Microstructure and Thermal Expansion of Hybrid - Copper Alloy Composites Reinforced with both Tungsten and Carbon Fibres

Tungsten as refractory material and high thermal conductive carbon fibres are promising candidates for production of copper matrix composites for high temperature applications. Three types of rod-like samples were prepared by gas pressure infiltration of different carbon/tungsten fibre preforms with copper and/or copper alloy (Cu-0.5Cr) respectively. The fibres are aligned parallel to rod axis and were combined with the tungsten wire cloth. The microstructure of prepared hybrid composites was examined. The samples were thermally cycled 3 times up to 550 degrees C at a relatively high heating/cooling rate (10 K/min) to touch real condition in applications where high heat is formed during short time. The thermal expansion behaviour in radial direction was also analysed. Results show that a combination of both types of reinforcements in rod-shapes samples insures good protection against composite disintegration during high temperature thermal loading.