- Email: [email protected]
[O67] Modeling of the thermophysical properties of Fe-Ni alloys with application to calculation of high-pressure phase equilibria
Y DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
of temperature, is considered to be an important nuclear material. However, the volume expansion and lattice distortion significantly affect the successful preparation of bulk zirconium hydride. Additionally, the Zr-H binary compounds generally show the brittle character. Those mentioned above make the preparation of the crackfree zirconium hydride extremely difficult. The thermodynamic information on the Zr-H-Nb system can be used to guide the preparation of the Nb-containing zirconium hydride. In this work, we try to use the CALPHAD method and the advanced computer technologies to solve the cracking problem and to improve the research efficiency on the zirconium hydride preparation. The thermodynamic parameters of the Zr-H-Nb ternary system are optimized at present, and the calculated results agree well with the experimental data. The equilibrium phase information and thermodynamic properties of the Zr-H-Nb system on the Zrrich side (wt.%Nb r 2.5) could be availably predicted by the thermodynamic modeling of the Zr-H-Nb system. According to the calculations and theoretical analysis, we obtain that the cooling rate and the hydrogen pressure are the most important factors in avoiding the cracking during the zirconium hydride preparation process. Therefore, a reasonable multi-step hydriding temperature curve and an adaptive hydrogen flow mechanism are made. In this way, the hydrogen absorption speed of the alloys is controlled effectively and the macro-cracking is inhibited. http://dx.doi.org/10.1016/j.calphad.2015.01.069
[O65] Optimization of Mechanical Properties of High Strength TRIP Steels Lin Li, Yi Gao, Yanlin He, Wen Shi, Mei Zhang, Xiao Gang Lu
Traditional TRIP steels have been developed for several decades, however, when the strength reaches 1000MPa, the elongation rate is difficult to be raised over 20%. In the light of thermodynamics, phase diagram of TRIP steel containing rather high amount of Al is optimized and the attractive function of Al, which largely increases carbon solubility in austenite is found. As higher carbon content leads to higher stability of austenite and better TRIP effect of TRIP steel, new composition of high strength TRIP steel with high amount Al is designed as well as heat treatment processes. The newly developed TRIP steel exhibits superior mechanical properties and the product of its strength and plasticity is higher than 30000 MPa, i.e., the target of the mechanical properties of 3th generation automotive steel. http://dx.doi.org/10.1016/j.calphad.2015.01.070
365
combustion for fuel from waste in the incineration plan TAMARA of the Karlsruhe Institute of Technology [2], we regarded the pyroxene too. The introduced amorphous structures were studied with XRD and we made the model glasses of the content for the system CaO-Al2O3-SiO2 in DTA. Together with the synthesis of the mixed oxide species we measured the temperatures of liquid-solid state of matter with aim to visualize the surface conditions for their condensation and drew the three dimensional plots with finite element methods of approximation for the solidification surfaces. The databases of thermodynamic properties of the pure substances were saved with opportunity to calculate their activities in the boiler area of waste treatment facility. Thus, we should remember that the practical application of our agglomerates is the anti-corrosion coatings, which should be stable against the influence of hot acid gases and have the higher polymerization ability on protected materials. According to the above systemized experimental results and the geological inventories of thallium incoming Tl þ 3-Al þ 3 in the analogous composites of natural grounds we simulated the aluminate and alum-silicate structures of TlAl3O6 and TlAlSiO5, TlAl3SiO8. The prognosis was succeeded with coupling of the sub-lattice and associate species models in terms of the quasichemical approach for the systems of the Tl2O3-Al2O3-SiO2 containing compounds and with help of IVTANTHERMO, FactSage and Thermo-Calc dates. The correction coefficients of methods of the CALPHAD numerical research and our mathematical models for approximation of the results of the investigated technical processes was implemented in the Object Pascal Program “MeRSdates” and realized with the software package. The solid-gas equilibriums describe the case of combustion for aluminum based fuels and of the condensation of Tl-Al-O plasma. These inter-state relations, characterized with diffusion of oxygen in the metallic propellant and with adhesion of the ionized substances on a defended surface, we compute with help of fugacities. They are the source of a power, influencing the species during the time of the heterogeneous interactions of the charged particles and mineralizing materials.
