On the Mechanics of Micro-Thin Foil Production

The mechanics of micro-thin foil or leaf production by hammering has been analyzed. It was found that the metal foil cannot be reduced by a compression process alone because of the large impact loads that would be required, due to interfacial friction between the foil and the separating paper sheets. It is demonstrated that a likely mechanism is a plastic stretching process of the metal combined with relatively large elastic stretching of the paper due to the Poisson effect when a blow is struck. The actual mechanism is probably a combination of stretching and slipping of the metal.