International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056 Volume: 07 Issue: 09 | Sep 2020 www.irjet.net p-ISSN: 2395-0072 © 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 2763 Mg and its Alloys, their Challenges and Opportunities for Implants: A Review Rohit 1 , Munish Gupta 2 , Puneet Katyal 3 , Vijender Gill 4 1 Student, Department of Mechanical Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India 2 Professor, Department of Mechanical Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India 3 Professor, Department of Mechanical Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India 4 Scholar, Department of Mechanical Engineering, Guru Jambheshwar University of Science and Technology, Hisar, Haryana, India --------------------------------------------------------------------------***----------------------------------------------------------------------- Abstract: Magnesium (Mg) and its alloys are lightweight metals with low density and elastic modulus, and having good mechanical properties and good biocompatibility. With these beneficial properties there are several challenges in magnesium alloy implants. Corrosion rate or degradation rate of mg and its alloys is fast due to which they mislays their mechanical integrity and fail to perform their function prior to complete healing of bone. There are many opportunities, to improve the corrosion resistance, mechanical strength, ductility etc., like alloying, mechanical working, surface modification, machining etc. Key words: Magnesium Alloys, Biocompatibility, Hydrogen Evolution, Corrosion, Ductility, Machining, Mechanical Working, Surface Treatment and Coating Introduction: Magnesium and its alloys are the degradable biomaterials having mechanical properties same as the human bones. Mg is a non-toxic tenor and in an environment of the human body, it degrades completely [1]–[3]. Degradable biomaterial for an implant should have good biocompatibility, sufficient mechanical strength, high corrosion resistance, high wear resistance and degradation rate should be matched with bone healing rate [4]. For many enzymes, magnesium is a cofactor and it is also stabilized the structures of RNA and DNA. In the human body, magnesium is the fourth most abundant element essential for human metabolism [5]–[8]. Machining of magnesium and its alloys is simple due to their lower density, higher specific strength and elastic modulus nearly similar to bone [9]–[11]. Mg and its alloys eliminating the stress shielding problem due to their low modulus of elasticity, it’s about 45GPa that is approximately close to the elastic modulus of natural bone (10-30GPa) [12]. Biomaterials play a crucial role to repair or replace the damaged or diseased bone tissue of human being and animals, and also improve life quality [13], [14]. Implant materials are of two types, degradable and non-degradable implant material. Non-degradable implant material is used for permanent implant. Such similar problems occurs in permanent implants are inflammatory reactions, physical irritation, impact of stress shielding due to larger modulus of elasticity or young’s modulus and material issues like corrosion, wea r and bacterial formation [15]–[17]. Now a day, magnesium and magnesium alloys are highly used as a biodegradable implant due to their good properties, stimulated bone growth, good bio-resorption and non-inflammatory reactions [18], [19]. An eligible biodegradable implant is that in which corrosion rate is matched with the bone healing rate, properties of implant material are enough to supply the expected endorsement during the period of bone healing, when the objective bone is healed completely then implanted material completely degrades in the body [20]. Challenges in Mg-alloy implants: For the implantation of mg in the human and animal body many types of biodegradable mg alloys are developed, but approximately all suffering with fast degradation rate and mechanical support is also relatively insufficient [7]. Mg alloys show poor workability and low ductility at room temperature due to its hexagonal closed pack crystal structure. These properties make challenges for stent applications. The large challenges for magnesium and their alloy implantations are higher rate of degradation, rapid rate of corrosion, hydrogen gas evolution, poor mechanical integrity, low ductility, alloying elements toxicity and biocompatibility of the implants.