Internal friction in vanadium after heating at low air pressure

Abstract

Edington and Smallman have studied, using electron microscopy techniques, polycrystalline samples of vanadium after heating at low air pressures. They report the existence of a body- centred tetragonal phase similar to the β phase with a high concentration of twins. They also observed, on cooling from 1300° C, a martensitic transform ation. During the preparation of polycrystalline vanadium samples with different am ounts of oxygen, intended for internal friction studies, we observed the presence of microstructures which are similar to those, reported by Edington and Smallman, and which were obtained after heating for 10 to 24 h in an air pressure of 5 x 10-3 torr.