam materials such as titanium alloys, tantalum, iron, zinc, and magnesium alloys have been commonly employed as implants in biomedical applications. They are often used to replace and regenerate the damaged bones or to provide structural support for healing bone defects. The bone cells develop on the porous regions of the implants. These cells develop over the surface of the foam, which imparts the integrity and strength. The scaffolds help in regeneration of the biological structural components of the extracellular matrix. This chapter focuses on the commonly used metallic foams for bone tissue engineering, their properties, applications, and cellular interactions.