INFLUENCE OF REINFORCEMENT SIZE ON MICROPLASTIC DEFORMATION BEHAVIOR OF SiCP/Al COMPOSITES

The microplastic deformation behavior of 20 vol.% SiCp/Al composites with various SiC particle sizes were investigated. The SiC particles are in four nominal sizes of 1, 5, 20 and 56 µm. The experimental results showed that the micro-yield strength is very sensitive to composite microstructure features. As the particle size increases, the micro-yield strength of composites decrease firstly, and then increase. The observed results were attributed to thermal residual stress and dislocation density due to the large difference in coefficient of thermal expansion between the matrix and reinforcement.