Silver Aluminium Titanium

Transcription

1 16 Ti Silver uminium Titanium Hans Leo Lukas Literature Data Köster and Sampaio [1957Koe] investigated ternary isothermal sections at 0 C, 1000 C and 1100 C by X-ray and metallographic analyses (x Ti > 25 at.% and x < 42 at.%). At these temperatures they found the binary -Ti phases in equilibrium with an -rich melt or with the silver solid solution, (). Hashimoto et al. [1983Has] determined the 0 C isothermal section (x < 75 at.%) and a vertical section from Ti+51 at.% to +7.5 at.% by electron microprobe, X-ray diffraction, scanning electron microscopy and DTA. These authors analyzed also the ternary solubilities of the () solid solution at 0 C. Mabuchi et al. [1990Mab] detected a ternary phase Ti( 1-x x ) 3 of the AuCu 3 type (L1 2 ) with 0.1<x<0.25. This phase has also a considerable homogeneity range with respect to the ratio Ti:(+), at.% Ti at 1000 C. [1957Koe] did not investigate the area of this phase and [1986Has] investigated one alloy in this area (65 at.% +10 at.% ), reported it as single phase at 0 C, but interpreted it as a solid solution of the phase. Several papers [1991Dur, 1992Dur, 1993Nak, 1999Yam] compare L1 2 phases Ti( 1-x X x ) 3 with different elements X (, Co, Cr, Cu, Fe, Mn, Ni, Pd, Zn) but similar compositions of X. Yamamoto et al. [1999Yam] reported the homogeneity range of the L1 2 phase at 1177 C. Tian and Nemeto [02Tia] studied the precipitation of Ti and Ti 2 from the L1 2 phase, homogenized at 1000 C, as well as that of L1 2 from Ti during annealing at lower temperatures ( C). The present evaluation updates that of [1990Luk]. Binary Systems The three binary systems are accepted from the SGTE assessments in [02LB]. For -Ti [02Li] and -Ti [03Sch] the MSIT Workplace provides assessments with nearly equivalent contents. For -Ti the [03Sch] evaluation states, that there is still some uncertainty, especially on the area between Ti and. The -Ti system used by [1957Koe] assumed a much higher temperature of peritectic formation of the Ti 2 phase (12 C) than [02LB] (9 C). l three [02LB] diagrams are based on thermodynamic calculations, two of them published before: - [1995Lim], -Ti [1998Sau]. Solid Phases A single ternary phase, J, of the AuCu 3 (L1 2 ) type was found near. Like, Ti 2, 11, Ti and it is an ordered form of a close packed crystal structure [1991Dur, 1992Dur]. Some more binary -Ti phases between Ti and were not considered as stable phases in the accepted binary -Ti system. l solid phases regarded to be stable in the evaluations are summarized in Table 1. Invariant Equilibria A tentative reaction scheme was given by [1957Koe]. Due to the discrepancies between the binary systems used by [1957Koe] and those accepted here, it needs modification. Using the approximate thermodynamic description given below in section Thermodynamics a tentative reaction scheme above 0 C can be calculated. Figure 1 shows the result. The temperatures and phase compositions of the ternary invariant reactions must be taken as tentative only, therefore no table of invariant reactions is given. Below 0 C the system is nearly degenerate and the reaction scheme is equal to the binary - system with either the J phase or being in equilibrium with the - phases, but not taking part in the reactions.

