Фазовая диаграмма системы Cu-Sm

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Cu-Sm (Copper-Samarium) P.R. Subramanian and D.E. Laughlin The Cu-Sm equilibrium diagram has been determined by several investigators [ 64Cop, 73Tor, 75Kuh, 77Gol]. The investigation of [64Cop] was partial and restricted to the region between 50 and 100 at.% Sm. The other investigations are in agreement with regard to the existence of Cu6Sm, Cu2Sm, and CuSm. However, [73Tor] reported a phase diagram without the existence of Cu4Sm, whereas the diagram of [77Gol] does not show the existence of Cu5Sm. [74Rus] gave the crystal structures and melting temperatures for the above-mentioned five intermediate phases without including any phase diagram. Also, [74Rus] reported the existence of an additional phase, Cu3Sm. The phase diagram of [ 75Kuh], essentially complete with regard to the existence of the various intermediate phases, was determined by differential thermal analysis (DTA), metallography, and electronprobe microanalysis. The Sm used in their alloys was cited as being 99.9 % pure (relative to other rare earth materials) and contained oxygen, primarily as Sm2O3. Because there is a considerable degree of conflict in the reported phase relationships and melting temperatures, the accepted data are those that agree with the systematics of the Cu-lanthanide systems. The assessed phase diagram is comparable to that of [75Kuh]; however, some changes have been incorporated, as noted below. The melting points of Cu6Sm and Cu5Sm and the Cu-Cu6Sm eutectic temperature have been lowered in accordance with the systematics of Cu-lanthanide systems. As such, the assessed liquidus has also been shifted toward lower temperatures, especially in the vicinity of 10 to 25 at.% Sm. Additionally, the assessed liquidus shows the existence of the Cu2Sm-CuSm eutectic at 720 C, along with the congruent melting of CuSm. The existence of this eutectic was proposed by [73Tor]. Although this has not been corroborated by other researchers, the DTA data of [75Kuh] show the presence of thermal arrests at 724 C, which is in close accord with the eutectic temperature of [ 75Tor]. The accepted eutectic temperatures are in agreement with the values obtained by interpolation of the corresponding temperatures for the other Cu- lanthanide systems. The assessed liquidus in the Cu-rich and Sm-rich regions was derived from thermodynamic modeling, whereas the liquidus between 9 and 71 at.% Sm was estimated from the available data, in conjunction with systematics of Cu-lanthanide systems. There is no evidence of any terminal solid solubility of Sm in (Cu). The terminal solubility of Cu in (aSm) is estimated to be less than 0.5 at.%. 64Cop: M. Copeland and H. Kato, Physics and Materials Problems of Reactor Control Rods, International Atomic Energy Agency, Vienna, 295-317 (1964); also see Rep. No. USBM-U-1031, Quarterly Metallurgical Progress Rep. No. 18, U.S. Bureau of Mines, Albany Metallurgy Research Center, Albany, OR,3-16 (1963). 73Tor: R.S. Torchinova, B.F. Terekhova, and E.M. Savitskii, Redkozemel'nye Metally, Splavy, I Soyedineniya (Rare-Earth Metals, Alloys and Compounds), Nauka, Moscow, 166-168 (1973) in Russian. 74Rus: P.G. Rustamov, O.M. Aliev, G.G. Guseinov, and M.A. Alidzhanov, Tezisy Dokl. Vses. Knof. Kristallokhim. Intermet. Soedin. (All-Union Conference on the Crystal Chemistry of Intermetallic Compounds), R.M. Rykhal, Ed., L'vov Gos. Univ. L'vov, USSR, 112 (1974) in Russian. 75Kuh: K.Kuhn and A.J. Perry, Met. Sci., 9(7), 339-341 (1975). 77Gol: L.A. Golubkov, N.M. Shibanova, Y.G. Saksonov, and G.Y. Fedorova, Izv. Akad. Nauk SSSR, Met., (6), 180-184 (1977); TR: Russ. Metall., (6), 147-148 ( 1977). Published in Bull. Alloy Phase Diagrams, 9(3a), Aug 1988. Complete evaluation contains 2 figures, 5 tables, and 23 references. Special Points of the Cu-Sm System