Фазовая диаграмма системы Ce-Mg

К оглавлению: Другие диаграммы (Others phase diargams)


Ce-Mg (Cerium-Magnesium) A.A. Nayeb-Hashemi and J.B. Clark The equilibrium phases of the Mg-Ce system are (1) the liquid; (2) the terminal solid solution, (Mg), with a maximum solid solubility of 0.09 at.% Ce at the eutectic temperature (592 с 2 C); (3) the Mg12Ce(I) phase (~7.69 at.% Ce), with a tetragonal structure and possibly a narrow range of homogeneity; ( 4) an ordered body-centered orthorhombic phase, Mg12Ce(II), with possible homogeneity; (5) the Mg10.3Ce compound (8.85 at.% Ce), with the hexagonal Ni17Th2-type structure, stable between 611 and 621 C; (6) the Mg41Ce5 compound (10.87 at.% Ce) of tetragonal structure, with no reported homogeneity range; (7) the Mg3Ce compound with the Bi3F structure with some undetermined homogeneity range on the Mg-rich side; (8) the stoichiometric Mg2Ce compound of cubic Cu2Mg structure, stable between 615 and 750 C; (9) the stoichiometric MgCe compound of cubic CsCl-type structure; (10) the terminal ( dCe) solid solution of cubic W-type structure; and (11) the terminal (gCe) solid solution of cubic Cu-type structure, with a maximum solid solubility of Mg in (gCe) of 8.2 at.% Mg (91.8 at.% Ce). The Mg-rich side of the diagram (0 to 18 at.% Ce) is based on the work of [ 37Hau] and [65Woo], and the remainder of the diagram is taken from [47Vog] and [65Jos], with some adjustments. The assessed diagram was obtained by thermodynamic modeling of the experimental data. Agreement between the experimental phase diagram boundaries and the experimental thermodynamic data is quite satisfactory. In the assessed diagram, the Mg-rich eutectic is placed at 4.3 с 0.1 at.% Ce and 592 с 2 C. The maximum solid solubility of Ce in (Mg) is 0.09 at.% Ce [57Par]. Thermal analysis by [47Vog] showed significant solid solubility of Mg in (dCe). However, the homogeneity field of (dCe) was not determined. [73Bus], [76Bus], and [78Bus] determined the magnetic properties of MgRE, Mg3RE, and Mg2RE compounds in the temperature range 4.2 to 300 K with a magnetic field up to 18 kOe, respectively. The MgCe compound showed Curie- Weiss behavior. Mg2Ce ordered ferromagnetically below 100 K, and Mg3Ce was found to have an asymptotic Curie temperature of -46 K. For MgRE compounds, magnetization vs temperature curves rose with temperature to a maximum, characteristic of paramagnetic-antiferromagnetic transition. The temperature corresponding to the maximum for the MgCe compound was reported as 18 K. 37Hau: J.L. Haughton and T.H. Schofield, J. Inst. Met., 60, 339-344 (1937). 47Vog: R. Vogel and T. Heumann, Z. Metallkd., 38, 1-8 (1947) in German. 57Par: J.J. Park and L.L. Wyman, WACD Tech. Rep. 57-504, 33 (1957). 65Jos: R.R. Joseph and K.A. Gschneidner, Jr., Trans. AIME, 223, 2063-2069 ( 1965). 65Woo: D.H. Wood and E.M. Cramer, J. Less-Common Met., 9, 321-337 (1965). 73Bus: K.H.J. Buschow, J. Less-Common Met., 33, 239-244 (1973). 76Bus: K.H.J. Buschow, J. Less-Common Met., 44, 301-306 (1976). 78Bus: K.H.J. Buschow, R.C. Sherwood, and F.S.L. Hsu, J. Appl. Phys., 49(3), 1510-1512 (1978). Published in Phase Diagrams of Binary Magnesium Alloys, 1988. Complete evaluation contains 2 figures, 9 tables, and 61 references. Special Points of the Mg-Ce System