Structural Phase Transformations during a Solid-State Reaction in a Bilayer Al/Fe Thin-Film Nanosystem

Altunin, Roman R.; Жарков, С. М.

doi:10.1134/s1063783420010059

Cited by 13 publications

(6 citation statements)

References 29 publications

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“…The analysis of the obtained electron diffraction patterns allowed determining the sequence of phase transformations occurring in the solid-state reaction between dissimilar nanolayers. The authors successfully used the method to investigate the process of phase formation during the solid-state reaction in different thin-film nanosystems: Al/Cu [ 25 , 26 ], Al/Pt [ 27 ], Al/Ag [ 28 , 29 ], Cu/Au [ 30 ], Al/Fe [ 31 ], Fe/Si [ 32 ], Fe/Pd [ 30 , 33 , 34 ], Fe-ZrO 2 [ 35 ], Co-ZrO 2 [ 36 ], and Co-In 2 O 3 [ 37 ]. In the present study, in order to estimate the kinetic parameters of the solid-state reaction (activation energy, pre-exponential factor, and reaction order), a series of heating procedures was performed at different rates.…”

Section: Methodsmentioning

confidence: 99%

Solid-State Reaction in Cu/a-Si Nanolayers: A Comparative Study of STA and Electron Diffraction Data

et al. 2022

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The kinetics of the solid-state reaction between nanolayers of polycrystalline copper and amorphous silicon (a-Si) has been studied in a Cu/a-Si thin-film system by the methods of electron diffraction and simultaneous thermal analysis (STA), including the methods of differential scanning calorimetry (DSC) and thermogravimetry (TG). It has been established that, in the solid-state reaction, two phases are formed in a sequence: Cu + Si → η″-Cu3Si → γ-Cu5Si. It has been shown that the estimated values of the kinetic parameters of the formation processes for the phases η″-Cu3Si and γ-Cu5Si, obtained using electron diffraction, are in good agreement with those obtained by DSC. The formation enthalpy of the phases η″-Cu3Si and γ-Cu5Si has been estimated to be: ΔHη″-Cu3Si = −12.4 ± 0.2 kJ/mol; ΔHγ-Cu5Si = −8.4 ± 0.4 kJ/mol. As a result of the model description of the thermo-analytical data, it has been found that the process of solid-state transformations in the Cu/a-Si thin-film system under study is best described by a four-stage kinetic model R3 → R3 → (Cn-X) → (Cn-X). The kinetic parameters of formation of the η″-Cu3Si phase are the following: Ea = 199.9 kJ/mol, log(A, s−1) = 20.5, n = 1.7; and for the γ-Cu5Si phase: Ea = 149.7 kJ/mol, log(A, s−1) = 10.4, n = 1.3, with the kinetic parameters of formation of the γ-Cu5Si phase being determined for the first time.

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Section: Methodsmentioning

confidence: 99%

Solid-State Reaction in Cu/a-Si Nanolayers: A Comparative Study of STA and Electron Diffraction Data

et al. 2022

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“…Our study is focused on Fe 2 CoAl belonging to a very promising class of materials based on Fe and Al [19][20][21][22][23][24][25][26]. Earlier experimental studies [27][28][29][30][31][32][33][34][35][36][37] are currently complemented by research efforts related to applications in high-temperature coatings [38][39][40][41][42][43][44] and composites [45][46][47][48][49], new preparation techniques [50][51][52][53] and their material properties [54,55]. Theoretical studies of iron aluminides include ab initio calculations of single-phase materials [56][57][58][59][60][61][62][63][64][65] and nanocomposites [66,…”

Section: Introductionmentioning

confidence: 99%

A Quantum-Mechanical Study of Antiphase Boundaries in Ferromagnetic B2-Phase Fe2CoAl Alloy

et al. 2021

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In this study, we performed a quantum mechanical examination of thermodynamic, structural, elastic, and magnetic properties of single-phase ferromagnetic Fe2CoAl with a chemically disordered B2-type lattice with and without antiphase boundaries (APBs) with (001) crystallographic orientation. Fe2CoAl was modeled using two different 54-atom supercells with atoms on the two B2 sublattices distributed according to the special quasi-random structure (SQS) concept. Both computational models exhibited very similar formation energies (−0.243 and −0.244 eV/atom), B2 structure lattice parameters (2.849 and 2.850 Å), magnetic moments (1.266 and 1.274 μB/atom), practically identical single-crystal elastic constants (C11 = 245 GPa, C12 = 141 GPa, and similar C44 = 132 GPa) and auxetic properties (the lowest Poisson ratio close to −0.1). The averaged APB interface energies were observed to be 199 and 310 mJ/m2 for the two models. The studied APBs increased the total magnetic moment by 6 and 8% due to a volumetric increase as well as local changes in the coordination of Fe atoms (their magnetic moments are reduced for increasing number of Al neighbors but increased by the presence of Co). The APBs also enhanced the auxetic properties.

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“…The Fe 3 Al intermetallic compound belongs to a promising class of Fe-Al-based materials possessing relatively low density, unusual resistance to oxidation, and low cost of raw materials [1][2][3]; some of them suffer from room-temperature brittleness [4][5][6][7][8]. Earlier experimental studies of these materials [9][10][11][12][13][14][15][16][17][18][19] were recently complemented by research focused on their use in high-temperature coatings [20][21][22][23][24][25][26] or composites [27][28][29][30][31], novel preparation techniques [32][33][34][35], and their materials properties [36,37]. Theoretical studies cover quantum mechanical calculations of single-phase materials [38][39][40][41][42][43][44][45][46]…”

Section: Introductionmentioning

confidence: 99%

The Impact of Vibrational Entropy on the Segregation of Cu to Antiphase Boundaries in Fe3Al

2021

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We performed a quantum mechanical study of segregation of Cu atoms toward antiphase boundaries (APBs) in Fe3Al. The computed concentration of Cu atoms was 3.125 at %. The APBs have been characterized by a shift of the lattice along the ⟨001⟩ crystallographic direction. The APB energy turns out to be lower for Cu atoms located directly at the APB interfaces and we found that it is equal to 84 mJ/m2. Both Cu atoms (as point defects) and APBs (as extended defects) have their specific impact on local magnetic moments of Fe atoms (mostly reduction of the magnitude). Their combined impact was found to be not just a simple sum of the effects of each of the defect types. The Cu atoms are predicted to segregate toward the studied APBs, but the related energy gain is very small and amounts to only 4 meV per Cu atom. We have also performed phonon calculations and found all studied states with different atomic configurations mechanically stable without any soft phonon modes. The band gap in phonon frequencies of Fe3Al is barely affected by Cu substituents but reduced by APBs. The phonon contributions to segregation-related energy changes are significant, ranging from a decrease by 16% at T = 0 K to an increase by 17% at T = 400 K (changes with respect to the segregation-related energy difference between static lattices). Importantly, we have also examined the differences in the phonon entropy and phonon energy induced by the Cu segregation and showed their strongly nonlinear trends.

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Structural Phase Transformations during a Solid-State Reaction in a Bilayer Al/Fe Thin-Film Nanosystem

Cited by 13 publications

References 29 publications

Solid-State Reaction in Cu/a-Si Nanolayers: A Comparative Study of STA and Electron Diffraction Data

Solid-State Reaction in Cu/a-Si Nanolayers: A Comparative Study of STA and Electron Diffraction Data

A Quantum-Mechanical Study of Antiphase Boundaries in Ferromagnetic B2-Phase Fe2CoAl Alloy

The Impact of Vibrational Entropy on the Segregation of Cu to Antiphase Boundaries in Fe3Al

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