Elastic Moduli of Silicon Carbide Particulate Reinforced Aluminum Metal Matrix Composites

Abstract

The mechanical properties of metal matrix composites (MMCs) reinforced by discontinuous silicon carbides are governed by the properties of the reinforcing phase, as well as their morphology (whisker vs. particulate), orientation and volume fraction. The morphology of SiC particles and their orientation are major variables affecting the anisotropic properties of these composites. SiC whisker (SiC_W) reinforced aluminum MMCs tend to have higher strengths and moduli in the extrusion direction due to the high degree of whisker alignment in that direction, and these values are higher than those for SiC particulate (SiC_p) reinforced composites at a given reinforcement level [1]. SiC_p reinforced MMCs are known to be more isotropic in the extrusion plane. In situations requiring multidirectional reinforcement, particulate reinforced composites can outperform whisker reinforced composites. Thus, it is important to characterize the mechanical properties of these composites in order to develop the criteria for selecting microstructural design variables.