Young's modulus of cast HMS 2112-Cf composite - Prediction and ultrasonic evaluation

Abstract

Various models for the prediction of strengthening mechanism of metal matrix composites (MMCs) containing either fibres or particulates are analysed. Assuming that the matrix strengthening by dislocations could be treated as equivalent to the effect of different volume fraction of dispersoids, as well as by considering the effect of morphology of reinforcement on the Young's modulus, an expression for Young's modulus for MMCs has been derived. The Young's modulus values thus predicted, using this model, have been validated by ultrasonically-derived values of Young's modulus of an Al-alloy matrix composite containing 5, 8 and 12 wt% chopped carbon fibre (Cf) dispersoids, in as cast and extruded conditions. Further, the theoretically- and ultrasonically-derived Young's modulus of cast Al-altoy-Cf, composites with 5 and 8 wt% Cf have been found to be comparable with the reported values of Young's modulus for these weight fractions.