Фазовая диаграмма системы Mn-Si

К оглавлению: Другие диаграммы (Others phase diargams)


Mn-Si (Manganese-Silicon) A.B. Gokhale and G.J. Abbaschian The partial system Mn-MnSi was studied by [33Vog], who established the liquidus and the presence of Mn3Si, Mn5Si3, and MnSi in this composition range. However, [33Vog] omitted the high-temperature allotrope of Mn (dMn) from their liquidus construction and also did not detect the presence of the intermediate phases R and n at compositions less than 20 at.% Si. Later investigations of equilibria in Mn-Si have been carried out in narrow composition ranges. The data of [64Wie] from 0 to 24 at.% Si appear to be the most reliable, so these data have been used as the primary source in constructing the equilibria in this composition range, but below 3.75 at.% Si it is speculative. Because [ 33Vog] omitted (dMn) from their liquidus construction, it has been reconstructed in the present evaluation using the currently accepted values of the transformation gMn to dMn and the melting temperature of dMn. The maximum solid solubility of Si in (gMn) appears to be close to 2.8 at.% Si at 1155 C (speculative). The region of stability of (bMn) is increased by Si addition, ranging from 1155 C to ~635 C and 0 to 16.7 at.% Si (maximum). Although [33Vog] indicated that the (bMn) to (aMn) transformation temperature is raised by the addition of Si, [64Wie] indicated the reverse. The designation R is based on a structural similarity with the "R" phase formed in Co-Cr-Mo alloys [64Kuz]. [64Wie] indicated that R forms peritectoidally at 880 C and 15.3 at.% Si, and exists over a rather wide homogeneity range; thus, the designation R is preferred over the stoichiometric designation Mn6Si. R exhibits a low-temperature homogeneity range of 13 to 14.9 at.% Si [82Luk]. [82Luk] set the low-temperature homogeneity limits for the n phase between 17. 5 and 18 at.% Si. The phase has been designated as x [64Wie], N [65Gla], and Mn9Si2 [82Luk]. Due to the rather wide homogeneity range, the stoichiometric designation is not preferred, and the original designation n has been retained. [65Let] indicated a peritectic formation of Mn3Si at 1070 C and 25.4 at.% Si, with a polymorphic transformation at 677 C. bMn3Si is stable from 25 to 25.6 at.% Si at 900 C [74Bab]. [74Kal] indicated a low-temperature polymorphic transformation in Mn3Si at 22 K. Although the presence of Mn5Si2 was first reported by [64Sen], its existence remains speculative due to lack of supporting evidence from other investigations on phase equilibria. However, on the basis of a structural study of Mn5Si2 by [71Sho], its presence is tentatively accepted. According to [64Sen], Mn5Si2 forms peritectoidally at 850 C. The liquidus for 30 to 50 at.% Si is constructed on the basis of the most recent data available [33Vog], whereas for 50 to 70 at.% Si it is based on the data of [61Dud], [66Mor], and [70Mag]. Two eutectics exist: between Mn5Si3 and MnSi at 1234 C and 45.6 at.% Si and between MnSi1.75-x and (Si) at 1150 C and 67.9 at.% Si. The latter eutectic temperature is based on [61Dud], [62Dud], [66Mor], and [70Mag], and the composition is based on [61Fuj], [66Mor], and [ 70Mag]. Although the eutectic arrest data appear somewhat scattered, the temperature range is only about 8 C. The intermediate phase Mn5Si3 is the highest melting compound in the system. [ 65Let2] placed the congruent melting point at 1300 C, which is the preferred value. Because the homogeneity range of Mn5Si3 has not been reported, it is shown as a stoichiometric line compound. MnSi melts congruently at 1276 C [33Vog]. The data of [33Vog] are supported by the work of [64Kor] and the shape of the liquidus, so a congruent point at 1276 C is preferred. The assessed liquidus for 70 to 100 at.