Фазовая диаграмма системы Ag-In

К оглавлению: Другие диаграммы (Others phase diargams)


Ag-In (Silver-Indium) M.R. Baren The assessed Ag-In phase diagram is based mainly on the work of [70Cam]. The liquidus down to 700 C and the (Ag) solidus are due to [35Wei]. The (Ag) solid-solubility phase boundary is estimated from the solid solubility data of [65Str] at 25 C and is approximately 1 at.% to the In-rich side of the [35Wei] curve. [70Cas] concluded that the significant solid solubility of In in (Ag) and lack of solid solubility of Ag in (In) are direct results of the more exothermic nature of the formation reaction in the Ag-rich alloy composition range. The portion of the assessed phase diagram in the composition range between about 20 and 33 at.% In is still in doubt. [61Mor] reported the b phase, which occurs from 25 to 30 above 660 C. According to [70Cam], the difficulty in bringing the phase to thermodynamic equilibrium even after many weeks of annealing often led to the persistence of z stable at room temperature. The homogeneous z phase has a maximum In solubility of 46 at.% at 205 C. At 205 C, the z phase decomposes by the metatectic reaction z = g + L in the composition range 33 to 46 at.% In. [70Cam] observed eutectic arrests at compositions in the region between the g and AgIn2. This effect was due to the presence of metastable liquid, which finally froze at the eutectic temperature and occurred even with very slow cooling rates. [70Cam] found that the z phase occurred metastably at several compositions. An alloy containing 38.5 at.% In contained substantial z phase when not heat treated. However, after annealing at 135 C, the amount of z diminished. An alloy with 64.6 at.% In contained metastable z even after prolonged annealing at 135 C, although the z decreased with increased annealing time. According to the phase diagram, an alloy containing 22.2 at.% In should consist of (Ag) + a› below 187 C. However, the z phase was still present even after annealing at 129 C for 3 weeks. An alloy of the same composition left for 2 months at room temperature indicated less z phase, which apparently transformed slowly to the (Ag) + a› phases. [68Sri] studied alloys splat cooled to -190 C containing 70 to 80 at.% In. These alloys showed the presence of metastable fcc phases of the A1 type, which they designated as (Ag). Excessive broadening of the diffraction peaks of these alloys indicated the possibility of a tetragonal or more complex distortion of the fcc structure. [82Fra] studied alloys containing 11.1 to 29.7 at.% In after rapidly quenching to -183 C. A metastable phase was found and its terminal solid solubility was reduced. [82Fra] proposed a stacking fault mechanism for the transformation from fcc to cph brought about by the rapid quenching of the alloys. 28Gol: V.M. Goldschmidt, Z. Phys. Chem. (Leipzig), 133, 197 (1928). 35Wei: F. Weibke and H. Eggers, Z. Anorg. Chem., 222, 145-160 (1935). 51Hel: E. Hellner, Z. Metallkd., 42, 17 (1951). 61Mor: D.P. Morris and I. Williams, Acta Crystallogr., 14, 74 (1961). 61Kin: H.W. King and T.B. Massalski, Philos. Mag., 6, 669-682 (1961). 65Str: M.E. Straumanis and S.M. Riad, Trans. Met. Soc. AIME, 233, 964-967 ( 1965). 68Sri: P.K. Srivastave, B.C. Geissen, and N.J. Grant, Acta Metall., 16, 1199- 1202 (1968). 70Cam: A.N. Campbell, R. Wageman, and R.B. Ferguson, Can. J. Chem., 48(11), 1703-1715 (1970). 70Cas: R. Castanet, Y. Clair, and M. Laffitte, J. Chim. Phys., 67, 789-793 ( 1970). 82Fra: V. Franetovic, D. Kunstelj, and A. Bonefalic, J. Mater. Sci., 17, 2771- 2780 (1982). Submitted to the APD Program. Complete evaluation contains 2 figures, 5 tables, and 20 references. Special Points of the Ag-In System