Фазовая диаграмма системы Cu-Zr

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Cu-Zr (Copper-Zirconium) D. Arias and J.P. Abriata The assessed Cu-Zr phase diagram is based on the experimental work of [53Lun], [72Per], [75Bse], [78Kuz], and [85Gli]. The assessed diagram differs from those given in previous compilations and evaluations in various details of the intermediate phases as well as of the invariant equilibria. The equilibrium phases are (1) the liquid, L; (2) the fcc terminal solid solution, (Cu), with a maximum solid solubility of ~0.12 at.% Zr at 972 C; (3) the intermediate compound Cu9Zr2, with a complex crystal structure derived from the AuBe5-type structure, stable up to the peritectic temperature 1012 C; (4) the Ag51Gd14-type hexagonal intermediate compound Cu51Zr14, stable up to the congruent melting point of 1115 C; (5) the orthorhombic compound Cu8Zr3, isostructural with Cu8Hf3, stable up to the peritectic temperature of 975 C; ( 6) the orthorhombic Ni10Zr7-type intermediate compound Cu10Zr7, stable up to the congruent melting temperature of 895 C; (7) the cubic CsCl-type intermediate compound CuZr, stable from 715 C up to its congruent melting temperature of 935 C; (8) the tetragonal MoSi2-type intermediate compound CuZr2, stable up to the congruent melting temperature of 1000 C; (9) the cph terminal solid solution, (aZr), stable up to 865 C and having a maximum solubility of ~0.2 at.% Cu at 822 C; and (10) the bcc terminal solid solution, (bZr), stable between 822 and 1855 C and having a maximum solubility of ~5.7 at.% Cu at 995 C. Homogeneity ranges are presumed to be quite restricted for all of the intermediate phases, and their actual compositions seem to correspond closely to those indicated by their respective chemical formulas. No experimental data exist for the L/L + (Cu) and L/L + Cu9Zr2 phase boundaries, so the corresponding curves drawn in the assessed diagram are only tentative. No experimental data exist for the boundary L/L + Cu8Zr3. Thus, the corresponding curve indicated in the assessed diagram is tentative, but is plotted to be compatible with the previously assessed L/L + Cu51Zr14 phase boundary and with the temperature 885 C and L composition of ~38.2 at.% Zr [ 53Lun] for the eutectic reaction L = Cu5Zr2 + Cu3Zr2 (where, according to the present evaluation, Cu5Zr2 and Cu3Zr2 stand for Cu8Zr3 and Cu10Zr7, respectively. No data exist for the L + (bZr)/(bZr) boundary, so the shape of the L + (bZr) two-phase field shown in the assessed diagram is merely tentative. [71Tre] found that after quenching from 900 C, alloys with compositions between 95 and 98 at.% Zr contained w-phase precipitates. The w-phase was also observed by [82Alt] and [84Den] during the first step in the crystallization process of Zr-rich amorphous alloys. [80Car] found a martensitic-type transformation in the CuZr intermetallic compound upon quenching from 900 C with Ms = 167 C. Amorphous Cu-Zr alloys were produced within the composition range of 10 to 80 at.% Zr by numerous investigators. Zr-rich amorphous alloys show superconductivity. The crystallization temperature TCr of amorphous Cr-Zr alloys was studied by many investigators. The general trend of TCr is to decrease with increasing Zr content. Typically, for a heating rate of ~40 C/min, TCr varies from ~800 K for 35 at.% Zr to ~620 K for 75 at.% Zr [78Rap, 82Alt]. The dependence of TCr on the heating rate is also significant. For example, [82Ans] found in a 62 at. % Zr amorphous alloy that TCr = 669 K and TCr = 723 K for heating rates of 0.5 C/min and 100 C/min, respectively. Thermodynamic modelings of the Cu-Zr phase diagram, including a discussion of the metastable amorphous phase, were performed by [85Sau], [86Sau], and [88Bor] . In view of the uncertainties that exist regarding the thermochemical properties of the Cu-Zr system, further experimental investigation of these properties are necessary to allow the development of more realistic modelings of the Cu-Zr system. 53Lun: C.E. Lundin, D.J. McPherson, and M. Hansen, Trans. AIME, 197, 273-278 ( 1953). 62Nev: M. Nevitt, Trans. Metall. Soc. AIME, 224, 195-196 (1962). 71Tre: I.A. Tregubov and O.S. Ivanov, Phase Diagram of the Zr-Cu-Mo System at Temperatures from 900 C to 600 C, Diagrammy Sostoyaniya Metal Sistem Nauka, Moscow, 67-71 (1971) in Russian. 72Per: A.J. Perry and W. Hugi, J. Inst. Met., 100, 378-380 (1972). 75Bse: L. Bsenko, J. Less-Common Met., 40, 365-366 (1975). 78Kuz: G.M. Kuznetsov, V.N. Fedorov, A.L. Rodnyanskaya, and A.V. Nikonova, Sov. Non-Ferrous Met. Res., 6, 267-268 (1978). 79Bse: L. Bsenko, Acta Univ. Uppsala., Abstr. Uppsala Diss. Fac. Sci., 513, 1- 47 (1979). 80Car: E.M. Carvalho and I.R. Harris, J. Mater. Sci., 15, 1224-1230 (1980). 82Alt: Z. Altounian, Tu Guo-hua, and J.O. Strom-Olsen, J. Appl. Phys., 53, 4755-4760 (1982). 82Ans: I. Ansara, A. Pasturel, and K.H.J. Buschow, Phys. Status Solidi (a), 69, 447-453 (1982). 84Den: F.J.A. Den Broeder, J.M. Vandenberg, and C.W. Draper, Thin Solid Films, 111, 43-51 (1984). 85Gli: J.L. Glimois, P. Forey, and J.L. Feron, J. Less-Common Met., 113, 213- 224 (1985) in French. 85Sau: N. Saunders, Calphad, 9, 297-309 (1985). 86Sau: N. Saunders and A.P. Miodownik, J. Mater. Res., 1, 38-46 (1986). 88Bor: R. Bormann, F. Gartner, and F. Haider, Mater. Sci. Eng., 97, 79-81 ( 1988). Submitted to the APD Program. Complete evaluation contains 1 figure, 9 tables, and 50 references. Special Points of the Cu-Zr System