The creep behavior of discontinuously reinforced metal-matrix composites

Discontinuously reinforced metal-matrix composites (MMCs) have extensive potential for use in structural applications at elevated temperatures. However, any use at high temperatures will require a detailed understanding of the creep characteristics of the MMCs and especially the dependence of the measured creep rates on the magnitudes of the applied stress and the testing temperatures. This report examines these characteristics with special reference to the well-documented creep behavior of conventional solid-solution alloys. It is shown that creep of these MMCs is controlled by deformation in the matrix alloys and this deformation may be interpreted using a similar approach to that already developed for the creep of solid solution alloys. However additional parameters must be considered in analyzing the creep of MMCs, including the possible presence of a threshold stress and the potential for load transfer and additional substructural strengthening.