Mechanical properties of Al-Si alloy/Si3N4 interpenetrating phase composite based on a preform fabricated at 1200°C

Interpenetrating phase composites with three-dimensional co-continuous architecture are promising materials for advanced structural applications due to their excellent combination of properties. In this work, a novel and low-cost Al-Si alloy/Si3N4 3 N 4 IPC was fabricated via squeeze infiltration of Al11Si alloy melt into a porous Si3N4 3 N 4 preform manufactured at a low temperature of 1200 degrees C using H3PO4 3 PO 4 as pore-former and binder. Microstructures of IPC show a good infiltration quality and strong interfacial bonding between metal and ceramic phases without any intermediate reaction products. The fabricated IPC exhibited significantly higher specific hardness and stiffness than the Al11Si alloy. Moreover, an excellent damage tolerance, a substantial increase in compressive strength of 420 %, flexural strength of 168 %, and a significant reduction in wear rate of 95 % in the IPC was achieved with respect to Al11Si. The flexural strength and fracture toughness values of the fabricated IPC compare well to values of Al alloy/Si3N4 3 N 4 IPCs reported in the literature, despite being processed using a porous Si3N4 3 N 4 preform fabricated at a much lower temperature.