2 Ti 17 After the calculation the solubility in the phase decreases very rapidly above 1000 C and thus there appears twice a four phase reaction between liquid,, (Ti)(h) and (at 12 and 1033 C). This may be an artefact, although the three phase field liquid+(ti)(h)+ between these two temperatures is supported by the 1100 C isothermal section reported by [1957Koe]. Isothermal Sections The sections at 1100, 1000 and 0 C, (Fig. 2, Fig. 3 and Fig. 4), are drawn from thermodynamic calculations using the description given in the next section. The homogeneity range of the J phase as well as the +(Ti)(h)+liquid equilibrium at 1000 C are modified to fit to the reported measured points of [1957Koe, 1986Has, 1990Mab]. The sections differ from those of [1957Koe] due to the differences in the accepted binary systems and due to the consideration of the J phase. In Köster s diagrams Ti 2 appears as stable above 1100 C and all phases between and Ti were not yet known. The 0 C section of [1983Has] differs from that given by [1957Koe] for the same temperature mainly by the equilibria containing the -Ti phases Ti and Ti 2. The calculation strongly supports the equilibria given by [1983Has]. The Ti solubility measurements in liquid and solid reported by [1983Has] gave significantly lower values than compatible with the -Ti system of [02LB]. so [1983Has] did not consider the Ti 2 phase between Ti and and they did not distinguish J from. The solubilities in, Ti and are accepted from [1957Koe]. Thermodynamics The thermodynamic data sets as used in [02LB] allow approximate calculation of the ternary system. Without the introduction of ternary parameters, however, the homogeneity ranges of the (Ti)(h) and ) solid solutions in this calculation disagree significantly with [1957Koe] and [1986Has]. For phases with only small ternary solubilities the calculated equilibria agree fairly well with those reported by [1957Koe] and [1986Has]. Using the thermodynamic descriptions of the binary systems [02LB] with additional ternary terms of x x x Ti J mol -1 for G bcc and (+000!12T)x x x Ti J mol -1 for G hcp the ternary system can be approximately calculated. The ternary phase J can be roughly approximated by a stoichiometric phase Ti with the Gibbs energy of formation G J G hcp Ti -0.12Gfcc G fcc =! T J mol-1. References [1957Koe] Köster, W., Sampaio, A., The Ternary System Titanium-Silver-uminium (in German), Z. Metallkd., 48, (1957) (Equi. Diagram, Experimental, #, *, 12) [1962Poe] Pötzschke, M., Schubert, K., On the Constitution of some T 4 -B 3 Systems or Quasi-T 4 -B 3 Systems (in German), Z. Metallkd., 53, (1962) (Crys. Structure, Experimental, 44) [1965Ram] Raman, A., Schubert, K., On the Constitution of some loy Series Related to II (in German), Z. Metallkd., 56, (1965) (Crys. Structure, Equi. Diagram, Experimental, 13) [1965Sch] Schubert, K., On the Constitution of the Systems Titanium-Copper and Titanium-Silver (in German), Z. Metallkd., 56, (1965) (Crys. Structure, Experimental, 14) [1983Has] Hashimoto, K., Doi, H., Tsujimoto, T., Experimental Study on Phase Diagrams of the Ternary Ti-- System, (in Japanese), J. Jpn. Inst. Met., 47, (1983), English translation published in: Trans. Jpn. Inst. Met., 27, (1986) (Equi. Diagram, Experimental, #, 13) [1986Has] Hashimoto, K., Doi, H., Tsujimoto, T., Experimental Study on the Phase Diagram of the Ternary Ti-- System, Trans. Jpn. Inst. Met., 27(2), (1986) (Equi. Diagram, Experimental, 13) [1990Luk] Lukas H.L., Silver-uminium-Titanium, MSIT Ternary Evaluation Program, in MSIT Workplace, Effenberg, G. (Ed.), MSI, Materials Science International Services GmbH,

3 18 Ti [1990Mab] [1990Sch] [1991Dur] [1992Dur] [1993Nak] [1995Lim] [1998Sau] [1999Yam] [01Bra] [02Tia] [02LB] [02Li] [03Sch] Stuttgart; Document ID: (1990) (Crys. Structure, Equi. Diagram, Assessment, 7) Mabuchi, H., Hirukawa, K., Katayama, K., Tsuda, H., Nakayama, Y., Formation of Ternary L1 2 Compounds in -Base loys Containing, Scr. Metall., 24, (1990) (Equi. Diagram, Experimental, #, 25) Schuster, J.C., Ipser, H., Phases and Phase Relations in the Partial System -Ti, Z. Metallkd., 81(6), (1990) (Crys. Structure, Equi. Diagram, Experimental, Review, 33) Durlu, N., Inal, O.T., Yost, F.G., L1 2 -Type Ternary Titanium uminides of the Composition Ti 25 X 8 67, TiA 3 -Based or Ti 2 -Based?, Scr. Metall., 25, (1990) (Theory, Crys. Structure, 30) Durlu, N., Inal, O.T., L1 2 -Type Ternary Titanium uminides as Electron Concentration Phases, J. Mater. Sci., 27, (1992) (Theory, Crys. Structure, 41) Nakayama Y., Mabuchi, H., Formation of Ternary L1 2 Compounds in -Base loys, Intermetallics, 1, (1993) (Equi. Diagram, Experimental, ) Lim, S.S., Rossiter, P.L., Tibballs, J.E., Assessment of the - Binary Phase Diagram, Calphad, 19(2), (1995) (Equi. Diagram, Thermodyn., Calculation, 27) Sauter, N., System -Ti in COST 507, Thermochemical Database for Light Metal loys, Vol. 2, I. Ansara, A.T. Dinsdale, M.H. Rand (Eds.), Office for Official Publications of the European Communities, Luxembourg, (1998) (Assessment, Equi. Diagram, Thermodyn., Calculation, 27) Yamamoto, Y., Hashimoto, K., Kimura, T., Nobuki, M., Kohno, N., L1 2 Single Phase Region in -Ti Base Ternary and Quaternary Systems at 1450 K (in Japanese), J. Jpn. Inst. Met. 63(10), (1999) (Equi. Diagram, Experimental, 15) Braun, J., Ellner, M., Phase Equilibria Investigations on the uminium-rich Part of the Binary System Ti-, Metall. Mater. Trans. A, 32A, (01) (Crys. Structure, Equi. Diagram, Experimental, #, *, 34) Tian, W.H., Nemoto, M., Precipitation Behavior in -Modified L1 2-3 Ti and L1 0 -Ti(), Mater. Sci. Eng. A., , (02) (Crys. Structure, Equi. Diagram, Experimental, 29), Numerical Data and Functional Relationship in Science and Technology, New Series, Ed. in Chief: W. Martienssen, Group IV: Physical Chemistry, Vol. 19, Thermodynamic Properties of Inorganic Materials compiled by SGTE, Subvol. B, Binary Systems: Phase Diagrams, Phase Transition Data, Integral and Partial Quantities of loys. Part 1. Elements and Binary System from - to Au-Tl. Ed. Lehrstuhl f. Werkstoffchemie, RWTH Aachen; Authors: Scientific Group Thermodata Europe (SGTE) Springer Verlag, Berlin, Heidelberg, pp , pp Ti, pp Ti (02) Li, C., Lebrun, N., Dobatkina, T., Kuznetsov, V., -Ti (Silver-Titanium), MSIT Binary Evaluation Program, in MSIT Workplace, Effenberg, G. (Ed.), MSI, Materials Science International Services GmbH, Stuttgart; Document ID:.6.1., (02) (Equi. Diagram, Assessment, 5) Schmid-Fetzer, R., -Ti (uminium-titanium), MSIT Evaluation Program, in MSIT Workplace, Effenberg, G. (Ed.), MSI, Materials Science International Services GmbH, Stuttgart, to be published, (02) (Equi. Diagram, Assessment, 86)

