Constitution of the alloys and the Sc-Ru-Rh phase diagram. V. isothermal section of the partial Sc-ScRu-ScRh system at a temperature of 930℃

摘要

By the results of investigation of the annealed alloys by metallography, X-ray diffraction and microprobe analysis methods, the isothermal section of the partial Sc-ScRu-ScRh system at 930℃ is plotted first. It is established that since the ternary compounds are absent in the system, then the intermediate phases based on the binary compounds, existing in the formation Sc-Ru and Sc-Rh systems: Sc{sub}5Ru{sub}3, Sc{sub}2Ru, Sc{sub}11Ru{sub}4, Sc{sub}44Ru{sub}7, Sc{sub}3Rh, theδ andη phases (continuous series of solid solutions between isostructural phases, respectively, ScRu and ScRh (CsCl-type structure); Sc{sub}57Ru{sub}13 and Sc{sub}57Rh{sub}13 (Sc{sub}57Rh{sub}13-type structure) as well as a scandium solid solution take part in the phase equilibria in the system. Eight corresponding single-phase regions, five three-phase fields (δ++, ++η, +δ+η, +δ+η, +<α-Sc >+η) as well as twelve corresponding two-phase regions are the constituents of the isothermal section. Unlike the phase equilibria at subsolidus temperatures, at 930℃ the phase equilibria, related with disintegration of the phase based on Sc{sub}2Rh (γ') are absent, and new equilibria related with formation of the Sc{sub}44Ru{sub}7 (θ) phase are appeared.