S. Sankaranarayanan

Mg/BN nanocomposites: Nano-BN addition for enhanced room temperature tensile and compressive response

The present study elucidates the effects of nanoscale boron nitride particles addition on the microstructural and mechanical characteristics of monolithic magnesium. Novel light-weight Mg nanocomposites containing 0.3, 0.6 and 1.2u2009vol% nano-size boron nitride particulates were synthesized using the disintegrated melt deposition method followed by hot extrusion. Microstructural characterization of developed Mg/x-boron nitride composites revealed significant grain refinement due to the uniform distribution of nano-boron nitride particulates. Texture analysis of selected Mg-1.2 boron nitride nanocomposite showed an increase in the intensity of fiber texture alongside enhanced localized recrystallization when compared to monolithic Mg. Mechanical properties evaluation under indentation, tension and compression loading indicated superior response of Mg/x-boron nitride composites in comparison to pure Mg. The uniform distribution of nanoscale boron nitride particles and the modified crystallographic texture achieved due to the nano-boron nitride addition attributes to the superior mechanical characteristics of Mg/boron nitride nanocomposites.

Using Energy Efficient Microwaves to Synthesize High Performance Energy Saving Magnesium (Nano) Composites

Magnesium (with density, p = 1.74 g/cc) being ∼ 30% lighter than aluminum and ∼ 70% lighter than steel is an attractive and a viable candidate for the fabrication of lightweight structures. Being the designers’ choice for weight critical applications, extensive research efforts are underway into the development of magnesium metal matrix composites (Mg-MMCs) through various cost-effective fabrication technologies. In recent years, there has been a progressive advancement in utilizing the microwave energy to consolidate powder materials and the present study accentuates the use of energy efficient and environment friendly microwave sintering process to synthesize magnesium based composite materials. The processing advantages of the innovative and cost effective microwave assisted bidirectional rapid sintering technique followed by hot extrusion are first briefly introduced. Subsequently, the properties of various Mg-MMCs (containing micro/nano sized, ceramic/metal/amorphous reinforcement particles) synthesized using this technique are presented. Special emphasis has been made on the commending properties displayed by the nanoparticle reinforced Mg composites (Mg-MMNCs). Finally, an account of on-going research initiatives in the development of novel light weight Mg-composites is highlighted.

Microstructure and mechanical properties of Mg–Al alloys with in situ Al4C3 phase synthesised by CO2 incorporation during liquid state processing

In this work, Mg–Al alloys containing 7 wt.% and 9 wt.% Al were synthesised by the incorporation of carbon dioxide during casting, using the disintegrated melt deposition technique and were characterised after extrusion. Microstructural studies revealed fine–grained structure and phase analyses of Mg–7Al–CO2 and Mg–9Al–CO2 showed the presence of Al4C3 phase formed in situ during processing. Evaluation of mechanical properties of these alloys phase showed improvements in hardness, yield strength and ultimate tensile strength when compared to those without the incorporation of CO2. The observed enhancement in mechanical properties was attributed to the dispersion strengthening effect brought forth by the in situ Al4C3 phase. Based on the processing–structure–property correlation, the significant influence of CO2 incorporation and the processing methods on the microstructural and mechanical properties of the alloys are discussed.