Electrical resistivity of metal matrix composites

Theoretical models for predicting the electrical resistivity of metal matrix composites reinforced with continuous fibers, short fibers, and particulates were developed by integrating thin slices of composite cells. The experimental electrical resistivity of aluminum, copper, and silver matrix composites was measured and compared with theoretical values derived from the models. Experimental resistivity of composites followed the trend of theoretical prediction, increasing with increasing volume fraction and decreasing size of reinforcement. Deformation regions containing residual stresses and dislocations formed around the reinforcement and raised the resistivity of composites. The magnitude of residual stresses and the dislocation density were found to depend on the type, size and shape of reinforcement, as well as the matrix type. The effective size of the deformation regions varied due to their overlapping and better fitted the calculated curves through empirical modification. Theoretical prediction of resistivity that takes into account the effect of residual stresses and dislocations, and the overlapping of deformation regions agreed reasonably well with experimental results.