Fabrication and thermal conductivity of short graphite fiber/Al composites by vacuum pressure infiltration

Short graphite fiber/Al composites were fabricated by a modified two-step vacuum pressure infiltration technique. Copper-coated graphite fibers preform was infiltrated with liquid aluminum at 800℃ under infiltration pressure of 1 MPa and solidification pressure of 30 MPa for 30 min. The effects of surface modification and the processing parameters of vacuum pressure infiltration on relative density and thermal conductivity of the composites were systematically studied. The results show that short graphite fiber/Al composite with relatively high density of 99.1% and thermal conductivity of 208 W·m⁻¹·K⁻¹ was successfully fabricated. Through the application of copper coating onto the graphite fibers, the in-plane thermal conductivity of the composite was effectively enhanced from 117 W·m⁻¹·K⁻¹ to 208 W·m⁻¹·K⁻¹ as a result of improved interfacial bonding. The obtained short graphite fiber/Al composites are promising materials for electronic packing applications.