Thermodynamic Properties of Elements and Compounds in Al-Sc Binary System from Ab Initio Calculations Based on Density Functional Theory

Zhou, Zeyou; Wu, Bo; Dou, Shushi; Zhao, Chunfeng; Xiong, Yong‐Chen; Wu, Yufeng; Yang, Shangjin; Wei, Zhenyi

doi:10.1007/s11661-013-2117-9

Cited by 13 publications

(4 citation statements)

References 55 publications

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“…Our recent [ 27 ] first principles analysis of calorimetric data for Al and Al

Sc provided us with a fundamental understanding of the intriguing features observed in the low-temperature regime. Electronic excitations and a non-adiabatic electron–phonon coupling are responsible for a very good agreement with measurements up to 400 K. Existing theoretical predictions for the heat capacity of Al

Sc beyond 400 K (up to 1000 K) are either based on the harmonic or quasiharmonic approximation [ 28 , 63 ] and neglect the volume dependence of the electronic free energy [ 29 ], phonon anharmonicity, and the explicit electron–phonon coupling.…”

Section: Results and Discussionmentioning

confidence: 58%

“…We recently published the first calorimetric data [ 27 ] of Al

Sc phase up to 400 K together with its detailed ab initio based investigation, explaining the rich feature set observed for

K. On the one hand, calorimetric data of the Al

Sc phase for

K are currently missing. On the other hand, there are discrepancies for the coefficient of thermal expansion (CTE) between the available dilatometric data [ 12 ], which yield a constant CTE of 1.6 × 10

between 298–1173 K, and the ab initio predictions, which report both a continuously increasing [ 22 , 28 ] CTE as well as a constant [ 29 ] CTE beyond room temperature. Here, the considered finite-temperature excitation effects in the existing ab initio based investigations for Al

Sc still lack the contributions due to the phonon anharmonicity.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

et al. 2021

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We present a first-principles assessment of the finite-temperature thermodynamic properties of the intermetallic Al3Sc phase including the complete spectrum of excitations and compare the theoretical findings with our dilatometric and calorimetric measurements. While significant electronic contributions to the heat capacity and thermal expansion are observed near the melting temperature, anharmonic contributions, and electron–phonon coupling effects are found to be relatively small. On the one hand, these accurate methods are used to demonstrate shortcomings of empirical predictions of phase stabilities such as the Neumann–Kopp rule. On the other hand, their combination with elasticity theory was found to provide an upper limit for the size of Al3Sc nanoprecipitates needed to maintain coherency with the host matrix. The chemo-mechanical coupling being responsible for the coherency loss of strengthening precipitates is revealed by a combination of state-of-the-art simulations and dedicated experiments. These findings can be exploited to fine-tune the microstructure of Al-Sc-based alloys to approach optimum mechanical properties.

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“…Our recent [ 27 ] first principles analysis of calorimetric data for Al and Al

Section: Results and Discussionmentioning

confidence: 58%

“…We recently published the first calorimetric data [ 27 ] of Al

Sc phase up to 400 K together with its detailed ab initio based investigation, explaining the rich feature set observed for

K. On the one hand, calorimetric data of the Al

Sc phase for

Sc still lack the contributions due to the phonon anharmonicity.…”

Section: Introductionmentioning

confidence: 99%

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

et al. 2021

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“…This is in accordance with lower diffusivity of Zr in Al matrix. [22,45] The second annealing stage (II-CDB stage as well as II-stage in resistivity spectrum), which appears above this temperature (see in Figures 5,8,9, and 10(b)), is connected not only with an increase of F Sc but also with a rise of F Zr .…”

Section: Discussionmentioning

confidence: 91%

Early Stages of Precipitation Process in Al-(Mn-)Sc-Zr Alloy Characterized by Positron Annihilation

