Abstract
Thin films of oxides, hydroxides or metals have been shown to increase the stress at which plastic deformation starts by an amount which cannot be explained by the strength of the films themselves. Most experiments have been on creep, showing the effect of oxides and hydroxides. This paper records an investigation into the effect of thin films of gold on the stress-strain curves of cadmium crystals.
The crystals were grown in an Andrade-Roscoe furnace and extended in a rigid frame machine with a Polanyi beam and photographic recording. The gold films were deposited by sputtering.
It was found that thin gold films increased the stress at which plastic deformation started by about 6 g wt mm-2. The increase was independent of film thickness for films of 1500-24000 Å. The nature of the effect of the film upon the stress-strain curves depended upon the orientation of the crystals.