Investigation of the thermodynamic properties of Al4C3: A combined DFT and DSC study

Pisch, A.; Pasturel, A.; Deffrennes, Guillaume; Dezellus, Olivier; Benigni, Pierre; Mikaelian, Georges

doi:10.1016/j.commatsci.2019.109100

Cited by 11 publications

(11 citation statements)

References 47 publications

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“…Phonon calculation in the quasiharmonic approximations were performed from 0 to 1000 K leading to the heat capacity of the phase and the standard entropy of formation of T2-Al2MgC2 was found to be 70.0 J.mol -1 .K -1 [2]. Below 300 K, previous results on Al4C3 [1] that were found in very good agreement with the experimental literature data support the validity of the calculations performed by the authors on the ternary carbide. From 300 to 871 K, DSC measurements were also performed by Deffrennes et al [2] and a satisfying agreement was obtained between the DFT and DSC results.…”

Section: The Al-c-mg Ternary Systemsupporting

confidence: 80%

“…Table 2 Coordinates of atoms in Al4C3 (space group 166, R-3m) as determined by [48] Atom Wyckoff position Site symmetry x y z Al1 6c 3m 0 0 0.29422(6) Al2 6c 3m 0 0 0.12967(7) C1 3a -3m 0 0 0 C2 6c 3m 0 0 0.2168 2The standard enthalpy of formation of those end-members was investigated by DFT. The Strongly Conditioned and Appropriately Normed (SCAN) semi-local density functional [58,59] was selected in compliance with previous work performed on Al4C3 [1] and T2-Al2MgC2 [2]. Extensive details on the calculations can be found elsewhere [1,2].…”

Section: Determination Of the End-members Of The Mg Solution In Al4c3mentioning

confidence: 99%

“…The Strongly Conditioned and Appropriately Normed (SCAN) semi-local density functional [58,59] was selected in compliance with previous work performed on Al4C3 [1] and T2-Al2MgC2 [2]. Extensive details on the calculations can be found elsewhere [1,2]. It is to note that Zero Point Energy (ZPE) correction were not performed in this work as phonon calculations were not conducted.…”

Section: Determination Of the End-members Of The Mg Solution In Al4c3mentioning

confidence: 99%

“…On the one hand, there is the prospect of an application of Al-C-Mg carbides in electronic. Al4C3 and Al2MgC2 are semiconductors with an indirect band gap calculated by DFT at respectively 1.34 [1] and 1.73 eV [2], although it is to be noted that those values are very likely to be underestimated. Plus, Al4C3 can contain a significant amount of Mg in solid solution [2,3] pointing to the possibility of a p-type doping.…”

Section: Introductionmentioning

confidence: 99%

“…In the scope of the thermodynamic modeling of the Al-C-Mg system, experimental investigations coupled with DFT calculations on the thermodynamic properties of Al4C3 [1] and Al2MgC2 [2] were recently performed. Notably, the thermodynamic description of the Al-C system was revised [39] as conflicting results could be found regarding the enthalpy of formation of Al4C3 [1] and phase equilibria [39].…”

Section: Introductionmentioning

confidence: 99%

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Thermal stability of Al2MgC2 and thermodynamic modeling of the Al–C–Mg system - Application to grain refinement of Mg–Al alloys

Deffrennes

Gardiola

Lomello-Tafin

et al. 2019

Calphad

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In the scope of supporting the development of Mg-Al alloys and related materials, an experimental study coupled with a CALPHAD thermodynamic modeling of the Al-C-Mg system was conducted. The peritectic decomposition of Al2MgC2 to form Al4C3, graphite and a liquid phase was measured at 1559±10 K by DTA. In order to model the Mg solubility in Al4C3, DFT calculations were performed on the end-member phases Mg4C3, Al2Mg2C3 and Mg2Al2C3 and it was shown that Mg substitutes on the Al2 crystallographic site of the carbide structure. Based on recent literature data and a revised Al-C binary, a model description of the Al-C-Mg ternary is proposed for the first time. More specifically, it is used to calculate the liquidus projection and the phase formation sequence during Scheil solidification of a 91Mg-9Al wt% alloy inoculated with carbon. This work provides a convincing argument that Al2MgC2 is the nucleant responsible for the grain refinement of Mg-Al alloys inoculated by C.

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Section: The Al-c-mg Ternary Systemsupporting

confidence: 80%

Section: Determination Of the End-members Of The Mg Solution In Al4c3mentioning

confidence: 99%

Section: Determination Of the End-members Of The Mg Solution In Al4c3mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Thermal stability of Al2MgC2 and thermodynamic modeling of the Al–C–Mg system - Application to grain refinement of Mg–Al alloys

Deffrennes

Gardiola

Lomello-Tafin

et al. 2019

Calphad

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Thermodynamic modelling of the Ca–O system including 3rd generation description of CaO and CaO2

Deffrennes

Jakse

Alvares

et al. 2020

Calphad

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A complete thermodynamic description of the Ca-O system is proposed including 3 rd generation modelling of crystalline CaO, liquid and amorphous CaO, and crystalline CaO2. Compared to previous modellings, a more robust description of the thermodynamic properties of the binary phases is achieved using data recently obtained by density functional theory calculations and molecular dynamics simulations. The heat capacity of crystalline CaO is reassessed, leading to a noticeably higher value below the melting point compared to previous modellings and resulting in a slightly higher standard entropy. It is highlighted that the parameters given in terms of polynomial functions of temperature that were employed so far in 3 rd generation models to describe anharmonic contributions in the heat capacity of compounds were not suited to satisfactorily describe the thermodynamic properties of crystalline CaO. It is suggested that this observation can be generalized to most refractory oxides. Alternative terms are proposed in the Gibbs energy function that give more flexibility in fitting the experimental data and lead to more numerically reasonable values for the parameters. The liquid and amorphous CaO phase is described using the two-state model, leading to a significant improvement in the description of its heat capacity. The description of crystalline CaO2 is also improved as only estimates of the thermodynamic properties of the compound were available in previous modellings of the system. Finally, phase equilibria data on the Ca-CaO liquidus is reviewed, and it is highlighted that slight discrepancies in the relatively low temperature measurements can lead to significantly different descriptions of the liquid phase.

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The third generation Calphad description of Al–C including revisions of pure Al and C

Kaplan

Mao

et al. 2021

Calphad

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Investigation of the thermodynamic properties of Al4C3: A combined DFT and DSC study

Cited by 11 publications

References 47 publications

Thermal stability of Al2MgC2 and thermodynamic modeling of the Al–C–Mg system - Application to grain refinement of Mg–Al alloys

Thermal stability of Al2MgC2 and thermodynamic modeling of the Al–C–Mg system - Application to grain refinement of Mg–Al alloys

Thermodynamic modelling of the Ca–O system including 3rd generation description of CaO and CaO2

The third generation Calphad description of Al–C including revisions of pure Al and C

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