Self-Healing Phenomena in Metals

In comparison to other materials, in metals and metallic systems self-healing of cracks and crack-initiating defects is difficult to achieve due to the fact the solute atoms that act as healing agents are relatively small and generally have a relatively low mobility at the prevailing operating temperatures. In this review, the scientifically most interesting and industrially most promising approaches to self-healing metals are presented and discussed. The various approaches are separated in autonomous healing methods based on an intrinsic (solid-state diffusion) mechanism and assisted healing methods that need an external intervention. Some promising routes are identified while in other cases the approach has too many intrinsic limitations. Recently, a number of computational studies using molecular dynamics and finite element modeling have been performed to analyze the self-healing potential of metal systems as a function of the imposed conditions and to guide the further development of this family of self-healing materials.