Influence of residual stress on thermal expansion behavior

We demonstrate that the thermal expansion behavior of a material can be sub stantially modified by the presence of residual stresses. In the case of a composite tube made of two layers of dissimilar steels, in situ neutron dif fraction measurements revealed a significant difference in the coefficients of thermal expansion along the radial and tangential directions. It is sho wn that the observed difference in thermal expansion is due to the change o f residual stresses with temperature. (C) 1999 American Institute of Physic s. [S0003-6951(99)01647-2].