Faculty Publications
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Item Tribological Response of Magnesium/Glass Microballoon Syntactic Foams(Springer Science and Business Media Deutschland GmbH, 2022) Manakari, V.; Parande, G.; Doddamani, M.; Srivatsan, T.S.; Gupta, M.Magnesium (Mg)-based materials have great potential to replace the existing aluminum alloys and steels used in applications spanning the industries of defense, aerospace, and automotive due in essence to their excellent specific strength [σ/ρ], damping characteristics, and impact resistance. In this research study, we design an ultralow density magnesium/glass microballoon (GMB) syntactic foam having a density of 1.47 g/cc using the technique of Disintegrated Melt Deposition (DMD). The resultant material offered a healthy combination of extraordinary properties outperforming the existing aluminium and iron syntactic foams in terms of a noticeable improvement in specific strength [σ/ρ]. Further, the wear resistance of magnesium under dry sliding conditions showed a significant enhancement (~2.5 times) following the addition of glass microballoon (GMB). Abrasion and oxidation were identified to be the dominant wear mechanisms post worn-surface analysis. Morphology of the worn specimen provided clean, clear, and convincing evidence for the occurrence of delamination wear, which has traditionally limited the competitive advantage of magnesium and its alloy counterparts for selection and use in safety–critical components in transportation vehicles. This can be effectively overcome by the development of the proposed syntactic foams, which provide a unique cushioning effect against the applied load. © 2022, The Minerals, Metals & Materials Society.Item Role of Rare Earth Oxide Reinforcements in Enhancing the Mechanical, Damping and Ignition Resistance of Magnesium(Springer, 2019) Kujur, M.S.; Manakari, V.; Parande, G.; Doddamani, M.; Mallick, A.; Gupta, M.Magnesium based nanocomposites, on account of their excellent dimensional stability coupled with mechanical integrity, have provided the much-needed impetus for utilization in both aerospace-related and automobile-related applications. However, the perceived easy ignition and flammability of magnesium alloys create a detrimental safety feature that hinders the aerospace application opportunities. Incorporation of rare earth metal oxides into magnesium matrix can induce ‘reactive element effect’ (REE), due to their strong rare earth–oxygen interactions. Along with enhancing the protective characteristics of oxides on many metals and alloys, the addition of such rare earth oxides also helps in realizing a refined microstructure and good strength–ductility combination in the composites. This manuscript presents the mechanical properties, damping and ignition resistance characteristics of the new and improved composite materials engineered by reinforcing magnesium with rare earth oxide nanoparticle. Rationale for the observed properties is discussed while concurrently establishing the relationship between microstructure of the engineered composites and resultant mechanical properties. © 2019, The Minerals, Metals & Materials Society.Item Enhancing the ignition, hardness and compressive response of magnesium by reinforcing with hollow glass microballoons(MDPI AG Postfach Basel CH-4005, 2017) Manakari, V.; Parande, G.; Doddamani, M.; Gupta, M.Magnesium (Mg)/glass microballoons (GMB) metal matrix syntactic foams (1.47-1.67 g/cc) were synthesized using a disintegrated melt deposition (DMD) processing route. Such syntactic foams are of great interest to the scientific community as potential candidate materials for the ever-changing demands in automotive, aerospace, and marine sectors. The synthesized composites were evaluated for their microstructural, thermal, and compressive properties. Results showed that microhardness and the dimensional stability of pure Mg increased with increasing GMB content. The ignition response of these foams was enhanced by -22 °C with a 25 wt % GMB addition to the Mg matrix. The authors of this work propose a new parameter, ignition factor, to quantify the superior ignition performance that the developed Mg foams exhibit. The room temperature compressive strengths of pure Mg increased with the addition of GMB particles, with Mg-25 wt % GMB exhibiting the maximum compressive yield strength (CYS) of 161 MPa and an ultimate compressive strength (UCS) of 232 MPa for a GMB addition of 5 wt % in Mg. A maximum failure strain of 37.7% was realized in Mg-25 wt % GMB foam. The addition of GMB particles significantly enhanced the energy absorption by -200% prior to compressive failure for highest filler loading, as compared to pure Mg. Finally, microstructural changes in Mg owing to the presence of hollow GMB particles were elaborately discussed. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.Item Evaluation of wear resistance of magnesium/glass microballoon syntactic foams for engineering/biomedical applications(Elsevier Ltd, 2019) Manakari, V.; Parande, G.; Doddamani, M.; Gupta, M.Friction and wear behaviour of magnesium/glass microballoon (GMB) foams synthesized by Disintegrated Melt Deposition (DMD) were investigated under dry sliding conditions. The coefficient of friction (?) decreases with increasing GMB content. Mg-25wt.% GMB exhibits ?13% lower ? pure compared to magnesium. Wear resistance of magnesium showed a significant enhancement (?2.5 times) post GMB addition. Abrasion and oxidation were identified as dominant wear mechanisms post worn-surface analysis. Delamination wear, which has traditionally limited the advantages of composites with discontinuous reinforcements in sliding wear conditions for structural and biomedical applications can be effectively addressed by the development of these proposed syntactic foams. © 2019 Elsevier Ltd and Techna Group S.r.l.Item In-vitro degradation of hollow silica reinforced magnesium syntactic foams in different simulated body fluids for biomedical applications(MDPI AG, 2020) Manakari, V.; Kannan, S.; Parande, G.; Doddamani, M.; Columbus, S.; Priya Sudha, K.; Vincent, S.; Gupta, M.This article reports the mechanical and biocorrosion behaviour of hollow silica nanosphere (SiO2) reinforced (0.5–2 vol.%) magnesium (Mg) syntactic foams. Room temperature tensile properties’ characterization suggests that the increased addition of hollow silica nanospheres resulted in a progressive increase in tensile yield strength (TYS) and ultimate tensile strength (UTS) with Mg-2 vol.% SiO2 exhibiting a maximum TYS of 167 MPa and a UTS of 217 MPa. The degradation behaviour of the developed Mg-SiO2 syntactic foams in four different simulated body fluids (SBFs): artificial blood plasma solution (ABPS), phosphate-buffered saline solution (PBS), artificial saliva solution (ASS) and Hanks’ balanced saline solution (HBSS) was investigated by using potentiodynamic polarization studies. Results indicate that corrosion resistance of the Mg-SiO2 syntactic foam decreases with increasing chloride ion concentration of the SBF. Mg-1.0 vol.% SiO2 displayed the best corrosion response and its corrosion susceptibility pertaining to corrosion rate and polarisation curves in different SBF solutions can be ranked in the following order: ABPS > PBS > HBSS > ASS. The surface microstructure demonstrated the presence of a better passivated layer on the syntactic foams compared to pure Mg. The observed increase in corrosion resistance is correlated with intrinsic changes in microstructure due to the presence of hollow silica nanospheres. Further, the effect of corrosive environment on the degradation behaviour of Mg has been elucidated. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.