A Method of Examining Structural Changes of Metals on Deformation in Liquid Helium: Examination of Indium

A Debye–Scherrer type of X-ray camera is described in which a soft metal can be deformed by extension and photographed in situ in liquid helium. Using this camera we have examined deformed indium at 4.2°K. and find no evidence of a lattice transformation when a tensile strain of ~ 15% is applied. The investigation was undertaken to examine the suggestion of Swenson, stemming from the observation of anomalies in the mechanical properties of indium at low temperatures, that a very slight deformation of indium at 4.2°K. might transform the face-centered tetragonal to a close-packed structure.