Influence of Particle Size Distribution on Mechanical Properties and Microstructural Evolution of L-CU/Fly Ash Composite

In the present work the combined effects of particle size and distribution on the mechanical properties of the fly ash particle reinforced Al–Cu alloy composites is investigated. It has been shown that small ratio between matrix/reinforcement particles sizes resulted in more uniform distribution in the matrix. The particles distributed more uniformly in the matrix with increasing in mixing time. The results also showed that homogenous distribution of the fly ash particles resulted in higher hardness, ultimate tensile strength, yield strength and elongation. Fracture surface observations showed that the dominant fracture mechanism of the composites with small fly ash particle size (27μm) is ductile fracture of the matrix, accompanied by the “pull-out” of the particles from the matrix, while the dominant fracture mechanism of the composites with large fly ash particle size (77μm) is ductile fracture of the matrix, accompanied by the fly ash particle fracture.