NONDESTRUCTIVE EDDY-CURRENT EVALUATION OF ANISOTROPIC CONDUCTIVITIES OF SILICON-CARBIDE REINFORCED ALUMINUM METAL-MATRIX COMPOSITE EXTRUSIONS

Nondestructive eddy current methods were used to evaluate the electrical conductivity behavior of silicon-carbide particulate (SiC(p)) reinforced aluminum (A1) metal-matrix composite extrusions. The composites investigated included 2124, 6061, and 7091 A1 base alloys reinforced by SiC(p). The composite extrusions exhibited anisotropic conductivities with the maximum conductivity occurring along the extrusion plane. Microstructural characterization showed that the observed anisotropic conductivities could result from the preferred orientation distribution of SiC(p). A theoretical model was formulated to quantify the influence of composite constituents (SiC(p), intermetallics, and A1 base alloy) on the anisotropic conductivities of the composites. The theoretical predictions of conductivities were found to be in good agreement with the experimental results.