Effect of the Particle Size and Matrix Strength on Strengthening and Damage Process of the Particle Reinforced Metal Matrix Composites

Roles of the particle, strengthening, and weakening during deformation of the particle reinforced metal matrix composite, were studied using in situ technique. Composites with three different strengths Al-Cu-Mg alloy matrices reinforced by three sizes SiC particles were manufactured and subjected to in situ tensile testing. Based on in situ observation, damage process, fraction and size distribution of the cracked particles were collected to investigate the behavior of the particle during composite deformation. The presence of the particle strengthens the composite, while the particle cracking under high load weakens the composite. This strengthening to weakening transformation is controlled by the damage process of the particle and decided by the particle strength, size distribution, and the matrix flow behavior together. With a proper match of the particle and matrix, an effective strengthening can be obtained. Finally, the effective match range of the particle and the matrix was defined as a function of the particle size and the matrix strength.