First-principles investigation of the Al–Si–Sr ternary system: Ground state determination and mechanical properties

Garay-Tapia, A.M.; Romero, Aldo H.; Trápaga, G.; Arróyave, Raymundo

doi:10.1016/j.intermet.2011.09.001

Cited by 20 publications

(4 citation statements)

References 46 publications

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“…Although these studies were able to confirm the relevance of the modifier in the silicon These phases have never been shown for the Al-Si-Sr system, although several ternary phases were calculated [148]. Nevertheless, these early investigations proved the potential of APT to study eutectic modification.…”

Section: Recent Developmentsmentioning

confidence: 91%

Eutectic Modification of Al-Si casting alloys

Barrirero

2019

Linköping Studies in Science and Technology. Dissertations

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Section: Recent Developmentsmentioning

confidence: 91%

Eutectic Modification of Al-Si casting alloys

Barrirero

2019

Linköping Studies in Science and Technology. Dissertations

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“…Density functional theory (DFT) has been used to study the stability of several known Al-Si-Sr phases 27 28 , of which some were known and some others have been newly identified as stable structures. Thermodynamic properties and vibration spectra of these intermetallics are also reported.…”

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confidence: 99%

Self-organized Sr leads to solid state twinning in nano-scaled eutectic Si phase

Albu

Pal

Gspan

et al. 2016

Sci Rep

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A new mechanism for twin nucleation in the eutectic Al-Si alloy with trace Sr impurities is proposed. Observations made by sub-angstrom resolution scanning transmission electron microscopy and X-ray probing proved the presence of <110> Sr columns located preferentially at twin boundaries. Density functional theory simulations indicate that Sr atoms bind in the Si lattice only along the <110> direction, with preferential positions at first and second nearest neighbors for interstitial and substitutional Sr, respectively. Density functional theory total energy calculations confirm that twin nucleation at Sr columns is energetically favorable. Hence, twins may nucleate in Si precipitates after solidification, which provides a different perspective to the currently accepted mechanism which suggests twin formation during precipitate growth.The past decades have witnessed a noticeable increase in research and improvement of light Al-Si cast alloys for use in domestic, military, automotive, and aerospace components 1,2 . Given the widespread (80%) use of this alloy system optimization of the microstructure is of crucial matter to ensure superior mechanical properties for the as-cast finished products 3 . Of particular importance are the nucleation and growth mechanisms of the eutectic Si phase which can be manipulated through changes in impurity concentration or kinetics of the eutectic reaction 4-11 . Several theories have been proposed to explain the mechanisms leading to refinement and twinning with the most broadly accepted ones being "impurity-induced twinning" (IIT) 6 and the "twin plane re-entrant growth mechanism" (TPRE) 7,8,10 . Various experimental studies and sophisticated microscopic and tomographic investigations have been carried out for verification [12][13][14][15][16][17] . Recently, the twin formation mechanism which entails solute adsorption (along the < 112> Si) and entrapment during Si growth was presented by Li 14,18 .It has been concluded that none of the existing theories explains microstructural refinement and twinning induced by all atomic modifiers (Ba, Ca, Na, Sc or rare earths such as Yb, Y, Sb) 6,[19][20][21][22][23][24][25] . Furthermore, twin formation in eutectic silicon and in presence of traces of impurities (< 0.1 wt%) has also been observed upon alloy annealing 26 , which indicates that solute re-organization during the heat treatment may also lead to twin formation.Density functional theory (DFT) has been used to study the stability of several known Al-Si-Sr phases 27,28 , of which some were known and some others have been newly identified as stable structures. Thermodynamic properties and vibration spectra of these intermetallics are also reported. Yue et al. 29 used ab-initio molecular dynamics to study the structure of liquid Al-Si-Sr at the eutectic concentration of Al and Si. They indicate that the presence of Sr reduces the diffusion coefficient of both Al and Si in the melt and observed that Sr binds preferentially with Si.This work targets the twinning mechanism in the pres...

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“…It is necessary to obtain basic physical parameters (i.e., lattice parameter, electron work function, bonding charge density) of target alloys and to establish their correlation with the mechanical properties (i.e., Young's modulus, hardness, and strength) [98,99] . In a target alloy with a relatively high content of alloying elements, the second phase is usually introduced during the refinement and modification process of the casting aluminum alloy, and the uniform dispersion of the hard fine particles plays a vital role in the improvement of the strength and ductility in casting aluminum alloy [123] . Therefore, it is vital to determine the modulus of the second phase in aluminum alloys.…”

Section: Physics-based Calculationsmentioning

confidence: 99%

Boosting for concept design of casting aluminum alloys driven by combining computational thermodynamics and machine learning techniques

Wang¹,

Liu²,

Gao³

et al. 2021

JMI

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Casting aluminum alloys are commonly used in industries due to their excellent comprehensive performance. Alloying/microalloying and post-solidification heat treatments are the most common measures to tune the microstructure for enhancing their mechanical properties. However, it is very challenging to achieve accurate and efficient development of novel casting aluminum alloys using the traditional trial-and-error method. With the rapid development of computer technology, the computational thermodynamics (CT) in the framework of the CALculation of PHAse Diagram approach, the data-driven machine learning (ML) technique, and also their combinations have been proved to be effective approaches for the design of casting aluminum alloys. In this review, the state-of-the-art computational alloy design approaches driven by CT and ML techniques, as well as their combinations, were comprehensively summarized. The current status of the thermodynamic database for aluminum alloys, as the core for CT, was also briefly introduced. After that, a variety of successful case studies on the design of different casting aluminum alloys driven by CT, ML, and their combinations were demonstrated, including common applications, CT-driven design of Sc-additional Al-Si-Mg series casting alloys, and design of Srmodified A356 alloys driven by combing CT and ML. Finally, the conclusions of this review were drawn, and perspectives for boosting the computational design approach driven by combining CT and ML techniques were pointed out.

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First-principles investigation of the Al–Si–Sr ternary system: Ground state determination and mechanical properties

Cited by 20 publications

References 46 publications

Eutectic Modification of Al-Si casting alloys

Eutectic Modification of Al-Si casting alloys

Self-organized Sr leads to solid state twinning in nano-scaled eutectic Si phase

Boosting for concept design of casting aluminum alloys driven by combining computational thermodynamics and machine learning techniques

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