Phase diagrams for hydrogen in metals as deduced from ferroelastic properties

Abstract Qualitative and partly quantitative arguments in favour of the interpretation that the long‐range elastic dipole‐dipole interaction is responsible for phase transitions of hydrogen in metals are presented. The measurement of the response of interstitially dissolved hydrogen to an applied external elastic field yield certain combinations of the components of the elastic dipole moment tensor. These combinations determine the interaction energies which are relevant for the phase transitions "condensations" and "ordering" of hydrogen. Experimental results of Gorsky‐Effect measurements on H in V, Nb, Ta, Pd are discussed.