The influence of Cr on structure and thermal expansion of copper matrix composites reinforced with unidirectionally aligned continuous high modulus C fibres

The influence of Cr on structure and thermal expansion of copper matrix composites reinforced with unidirectionally aligned continuous high modulus K1100 carbon fibres was studied. It appears that the addition of 1 wt.% of Cr has dramatically improved the wetting of K1100 fibres with the matrix alloy CuCr1, facilitating thus the composite preparation via gas pressure infiltration. Due to the chemical reaction with K1100 fibres a reactive interfacial bonding has been formed. The lack of wetting resulted in larger voids and weak interfacial bonding in Cu-K1100 fibres. The results of thermal expansion measurements confirmed large anisotropy of properties as well as very good structural stability of both composites exhibiting no signs of possible disintegration. This however will have to be further confirmed by increasing the number of thermal cycles. The effect of Cr on the thermal expansion of composites under investigation was found less apparent as in short fibre or particulate reinforced composites.