The Electron Microscopic Observation of Mechanical Twins in Gadolinium

Abstract

Mechanical twinning in gadolinium has been observed using an electron microscope. The analysis of electron diffraction patterns revealed that the twinning elements are K1 = K2 = (1012) and η1 = η2 = [1011]. The possible mechanism of genesis for these twins are investigated. It is found that the twins are nucleated due to thermal stresses set up in the films as a result of electron irradiation. There is no evidence for the pole dislocation mechanism to be operative in the present case, instead, the observations suggest that the twin formation is in accordance with the Bell‐Cahn mechanism. Copyright © 1969 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim