Multiscale homogenization models for the elastic behaviour of metal/ceramic composites with lamellar domains

This study predicts the elastic properties of an innovative metal–ceramic composite with statistically oriented domains of parallel ceramic platelets embedded in a eutectic Al–Si-alloy. For this purpose, a two-step homogenization procedure was employed by finite element- and micromechanical modelling. In a first step, the microstructure of the specimen was divided in domains with the same orientation of lamellae and the elastic properties of single domains were calculated while a precise representation of the shape of the lamellae was attempted. In a second step the elastic constants of a large specimen consisting of many domains were computed both by finite element and micromechanical modelling. The experimental Young’s modulus of such poly-domain specimens was determined by an acoustic resonance method and was lower than predicted. The differences can be explained by microcracks caused by large residual microstresses produced in these materials when they are cooled from the manufacturing temperature.