Fabrication of Unidirectionally Orientated Carbon Fiber Reinforced Cu-Based Composites by Hot Extrusion and Evaluation of Their Thermal Properties

Abstract

Unidirectional orientation of the carbon fiber is essential in the fabrication of Cu-carbon fiber composites with high thermal conductivity, because the fiber exhibits its very high thermal conductivity only in the longitudinal direction. In this study, hot extrusion of a mixture of Cu powder and carbon fiber was applied to fabricate the unidirectionally orientated carbon fiber reinforced Cu-based composite and the effects of the volume fraction of carbon fiber on the thermal conductivity have been investigated. It has been demonstrated that hot extrusion of the Cu powder-carbon fiber mixture successfully align the fiber to orient along the extrusion direction, and consequently, the thermal conductivity in this direction increases with the volume fraction of carbon fiber. For the composite with more than 30 vol% carbon fiber, the application of ultrasonic vibration treatment to the powder-fiber mixture is effective for improving the homogeneity of the mixing and hence increasing the relative density and the thermal conductivity of the composite.