| 1. |
- Borgenstam, Annika, et al.
(författare)
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DICTRA, a tool for simulation of diffusional transformations in alloys
- 2000
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 21:3, s. 269-280
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Tidskriftsartikel (refereegranskat)abstract
- In the present paper, a general survey of the diffusion-controlled transformations (DICTRA) software is given. DICTRA is an engineering tool for diffusion simulations in multicomponent alloys. The simulations are based on multicomponent diffusion and thermodynamic data, both obtained by analyzing and assessing experimental information. This allows for many different cases to be studied as soon as the underlying data are available. DICTRA is not a complete simulation tool because only geometries that can be transformed into one space variable can be treated, but many well posed problems of practical interest may be solved. The program contains several different models, which are discussed in the present paper. Each model has its own applications and several examples from recent simulations are given in order to demonstrate the usage of the particular models.
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| 2. |
- Borggren, U., et al.
(författare)
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A thermodynamic database for special brass
- 2003
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 24:2, s. 110-121
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Tidskriftsartikel (refereegranskat)abstract
- In the present work a thermodynamic database for brass alloys is developed. The database may be used to calculate phase diagrams and property diagrams and to simulate solidification, calculations that may be used to develop new alloys and to increase the understanding of existing ones. When developed, such a database reduces the need for further experimental investigations considerably. The present work is focused on so-called special brass (i.e., alloys of Cu and Zn with small additions of, for instance, Al, As, B, Fe, Pb, and/or Si). The database was created using available thermodynamic descriptions and unavailable systems were assessed using the CALPHAD technique. Experimental information was taken from literature and from experimental results obtained in the present work. The database contains the elements Al, Cu, Pb, Si, and Zn. Calculated phase diagrams show that the peritectic reaction in the Cu-Zn system is very sensitive to small additions of Al and Si, which moves the peritectic reaction towards lower Zn contents and higher temperatures.
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| 3. |
- Bratberg, Johan, et al.
(författare)
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A thermodynamic assessment of the Co-V system
- 2003
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 24:6, s. 495-503
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Tidskriftsartikel (refereegranskat)abstract
- A thermodynamic evaluation of the binary Co-V system has been done using experimental thermochemical and phase diagram data. A consistent thermodynamic description, using a Redlich-Kister model for solution phases and sublattice models for the intermetallics, was obtained, and it agreed well with the critically evaluated experimental data. The model for the solid phases accounts for the magnetic contribution to the Gibbs energy. The addition of a composition dependent magnetic term also led to the prediction of an fcc-Co miscibility gap. The model parameters have been determined using a computerized optimization technique. Several diagrams and tables concerning phase equilibria are presented.
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| 4. |
- Forsberg, Annika, et al.
(författare)
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Thermodynamic evaluation of the Fe-Mn-Si system and the γ/ε martensitic transformation
- 1993
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Ingår i: Journal of phase equilibria (Print). - 1054-9714 .- 1544-1032. ; 14:3, s. 354-363
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic properties of the Fe-Mn-Si system are analyzed by means of thermodynamic models for the individual phases. Special attention is paid to the γ → ε martensitic transition. A complete set of parameters, from which arbitrary sections of the phase diagram as well as the Ms and As temperatures may be calculated, is given.
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| 5. |
- Frisk, K., et al.
(författare)
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Development of a database for cemented carbides : Thermodynamic modeling and experiments
- 2001
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Ingår i: Journal of phase equilibria (Print). - 1054-9714 .- 1544-1032. ; 22:6, s. 645-655
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Tidskriftsartikel (refereegranskat)abstract
- A new database, for thermodynamic information for cemented carbides has been developed. A full description of the alloy system C-Co-N-Nb-Ta-Ti-W is presented. The work has involved both thermodynamic evaluations of lower order systems and experimental investigations. Full new assessments of the quaternary Ti-W-C-N, Ta-W-C-N, and Nb-W-C-N systems have been performed, including tests of the influence of model parameters on miscibility gaps in higher order systems. A new improved description of the Co-W-C system based on new experiments is used in the present work. The main results of the experimental work are measurements of the composition of the cubic carbide in selected equilibria; measurements of the temperatures of the liq + fcc + WC + gr. and liq + fcc + WC + M6C equilibria in the Co-W-C and Co-W-X-C (X = Ti, Ta, Nb) systems; and measurements of the solubility of Ti, Ta, and Nb in liquid in multicomponent alloys. The results of the assessments have been implemented into a new database. The database has successfully been used in a parallel project to simulate the formation of gamma -phase free zones in cemented carbides. A few other applications of industrial relevance are presented.
