Pub Date : 2024-09-13DOI: 10.1016/j.calphad.2024.102741
Dupei Ma , Lunjun Gong , Zhi Li , Jingxian Hu , Fucheng Yin , Yu Wu , Yan Liu
The isothermal section at 900 °C of the Ti-poor part of the Ni−Ti−Ru ternary system was measured experimentally, combined with SEM-EDS, XRD, TEM and DSC techniques. Four three-phase equilibria regions were confirmed at 900 °C isothermal section and a ternary compound τ with Face-centered-cubic structure can existed stably. The isothermal section at 900 °C measured in this study and the experimental data from our previous work were adopted in the present optimization. The calculated Ni−Ti−Ru ternary system was summarily presented in the form of isothermal sections, liquids projection and reaction scheme, with appropriate comparisons with available experimental data.
结合 SEM-EDS、XRD、TEM 和 DSC 技术,通过实验测量了镍钛钌三元体系贫钛部分在 900 °C 时的等温截面。在 900 °C等温截面上确认了四个三相平衡区域,并且具有面心立方结构的三元化合物 τ 可以稳定存在。本研究中测得的 900 °C 等温截面和我们之前工作中的实验数据被采用于本次优化。计算得出的镍钛钌三元体系以等温截面、液体投影和反应方案的形式进行了总结,并与现有的实验数据进行了适当的比较。
{"title":"An experimental study and thermodynamic evaluation of the Ti-poor part of the Ni−Ti−Ru ternary system","authors":"Dupei Ma , Lunjun Gong , Zhi Li , Jingxian Hu , Fucheng Yin , Yu Wu , Yan Liu","doi":"10.1016/j.calphad.2024.102741","DOIUrl":"10.1016/j.calphad.2024.102741","url":null,"abstract":"<div><p>The isothermal section at 900 °C of the Ti-poor part of the Ni−Ti−Ru ternary system was measured experimentally, combined with SEM-EDS, XRD, TEM and DSC techniques. Four three-phase equilibria regions were confirmed at 900 °C isothermal section and a ternary compound τ with Face-centered-cubic structure can existed stably. The isothermal section at 900 °C measured in this study and the experimental data from our previous work were adopted in the present optimization. The calculated Ni−Ti−Ru ternary system was summarily presented in the form of isothermal sections, liquids projection and reaction scheme, with appropriate comparisons with available experimental data.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142228677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1016/j.calphad.2024.102746
Genfeng Shang, Yuqin Xing, Zi-Tian Zhang, Xiao-Gang Lu
As a core of the high entropy alloys, the Co-Cr-Fe-Ni system has been widely investigated. In the present work, the thermodynamics of the Co-Cr-Fe-Ni system and the atomic mobilities of its fcc phase have been evaluated by means of the CALPHAD approach. First-principles calculations were performed to obtain the total energies for the end-member compounds of the σ phase in the Co-Cr-Fe-Ni system. Combining with the experimental data and thermodynamic modeling of the sub-systems from the literature, a set of self-consistent thermodynamic parameters were derived and extrapolated to obtain a thermodynamic description of the Co-Cr-Fe-Ni quaternary system. In order to verify the accuracy of the model parameters, the phase equilibria of a series of the CoCrxFeNi alloys with different Cr contents were determined using DSC, BSE and XRD analysis. Subsequently, based on the diffusion experimental data, the atomic mobilities of the fcc Cr-Fe-Ni alloys were reassessed using the DICTRA software. A mobility database for the fcc Co-Cr-Fe-Ni quaternary system was constructed by directly extrapolating the atomic mobilities of all sub-systems, and comprehensive comparisons prove the consistency between the present assessments and the experiments. In addition to the direct extrapolation approach, extra four-body interaction parameters concerning all four components were added and assessed. The results demonstrate that the extra interaction contributions are ignorable, so that the direct extrapolation from the sub-systems to the quaternary system is feasible in the fcc Co-Cr-Fe-Ni quaternary system.
