High-temperature deformation of metal-matrix composites will be studied from the micromechanics standpoint. The study will also include the influence of distributed damage in the ductile matrix on the overall time-dependent behavior of the material. Guided by the observations that most metallic constituents may undergo both primary and secondary creep in addition to the usual elastic deformation, and that the creep rate usually depends on stress nonlinearly, the following four specific problems will be examined: (1) stress-strain relation of the composite under a constant strain rate, (2) higher creep strain range, and (4) the extension to a higher particle or fiber concentration. These studies will be carried out with a special reference to the practical and potential service environments. Whenever possible, simple macroscopic constitutive theories which can reflect the essential features of these micromechanical considerations will be developed for design and analysis. The aim is to translate this scientific knowledge into use, so that the microstructures which would provide the strongest creep resistance under the service conditions could be identified.
