| Magnesium matrix composites are very promising materials in the transportation and aerospace industries due to their enhanced characteristics and cost effectiveness. Based on the new AJ52 alloy, special attention is given to squeeze casting MMCs, with Saffil(TM) Al2O3 fibers used as the reinforcement. In order to obtain an even distribution of the fiber in the matrix, a porous preform was produced using vacuum filtration. The composites with fiber volume fraction of 5, 10, and 15% were squeeze cast and the microstructure and mechanical properties were investigated. The main advantage of squeeze casting in fabricating of MMCs is that it can overcome the poor wettability of magnesium alloys on ceramic fibers, enhancing the bonding at the interface and transferring the load from the weak matrix to the high strength short fibers.; The results showed an increase of tensile strength by 40%, i.e., from 169 to 237 MPa despite a 13% increase of the density from 1.80 to 2.04 g/cm 3. Also an increase of the matrix hardness was observed which is attributed to the reinforcement. Moreover, a correlation between tensile and shear punch tests was developed in order to overcome the difficulty of machining large composite tensile samples. |
