Thermally Induced Strains in Evaporated Films

Abstract

Evaporated films may have different thermal expansion coefficients from their substrates. When the temperature of such a combination is changed, thermal strains are introduced into the film. Calculations of the thermal strains and strain energies for the differently oriented grains in a polycrystalline sample were made. The theoretical results were checked by x-ray diffractometry, using thick gold and copper films bonded to glass substrates by means of thin chromium films. The calculations are useful in investigations of x-ray line shifts, elastic constants, adhesion, and relative grain growth in polycrystalline films formed on cold substrates and annealed.