Effects of SiC particle size on mechanical properties of SiC particle reinforced aluminum metal matrix composite

In this paper, effects of SiC particle size on the mechanical properties and the failure mechanisms of Al/SiC composites under compression with strain rates ranging from 0.001 to 5200 s⁻¹ were investigated. Al/SiC composites consisting of 65 wt% SiC particles with the average size of 10 μm and 50 μm were studied respectively. The quasi-static (strain rate of 0.001s⁻¹) and dynamic compression tests (strain rates of 2200s⁻¹-5200s⁻¹) were performed separately for both materials with different SiC particle size. And optical microscope (OM) was used to observe the failure characteristics of the reclaimed specimens. The results show that as the increasing strain rate, results in the improvement of yield strength of both composites. Moreover, the composites with the SiC particle size of 10 μm have a larger yield strength than that 50 μm one. The microstructure analyses reveal that separation of SiC particles from aluminum matrix and fragmentation of SiC particles are the main failure mechanisms of Al/SiC composites subjected to compressive loading. The adhesive force between the SiC particles and aluminum matrix has a significant effect on the compressive resistance of the composites. The Al/SiC composites with the small SiC particles size are superior to the larger one under compressive loading due to the more compact interface and larger tension for the movement of dislocations. The perforation test was carried out for the material with the SiC particle average size of 10 μm, and its anti-penetration performance is about 1.50 times higher than 10CrNiMo steel.