Low thermal expansion composite with interpenetrating aluminum and silicon networks fabricated by liquid Al-Si infiltration of a silicon particle preform

This paper provides a new method for fabricating interpenetrating A/B network composites. This method involves the infiltration of an A-B alloy liquid into a B particle preform, such that the A-B alloy liquid partially dissolves the B particles, thereby causing the change of the B particles into a B network, to which the A-B alloy also contributes, so that the volume fraction of the B network is higher than that of the B particles in the preform. With Al as A and Si as B, this work also provides a new composite, which comprised interpenetrating Al (31 vol.%) and Si (69 vol.%) networks. This Al/Si composite was fabricated by liquid Al-30Si-1Mg infiltration of a 50 vol.% Si particle preform. It exhibited a low thermal expansion coefficient of 7.2×10^-6 °C^-1 at 30-100 °C.