Processing Fracture Toughness and Damage Mechanics Studies of MMC for Aerospace

Aluminum metal matrix composites (MMCs) find important applications in aerospace where specific stiffness is important. Low cost fly ash reinforcement is widely used in aluminium metal matrix composite due to its property of low density, high young modulus and strength apart from good mechanical and chemical compatibility & thermal stability. In the present paper the influences of weight fraction of particulate reinforcement on tensile, fracture toughness have been evaluated. The fracture toughness (KIC) of the aluminum fly ash composite increases by almost 24% that of base alloy. The load and COD plot shows hysteresis loop in loading and unloading compliance curve. This is indicative of crack closure. The reason for crack closure may be surface roughness resulting from reinforcement particles in the composites. The fracture behavior and micro-mechanism of failure in base alloy and composites have been observed under SEM and optical microscopy.