Vlach

Čı́žek

Melikhova

et al. 2015

Metall Mater Trans A

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Thermal effects on the precipitation stages in as-cast Al-0.70 at. pct Mn-0.15 at. pct Sc-0.05 at. pct Zr alloy were studied. The role of lattice defects was elucidated by positron annihilation spectroscopy (lifetime and coincidence Doppler broadening) enabling investigation of solutes clustering at the atomic scale. This technique has never been used in the Al-Sc-and/or Al-Zr-based alloys so far. Studies by positron annihilation were combined with resistometry, hardness measurements, and microstructure observations. Positrons trapped at defects are preferentially annihilated by Sc electrons. Lifetime of trapped positrons indicates that Sc atoms segregate at dislocations. Maximum fraction of positrons annihilated by Sc electrons occurring at 453 K (180°C) suggests that clustering of Sc bound with vacancies takes place. It is followed by peak of this fraction at 573 K (300°C). A rise of the contribution of trapped positrons annihilated by Zr electrons starting at 513 K (240°C) and attaining maximum also at 573 K (300°C) confirms that Zr participates in precipitation of the Al 3 Sc particles already at these temperatures. The pronounced hardening at 573 K (300°C) has its nature in the precipitation of the Al 3 Sc particles with a Zr-rich shell. The contribution of trapped positrons annihilated by Mn electrons was found to be negligible.

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“…Based on the above results, we have further calculated the coarsening rate of Al 2 RE particles according to Lifshitz and Slyozov [79] and Wagner [80] (LSW) methods, namely K LSW , which is expressed as [61,81]:…”

Section: Particle Nucleation and Growthmentioning

confidence: 99%

First-principles study of the mixing effects of rare earth solute atoms on the physical properties of Al₂RE phases in Al-based alloys at finite temperatures

et al. 2023

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The structural stability, mechanical properties, internal nucleation and growth mechanisms, and surface energies of Al2RE (RE=Sc, Y, La-Lu) second phases in Al alloys have been investigated by combining first-principles calculations with the Debye model. The results show that the lattice mismatch of Al2RE precipitates with Al matrix, which determines the strength of materials associated with dislocation slips, are closely related to the transferred electron et between Al and RE atoms. Furthermore, the methods of cluster expansion (CE) and special quasi-random structures (SQS) have been adopted to calculate the mixing enthalpy Hx of Al2RE11-xRE2x (RE1=La, Ce, Pr, Nd; RE2 is the rest RE atoms) for studying the possibility of replacing in the Al2RE (RE=La, Ce, Pr, Nd) compounds, which is explored in experiments, and it is found that the mixing enthalpy Hx increases with the substitute concentration. The calculated elastic constant Cij, bulk modulus B, shear modulus G, Young’s modulus E decrease with increasing atomic number from Sc to Y at first, and then increases to Lu; while the Cauchy pressure C12-C44 and pugh’s ratio B/G show the opposite trends. Moreover, the critical nucleation radius R* and coarsening rate KLSW of Al2RE are obtained from the classical nucleation theory (CNT) and LSW model, respectively. The results show that, the R* for all interfaces decreases from Y to La at first, and then increases linearly to Lu; whereas the KLSW of all models increases from Y to Ce firstly, and then changes very little. Finally, the calculated surface energy Esur of all Al2RE compounds is much higher than that of Al, and with the increase of atomic number, Esur of Al2RE intermetallic compounds decreases firstly from Sc to La, and then increases to Lu. The result is helpful for the further optimal designing high performance of Al alloys.

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Thermodynamic Properties of Elements and Compounds in Al-Sc Binary System from Ab Initio Calculations Based on Density Functional Theory

Cited by 13 publications

References 55 publications

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

Early Stages of Precipitation Process in Al-(Mn-)Sc-Zr Alloy Characterized by Positron Annihilation

First-principles study of the mixing effects of rare earth solute atoms on the physical properties of Al₂RE phases in Al-based alloys at finite temperatures

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Thermodynamic Properties of Elements and Compounds in Al-Sc Binary System from Ab Initio Calculations Based on Density Functional Theory

Cited by 13 publications

References 55 publications

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

A Combined Experimental and First-Principles Based Assessment of Finite-Temperature Thermodynamic Properties of Intermetallic Al3Sc

Early Stages of Precipitation Process in Al-(Mn-)Sc-Zr Alloy Characterized by Positron Annihilation

First-principles study of the mixing effects of rare earth solute atoms on the physical properties of Al2RE phases in Al-based alloys at finite temperatures

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Product

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First-principles study of the mixing effects of rare earth solute atoms on the physical properties of Al₂RE phases in Al-based alloys at finite temperatures