Transverse creep behavior of a unidirectional metal matrix composite

The creep behavior under transverse tensile loading of a unidirectional silicon carbide/aluminum (SiC/Al) composite was characterized experimentally and analyzed by means of a micromechanical model based on the average field theory. Creep testing was conducted on the unreinforced aluminum matrix as well as the composite over a temperature range from 24 degrees C (75 degrees F) and 288 degrees C (550 degrees F). It was found that the minimum creep strain rate in the composite can be described by an Arrhenius type power law equation similar to the one used for the unreinforced matrix, This creep rate for the composite is less sensitive to stress amplitude and temperature than that of the matrix material. During creep, a gradual stress transfer takes place between matrix and fibers, followed by stress redistribution and stress relaxation in the matrix, resulting in higher creep resistance, The measured creep strains for various stress amplitudes and at various temperatures were in favorable agreement with predictions.