Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

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VIT University

Magnesium alloys have gained increasing attention for biomedical applications due to their biocompatibility and the biodegradability. Hydroxyapatite (HA) is known to be a highly bioactive because of its similar chemical and crystallographic structures to bone. Therefore, HA is believed to be a potential ceramic material for the fabrication of Mg based composites, to combine the advantages of both Mg and HA. But, in general, the composites known to be more susceptible to corrosion attack than the matrix alloy. Hence, in the present work, Sn is used as an alloying element to evaluate its effect on mechanical as well as corrosion properties of Mg/HA composites. Mg with 5 wt% HA and Mg-1 wt% Sn-5 wt% HA composites were prepared separately by stir assisted squeeze casting route. The phase analysis and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) respectively. Mechanical properties were evaluated by conducting the compression and micro hardness tests. Corrosion properties of as-cast composites were studied by linear polarization, Tafel and electrochemical impedance spectroscopy (EIS) techniques. The results of both XRD and SEM-EDS revealed that the main constitutional phases of as-cast Mg/HA composites were α-Mg and HA whereas, in Mg-Sn/HA composites, the phase Mg2Sn was observed along with fine distribution of HA particles. In both the cases, no interfacial reactions observed. The yield strength, ultimate compression strength and hardness were found to be increased with the addition of Sn in Mg/HA composites. Furthermore, the addition of Sn also played an important role in increasing the corrosion resistance of the Mg/HA composites which was attributed the refinement of grain size and the formation of Mg2Sn phase along the grain boundaries. Hence, it was concluded that the addition of Sn improves both mechanical and corrosion properties of Mg/HA composites. © 2019

Mechanical

School of Mechanical Engineering

Chennai Campus

World University root node

Fulltext

Journal of Magnesium and Alloys

Mechanical and corrosion behaviour of hydroxyapatite reinforced Mg-Sn alloy composite by squeeze casting for biomedical applications

The present study focuses on the influence of tin coated hydroxyapatite (HA) particles reinforced in Mg-5 wt.% Sn matrix on corrosion resistance. Electroless coating process has been used to coat hydroxyapatite particles with tin. From the results, it was understood that the electroless coating is a potential technique to successfully coat Sn on HA particles which helps in refinement of grains and uniform distribution of phases. It also prevents the dissociation of HA, thereby formation of unwanted phases such as CaSn which could be detrimental for corrosion properties due to galvanic coupling. The biodegradation was reduced by the addition of Sn coated HA in comparison with reinforcement of uncoated HA particles. © 2020 Elsevier Ltd

Composites Communications

Electroless tin coated hydroxyapatite reinforced Mg–Sn alloy composite for enhanced bio corrosion resistance and bioactivity

The present work investigates the mechanical, corrosion and bioactive behaviour of Mg-1Sn reinforced with 5, 10 and 15 wt% of Al2O3 fabricated by squeeze casting route. The phase analysis and microstructure of as-cast composites were characterized by x-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) respectively. Mechanical properties were evaluated by conducting the compression test. In order to evaluate the in-vitro corrosion properties of as-cast composites, Tafel and electrochemical impedance spectroscopy (EIS) techniques were performed in simulated body fluid (SBF). In-vitro bioactivity test was also carried out in SBF for 7 days of immersion period. Compression test results have showed that the increase in Al2O3 content up to 10 wt% in Mg-1Sn matrix would increase the compression strength and deteriorate on further increase Al2O3 content. The similar trend was observed in case of corrosion behaviour indicating that beyond 10 wt% of Al2O3, both mechanical and corrosion properties diminish. However, bioactivity performance was almost similar in case of all the composites and was better compared to Mg-1Sn alloy without the addition of Al2O3. Hence, it was concluded that the addition of Al2O3 increases the bioactivity of the Mg-1Sn alloy and up to the 10 wt% addition would enhance the mechanical and corrosion properties and further increase in Al2O3 content, they seem to be declining. © 2019 IOP Publishing Ltd.

Materials Research Express

Mg-1Sn/Al2O3 biodegradable composites: Effect of Al2O3 addition on mechanical, in-vitro corrosion and bioactivity response

A novel quaternary Magnesium (Mg) alloy was prepared by using elemental powders through powder metallurgical techniques assisted with hybrid microwave sintering. Through the alloying elements, the microstructure and mechanical properties of quaternary Mg-6Al-3Ca-1Sn alloy were investigated. The microstructure of quaternary Mg alloy revealed the formation and distribution of intermetallic phases Mg2Sn, MgSnCa, MgAlCa, Mg17Al12 and Mg2Ca in α-Mg matrix. The addition of 1 wt% tin results in the equiaxed grain structure and exhibited the compression strength of 162 N/mm2 and hardness of 72 HV respectively. © 2017 Elsevier Ltd.

VIT Unitversity

Materials Today: Proceedings

Mechanical properties and Microstructure evolution of quaternary Mg-6Al-3Ca-1Sn alloy

Non-ferrous materials are widely used in industries, especially because of its corrosion resistance property. Among them Aluminium alloys are widely used because of its ease of machinability, good thermal Conductivity, less weight etc. Presently Aluminum is more used by industries than steel. Further Aluminium with alloy elements like copper, nickel, magnesium, tin etc. will enhance the properties of the materials and these alloyed elements have more industrial applications. Solution Treatment enhances the properties of these aluminium alloys. This work is focused on synthesis and characterization of hexenary aluminium Alloy (Al-Cu-Sn-Ni-Mg-Fe) by gravity die casting technique. The microstructure and wear behavior of as cast, solution treated alloys were elucidated by optical microscopy, pin-on-disc wear test. The mechanical properties were assessed by the tensile test, hardness test and compressive test. Solution treated aluminium alloy showed the remarkable improvement in wear resistance, hardness and tensile strength. The uniformly dispersed thermally stable θ and Ω phases in the aluminium matrix are one of the predominant factor in improving the hardness and tensile properties. The increase in hardness was achieved with solution treatment significantly reduced the wear rate. © 2006-2018 Asian Research Publishing Network (ARPN).

ARPN Journal of Engineering and Applied Sciences

Effect of solution treatment on microstructure, mechanical and wear characteristics of gravity die cast aluminium alloy

Magnesium (Mg) and its alloys have been widely researched for orthopedic applications recently. Mg alloys have stupendous advantages over the commercially available stainless steel, Co-Cr-Ni alloy and titanium implants. Till date, extensive mechanical, in-vitro and in-vivo studies have been done to improve the biomedical performance of Mg alloys through alloying, processing conditions, surface modification etc. This review comprehensively describes the strategies for improving the mechanical and degradation performance of Mg alloys through properly tailoring the composition of alloying elements, reinforcements and processing techniques. It also highlights the status and progress of research in to (i) the selection of nutrient elements for alloying, reinforcement and its effects (ii) type of Mg alloy system (binary, ternary and quaternary) and composites (iii) grain refinement for strengthening through severe plastic deformation techniques. Furthermore it also emphasizes on the importance of Mg composites with regard to hard tissue applications. © 2017