Influence of the preparation conditions of titanium hydride and deuteride TiHx(Dx) (X ≈ 2.00) on the specific heat around the δ-ɛ transition

Abstract

Titanium hydrides and deuterides (TiHx(Dx)) with hydrogen or deuterium concentraions near the stoichiometric limit, X = 2.00, were prepared in a Sieverts type apparatus under different experimental conditions; degassing time, sample temperature at which the hydrogenation takes place, stabilization time, cooling rate, purity and geometrical shape of the titanium samples. After the preparation the samples were analyzed by differential scanning calorimetry (DSC) to determine the main characteristics of the cubic-tetragonal (δ-ɛ) phase transition and to correlate these characteristics with the conditions under which the preparation was done. It was found that the cooling rate on crossing the (β + δ) field during the sample preparation is the most important factor affecting the specific heat jump in the δ-ɛ phase transition whenever other factors (titanium purity or crystalline quality of the original titanium) are not changed.