ON BENDING OF THIN FOILS HAVING A STRESSED SURFACE LAYER

When an oxide layer forms on a thin metal foil the latter often tends to deform in a manner suggesting that the oxide layer is under stress. A theoretical treatment is given of the problem of relating the magnitude of this stress to the measured distortion-usually a radius of curvature. The need to use the two-dimensional analogue of Young's modulus in the basic formula is explained. Corrections are derived to take account of the non-zero thickness of the stressed layer, the actual conditions during growth, and the possibility that the foil is initially wound into a tight spiral. © 1969 Pergamon Press. Printed in Great Britain.