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

Physicochemical analysis methods (metallography, X-ray diffraction, differential thermal analysis, and 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 structure at subsolidus temperature. Replacement of titanium by scandium stabilizes the high-temperature phase at room temperature. The martensitic transformation in TiRh alloys proceeds in two stages as follows: cubic (CsCl) → tetragonal (AuCu) → monoclinic (TiNi).