References [1] L. Kaufman, Computation aterials design, CALPHAD 39 (2012) 111. [2] H. Seifert, Hochtemperaturtechnik, Chemie Ingenieur Technik 84 (2012) 1070.
http://dx.doi.org/10.1016/j.calphad.2015.01.071
[O67] Modeling of the thermophysical properties of Fe-Ni alloys with application to calculation of high-pressure phase equilibria Eli Brosh
[O66] Thermodynamic Modeling of Crystal Structures for High-Temperature Anti-Corrosion Coatings Oleg Chizhko
In this paper we investigated the anti-corrosion properties of aluminum rich minerals for the type of silimanite, anorthite and mullite. Because of thermal treatment, with which this complex chemical compounds were produced during the time period [1] of
Fe-Ni alloys exhibit several anomalies which pose a major challenge for modeling. The thermal expansion is almost zero at the sharp minimum near the Fe-36% Ni composition which is the well-known INVAR phenomenon. The elastic and magnetic properties also exhibit complex dependence on composition and temperature. Much of these phenomena may be explained by considering the existence of two states of Fe in the FCC_A1 structure (R. J. Weiss 1963, Proc. Phys. Soc. 82, 281): an antiferromagnetic state with smaller molar volume and a ferromagnetic state with larger
366
Y. DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
Fig. 5. The comparison of excess Gibbs energy of mixing at 933 K for liquid.
molar volume. Among other advantages, the extension of this concept to high pressures is made straightforward by taking into account the effect of pressure on the energy difference between the two states. Current CALPHAD assessments of the Fe-Ni system are limited to the description of the Gibbs energy at ambient pressure and do not utilize the Weiss 2-states concept. In the present work, the 2-states concept is invoked into the CAPHAD calculation through a special form of pressure-dependent interaction coefficients, related to the fraction of ferromagnetic iron. This results in a description of the molar volume, thermal expansion and bulk modulus of Fe-Ni alloys and is readily extended to high pressure. In combination with a compatible description of the Fe-C system, the new model is utilized in calculation of high pressure phase equilibria in Fe-Ni-C alloys, applicable in industry and geology. http://dx.doi.org/10.1016/j.calphad.2015.01.072
[O68] Comparison of Muggianu model,Toop model and General solution model for predicting the thermodynamic properties of Mg-Al-Zn system Qun Luo, Qian Li, Jie-Yu Zhang, Kuo-Chih Chou
The thermodynamic calculations of Mg-Al-Zn(1-2-3) system were based on three extrapolation models: Muggianu model (symmetrical), Toop model (asymmetrical) and General solution model. The excess Gibbs energy of mixing at 933 K for liquid was calculated and shown in Fig. 5. Becausethe ternary interaction parameters (f) of Toop model and General solution model are very complex functions of composition and temperature, a first order approximation was used, where f was treated as linear combination of ternary composition x1, x2 and x3. The coefficients are function of temperature, which obtained by multiple linear regression. The calculated partial enthalpies of Zn in liquid with experimental data showed in Fig. 6. The phase boundaries of liquid and fcc(Al) at 0.0 4wt.Mg and Al-0.1 wt.Mg were calculated. The results suggested that the curves predicted by General solution model showeda better agreement than other two models. The error of Muggianu model often arises when the system is asymmetrical. The calculated result of Toop model is closely related with the
Fig. 6. The partial enthalpies of Zn in liquid at 933 K.
selection of asymmetric component. The General solution model can overcome the weakness of symmetrical and asymmetrical models.Therefore, it is more reasonable in theoretical prediction. http://dx.doi.org/10.1016/j.calphad.2015.01.073
[O69] Energetic investigation of metastable Al60Sm11-ω, Al5Sm-π, Al4Sm-γ,Al11Sm3-α and Al4Sm-β phase formation S.H. Zhou, M.J. Kramer, R.T. Ott, R.E. Napolitano
The Al-10 at. pct Sm alloy was investigated by both firstprinciples approach and experimental measurements. Experimental samples were processed in two ways: (1) arc melting (AM) the alloy on a copper hearth and (2) electromagnetic levitation (EML) melting the alloy following dropped into a copper hearth. The alloy samples were examined using scanning electron microscopy (SEM) and X-ray diffraction analyses (XRD). The results indicate that the Al4Sm-β phase is observed in both AM and EML samples and the Al11Sm3-α phase is identified in the EML sample with a relative slow cooling rate. In addition, the Al60Sm11-ω, Al5Sm-π and Al4Sm-γ phases observed upon devitrification of the amorphous samples in literature are energized using thermodynamic modeling. To evaluate the thermodynamic parameters, the zero-Kelvin enthalpies of formation were calculated with the first-principles approach. The thermodynamic properties of the Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al4Sm-β, and Al11Sm3-α phases were analyzed by combining the first-principles results and experimental data. To understand these metastable Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al11Sm3-α, Al4Sm-β, formation behavior, the energetics associated with varying degrees of chemical partitioning, i.e. Chemical Partitioning- Temperature-Phase Transformation (CPTPT), are quantified to shed light on the problem of the phase transformation far from equilibrium. The possible phase composition are presented over a range of temperature using a "Baker-Cahn" analysis of the energetics of solidification. The results indicate that the Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al4Sm-β, and Al11Sm3-α present under different degrees of chemical partitioning. http://dx.doi.org/10.1016/j.calphad.2015.01.074
