Magnesium nanocomposites reinforced with a high volume fraction of SiC particulates

The microstructure and indentation behavior of magnesium nanocomposites containing a high volume fraction (up to 15 vol.%) of nanometer-sized SiC was studied using X-ray diffraction, electron microscopy, and microindentation techniques. The indentation hardness and contact stiffness were found to increase with increasing volume fraction of the nanometer-sized SiC particles up to 10 vol.%. The magnesium nanocomposites with 15 vol.% SiC had a lower indentation hardness than that of 10 vol.% SiC. The strain rate sensitivity exponent of the Mg–SiC nanocomposites increased with increasing volume fraction of SiC. The decrease of the indentation hardness suggested that the deformation mechanism of the magnesium nanocomposites was likely altered when the critical volume percent of SiC nanoparticles was achieved, estimated at 10 vol.%.