Microstructure and Mechanical Properties of Silicon Nitride Reinforced Aluminum Matrix Composites Fabricated by Pressure Infiltration

Abstract

ABSTRACTThe present study aimed to investigate the microstructure and mechanical properties of aluminum matrix composites reinforced with high volume fraction of Si3N4 fabricated by the pressure casting technique, with variations in the composition of matrix alloy and microstructure of preforms. Characterization was carried out by a combination of metallography, flexural and load-controlled fatigue tests to study the flexural strength, fracture toughness and fatigue behavior in the composites. The findings indicated that increasing matrix strength resulted in an increase in flexural strength and fatigue resistance of composites. The fracture toughness of composites increased with the volume fraction of infiltrated tough Al phase. The CIP pressure exerted a significant effect on mechanical properties of composites. The improvement in mechanical properties of composites is associated with the load transfer effect from matrix to the stiffer reinforcement.