Modulus and yield stress anisotropy of short fibre metal-matrix composites

A continuum mechanics model based on the Eshelby method is used to predict the variation of elastic moduli and yield strengths of MMCs with loading orientation. These predictions are compared with mechanical data obtained both for aluminium reinforced with particulate SiC and for whisker-reinforced material. The modelled elastic properties correlate well with the data, and suggest a quick and accurate way of measuring effective inclusion volume fraction and aspect ratio. The model also accounts for the form, though not the magnitude, of the angular variation of the difference between compressive and tensile yield stresses. However, the relative magnitudes of the longitudinal and transverse yield stresses cannot be explained by considering only unrelaxed mean stresses.