Strengthening mechanisms and modelling of mechanical properties of submicron-TiB2 particulate reinforced Al 7075 metal matrix composites

The physics of matrix-reinforcement consonance in metal matrix composites (MMCs) is quite complex and it is difficult to quantify the effects of individual parameters on the composite properties. Strengthening mechanisms proposed so far are under assumptions of uniform particle dispersion and perfectly bonded interface. However, practically it is quite difficult to achieve a perfect uniformity in particle dispersion, and a perfect interface bonding may not be achieved through liquid state processing of MMCs. This paper accentuates on implementation of various established strengthening mechanisms on mechanical properties of Al 7075/submicron-TiB2 MMCs, synthesized through semisolid stirring and ultrasonic agitation assisted squeeze casting route. Analytical models were proposed to predict elastic modulus and yield strength of the MMCs considering the effects of porosity, and the proposed models were validated with the experimental results and predicted results of some established models. Reasonable agreement of the proposed model was attained with the experimental results and the established models, more prominently at higher volume fractions of particle incorporation.