A new axisymmetric plasticity theory of fibrous composites which was developed by the authors is applied to problems involving large uniform thermal changes. The determination of loading surfaces and internal microstress fields is described. To verify the accuracy of the theory, a simulation of the T6 temper, followed by uniaxial extension of a W-Al composite has been made. The resulting microstresses show an excellent agreement with available experimental magnitudes measured in situ by an X-ray technique. In addition, there is a very satisfactory agreement with results obtained by the finite-element method.