AN EDDY-CURRENT TECHNIQUE FOR THE MEASUREMENT OF CONSTITUENT VOLUME FRACTIONS IN A 3-PHASE METAL-MATRIX COMPOSITE

An eddy current technique is developed for the measurement of reinforc ement and intermetallics concentrations in extruded particulate-reinfo rced metal-matrix composites. The technique employs a theoretical cond uctivity model which accounts for the constituent phases, together wit h a measurement of two anisotropic conductivities on the composite, fo r determining the reinforcement and intermetallics volume fractions. T owards implementation of this technique, an analytical model is descri bed which relates the anisotropic conductivities of extruded particula te-reinforced composites to their microstructures. The volume fraction s were calculated using eddy current measurements made on a wide range of silicon carbide particulate (SiCp) reinforced aluminum matrix comp osite extrusions. The calculated values are shown to be in good agreem ent with the actual metallographically measured volume fractions of th e reinforcement and intermetallics. The technique may be adopted for a n on-the-fly assessment of product quality in a processing environment .