Thermal Expansion, Young’s Modulus and Poisson’s Ratio of Copper-Carbon Fiber Composite

The effect of fiber arrangements on the thermal expansion coefficient, the Young’s modulus and the Poisson’s ratio of copper-carbon fiber composite was studied. Results obtained in this study were as follows: (1) The average linear thermal expansion coefficient of the composite in the range from room temperature to 473 K became smaller as the volume of carbon fiber increased. The thermal expansion coefficient of the composite containing high modulus carbon fiber was smaller than that of the composite containing high strength carbon fiber. The effectiveness of fiber arrangements in reducing the thermal expansion coefficient was in the decreasing order of the 1) unidirectional, 2) spiral, 3) bidirectional and 4) plain weaving arrangement. (2) The Young’s modulus of the composite which contained high modulus carbon fiber was greater than that of the composite containing high strength carbon fiber. The Young’s modulus parallel to the fiber direction of the unidirectional composite was in proportion to the fiber content. Young’s modulus perpendicular to the fiber direction, on the other hand, decreased as the fiber content increased. The Young’s modulus of bidirectional and weave composites had a weak relation to the fiber content. (3) The above results were predictable from a careful application of the “rule of mixtures” for composites. (4) The Poisson’s ratio of the composite became smaller as the volume of carbon fibers increased. The effectiveness of fiber arrangements in reducing Poisson’s ratio was in the increasing order of the 1) parallel to the fiber direction of the unidirectioal, 2) bidirectional, 3) plain weaving and 4) perpendicular to the fiber direction of the unidirectional arrangement. (5) In the thermal fatigue tests, no degradation in the thermal expansion coefficient of this composite was observed.