{"title":"Thermodynamic assessment of the Co-Cr-Fe-Ni quaternary system and diffusion study of its fcc phase","authors":"Genfeng Shang, Yuqin Xing, Zi-Tian Zhang, Xiao-Gang Lu","doi":"10.1016/j.calphad.2024.102746","DOIUrl":"10.1016/j.calphad.2024.102746","url":null,"abstract":"<div><p>As a core of the high entropy alloys, the Co-Cr-Fe-Ni system has been widely investigated. In the present work, the thermodynamics of the Co-Cr-Fe-Ni system and the atomic mobilities of its fcc phase have been evaluated by means of the CALPHAD approach. First-principles calculations were performed to obtain the total energies for the end-member compounds of the σ phase in the Co-Cr-Fe-Ni system. Combining with the experimental data and thermodynamic modeling of the sub-systems from the literature, a set of self-consistent thermodynamic parameters were derived and extrapolated to obtain a thermodynamic description of the Co-Cr-Fe-Ni quaternary system. In order to verify the accuracy of the model parameters, the phase equilibria of a series of the CoCr<sub><em>x</em></sub>FeNi alloys with different Cr contents were determined using DSC, BSE and XRD analysis. Subsequently, based on the diffusion experimental data, the atomic mobilities of the fcc Cr-Fe-Ni alloys were reassessed using the DICTRA software. A mobility database for the fcc Co-Cr-Fe-Ni quaternary system was constructed by directly extrapolating the atomic mobilities of all sub-systems, and comprehensive comparisons prove the consistency between the present assessments and the experiments. In addition to the direct extrapolation approach, extra four-body interaction parameters concerning all four components were added and assessed. The results demonstrate that the extra interaction contributions are ignorable, so that the direct extrapolation from the sub-systems to the quaternary system is feasible in the fcc Co-Cr-Fe-Ni quaternary system.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142172390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1016/j.calphad.2024.102742
Ondrej Zobac , Ales Kroupa , Alan Dinsdale
In a previous paper a method was developed to define Einstein temperatures for metastable phases of the elements and their relation to the so-called lattice stabilities used in the past, and also the variation of the Einstein temperature with composition to account for the composition dependence of the excess entropy. This approach was demonstrated successfully for the Al–Zn system. In this paper this approach is extended to cover the Al–Si and Si–Zn binary systems. The phase diagram for the Al–Si–Zn ternary system was then predicted from the thermodynamic description of the binary subsystems only without any ternary interaction parameters. Agreement with the experimental data is shown to be very good.
{"title":"Use of third generation data for the pure elements to model the thermodynamics of binary alloy systems: Part 3 – The theoretical prediction of the Al–Si–Zn system","authors":"Ondrej Zobac , Ales Kroupa , Alan Dinsdale","doi":"10.1016/j.calphad.2024.102742","DOIUrl":"10.1016/j.calphad.2024.102742","url":null,"abstract":"<div><p>In a previous paper a method was developed to define Einstein temperatures for metastable phases of the elements and their relation to the so-called lattice stabilities used in the past, and also the variation of the Einstein temperature with composition to account for the composition dependence of the excess entropy. This approach was demonstrated successfully for the Al–Zn system. In this paper this approach is extended to cover the Al–Si and Si–Zn binary systems. The phase diagram for the Al–Si–Zn ternary system was then predicted from the thermodynamic description of the binary subsystems only without any ternary interaction parameters. Agreement with the experimental data is shown to be very good.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1016/j.calphad.2024.102740
Ping Wu , Ashutosh Agarwal , Hasanthi L. Senevirathna , Shunnian Wu , Cheng-Fu Yang
This paper introduces an innovative theory for customizing photoluminescence (PL) emission wavelengths in rare earth ion (Eu2+) doped alkaline earth metals (Ca, Mg) silicates, rooted in the entropy of fusion and configurational entropy of congruent and incongruent silicates, respectively, aiming to reveal dynamic deformation of the tetrahedral SiO4 ligand within these materials. Using FactSage, we computationally calculate the fusion entropy of congruent silicates in the CaO-MgO-SiO2 system. Synthesized ternary silicates confirm our theory by highlighting correlations between lower/higher fusion entropy (for congruent) and configurational entropy (for incongruent) silicates, leading to red/blue shifts in PL emission wavelengths. In binary silicate systems, we observe an inverse correlation between PL emission wavelengths and fusion entropy of congruent silicates or pseudo-congruent silicates like MgSiO3, whose solid-liquid decomposition temperature is close to its melting point. Furthermore, the non-ideal liquid phase entropy of incongruent silicates positioned between congruent CaMgSi2O6 (Pyroxene) and congruent Ca2MgSi2O7 (Akermanite) in the MgO-CaO-SiO2 ternary phase diagram comprehensively explains diverse PL emission wavelengths. Beyond its scholarly impact, this work expands perspectives in lighting and photonic research, opening an exciting frontier in entropy-lighting research and enabling predictions of host chemical composition and tunable PL emission wavelengths, particularly relevant to LED technologies.
