Фазовая диаграмма системы Hf-Mn

К оглавлению: Другие диаграммы (Others phase diargams)


Hf-Mn (Hafnium-Manganese) H. Okamoto The assessed Hf-Mn phase diagram is based primarily on [69Shu] and [76Sve], with review of the data of [54Ell] and [68Sve]. The equilibrium phases are (1) the liquid, L; (2) the bcc W-type terminal solid solution, (bHf); (3) the cph Mg-type terminal solid solution, (aHf); (4) Ti2Ni-type Hf2Mn; (5) hexagonal b- and aHfMn2; and (6) the (dMn), (gMn), (bMn), and (aMn) terminal solid solutions. The (bHf) and (aHf) phase fields adopted from [69Shu] and shown in the assessed diagram are tentative, due to insufficient data. The homogeneity range of Hf2Mn in the assessed diagram is tentative because [ 60Nev] and [68Sve] found this phase at 50 at.% Mn, whereas [69Shu] and [79Van] assigned Hf3Mn2 and Hf2Mn stoichiometry, respectively. [68Sve] considered that "HfMn" forms by the (bHf) + HfMn2 = "HfMn" peritectoid reaction at 1250 C, which is the L = (bHf) + "Hf3Mn2" eutectic reaction temperature in [69Shu]. Because [68Sve] and [69Shu] include the same authors, the earlier report is regarded as obsolete. A wide homogeneity range of HfMn2 was observed by [69Shu] and [76Sve], but with about 5 at.% displacement. The results of [76Sve] are accepted in the assessed diagram, because some data points of [69Shu] taken from the diagram were in disagreement with values given in their text, and [76Sve] showed the lattice parameter data used to determine the phase boundaries. The solubilities of Hf in various forms of Mn shown in the assessed diagram are adopted from [69Shu], but may be approximate, due to insufficient data. The (bMn) = HfMn2 + (aMn) eutectoid reaction temperature was shown at ~740 C in [69Shu] with respect to the bMn = aMn allotropic transformation temperature of 750 C. The eutectic reaction is shown in the assessed diagram at 27 C below the assessed bMn = aMn allotropic transformation temperature. 54Ell: R.P. Elliott, Tech. Rep. 1, OSR Tech. Note OSR-TN-54-247, Armour Research Foundation, Chicago, IL, 11 p (1954). 60Nev: M.V. Nevitt, J.W. Downey, and R.A. Morris, Trans. Met. Soc. AIME, 218( 12), 1019-1021 (1960). 61Ell: R.P. Elliott, Trans. ASM, 53, 321-329 (1961). 61Wer: J.H. Wernick and S.E. Haszko, Phys. Chem. Solids, 18(2-3), 207-209 ( 1961). 68Sve: V.N. Svechnikov, A.K. Shurin, G.P. Dmitrieva, and R.A. Alfintseva, Diagrammy Sostoyaniya Metallich Sistem, Nauka, Moscow, 153-156 (1968) in Russian. 69Shu: A.K. Shurin and G.P. Dmitrieva, Dop. Akad. Nauk Ukr. RSR A, 31(1), 67- 69 (1969) in Ukrainian. 76Sve: V.N. Svechnikov and V.V. Petkov, Akad. Nauk. Ukr. SSR, Metallofiz., 64, 24-28 (1976) in Russian. 79Van: R.M. Van Essen and K.H.J. Buschow, J. Less-Common Met., 64(2), 277-284 ( 1979). Submitted to the APD Program. Complete evaluation contains 1 figure, 3 tables, and 8 references. Special Points of the Hf-Mn System