Microstructure modeling and eddy current determination of constituent volume fractions in metal matrix composites

A nondestructive testing (NDT) technique was developed for the quantitative determination of the reinforcement volume fractions in particulate reinforced metal matrix composites. The proposed technique employed a composite micromechanics for the microstructure of the composite medium together with the measurement of anisotropic electrical conductivity. When the measured conductivity was coupled with the theoretically predicted conductivity, the unknown reinforcement volume fraction was calculated. An analytical model based on the Mori-Tanaka method was described which relates the NDT signatures to the composite microstructure. The volume fractions were calculated using eddy current measurements made on a wide range of silicon carbide particulate (SiCp) reinforced aluminum (Al) matrix composites. The calculated SiCp volume fractions were in good agreement with the measured volume fractions in the range of 0-40 percent. The technique was also found to be effective in estimating the total volume percentage of reinforcement and intermetallic compound formed during the processing stage.