{"title":"A novel photoluminescence theory and design rule based on solution entropy for rare earth ion doped alkaline metal silicates","authors":"Ping Wu , Ashutosh Agarwal , Hasanthi L. Senevirathna , Shunnian Wu , Cheng-Fu Yang","doi":"10.1016/j.calphad.2024.102740","DOIUrl":"10.1016/j.calphad.2024.102740","url":null,"abstract":"<div><p>This paper introduces an innovative theory for customizing photoluminescence (PL) emission wavelengths in rare earth ion (Eu<sup>2+)</sup> doped alkaline earth metals (Ca, Mg) silicates, rooted in the entropy of fusion and configurational entropy of congruent and incongruent silicates, respectively, aiming to reveal dynamic deformation of the tetrahedral SiO<sub>4</sub> ligand within these materials. Using FactSage, we computationally calculate the fusion entropy of congruent silicates in the CaO-MgO-SiO<sub>2</sub> system. Synthesized ternary silicates confirm our theory by highlighting correlations between lower/higher fusion entropy (for congruent) and configurational entropy (for incongruent) silicates, leading to red/blue shifts in PL emission wavelengths. In binary silicate systems, we observe an inverse correlation between PL emission wavelengths and fusion entropy of congruent silicates or pseudo-congruent silicates like MgSiO<sub>3</sub>, whose solid-liquid decomposition temperature is close to its melting point. Furthermore, the non-ideal liquid phase entropy of incongruent silicates positioned between congruent CaMgSi<sub>2</sub>O<sub>6</sub> (Pyroxene) and congruent Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub> (Akermanite) in the MgO-CaO-SiO<sub>2</sub> ternary phase diagram comprehensively explains diverse PL emission wavelengths. Beyond its scholarly impact, this work expands perspectives in lighting and photonic research, opening an exciting frontier in entropy-lighting research and enabling predictions of host chemical composition and tunable PL emission wavelengths, particularly relevant to LED technologies.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-10DOI: 10.1016/j.calphad.2024.102743
Dong-Ju Chu , Chanhee Park , Joonho Lee , Woo-Sang Jung
The formation of the η phase in two nickel-based superalloys that have similar amounts of titanium and aluminum but different Ti/Al ratios was investigated. The aging was carried out at 750 °C, 800 °C, and 850 °C for 10000 h. The microstructures were observed using SEM and TEM, and equilibria phases were calculated using a Thermo-Calc. equipped with TCNI11 database. Results showed that the number and size of η phase increased with aging temperature and Ti/Al ratios. The size of the γ′ phase was also found to be increased with aging temperature, but it was not significantly affected by the Ti/Al atomic ratio. However, the η phase was not predicted to be the thermodynamic equilibrium phase in the alloy using Thermo-Calc. with the TCNI11 database. The η phase was expected to be the equilibrium phase with Ti/Al ratios higher than 1.85 at 850 °C for Ni-27.0Cr-19.1Co-0.91Nb-0.29Mo-0.14C-xTi-yAl alloys. However, the result does not match the experimental observations or other literature. It is suggested that the effect of titanium on the formation of the η phase may be underestimated in the TCNI11 database. Therefore, it is necessary to enhance the accuracy of predicting the formation of the η phase by modifying at least one of the thermodynamic parameters, including the phase equilibrium of the ternary Ni-Ti-Al system.
