Microstructure and tensile properties of Si3N4p/2024Al composite fabricated by pressure infiltration method

2024Al matrix composite reinforced with 45 vol.% Si3N4 particles (Si3N4p/2024 composite) with average particle size of 1.5 μm was fabricated by pressure infiltration method. The tensile behaviour and microstructure of Si3N4p/2024 composite were investigated. β-Si3N4 was the main reinforcement, while α-Si3N4 and few large Si particles were also observed in composite. Few aligned linear dislocations were observed in Si3N4 particles due to internal and thermal stresses. MgAl2O4 was observed at Si3N4–Al interface. Fracture of Si3N4p/2024Al composite was characterized by brittle fracture, indicating strong Si3N4–Al interfacial bonding. Dislocation density in Si3N4 particles and Al matrix increased after tensile testing.