Фазовая диаграмма системы Nd-Y

К оглавлению: Другие диаграммы (Others phase diargams)

Nd-Y (Neodymium-Yttrium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed phase diagram for the Nd-Y system is based primarily on the work of [65Bea]. A nearly straight line relationship exists for the liquidus and solidus curves. The transformation temperature from the hexagonal forms of Nd and Y to their bcc form also varies in a nearly linear mode. The (bNd) and (bY) phases are mutually soluble, forming a continuous phase field across the diagram. [65Bea] indicated a peritectoid horizontal by dashed lines to account for decomposition of the d phase on heating. Because a short nonisothermal arrest was observed at 630 C, but no thermal arrests were observed on either side of that point, [65Bea] suggested the possibility of a congruent transformation of the d phase to a single-phase hexagonal solid solution. Because [66Lun] researched the nature of the d phase and disproved its formation by a peritectoid reaction, the present diagram has been drawn to indicate the d phase to be the result of a congruent transformation. [66Jay] investigated the effect of pressure and temperature on the phase transformation sequence of several intra-rare earth alloy systems and included the d-phase-type NdY. The alloys were subjected to 40 kbar pressure at 450 C for about 5 h in a piston-cylinder apparatus. After the pressure had been released and the temperature reduced to ambient, X-ray patterns of the NdY specimen revealed a partial conversion of the Sm-type phase to a pressure- induced dcph phase. Such a transformation is sluggish, and the conversion to the high-pressure form is temperature and time dependent. 65Bea: B.J. Beaudry, M. Michel, A.H. Daane, and F.H. Spedding, in Rare Earth Research III, L. Eyring, Ed., Gordon and Breach Science Publishers, New York, 247 (1965). 66Jay: A 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. of Denver, Denver, CO (1966). Published in Bull. Alloy Phase Diagrams, 3(2), Sep 1982. Complete evaluation contains 3 figures and 8 references. 1