研究了钛和铝含量相似但钛/铝比例不同的两种镍基超级合金中 η 相的形成。使用 SEM 和 TEM 观察了微观结构,并使用配备 TCNI11 数据库的 Thermo-Calc 计算了平衡相。结果表明,η 相的数量和大小随老化温度和钛/铝比率的增加而增加。γ′相的尺寸也随着老化温度的升高而增大,但受 Ti/Al 原子比的影响不大。然而,使用 TCNI11 数据库的 Thermo-Calc 预测合金中的η相并不是热力学平衡相。对于镍-27.0Cr-19.1Co-0.91Nb-0.29Mo-0.14C-xTi-y-Al 合金,当 Ti/Al 比率高于 1.85 时,η 相预计将在 850 °C 时成为平衡相。然而,这一结果与实验观察或其他文献不符。这表明 TCNI11 数据库可能低估了钛对η相形成的影响。因此,有必要通过修改至少一个热力学参数(包括三元镍-钛-铝体系的相平衡)来提高预测 η 相形成的准确性。
{"title":"Formation of eta phase during aging at 750–850 °C for Ni-base superalloys with different Ti/Al ratios","authors":"Dong-Ju Chu , Chanhee Park , Joonho Lee , Woo-Sang Jung","doi":"10.1016/j.calphad.2024.102743","DOIUrl":"10.1016/j.calphad.2024.102743","url":null,"abstract":"<div><p>The formation of the η phase in two nickel-based superalloys that have similar amounts of titanium and aluminum but different Ti/Al ratios was investigated. The aging was carried out at 750 °C, 800 °C, and 850 °C for 10000 h. The microstructures were observed using SEM and TEM, and equilibria phases were calculated using a Thermo-Calc. equipped with TCNI11 database. Results showed that the number and size of η phase increased with aging temperature and Ti/Al ratios. The size of the γ′ phase was also found to be increased with aging temperature, but it was not significantly affected by the Ti/Al atomic ratio. However, the η phase was not predicted to be the thermodynamic equilibrium phase in the alloy using Thermo-Calc. with the TCNI11 database. The η phase was expected to be the equilibrium phase with Ti/Al ratios higher than 1.85 at 850 °C for Ni-27.0Cr-19.1Co-0.91Nb-0.29Mo-0.14C-xTi-yAl alloys. However, the result does not match the experimental observations or other literature. It is suggested that the effect of titanium on the formation of the η phase may be underestimated in the TCNI11 database. Therefore, it is necessary to enhance the accuracy of predicting the formation of the η phase by modifying at least one of the thermodynamic parameters, including the phase equilibrium of the ternary Ni-Ti-Al system.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142164926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-04DOI: 10.1016/j.calphad.2024.102730
R. Besson, L. Thuinet
Intense researches on new kinds of materials, especially those with marked multi-principal-element character, currently give rise to all-intricate multiphase environments, for which reliably predicting structure and stability becomes extremely difficult to achieve with macroscopic phenomenological modellings. The purpose of this work is to demonstrate how this issue can be overcome by sticking down to the atomic scale, through ab initio-based thermodynamics within the Independent-Point-Defect Approximation (IPDA), which offers an efficient framework to investigate systems involving various chemistries and crystallographies. As a case study of significant intricacy, we consider ternary AlBTi viewed as an approximant for Al-based alloys reinforced with TiB particles and including AlB and AlTi additional compounds. Firstly, our IPDA investigations reveal unexpected discrepancies among neighbouring metallic borides, and predict point defect structures at odds with earlier pictures commonly employed hitherto, which suggests that many complex compounds may suffer from inadequate phenomenological modellings. Furthermore, we show that far-reaching conclusions on phase stability can be drawn only if the scope of analysis is broadened up to encompass global multiphase IPDA-based thermodynamics, a task which constitutes the core and the methodological originality of this work. Our approach thus provides reliable arguments to interpret the occurrence of various kinds of poorly known compounds, as illustrated by the controversial behaviour of AlTi and AlB in TiB-reinforced Al-based composites. Finally, our work allows to conclude that the robust and handsome IPDA approach can be extended to highly intricate multiphase situations, e.g. to investigate other classes of multiphase multi-principal-element materials, which due to the presence of complex crystal structures can hardly be explored by alternative methods.
