Фазовая диаграмма системы Al-Pr

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Al-Pr (Aluminum-Praseodymium) K.A. Gschneidner, Jr. and F.W. Calderwood The assessed phase diagram for the Al-Pr system is based primarily on the work of [66Bus], [67Bus], [67Gom], and [69Dri]. The system is characterized by six intermediate phases. AlPr3 forms peritectoidally from aPr and AlPr2 at 630 C. Two allotropes of this composition exist: a hexagonal form below 330 C and a cubic form above 330 C. AlPr2 forms peritectically from the melt and bAlPr at 735 C. bAlPr forms peritectically from the melt and Al2Pr at 905 C. bAlPr transforms from orthorhombic AlEr-type structure to the orthorhombic AlCe-type structure when cooled below 700 C. The only congruently melting compound in the Al-Pr system is Al2Pr, which melts at 1480 C. Al3Pr is formed peritectoidally at 1075 C from Al2Pr, and bAl11Pr3 is formed peritectically from Al2Pr and melts at 1240 C. On cooling below 965 C, bAl11Pr3, which has tetragonal Al-deficient Al4Ba-type structure, transforms to aAl11Pr3, which has orthorhombic structure. Two eutectics occur in this system. The eutectic between Pr and AlPr2 at 650 C has a composition of about 82 at.% Pr. The second eutectic, which occurs at 640 C between aAl11Pr3 and Al, has a composition of about 5 at.% Pr. A solubility of 0.01 at.% for Pr in Al has been reported at the eutectic temperature [69Dri]. [64Kri] reported a cubic CsCl-type structure for AlPr, which is believed to be a metastable structure. 64Kri: P.I. Kripyakevich and I.I. Zalutskii, Acad. Nauk SSSR, Inst. Met. Trudy, 144, (1964); TR: AD-635, 829, May (1966). 66Bus: K.H.J. Buschow and J.H.N. van Vucht, Z. Metallkd., 57, 162 (1966). 67Bus: K.H.J. Buschow and J.H.N. van Vucht, Philips Res. Rep., 22, 233 (1967). 67Gom: A.H. Gomes de Mesquita and K.H.J. Buschow, Acta Crystallogr., 22, 497 ( 1967). 69Dri: M.E. Drits, E.S. Kadaner, and N.D. Shoa, Izv. Akad. Nauk SSSR, Met., (1) , 219 (1969); TR: Russ. Metall., (1), 113 (1969). Published in Bull. Alloy Phase Diagrams, 10(1), Feb 1989. Complete evaluation contains 1 figure, 1 table, and 28 references. 1