SILICON-ALUMINUM NETWORK COMPOSITES FABRICATED BY LIQUID-METAL INFILTRATION

This paper provides a new method for fabricating interpenetrating silicon-aluminium network metal-matrix composites. This method involves the infiltration of an aluminium-silicon alloy (Al-12Si-1Mg or Al-30Si-1Mg) liquid into a silicon particle (50 vol%) preform. The silicon particles were partially dissolved by the liquid alloy and, together with silicon contributed by the original Ar-Si-Mg matrix, resulted in an Si network after solidification. The network composites were metallurgically sound, with no porosity, and exhibited a thermal expansion coefficient down to 7.7 x 10(-6)degrees C-1 at 50-100 degrees C, compressive strength up to 580 MPa, tensile strength up to 160 MPa and Vickers hardness up to 390.