Analysis of Internal Stress Relaxation in an Al/SiC Composite by Neutron Diffraction

Residual thermal stresses in a SiC whisker reinforced/Al 7075 matrix composite were measured as a function of temperature by means of the neutron diffraction technique. The residual stresses in both phases decrease in magnitude with increasing temperature and at the 'equivalent temperature', measured to be about 500K, they reach the stress-free state. Increasing the temperature, these stresses increase numerically in a reverse sense for both phases. The experimental results are explained with an analytical model, developed on the basis of Eshelby's equivalent inclusion method.