{"title":"Bridging the gap between atomic scale and thermodynamics for structurally complex multiphase multi-element systems: Metallic borides in Al-based metal–matrix composites as a case study","authors":"R. Besson, L. Thuinet","doi":"10.1016/j.calphad.2024.102730","DOIUrl":"10.1016/j.calphad.2024.102730","url":null,"abstract":"<div><p>Intense researches on new kinds of materials, especially those with marked multi-principal-element character, currently give rise to all-intricate multiphase environments, for which reliably predicting structure and stability becomes extremely difficult to achieve with macroscopic phenomenological modellings. The purpose of this work is to demonstrate how this issue can be overcome by sticking down to the atomic scale, through ab initio-based thermodynamics within the Independent-Point-Defect Approximation (IPDA), which offers an efficient framework to investigate systems involving various chemistries and crystallographies. As a case study of significant intricacy, we consider ternary Al<img>B<img>Ti viewed as an approximant for Al-based alloys reinforced with TiB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> particles and including AlB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> and Al<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Ti additional compounds. Firstly, our IPDA investigations reveal unexpected discrepancies among neighbouring metallic borides, and predict point defect structures at odds with earlier pictures commonly employed hitherto, which suggests that many complex compounds may suffer from inadequate phenomenological modellings. Furthermore, we show that far-reaching conclusions on phase stability can be drawn only if the scope of analysis is broadened up to encompass global multiphase IPDA-based thermodynamics, a task which constitutes the core and the methodological originality of this work. Our approach thus provides reliable arguments to interpret the occurrence of various kinds of poorly known compounds, as illustrated by the controversial behaviour of Al<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>Ti and AlB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> in TiB<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>-reinforced Al-based composites. Finally, our work allows to conclude that the robust and handsome IPDA approach can be extended to highly intricate multiphase situations, e.g. to investigate other classes of multiphase multi-principal-element materials, which due to the presence of complex crystal structures can hardly be explored by alternative methods.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142136093","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.calphad.2024.102729
Zheng-jian Liu , Li-ming Ma , Jian-liang Zhang , Yao-zu Wang , Qiu-ye Cai , Hui-qing Jiang , Ze-dong Zhang
To investigate the mechanism of slag formation during pellet consolidation, we combined thermodynamic calculations and experimental methods to study the effects of roasting temperature, basicity, and SiO2 content on slag formation. The results indicate that as the temperature increases, the solid phases clinopyroxene, orthopyroxene, and melilite transform into slag within the pellet. The roasting temperature and basicity of slags formed by different particles varied considerably. At 1250 °C, the slag content is less than 5 % in low-silica fluxed pellets, less than 15 % in medium-silica fluxed pellets, and up to approximately 20 % in high-silica fluxed pellets. Phase diagram analysis showed that CaFe2O4 and Ca2Fe2O5 formed in the pellet due to basicity differences SEM-EDS analysis showed that the slag in fluxed pellets primarily comprises the silicates Ca3Fe2(SiO4)3 and (Mg, Fe)2SiO4, as well as ferrate. The slag is distributed in a reticulated pattern within the pellets, with some quartz remaining undissolved in the slag phase and existing independently in pores.
