Diffusion-induced recrystallization (DIR) is a mechanism which destabilizes thin film multilayers. New grains formed are distinguished by preferred composition levels characteristic for the diffusion couple. By evaluating these concentrations for different material combinations, it is demonstrated that a break of coherency by spontaneous relaxation is the key to understanding the DIR process. Based on this, a thermoelastic model is derived to predict whether DIR can be expected for a given multilayer and to calculate the characteristic concentration levels.