Microstructure and tensile properties of Si_3N_4p/2024Al composite fabricated by pressure infiltration method

摘要

2024A1 matrix composite reinforced with 45 vol.% Si_3N_4 particles (Si_3N_4p/2024 composite) with average particle size of 1.5 um was fabricated by pressure infiltration method. The tensile behaviour and micro structure of Si_3N_4p/2024 composite were investigated. p-Si_3N_4 was the main reinforcement, while a-Si_3N_4 and few large Si particles were also observed in composite. Few aligned linear dislocations were observed in Si_3N_4 particles due to internal and thermal stresses. MgAl2O4 was observed at Si_3N_4-Al interface. Frac ture of Si_3N_4p/2024Al composite was characterized by brittle fracture, indicating strong Si_3N_4-Al interfa cial bonding. Dislocation density in Si_3N_4 particles and Al matrix increased after tensile testing.