Influence of Ti coatings on the fatigue behaviour of Al-Matrix MMCs. Part II: FEM simulations

Abstract Part I of this paper showed that fatigue behaviour of Al-based metal matrix composites (MMCs) can be remarkably improved by means of titanium coatings deposited by sputtering at room temperature. Part II presents the results of finite element (FE) simulations carried out to clarify some aspects of the phenomenon, i.e. the effect of surface cavities. In particular, it was found that the effect of titanium thickness on stress distribution in the substrate is negligible if its surface is smooth. Coatings are effective in improving fatigue life because they seal the cavities present on the surface of MMCs: the better the filling of voids, the higher the stress reduction in the substrate during fatigue tests. After complete filling of cavities, further titanium deposition is useless for reducing stresses and improving fatigue behaviour.