4 Ti 19 Table 1: Crystallographic Data of Solid Phases Phase/ Temperature Range [ C] (Ti)(h) < 1500 () < 962 () < 661 Ti 2 < 9 Ti < 10 < 1190 Ti < 1444 Ti 2 < < (h) (r) < < 727 Pearson Symbol/ Space Group/ Prototype ci2 Im3m W hp2 P6 3 /mmc Mg cf4 Fm3m Cu cf4 Fm3m Cu ti6 I4/mmm MoSi 2 tp4 P4/nmm TiCu hp8 P6 3 /mmc Ni 3 Sn tp4 P4/mmm CuAu ti24 I4 1 /amd HfGa 2 ti16 I4/mmm Zr 3 ti8 I4/mmm ci2 Im3m W cp P $Mn hp2 P6 3 /mmc Mg * J, Ti( 1-x x ) 3 cp4 Pm3m AuCu 3 Lattice Parameters [pm] Comments/References a = pure element, 900 C a = c = pure element, 25 C a = 8.57 pure element, 25 C a = 4.96 pure element, 25 C a = 295 c = 11 a = 290 c = 814 a = c = a = c = 7.6 a = c = 2497 a = c = a = 384 c = a = a = a = c = a = to 0.4 [1965Sch] [1965Sch] [01Bra] [01Bra] [1962Poe, 1990Sch] [1965Ram, 1990Sch] [1965Ram, 1990Sch] 700 C [V-C2] [V-C2] [V-C2] [1990Mab]

5 Ti -Ti --Ti -Ti 12 L+(Ti)(h)+ P 1 L + (Ti)(h) + L L+ Ti+ U 1 12 L + Ti + 11 τ P 2 L+ 11 Ti p 1 l + (Ti)(h) 1444 p 2 l + Ti 1279 p 3 l + Ti e 1 l p 4 l + (Ti)(h) Ti 9 e 5 l () + Ti 9 p 5 Ti+(Ti)(h) Ti e 6 (Ti)(h) +Ti 2 (Ti)(h) (Ti)(h)+ L+ U 3 L+(Ti)(h)+ 975 L+(Ti)(h) +Ti U 4 L+Ti+ 953 L+Ti +() U 5 Ti+(Ti)(h)+ 902 Ti+(Ti)(h) +Ti 2 U 7 Ti+Ti L + Ti () + τ U 10 L+() Ti+() +()+Ti L+()+Ti 12 L τ U 2 L Ti+Ti 2, τ D 1 Ti+Ti 2 11 L++() Ti 2, τ D 2 L++ +Ti L+ ()+ U 6 L+Ti+ 11 +Ti 2 L+()+ 849 L+ ()+Ti U 8 +()+Ti 832 +() Ti+ U 9 +Ti+ ()+Ti+ L+Ti 1181 e 2 11 Ti+Ti e 3 Ti+ 996 e Ti 2 Fig. 1: --Ti. Tentative reaction scheme

6 Ti 21 Fig. 2: --Ti. Isothermal section at 1100 C Data / Grid: at.% Axes: at.% +L 11 Ti 2 Ti τ τ+l +Ti+L TiA+L +L (Ti)(h) (Ti)(h)+L L Ti Fig. 3: --Ti. Isothermal section at 1000 C Data / Grid: at.% Axes: at.% +L 11 Ti 2 Ti τ τ+l Ti+ +L Ti+L + +L +L +L L (Ti)(h) (Ti)(h)+L Ti Ti

7 22 Ti Fig. 4: --Ti. Isothermal section at 0 C Data / Grid: at.% Axes: at.% +L Ti 2 Ti Ti+L L Ti+L Ti+() τ L +Ti+() +() + +Ti +Ti +Ti+() () Ti +Ti 2 Ti 2 Ti