Deformation in Al-SiC composites due to thermal stresses

Plastic strains and the extent of the plastic zone due to differential thermal expansion were experimentally determined in an Al--SiC composite (99.99% pure Al). The combined plastic shear strains gamma sub cpss at the Al/SiC interface for furnace-cooled, air-cooled and quenched samples were found to be 1.32, 1.23 and 0.99%, respectively. Profiles of gamma sub cpss were plotted vs. distance from the interface and compared with the theoretical distribution of effective strain epsilon . The theoretical extent of the plastic zone measured from the interface was found to be 1.3 multiplied by the particle radius. This value was slightly less than the observed value. The plastic deformation on the heating half of the thermocycle was found to be at least equal to the deformation on the cooling half. A theoretical treatment of the local plastic deformation in a short composite cylinder was suggested, from which the effective plastic strain epsilon and the extent of the plastic zone were determined. 14 ref.--AA