{"title":"Study of slag formation behavior in iron ore pellets based on thermodynamic calculations and experiments","authors":"Zheng-jian Liu , Li-ming Ma , Jian-liang Zhang , Yao-zu Wang , Qiu-ye Cai , Hui-qing Jiang , Ze-dong Zhang","doi":"10.1016/j.calphad.2024.102729","DOIUrl":"10.1016/j.calphad.2024.102729","url":null,"abstract":"<div><p>To investigate the mechanism of slag formation during pellet consolidation, we combined thermodynamic calculations and experimental methods to study the effects of roasting temperature, basicity, and SiO<sub>2</sub> content on slag formation. The results indicate that as the temperature increases, the solid phases clinopyroxene, orthopyroxene, and melilite transform into slag within the pellet. The roasting temperature and basicity of slags formed by different particles varied considerably. At 1250 °C, the slag content is less than 5 % in low-silica fluxed pellets, less than 15 % in medium-silica fluxed pellets, and up to approximately 20 % in high-silica fluxed pellets. Phase diagram analysis showed that CaFe<sub>2</sub>O<sub>4</sub> and Ca<sub>2</sub>Fe<sub>2</sub>O<sub>5</sub> formed in the pellet due to basicity differences SEM-EDS analysis showed that the slag in fluxed pellets primarily comprises the silicates Ca<sub>3</sub>Fe<sub>2</sub>(SiO<sub>4</sub>)<sub>3</sub> and (Mg, Fe)<sub>2</sub>SiO<sub>4</sub>, as well as ferrate. The slag is distributed in a reticulated pattern within the pellets, with some quartz remaining undissolved in the slag phase and existing independently in pores.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-30DOI: 10.1016/j.calphad.2024.102728
Miao Liu , Hang Su , Kun Song , Rucheng Wang , Xinyue Li , Liwen Hu , Xuewei Lv , Yuntao Xin
MnCr2O4, known for its unique structure and properties, finds wide applications in catalysts, magnetic materials, electrode materials, and other fields. In this study, high-purity MnCr2O4 samples were synthesized via the liquid-phase combustion method and characterized. Thermodynamic data within the temperature range of 350–1350 K was predicted using NKR, and experimental thermodynamic data within the temperature ranges of 15–300 K and 623–1273 K were determined using a PPMS and drop calorimeter. Based on this data, the heat capacity as a function of temperature for MnCr2O4 was calculated: , along with the enthalpy change, entropy change, and Gibbs energy change in the temperature range of 300∼1250 K. Thermodynamic analysis of the synthesis of MnCr2O4 in the field of materials and its treatment in metallurgy using experimental and computational results. This study addresses the thermodynamic knowledge gaps of MnCr2O4 and provides a valuable reference for its application in production practice.
MnCr2O4 以其独特的结构和性质而闻名,在催化剂、磁性材料、电极材料等领域有着广泛的应用。本研究采用液相燃烧法合成了高纯度 MnCr2O4 样品,并对其进行了表征。使用 NKR 预测了 350-1350 K 温度范围内的热力学温度数据,并使用 PPMS 和滴定量热仪测定了 15-300 K 和 623-1273 K 温度范围内的实验热力学温度数据。根据这些数据,计算出了 MnCr2O4 的热容量与温度的函数关系:Cp=161.0157+0.01864T-1589402.7435T-2(J/mol-K)(623∼1273K) 以及 300∼1250 K 温度范围内的焓变、熵变和吉布斯能变。该研究解决了 MnCr2O4 热力学知识的空白,为其在生产实践中的应用提供了有价值的参考。
