Effect of Applied Pressure on the Microstructure and Mechanical Properties of AZ91/Al2O3 Composite Produced by Squeeze Casting

The present paper is focused on the AZ91/Al2O3 composite obtained via infiltration of alumina preform by molten AZ91 alloy. The microstructure and mechanical properties of AZ91/Al2O3 composite were investigated as a function of applied pressure and volume fraction of reinforcement.For this purpose the applied pressure on the melt was chosen as 0, 50, 75 and 100 MPa and it was kept until solidification was completed. Results revealed that with increasing the applied pressure to 100 MPa, ultimate compressive strength and ductility of composite, improved as compare to the gravity casting specimens due to decrease of matrix grain size and better reinforcement-matrix cohesion. Also the strength and porosity of samples increased by increasing the volume fraction of reinforcement, and the matrix grain size decreased.