Process and Performance of β-SiCp/Al Prepared by Bottom-Vacuum Pressureless Infiltration

A composite material β-SiCp/Al was fabricated by a novel manufacturing process of bottom-vacuum pressureless infiltration. The β-SiC perform was oxidized at 1373 K and the infiltration in molten Al with the addition of Si and Mg. To evaluate the microstructure and the fractograph of the prepared composites, metallographic and scanning electron microscopes (SEM) were applied. The results reveal that SiC particles can be distributed in the aluminum matrix uniformly, the SiC preform can be completely infiltrated by the molten aluminum. X-ray diffraction (XRD) shows that the main crystalline phases in the composites are β-SiC and Al. There exist Mg2Si, MgAl2O4 interface products, brittle phases such as Al4C3 are not formed within the interface zone. Mechanical properties of the β-SiCp/Al composites were investigated by the wear and friction, Brinell hardness tests. The results prove that the wear mechanisms of the composites are abrasive and adhesive wear. With the increased of SiC volume fraction the wear rate of the composite decreases while the hardness increases.