{"title":"Thermodynamic data of a promising magnetic material MnCr2O4 and thermodynamic analysis of its application process","authors":"Miao Liu , Hang Su , Kun Song , Rucheng Wang , Xinyue Li , Liwen Hu , Xuewei Lv , Yuntao Xin","doi":"10.1016/j.calphad.2024.102728","DOIUrl":"10.1016/j.calphad.2024.102728","url":null,"abstract":"<div><p>MnCr<sub>2</sub>O<sub>4</sub>, known for its unique structure and properties, finds wide applications in catalysts, magnetic materials, electrode materials, and other fields. In this study, high-purity MnCr<sub>2</sub>O<sub>4</sub> samples were synthesized via the liquid-phase combustion method and characterized. Thermodynamic data within the temperature range of 350–1350 K was predicted using NKR, and experimental thermodynamic data within the temperature ranges of 15–300 K and 623–1273 K were determined using a PPMS and drop calorimeter. Based on this data, the heat capacity as a function of temperature for MnCr<sub>2</sub>O<sub>4</sub> was calculated: <span><math><mrow><msub><mi>C</mi><mi>p</mi></msub><mo>=</mo><mn>161.0157</mn><mo>+</mo><mn>0.01864</mn><mi>T</mi><mo>−</mo><mn>1589402.7435</mn><msup><mi>T</mi><mrow><mo>−</mo><mn>2</mn></mrow></msup><mrow><mo>(</mo><mrow><mi>J</mi><mo>/</mo><mtext>mol</mtext><mo>·</mo><mi>K</mi></mrow><mo>)</mo></mrow><mspace></mspace><mrow><mo>(</mo><mrow><mn>623</mn><mo>∼</mo><mn>1273</mn><mi>K</mi></mrow><mo>)</mo></mrow></mrow></math></span>, along with the enthalpy change, entropy change, and Gibbs energy change in the temperature range of 300∼1250 K. Thermodynamic analysis of the synthesis of MnCr<sub>2</sub>O<sub>4</sub> in the field of materials and its treatment in metallurgy using experimental and computational results. This study addresses the thermodynamic knowledge gaps of MnCr<sub>2</sub>O<sub>4</sub> and provides a valuable reference for its application in production practice.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1016/j.calphad.2024.102726
Samuel Krimmel , Richard Otis , Jian Luo , Yu Zhong
The development of conductive materials plays a crucial role in improving the efficiency of electrochemical processes. In polycrystalline materials, space charge layers (SCLs) adjacent to grain boundaries (GBs) often dictate charge transport behavior. This study explores relaxing the charge neutrality constraint in the CALculation of PHAse Diagrams (CALPHAD) approach as a new method to model the electrical conductivity effects of SCLs. A new charge-dependent defect chemistry analysis is applied to the wustite, magnetite, and hematite phases in the Fe–O binary system. Using pycalphad, charge-dependent results for the molar Gibbs energies, Brouwer diagrams, and charge carrier concentrations were determined for each phase at 1273K within the oxygen partial pressure stability ranges. With a negative charge of 0.16 × 10−19 C, the hematite and magnetite phases exhibit an increased charge carrier concentration. The opposite trend was observed for wustite. While further work is needed to quantify the electrical conductivity effects of the SCLs and GBs with this approach, it provides a robust thermodynamic foundation to rapidly develop and optimize conductive materials.