of temperature, is considered to be an important nuclear material. However, the volume expansion and lattice distortion significantly affect the successful preparation of bulk zirconium hydride. Additionally, the Zr-H binary compounds generally show the brittle character. Those mentioned above make the preparation of the crackfree zirconium hydride extremely difficult. The thermodynamic information on the Zr-H-Nb system can be used to guide the preparation of the Nb-containing zirconium hydride. In this work, we try to use the CALPHAD method and the advanced computer technologies to solve the cracking problem and to improve the research efficiency on the zirconium hydride preparation. The thermodynamic parameters of the Zr-H-Nb ternary system are optimized at present, and the calculated results agree well with the experimental data. The equilibrium phase information and thermodynamic properties of the Zr-H-Nb system on the Zrrich side (wt.%Nb r 2.5) could be availably predicted by the thermodynamic modeling of the Zr-H-Nb system. According to the calculations and theoretical analysis, we obtain that the cooling rate and the hydrogen pressure are the most important factors in avoiding the cracking during the zirconium hydride preparation process. Therefore, a reasonable multi-step hydriding temperature curve and an adaptive hydrogen flow mechanism are made. In this way, the hydrogen absorption speed of the alloys is controlled effectively and the macro-cracking is inhibited. http://dx.doi.org/10.1016/j.calphad.2015.01.069
[O65] Optimization of Mechanical Properties of High Strength TRIP Steels Lin Li, Yi Gao, Yanlin He, Wen Shi, Mei Zhang, Xiao Gang Lu
Traditional TRIP steels have been developed for several decades, however, when the strength reaches 1000MPa, the elongation rate is difficult to be raised over 20%. In the light of thermodynamics, phase diagram of TRIP steel containing rather high amount of Al is optimized and the attractive function of Al, which largely increases carbon solubility in austenite is found. As higher carbon content leads to higher stability of austenite and better TRIP effect of TRIP steel, new composition of high strength TRIP steel with high amount Al is designed as well as heat treatment processes. The newly developed TRIP steel exhibits superior mechanical properties and the product of its strength and plasticity is higher than 30000 MPa, i.e., the target of the mechanical properties of 3th generation automotive steel. http://dx.doi.org/10.1016/j.calphad.2015.01.070
365
combustion for fuel from waste in the incineration plan TAMARA of the Karlsruhe Institute of Technology [2], we regarded the pyroxene too. The introduced amorphous structures were studied with XRD and we made the model glasses of the content for the system CaO-Al2O3-SiO2 in DTA. Together with the synthesis of the mixed oxide species we measured the temperatures of liquid-solid state of matter with aim to visualize the surface conditions for their condensation and drew the three dimensional plots with finite element methods of approximation for the solidification surfaces. The databases of thermodynamic properties of the pure substances were saved with opportunity to calculate their activities in the boiler area of waste treatment facility. Thus, we should remember that the practical application of our agglomerates is the anti-corrosion coatings, which should be stable against the influence of hot acid gases and have the higher polymerization ability on protected materials. According to the above systemized experimental results and the geological inventories of thallium incoming Tl þ 3-Al þ 3 in the analogous composites of natural grounds we simulated the aluminate and alum-silicate structures of TlAl3O6 and TlAlSiO5, TlAl3SiO8. The prognosis was succeeded with coupling of the sub-lattice and associate species models in terms of the quasichemical approach for the systems of the Tl2O3-Al2O3-SiO2 containing compounds and with help of IVTANTHERMO, FactSage and Thermo-Calc dates. The correction coefficients of methods of the CALPHAD numerical research and our mathematical models for approximation of the results of the investigated technical processes was implemented in the Object Pascal Program “MeRSdates” and realized with the software package. The solid-gas equilibriums describe the case of combustion for aluminum based fuels and of the condensation of Tl-Al-O plasma. These inter-state relations, characterized with diffusion of oxygen in the metallic propellant and with adhesion of the ionized substances on a defended surface, we compute with help of fugacities. They are the source of a power, influencing the species during the time of the heterogeneous interactions of the charged particles and mineralizing materials.
References [1] L. Kaufman, Computation aterials design, CALPHAD 39 (2012) 111. [2] H. Seifert, Hochtemperaturtechnik, Chemie Ingenieur Technik 84 (2012) 1070.
