Effect of Silicon Contents of Aluminium Alloy on Properties of Si3N4/Al Composites Prepared by Pressureless Infiltration

Si3N4/Al composites with different silicon contents were prepared by pressureless infiltration, and microstrcuture and properties of the composites were investigated. The results show that interfacial reaction happened between the aluminium alloy and Si3N4. Ductile fracture of the aluminium alloy matrix and cleavage fracture of Si3N4 were the main fracture machanism of the composites. With the silicon mass fraction of the aluminium alloy increased from 0 to 12%, the hardness of the composites increased from 69 HRA to 77 HRA and the bending strength decreased from 498 MPa to 333 MPa.