Фазовая диаграмма системы B-Dy

К оглавлению: Другие диаграммы (Others phase diargams)

B-Dy (Boron-Dysprosium) P.K. Liao and K.E. Spear Experimental work on the phase equilibria for the Dy-B system is sparse [72Spe, 76Spe]. The assessed phase diagram is taken from [76Spe], which is largely estimated and based primarily on the diagram of [72Spe], except for inclusions of the Dy metal transformation at 1385 C and the presence of a 1-atm vapor phase. The equilibrium phases are (1) the liquid, L; (2) the terminal solid solutions, cph (aDy) and bcc (bDy); (3) the terminal solid solution rhombohedral (bB); and (4) five intermediate compounds, DyB2, DyB4, DyB6, DyB12, and DyB66. Both the (bB) and (Dy) solid solutions have negligible composition ranges. The melting behavior of the REB66 phases is difficult to determine because they are so rich in B. [72Spe] reported that solidified liquid samples containing DyB12 and DyB66 showed no evidence of a eutectic in the microstructures, but the evidence for peritectic melting of DyB66 is still not conclusive. [76Spe] investigated the rather wide homogeneity ranges for a number of REB6 phases and the hexaboride defect structures. All available experimental data indicate that the hexaboride is stoichiometric at its metal-rich phase boundary and becomes B-rich by the formation of up to approximately 30% metal vacancies. 59Eic: H.A. Eick and P.W. Gilles, J. Am. Chem. Soc., 81, 5030-5032 (1959). 61Lap: S. LaPlaca, I. Binder, and B. Post, J. Inorg. Nucl. Chem., 18, 113-117 ( 1961). 62Lap: S.J. LaPlaca, Brookhaven National Laboratory, private communication ( 1962), quoted by [64Pos]. 64Pos: B. Post, Boron, Metallo-Boron Compounds, and Boranes, R.M. Adams, Ed., Interscience, New York, 301-371 (1964). 65Gie: R.F. Giese, Jr., J. Economy, and V.I. Matkovich, Z. Krist. Allogr., 122, 144-147 (1965). 68Mor: O.A. Mordovin and E.N. Timofeeva, Russ. J. Inorg. Chem., 13(12), 1627- 1629 (1968). 70Car: J.-O. Carlsson and T. Lundstrom, J. Less-Common Met., 22, 317-320 (1970) . 71Pad: Yu.B. Paderno, V.V. Odintsov, I.I. Timofeeva, and L.A. Klochkov, High Temp., 9(1), 175-177 (1971). 72Fis: Z. Fisk, A.S. Cooper, P.H. Schmidt, and R.N. Castellano, Mater. Res. Bull., 7(4), 285-288 (1972). 72Sch1: K. Schwetz, P. Ettmayer, R. Kieffer, and A. Lipp, J. Less-Common Met., 26, 99-104 (1972) in German. 72Sch2: K. Schwetz, P. Ettmayer, R. Kieffer, and A. Lipp, Radex Rundsch., 3/4, 257-265 (1972) in German. 72Spe: K.E. Spear, Int. Symp. on Boron and Borides, Tbilisi, Georgia, USSR, Oct 9-11 (1972). 76Spe: K.E. Spear, Phase Diagrams, Vol. 4, Materials Science and Technology, Academic Press, New York, 91-159 (1976). 77Cal: B. Callmer, Acta Crystallogr. B, 33, 1951-1954 (1977). Submitted to the APD Program. Complete evaluation contains 1 figure, 3 tables, and 22 references. Special Points of the Dy-B System