http://dx.doi.org/10.1016/j.calphad.2015.01.071
[O67] Modeling of the thermophysical properties of Fe-Ni alloys with application to calculation of high-pressure phase equilibria Eli Brosh
[O66] Thermodynamic Modeling of Crystal Structures for High-Temperature Anti-Corrosion Coatings Oleg Chizhko
In this paper we investigated the anti-corrosion properties of aluminum rich minerals for the type of silimanite, anorthite and mullite. Because of thermal treatment, with which this complex chemical compounds were produced during the time period [1] of
Fe-Ni alloys exhibit several anomalies which pose a major challenge for modeling. The thermal expansion is almost zero at the sharp minimum near the Fe-36% Ni composition which is the well-known INVAR phenomenon. The elastic and magnetic properties also exhibit complex dependence on composition and temperature. Much of these phenomena may be explained by considering the existence of two states of Fe in the FCC_A1 structure (R. J. Weiss 1963, Proc. Phys. Soc. 82, 281): an antiferromagnetic state with smaller molar volume and a ferromagnetic state with larger
366
Y. DU et al. / CALPHAD: Computer Coupling of Phase Diagrams and Thermochemistry 51 (2015) 344–415
Fig. 5. The comparison of excess Gibbs energy of mixing at 933 K for liquid.
molar volume. Among other advantages, the extension of this concept to high pressures is made straightforward by taking into account the effect of pressure on the energy difference between the two states. Current CALPHAD assessments of the Fe-Ni system are limited to the description of the Gibbs energy at ambient pressure and do not utilize the Weiss 2-states concept. In the present work, the 2-states concept is invoked into the CAPHAD calculation through a special form of pressure-dependent interaction coefficients, related to the fraction of ferromagnetic iron. This results in a description of the molar volume, thermal expansion and bulk modulus of Fe-Ni alloys and is readily extended to high pressure. In combination with a compatible description of the Fe-C system, the new model is utilized in calculation of high pressure phase equilibria in Fe-Ni-C alloys, applicable in industry and geology. http://dx.doi.org/10.1016/j.calphad.2015.01.072
[O68] Comparison of Muggianu model,Toop model and General solution model for predicting the thermodynamic properties of Mg-Al-Zn system Qun Luo, Qian Li, Jie-Yu Zhang, Kuo-Chih Chou
The thermodynamic calculations of Mg-Al-Zn(1-2-3) system were based on three extrapolation models: Muggianu model (symmetrical), Toop model (asymmetrical) and General solution model. The excess Gibbs energy of mixing at 933 K for liquid was calculated and shown in Fig. 5. Becausethe ternary interaction parameters (f) of Toop model and General solution model are very complex functions of composition and temperature, a first order approximation was used, where f was treated as linear combination of ternary composition x1, x2 and x3. The coefficients are function of temperature, which obtained by multiple linear regression. The calculated partial enthalpies of Zn in liquid with experimental data showed in Fig. 6. The phase boundaries of liquid and fcc(Al) at 0.0 4wt.Mg and Al-0.1 wt.Mg were calculated. The results suggested that the curves predicted by General solution model showeda better agreement than other two models. The error of Muggianu model often arises when the system is asymmetrical. The calculated result of Toop model is closely related with the
Fig. 6. The partial enthalpies of Zn in liquid at 933 K.
selection of asymmetric component. The General solution model can overcome the weakness of symmetrical and asymmetrical models.Therefore, it is more reasonable in theoretical prediction. http://dx.doi.org/10.1016/j.calphad.2015.01.073
[O69] Energetic investigation of metastable Al60Sm11-ω, Al5Sm-π, Al4Sm-γ,Al11Sm3-α and Al4Sm-β phase formation S.H. Zhou, M.J. Kramer, R.T. Ott, R.E. Napolitano
The Al-10 at. pct Sm alloy was investigated by both firstprinciples approach and experimental measurements. Experimental samples were processed in two ways: (1) arc melting (AM) the alloy on a copper hearth and (2) electromagnetic levitation (EML) melting the alloy following dropped into a copper hearth. The alloy samples were examined using scanning electron microscopy (SEM) and X-ray diffraction analyses (XRD). The results indicate that the Al4Sm-β phase is observed in both AM and EML samples and the Al11Sm3-α phase is identified in the EML sample with a relative slow cooling rate. In addition, the Al60Sm11-ω, Al5Sm-π and Al4Sm-γ phases observed upon devitrification of the amorphous samples in literature are energized using thermodynamic modeling. To evaluate the thermodynamic parameters, the zero-Kelvin enthalpies of formation were calculated with the first-principles approach. The thermodynamic properties of the Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al4Sm-β, and Al11Sm3-α phases were analyzed by combining the first-principles results and experimental data. To understand these metastable Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al11Sm3-α, Al4Sm-β, formation behavior, the energetics associated with varying degrees of chemical partitioning, i.e. Chemical Partitioning- Temperature-Phase Transformation (CPTPT), are quantified to shed light on the problem of the phase transformation far from equilibrium. The possible phase composition are presented over a range of temperature using a "Baker-Cahn" analysis of the energetics of solidification. The results indicate that the Al60Sm11-ω, Al5Sm-π, Al4Sm-γ, Al4Sm-β, and Al11Sm3-α present under different degrees of chemical partitioning. http://dx.doi.org/10.1016/j.calphad.2015.01.074