Development of high strength magnesium-copper based hybrid composites with enhanced tensile properties

Abstract

The requirements for reduced fuel consumption and limited emission have triggered high consumption of magnesium in recent years due to its inherently low density and ensuing potential to exhibit advantageous specific mechanical properties. In the present study, monolithic and copper particulate reinforced magnesium composites were synthesised using an innovative disintegrated melt deposition technique followed by hot extrusion. Microstructural characterisation of the composite samples showed uniform distribution of Cu and Mg - Cu based intermetallic particulates in the matrix material, good interfacial integrity of the magnesium matrix with reinforcement particulates, and the presence of minimal porosity. Physical properties characterisation revealed that the addition of copper as reinforcement marginally reduced the coefficient of thermal expansion (CTE) of pure magnesium. Mechanical properties characterisation revealed that the addition of copper in magnesium led to significant improvement in hardness, elastic modulus, 0.2% yield strength and UTS, while the ductility was adversely affected. The results further revealed that the combination of 0.2% yield strength, UTS, and ductility exhibited by Mg - Cu formulations was superior to that of high strength magnesium alloy AZ91 reinforced with a much higher volume percentage of SiC. An attempt was made in the present study to correlate the effect of the presence of copper and its increasing amount with the microstructural, physical and mechanical properties of the magnesium.