AVALANCHE IN ADHESION AT METAL INTERFACES

Simulations have shown that as two metal surfaces approach each other, the surface layers can avalanche together when the rigid interfacial spacing falls below a critical distance. This is accompanied by a disc ontinuous decrease in the adhesive energy. Here we present an examinat ion of this phenomenon for the bce metals Fe and W using the Equivalen t Crystal Theory. In order to identify the circumstances under which a valanche might be inhibited, the effect of loss of registry between th e two surfaces is investigated in detail. The avalanche is inhibited w hen the two surfaces are sufficiently far out of registry and when onl y a few layers near the surface are allowed to relax. As the relaxing slabs get thicker a sharp avalanche reappears. However, as the loss of registry increases the energy released in the avalanche decreases.