Фазовая диаграмма системы Ru-Ti

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Ru-Ti (Ruthenium-Titanium) J.L. Murray Three determinations have been made of the Ti-Ru phase diagram [63Rau, 73Ere, 76Bor]. Qualitatively, these investigations are in accord; quantitative discrepancies are probably caused by the difficulty of bringing alloys into equilibrium and the high temperatures involved, which cause severe oxygen contamination. The work of [73Ere] and [76Bor] is preferred, because iodide Ti was used for preparation of the alloys, which were arc or levitation melted. The solubility of Ru in (aTi) is low (less than 0.1 at.%); the maximum solubility of Ru in (bTi) is 25 at.% at the peritectic temperature of 1575 C. The maximum solubility of Ti in (Ru) is about 14 at.% at 1825 C. In the (bTi)/[(aTi) + (bTi)] boundary ((bTi) transus), the scatter in the data is somewhat large. The microscopic work of [63Rau] was conducted with a greater number of alloys and is weighted more heavily than that of [76Bor]. TiRu melts congruently at 2130 с 50 C. [63Rau] reported additional thermal analysis data for the liquidus, but because very large uncertainties (с50 C) must be attached to these liquidus measurements, the assessed diagram is based only on the more accurate congruent melting point data, together with the requirement of consistency with the (bTi) boundaries. Based on the lattice parameter data of [63Rau], the homogeneity range is 45 to 52 с 1 at.% Ru. There is a rather large discrepancy in reported values of the L = TiRu + (Ru) eutectic temperature (1760 and 1855 C according to [63Rau] and [73Ere], respectively). The average of the two determinations, 1810 с 50 C, was used as a preliminary estimate for the eutectic temperature. The calculated eutectic temperature is 1825 C. Considering the large uncertainty in this temperature, the calculated value agrees well enough with the experimental data that it was used to draw the assessed diagram. The (Ru) solvus was investigated only by [73Ere], using metallography of alloys heat treated at 1100, 1400, and 1700 C in 5 at.% increments. The extrapolation of the solvus to 600 C in the assessed diagram was made using thermodynamic calculations. At low Ru content, (bTi) cannot be retained metastably during quenching, but transforms martensitically. At the lowest Ru content, the martensite, (a›Ti), has the cph structure. For Ru content exceeding 2 at.%, an orthorhombic martensite (a›Ti) has been observed [76Bor]. In alloys containing more than 2. 4 at.% Ru, (bTi) does not transform to (a›Ti) or (a›Ti) during quenching. As- quenched w was observed in alloys containing between 3.8 and 10.5 at.% Ru [ 76Bor]; at higher Ru concentrations, only the bcc phase is found after quenching. 63Rau: E. Raub and E. Roeschel, Z. Metallkd., 54(8), 455-462 (1963) in German. 73Ere: V.N. Eremenko, T.D. Shtepa, and V.G. Khoruzhaya, Izv. Akad. Nauk SSSR, Met., (2), 204-206 (1973) in Russian; TR: Russ. Metall., (2), 155-156 (1973). 76Bor: N.G. Boriskina and I.I. Kornilov, Izv. Akad. Nauk SSSR, Met., (2), 214- 217 (1976) in Russian; TR: Russ. Metall., (2), 162-165 (1976). Published in Phase Diagrams of Binary Titanium Alloys, 1987. Complete evaluation contains 3 figures, 8 tables, and 8 references. Special Points of the Ti-Ru System