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| 6. |
- Hallström, Samuel
(författare)
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Thermodynamic assessment of the Ni-Ru system
- 2004
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1547-7037 .- 0000-0000. ; 25:3, s. 252-254
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Tidskriftsartikel (refereegranskat)abstract
- The Ni-Ru system is assessed using the CALPHAD technique. The only available experimental information for this system concerns phase equilibria, whereas no thermochemical information has been found. The THERMO-CALC software is applied to obtain Gibbs energy (G) functions for the individual phases. The phase diagram calculated from the new G functions is in excellent agreement with the experimental diagram, and all the thermodynamic parameters are given in the Appendix. In addition, tentative activity diagrams and the metastable miscibility gaps in fcc and hcp phases are calculated from the new thermodynamic description.
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| 7. |
- Tang, W. J., et al.
(författare)
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Phase equilibria in the pseudobinary Ti0.5Ni0.5-Ti0.5Cu0.5 system
- 2000
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 21:3, s. 227-234
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Tidskriftsartikel (refereegranskat)abstract
- The pseudobinary Ti0.5Ni0.5-Ti0.5Cu0.5 system was analyzed using thermodynamic models for the Gibbs energy of individual phases in the system. The TiNi intermetallic phase crystallizes with the B2 CsCl-type structure and is an ordered form of the A2 BCC structure, It was treated with a two-sublattice model (Cu, Ni, Ti, Va)(0.5)(Cu, Ni, Ti, Va)(0.5), where Va represents a vacancy and one sublattice is occupied predominantly by Ti and the other by Ni and Cu. Other phases such as B11 based on a TiCu compound and low-temperature phases B19' and B19 were also described with two-sublattice models with different distribution of atoms on each sublattice, A thermodynamic description of the Ti0.5Ni0.5-Ti0.5Cu0.5 system was obtained from an optimization based on experimental information. The calculated diagram of the pseudobinary Ti0.5Ni0.5-Ti0.5Cu0.5 system at high temperatures exhibits eutectic solidification of liquid and shows satisfactory agreement with experimental data. The phase relations among the B2, B19', and B19 phases at low temperatures mere also assessed on the basis of experimental information from martensitic transformations.
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| 8. |
- Toffolon, C., et al.
(författare)
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Reassessment of the Nb-Sn system
- 2002
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 23:2, s. 134-139
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Tidskriftsartikel (refereegranskat)abstract
- A new assessment of the Nb-Sn system is proposed considering the Nb3Sn phase stable down below room temperature. The Gibbs energy of formation of the solution and compound phases in the Nb-Sn system were derived from an optimization procedure using all the available experimental thermodynamic and phase diagram data. In particular, the enthalpy of formation of the Nb3Sn phase at 1350 degreesC was determined experimentally in this study. The thermodynamic description of the intermetallic compounds was made using a sublattice model, while a Redlish-Kister polynomial was used for the solution phases.
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| 9. |
- Tolochko, O., et al.
(författare)
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Thermodynamic properties of supercooled Fe-B liquids - A theoretical and experimental study
- 2000
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Ingår i: Journal of phase equilibria (Print). - : Springer Science and Business Media LLC. - 1054-9714 .- 1544-1032 .- 1863-7345. ; 21:1, s. 19-24
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Tidskriftsartikel (refereegranskat)abstract
- The two-level model, recommended at the Ringberg 95 workshop, is applied to extrapolate the thermodynamic properties of liquid Fe-B alloys to large undercooling and to analyze the crystallization of glassy Fe85B15 alloys obtained by melt spinning. The new method yields practically the same phase diagram as the SGTE database but a superior result when evaluating the heat capacity, entropy, and crystallization heat at large undercooling. These properties are compared in the low-temperature range (700 to 800 K) with the experimental data obtained for an Fe85B15 metallic glass by scanning calorimetry. A good agreement between experiments and calculations is obtained when the observed magnetic transition at 530 K is taken into account.
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| 10. |
- Forsberg, S
(författare)
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Optimization of thermodynamic properties of the K2O-SiO2 system at high temperatures
- 2002
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Ingår i: Journal of Phase Equilibria. - 1054-9714. ; 23:3, s. 211-7
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Tidskriftsartikel (refereegranskat)abstract
- An optimized set of thermodynamic functions for the K2O-SiO2 system at 10(5) Pa pressure was obtained by considering available phase diagram and thermodynamic data. KSi0.25O and SiO2 were selected as components for the liquid phase. With respect to these components, the highly non-ideal interactions of potassium oxide and silica could be described by using only three temperature-independent Redlich-Kister coefficients for the excess G of the liquid phase. The result is in good agreement with experimental data.
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