Fabrication and characterisation of pure magnesium-30 vol.% SiCP particle composite

Pure magnesium-30 Vol.% SiC particle composite are fabricated by melt stir technique without the use of a flux or protective inert gas atmosphere. After hot extrusion with an extrusion ratio of 13, Mg-30 vol.% SiC, composites have been evaluated for their tensile properties at room and elevated temperatures (up to 400 degrees C). Composites in the as-cast conditions do not show any change in dendrite arm spacing/cell size compared to unreinforced pure magnesium. However, in the extruded conditions average grain size of the composites is 20 mu m compared to 50 mu m in the pure magnesium. Microstructure shows no evidence of reaction product at particle/matrix interface. At room temperature, stiffness and UTS of the extruded composites are 40 and 30% higher compared to unreinforced pure magnesium, signifying significant strengthening due to the presence of the SiC particles. Further, up to temperatures of 400 degrees C, composites exhibit higher UTS compared to pure magnesium. Mg composites show a wear rate lower by two orders of magnitude compared to purl Mg, when tested against steel disc using pin-on disc machine. (C) 2000 Elsevier Science S.A. All rights reserved.