Creep behavior of AE42 based hybrid composites

Magnesium alloy based hybrid composites with varying levels of delta-alumina short fibers (Saffil(f)(R) and SiC particles (SiCp) reinforcements have been prepared by the squeeze casting technique. The results of the studies done on the basis of microstructural changes and compression creep tests show that the composites with 10 vol% Saffil(f)(R) + 15 vol% SiCp exhibits relatively better creep resistance compared to its other counterparts with 10 vol% Saffil(f)(R) + 10 vol% SiCp and 15 vol% Saffil(f)(R) + 5 vol% SiCp. The effect of solutionising heat treatment on these composites does not yield any remarkable improvement in its creep properties. Investigations on these composites reveal the presence of Mg2Si and Al-RE precipitates. The presence of these precipitates was found to enhance the creep resistance of AE42 hybrid composites. The composites were found to exhibit threshold creep behavior as expected. The effective stress exponents and the activation energy values calculated suggest that 'glide and high temperature climb of dislocations' as the predominant creep mechanism. The interfacial reaction products were MgO and Mg2Si. The interfacial reaction product MgO is more pronounced along the Saffil(f)(R) compared to SiC, A similar behavior was observed in composites before and after heat treatment. (C) 2007 Elsevier B.V. All rights reserved.