Constitution of Rh—Sc—Ti Alloys in the 50% (ат.) Rh Section and Adjacent Composition Range

Abstract

Physicochemical analysis methods (metallography, X-ray diffraction, differential thermal analysis, resistometry) are used to examine phase equilibria in the Rh-Sc-Ti system in the ScRh-TiRh section and in the adjacent composition range. It is shown that the ScRh-TiRh section is quasibinary. Intermetallic ScRh and TiRh phases with the same crystalline structure form an infinite series of solid solutions with cubic CsCl-type structure at subsolidus temperature. Replacement of titanium by scandium stabilizes this high-temperature phase at room temperature. Martensitic transformation in TiRh alloys proceeds in two stages with the following change in crystalline structure: cubic (CsCl)—> tetragonal (AuCu)-monoclinic (TiNi).