% Si was constructed on the basis of the data of [61Dud], [70Mag], and the currently accepted melting temperature of Si. The solid solubility of Mn in (Si) has not been reported, but appears to be negligible. [74Pol] investigated the formation of metastable phases in Mn-Si by obtaining alloy films formed at an estimated cooling rate of 107 to 108 K/s by melt spinning on a Cu cylinder rotating at 8000 rpm. They determined the lattice parameters and ranges of stability of the various metastable phases for alloys quenched from two different superheats in the composition range 0 to 36.3 and 64.15 to 75.8 at.% Si. Their findings indicated the formation of an amorphous phase in the region of stability of Mn3Si. [61Dav] indicated that Mn3Si transforms martensitically from 600 to 650 C upon quenching from 800 C. 33Bor: B. Boren, Ark. Kemi., Miner. Geol., 11A(10), 1-28 (1933) in German. 33Vog: R. Vogel and H. Bedarff, Arch. EisenhЃttenwes., 7, 423-425 (1933-34) in German. 61Dav: K.N. Davydov, F.A. Sidorenko, and P.V. Geld, Fiz. Met. Metalloved., 12( 3), 424-430 (1961) in Russian; TR: Phys. Met. Metallogr., 12, 108-113 (1961). 61Dud: L.D. Dudkin and E.A. Kuznetsova, Dokl. Akad. Nauk SSSR, 141(1), 94-97 ( 1961) in Russian; TR: Proc. Acad. Sci. USSR, Chem. Sect., 141, 1085-1088 (1961) . 61Fuj: Y. Fujino, D. Shinoda, S. Asanabe, and Y. Sasaki, Jpn. J. Appl. Phys., 3, 431-435 (1961). 62Dud: L.D. Dudkin and E.S. Kuznetsova, Poroshk. Met., (6), 20-31 (1962) in Russian; TR: Sov. Powder Met. Metall. Ceram., (6), 418-427 (1962). 64Kor: V.A. Korshunov and P.V. Geld, Fiz. Met. Metalloved., 17(2), 292-293 ( 1964) in Russian; TR: Phys. Met. Metallogr., 17(2), 125-126 (1964). 64Kuz: Yu.B. Kuzma and E.I. Gladyshevskii, Russ. J. Inorg. Chem., 9(3), 373- 377 (1964). 64Sen: J.P. Senateur and R. Fruchart, Compt. Rend., 258, 1524-1525 (1964). 64Wie: P.F. Wieser and W.D. Forgeng, Trans. AIME, 230, 1675-1681 (1964). 65Gla: E.I. Gladyshevskii, P.I. Kripyakevich, and Ya.P. Yarmolyuk, Izv. Akad. Nauk SSSR, Neorg. Mater., 1(7), 1086-1089 (1965) in Russian; TR: Inorg. Mater., 1(7), 996-999 (1965). 65Let1: S.M. Letun, P.V. Geld, and N.N. Serebrennikov, Russ. Metall., 6, 97- 103 (1965). 65Let2: S.M. Letun and P.V. Geld, Teplofiz. Vys. Temp., 3(1), 47-56 (1965) in Russian; TR: High Temp., 3(1), 39-46 (1965). 66Mor: M.A. Morkhovets, E.I. Elagina, and N.Kh. Abrikosov, Izv. Akad. Nauk SSSR, Neorg. Mater., 2(4), 650-656 (1966) in Russian; TR: Inorg. Mater., 2(4), 561-565 (1966). 67Lan: G.H. Lander and P.J. Brown, Philos. Mag., (16), 521-542 (1967). 70Mag: T. Mager and E. Wachtel, Z. Metallkd., 61(11), 853-856 (1970) in German. 71Der: R. DeRidder and S. Amelinckx, Mater. Res. Bull., (6), 1223-1234 (1971). 71Sho: C.B. Shoemaker and D.P. Shoemaker, Acta Crystallogr. B, 27, 227-235 ( 1971). 74Bab: E.M. Babanova and Yu.A. Vereshchagin, Tr. Ural Politekh. Inst., 231, 15- 16 (1974) in Russian. 74Kal: G.I. Kalishevich, Yu.A. Vereshchagin, and P.V. Geld, Sov. Phys. Solid State, 16(6), 1151 (1974). 74Pol: A.F. Polesya and V.N. Gudzenko, Izv. Akad. Nauk SSSR, Neorg. Mater., 10( 6), 1011-1015 (1974) in Russian; TR: Inorg. Mater., 10(6), 869-872 (1974). 82Luk: G.M. Lukashenko and V.R. Sidorko, Poroshk. Metall., (7), 67-70 (1982) in Russian. Submitted to the APD Program. Complete evaluation contains 8 figures, 5 tables, and 57 references. Special Points of the Mn-Si System