Alloy Constitution and Phase Equilibria in the Hf–Ru–Rh System. II. Liquidus Surface, Melting Diagram, and Vertical Sections of the Partial Hf–HfRu–HfRh System

• Published in: Powder metallurgy and metal ceramics Vol. 54; no. 11-12; pp. 686 - 695
• Main Authors: Kriklya, L. S., Kornienko, K. E., Khoruzhaya, V. G., Petyukh, V. M., Duma, L. A., Meleshevich, K. A., Samelyuk, A. V.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.03.2016; Springer; Springer Nature B.V
• Subjects: Alloys; Analysis; Casting alloys; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Composition; Constitution; Crystallization; Glass; Hafnium base alloys; Liquidus; Materials Science; Metallic Materials; Natural Materials; Phase equilibria; Physicochemical Materials Research; Solid solutions; Solidus; Specialty metals industry; Ternary alloys
• ISSN: 1068-1302; 1573-9066
• DOI: 10.1007/s11106-016-9763-6

According to the constitution of the solidus surface in the Hf–Ru–Rh system over the composition range 50−100 at.% Hf and the data obtained in studying the as-cast alloys by physicochemical analysis techniques, we constructed, for the first time, the liquidus surface of the partial Hf–HfRu–HfRh system on the composition triangle and its melting diagram. The vertical sections at 5 at.% Ru, 10 at.% Rh, and 75 and 80 at.% Hf at the ratio Ru : Rh = 1 : 1 are presented. The processes that occur when the alloys are crystallized are shown in the reaction scheme. The primary crystallization regions for a continuous series of solid solutions between isostructural (CsCl type) phases formed by the HfRu compound and its high-temperature modification (δ phase) as well as β-Hf and γ-Hf 2 Rh (Ti 2 Ni type) solid solutions are parts of the liquidus surface. An invariant four-phase equilibrium involving liquid, L U + δ ⇆ γ + <β-Hf>, is observed at 1373°C in the system.