导电材料的开发在提高电化学过程的效率方面起着至关重要的作用。在多晶材料中,与晶界(GB)相邻的空间电荷层(SCL)往往决定了电荷传输行为。本研究探讨了放宽电荷中性约束的CALculation of PHAse Diagrams(CALPHAD)方法,以此作为模拟SCL导电效应的新方法。一种新的电荷依赖性缺陷化学分析被应用于 Fe-O 二元系统中的硅灰石、磁铁矿和赤铁矿相。利用 pycalphad,在 1273K 氧分压稳定范围内确定了每种相的摩尔吉布斯能、布鲁维图和电荷载流子浓度的电荷依赖性结果。当负电荷为 0.16 × 10-19 C 时,赤铁矿和磁铁矿相的电荷载流子浓度增加。而武钢则呈现出相反的趋势。虽然利用这种方法量化 SCL 和 GB 的导电效果还需要进一步的工作,但它为快速开发和优化导电材料提供了坚实的热力学基础。
{"title":"Charge-dependent CALPHAD analysis of defect chemistry and carrier concentration for space charge layers","authors":"Samuel Krimmel , Richard Otis , Jian Luo , Yu Zhong","doi":"10.1016/j.calphad.2024.102726","DOIUrl":"10.1016/j.calphad.2024.102726","url":null,"abstract":"<div><p>The development of conductive materials plays a crucial role in improving the efficiency of electrochemical processes. In polycrystalline materials, space charge layers (SCLs) adjacent to grain boundaries (GBs) often dictate charge transport behavior. This study explores relaxing the charge neutrality constraint in the CALculation of PHAse Diagrams (CALPHAD) approach as a new method to model the electrical conductivity effects of SCLs. A new charge-dependent defect chemistry analysis is applied to the wustite, magnetite, and hematite phases in the Fe–O binary system. Using pycalphad, charge-dependent results for the molar Gibbs energies, Brouwer diagrams, and charge carrier concentrations were determined for each phase at 1273K within the oxygen partial pressure stability ranges. With a negative charge of 0.16 × 10<sup>−19</sup> C, the hematite and magnetite phases exhibit an increased charge carrier concentration. The opposite trend was observed for wustite. While further work is needed to quantify the electrical conductivity effects of the SCLs and GBs with this approach, it provides a robust thermodynamic foundation to rapidly develop and optimize conductive materials.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142099465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-22DOI: 10.1016/j.calphad.2024.102727
Jiayin Li , Xinxin Li , Jin Wang , Jingyu Qin
We conducted ab initio molecular dynamics simulations to systematically examine the composition-dependent thermodynamic properties and atomic-scale interactions in liquid Ti–Al–Ni alloys throughout the entire ternary phase space at 2033 K. The calculated enthalpies of mixing demonstrated exothermic tendencies, with a distinct minimum in the composition of Ti0.0Al0.50Ni0.50, indicating significant Al–Ni attractive interactions. Incorporating ternary interaction parameters into the Redlich-Kister-Muggianu equation enabled accurate modeling of the complex variations in mixing enthalpy. Analysis of partial pair correlation functions and structure factors revealed chemical and topological short-range ordering (SRO), as well as medium-range ordering, within the liquid alloy. Quantifying deviations from ideal configurational entropy clarifies the coupling between chemical SRO and topological SRO, significantly impacting the overall Gibbs energy of mixing. This comprehensive atomistic study provides insights into the thermodynamics of Ti–Al–Ni alloys, paving the way for tailoring their properties for high-performance applications.
{"title":"Unveiling the thermodynamic landscape of liquid Ti–Al–Ni alloys through first-principles simulations","authors":"Jiayin Li , Xinxin Li , Jin Wang , Jingyu Qin","doi":"10.1016/j.calphad.2024.102727","DOIUrl":"10.1016/j.calphad.2024.102727","url":null,"abstract":"<div><p>We conducted <em>ab initio</em> molecular dynamics simulations to systematically examine the composition-dependent thermodynamic properties and atomic-scale interactions in liquid Ti–Al–Ni alloys throughout the entire ternary phase space at 2033 K. The calculated enthalpies of mixing demonstrated exothermic tendencies, with a distinct minimum in the composition of Ti<sub>0.0</sub>Al<sub>0.50</sub>Ni<sub>0.50</sub>, indicating significant Al–Ni attractive interactions. Incorporating ternary interaction parameters into the Redlich-Kister-Muggianu equation enabled accurate modeling of the complex variations in mixing enthalpy. Analysis of partial pair correlation functions and structure factors revealed chemical and topological short-range ordering (SRO), as well as medium-range ordering, within the liquid alloy. Quantifying deviations from ideal configurational entropy clarifies the coupling between chemical SRO and topological SRO, significantly impacting the overall Gibbs energy of mixing. This comprehensive atomistic study provides insights into the thermodynamics of Ti–Al–Ni alloys, paving the way for tailoring their properties for high-performance applications.</p></div>","PeriodicalId":9436,"journal":{"name":"Calphad-computer Coupling of Phase Diagrams and Thermochemistry","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142041092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}