CREEP-BEHAVIOR OF DISCONTINUOUS SIC-AL COMPOSITES

A review of creep data of discontinuous SiC-Al composites (whisker and particulate) shows that the creep behavior of these composites exhibits two main characteristics: (a) the stress dependence of the steady state (or minimum) creep rate, as described by the value of the stress exponent, is high and variable and (b) the temperature dependence of the steady: state (or minimum) creep rate, which is measured by the creep activation energy, is much larger than that for self-diffusion in aluminum. These two characteristics are examined in the light of theoretical treatments describing the origin of high temperature strengthening in discontinuous metal matrix composites and dislocation models proposed for dispersion-strengthened alloys.