General approach on the growth strain versus viscoplastic relaxation during oxidation of metals

High temperature oxidation of metals induces residual stresses in metals and growing oxides. In this work, the evolution of the residual stresses in those oxides layers, during isothermal oxidation of metals is studied. A new justification is proposed in order to explain the origin of those stresses leading to a proportional dependence between the growth strain and the oxide layer thickness. Moreover, we emphasize the relation between viscoplastic strain and growth strain. Using the mechanics of thin layers, as well as the analysis proposed to describe the growth strain, a system of equations is deduced that predicts the stresses evolution with oxidation time. Comparison with previous experimental results is also made. (C) 2007 Elsevier B.V. All rights reserved.