Фазовая диаграмма системы La-Y

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La-Y (Lanthanum-Yttrium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed phase diagram for the La-Y alloy system is based on the data of [ 62Spe], with revisions based on the work of [66Lun] on the formation of the Sm- type structure d in intra-rare-earth binary alloys. [66Lun] concluded that the Sm-type structure results from a recrystallization phenomenon formed by strains set up with the solid solution in the composition range where this structure exists. The (gLa) and (bY) phases are mutually soluble, forming a continuous phase field across the diagram. In the present diagram, the peritectoid formation of d shown by [62Spe] has been replaced by a congruent transformation. [66Jay] studied pressure-induced transformations in the La-Y system using a cylinder-piston apparatus. Appropriate amounts of the metals were arc melted under an argon atmosphere, then heat treated at 500 C for several days in sealed evacuated quartz tubes. The annealed specimens were single-phase materials of the expected structure. After a 5-h anneal at 40 kbar pressure and 450 C, temperature was reduced to ambient and pressure was released. A 30 at.% La specimen, normally having the cph structure, underwent no phase transition; a 40 at.% La specimen, also normally having a cph structure, transformed to the Sm-type structure; a 50 at.% La specimen, normally having the Sm-type structure, transformed to the dcph structure. 62Spe: F.H. Spedding, R.M. Valletta, and A.H. Daane, ASM Trans. Q., 55, 483 ( 1962). 66Jay: Jayaraman, R.C. Sherwood, H.J. Williams, and E. Corenzwit, Phys. Rev., 148, 502 (1966). 66Lun: C.E. Lundin, AD-633558 (also given as DRI-2326) final report, Denver Res. Inst., Univ. Denver, CO (1966). Published in Bull. Alloy Phase Diagrams, 3(1), Jun 1982. Complete evaluation contains 3 figures and 6 references. 1