Constitution of Alloys and Phase Diagram of the Hf–Ru–Rh System. IV. Liquidus Surface and Melting Diagram of the Partial Ru–HfRu–HfRh–Rh System

• Published in: Powder metallurgy and metal ceramics 2016-07, Vol.55 (3-4), p.201-209
• Main Authors: Kriklya, L. S., Kornienko, K. E., Khoruzhaya, V. G., Petyukh, V. M., Duma, L. A., Samelyuk, A. V., Sobolev, A. V.
• Format: Article
• Language: English
• Subjects: Alloys; Analysis; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Constitution; Crystallization; Glass; Hafnium; Liquidus; Materials Science; Melting; Metallic Materials; Natural Materials; Physicochemical Materials Research; Platinum group compounds; Ruthenium; Solid solutions; Specialty metals industry; Systems (metallurgical)
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-016-9795-y

Using the data obtained in study of the as-cast Hf–Ru–Rh alloys in the range 0–50 at.% Hf and considering the solidus surface constitution, physicochemical analysis techniques are employed to construct for the first time the liquidus surface of the Ru–HfRu–HfRh–Rh partial system onto the composition triangle, the melting diagram, and the reaction scheme reflecting processes during crystallization of the alloys. It is shown that five surfaces of primary crystallization of a continuous series of solid solutions between isostructural (CsCl-type) phases formed by compound HfRu and its high-temperature modification (δ phase), ruthenium and rhodium solid solutions, as well as the ε phase based on compound HfRh 3 (AuCu 3 -type structure) and θ phase based on compound Hf 3 Rh 5 (Hf 3 Rh 5 -type structure) are parts of the liquidus surface. Three invariant four-phase processes involving liquid take place at 1900, 1810, and 1720°C.