Фазовая диаграмма системы Ca-Mg

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Ca-Mg (Calcium-Magnesium) A.A. Nayeb-Hashemi and J.B. Clark The assessed phase diagram for the Mg-Ca system is very similar to the diagram reported by [Hansen]. Two eutectic reactions and a congruently melting compound characterize the system. The Mg-rich eutectic point is at 10.5 at.% Ca and 516.5 C, and the Ca-rich eutectic point is at 73 at.% Ca and 445 C [ 37Vos, 47Kle]. The melting point of Mg2Ca is 715 C. [46Bul] determined the ( Mg) solvus curve by resistivity measurements. In the present phase diagram, the (Mg) liquidus is taken from [37Vos], and the Mg2Ca liquidus is taken from [37Vos] and [47Kle]. Most of the (bCa) liquidus remains to be determined. The calculated liquidus temperatures are in good agreement with those of the assessed diagram, except for the Ca-rich side of Mg2Ca, and there is good agreement with the characteristic points of the diagram. The solid solubility of Mg in (Ca) has not been determined and apparently is negligible. There is no homogeneity field for the Mg2Ca compound. The (Mg) solidus is represented by an almost straight line originating from the melting point of Mg and terminating at 0.82 at.% Ca at 516.5 C [37Hau]. [78Ama] investigated glass formation in Mg-Ca alloys by rapid solidification. The complete glass phase in this system was formed in the composition range 57. 5 to 77.5 at.% Ca. 37Hau: J.L. Haughton, J. Inst. Met., 61, 241-246 (1937). 37Vos: H. VosskЃhler, Z. Metallkd., 29, 236-237 (1937) in German. 46Bul: W. Bulian and E. Fahrenhorst, Metallforschung, 1(3), 70 (1946) in German. 47Kle: W. Klemm and F. Dinkelacker, Z. Anorg. Allg. Chem., 255, 2-12 (1947) in German. 78Ama: R.S. Amand and B.C. Giessen, Scr. Metall., 12, 1021-1026 (1978). Published in Phase Diagrams of Binary Magnesium Alloys, 1988, and Bull. Alloy Phase Diagrams, 8(1), Feb 1987. Complete evaluation contains 2 figures, 8 tables, and 44 references. Special Points of the Mg-Ca System