The elasticity of pintsch crystals of tungsten

Abstract

The development of methods of preparing large single crystals of metals has provided a new field for research into the strength of materials, and a great deal of work has been carried out on the behaviour of such crystals when strained plastically. On the other hand, very little has yet been done towards investigating their elastic properties. An important exception is the work of Bridgman, who has determined the elastic constants of crystals of seven metals including tungsten. The apparent neglect by other workers of this branch of the subject is possibly due to the fact that, in general, single metallic crystals have such a limited range of primitive elasticity that plastic strains occur under very small stresses. Accurate static determinations of elastic constants are therefore difficult to carry out as the total load that can safely be applied to the test piece is generally very small. In these circumstances, dynamical methods offer a distinct advantage since the amplitudes of the oscillations studied, and therefore the magnitudes of the stresses involved, can be reduced almost indefinitely without loss of accuracy. The present paper deals with a first attempt at using dynamical methods in the study of the elasticity of single crystals. Tungsten was chosen as the first material to be investigated because single crystals in the form of wires of small diameter were easily obtainable. It was also felt that Bridgman’s results for this metal were so striking that confirmation of them would be valuable.