Interfacial Phenomena In Carbon-copper Alloy System And Preparation Of Carbon Fiber Fabric Reinforced Cu Matrix Composites

The wettability of carbon/copper alloys system is a critical factor in preparation of carbon-copper composite material. It has significant importance on the joining of carbon materials with copper alloy. In this paper, the carbon-copper alloy system was used as the research object. The wettability of Cu alloy system on the carbon substrate was studied at 1300℃ and different holding time with vacuum condition by the the sessile drop method. In order to clarify the wetting mechanism, the interface layer of Cu alloy and carbon was observed by Scanning electron microscope(SEM), the phase composition of the interface of which was analysed by X-ray diffraction(XRD). At the same time, a new type of carbon fiber fabric reinforced Cu matrix(Cf/Cu) composites was prepared by pressureless infiltration method in order to meet the high demand of electronic packaging materials and sliding conductive materials. Microstructure and phase composition of the composite were observed by SEM and XRD. The coefficient of thermal conductivity and thermal expansion of composite materials was measured.Research shows when the Cr content was same in the wetting experiment of molten Cu-Cr alloy on the carbon substrate, wetting angle of C/Cu-Cr alloy are reduced at the holding time for 0min to 30 min, but the wetting angle of C/Cu-Cr alloy is no longer reduced at the holding time greater than 30 min. When the holding time was same, the Cr content with higher than 2% has little effect on the wettability of C/Cu.when the V content was same in the wetting experiment of molten Cu-V alloy on the carbon substrate, wetting angle of C/Cu-V alloy are reduced at the holding time for 0min to 30 min, but the wetting angle of C/Cu-V alloy is no longer reduced at the holding time greater than 30 min. When the holding time was same, the wettability of C/Cu was improved by the V content increased with higher than 2%.when the content of Ti、Zr was same in the wetting experiment of molten alloy of Cu-Ti and Cu-Zr on the carbon substrate, the extension of holding time can improve the wettability of C/Cu alloy. When the holding time was same, the wettability of C/Cu was improved with the increase of the content of Ti、Zr. The structure of interface layer was C/ “Cu-rich” / carbide /Cu between alloy of Cu-Ti and Cu-Zr and C. A new wetting mechanism was developed as “Dissolved-reaction Control” wetting mechanism. At the same time, when the holding time is 60 min and the temperature is 1300℃, the wettability of Cu-10%Zr and C was the best.On the basis of wetting experiment, Cf/Cu composites were prepared by pressureless infiltration method that was a fiber reinforced copper matrix composite.Research shows that carbon fibers were distributed uniformly in the matrix of copper alloy, and there were no voids and defects in the matrix, and the ZrC layer was formed between the Cu and carbon. With the increase of Zr content, the thickness of ZrC interface layer of composite increased and the coefficient of the thermal conductivity and thermal expansion of the composite decreased. When the mass fraction of Zr was 30%, the horizontal and vertical coefficient of thermal conductivity of the composite reaches the lowest value of 139W/m·K and 85W/m·K respectively and the horizontal and vertical coefficient of thermal expansion of composite reached the lowest value of 5.9×10-6/℃ and 3.1×10-6/℃ respectively.