Grain boundary segregation and intermetallic precipitation in coarsening resistant nanocrystalline aluminum alloys

Devaraj, Arun; Wang, W.; Vemuri, R.S.; Kovařík, Libor; Jiang, Xuanyuan; Bowden, Michael; Trelewicz, Jason R.; Mathaudhu, Suveen; Rohatgi, Aashish

doi:10.1016/j.actamat.2018.09.038

Cited by 104 publications

(41 citation statements)

References 60 publications

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“…For grain growth of NC alloys subjected to precipitation of solute‐rich phase, the precipitation of solute‐rich phase reduces the GB excess, yet moreover the precipitated second phase particles exert the pinning force, which can provide the strong impeding force for grain growth. Therefore, it can be expected that the coupling effect from second phase particle and segregated solute atoms is stronger in stabilizing NC materials than the sole effect from segregated solute atoms 91–94 . To prove this, Devaraj et al 92 prepared the Al, Al‐5 at.% Mg, and Al‐10 at.% Mg films of thickness 100 nm using magnetron sputtering, 92 and studied the thermal stability of samples annealed at 573 K for 3 hours.…”

Section: Thermo‐kinetic Description Of Grain Growth Processmentioning

confidence: 99%

“…STEM images of as‐sputtered films of (A) pure Al, (B) Al‐5% Mg, and (C) Al‐10% Mg, and STEM images of annealed (573 K for 3 h) films of (D) pure Al, (E) Al‐5% Mg, and (F) Al‐10% Mg 92 …”

Section: Thermo‐kinetic Description Of Grain Growth Processmentioning

confidence: 99%

“…This agrees with the results found by a coupled Monte Carlo-molecular dynamics simulation-guided experimental approach in Al-Mg alloys. 92 On this basis, the enhanced thermal stability of Al-Mg alloy was attributed to the grain boundary segregation suppressing the driving force for grain growth coupled with nanoscale intermetallic precipitates reducing the grain boundary mobility via a Zener pinning mechanism.…”

Section: Experiments and Simulationsmentioning

confidence: 99%

See 2 more Smart Citations

Review of thermo‐kinetic correlation during grain growth in nanocrystalline materials

Peng

Jian

Liu

2020

Int J Ceramic Engine & Sci

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Nanocrystalline (NC) materials exhibit many unique properties over their coarse‐grained counterparts due to the high grain boundary density and the small grain size, but they are too difficult to be used in engineering environment because of the poor thermal stability. With regard of this, two strategies are previously proposed to enhance the thermal stability (or impede the grain growth) of NC materials, that is, the thermodynamic and the kinetic approaches. Recent investigations increasingly support that the two approaches may be physically interacted and acted on each other, and they can be treated together within a unified thermo‐kinetic framework. This paper reviews the progress in the investigation of thermo‐kinetic correlation during grain growth in NC materials. First, the theoretical models to describe the concept of the thermo‐kinetic correlation and the grain growth equations developed based on the thermo‐kinetic correlation are reviewed. Second, experimental and simulated evidences to support the coexistence of thermodynamic and kinetic effects are summarized. Third, the potential application of thermo‐kinetic correlation is analyzed and discussed. This paper shows that the stabilization of NC materials can be tailored by the selection of the suitable strategies. Finally, several directions that require further exploration are identified.

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Section: Thermo‐kinetic Description Of Grain Growth Processmentioning

confidence: 99%

Section: Thermo‐kinetic Description Of Grain Growth Processmentioning

confidence: 99%

Section: Experiments and Simulationsmentioning

confidence: 99%

See 1 more Smart Citation

Review of thermo‐kinetic correlation during grain growth in nanocrystalline materials

Peng

Jian

Liu

2020

Int J Ceramic Engine & Sci

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“…For Al-Mg alloys, researchers have identified that Mg dopants can improve the mechanical properties of materials, including yield strength and strain hardening, through the solid solution strengthening [16,17] and precipitates pinning GBs [18,19]. In addition to those mechanisms, Pun et al [2] found that GB segregation strengthening also contributes to the improved strength and hardness of Al-Mg alloys.…”

Section: Introductionmentioning

confidence: 99%

“…However, there are currently no atomic level mechanisms available for clearly explaining how the effect of Mg dopants segregated to GBs leads to improvement of the strength of NC Al. Moreover, it is well known that doping Mg can stabilize the grain growth of NC Al against elevated temperature [18]. However, it is unclear how Mg dopants segregated to GBs can affect the stability of the grain sizes of NC Al during the deformation process.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Study of the Effect of Magnesium Dopants on the Strength of Nanocrystalline Aluminum

Kazemi

Yang

2019

JOM

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Atomistic simulations have been used to study the deformation mechanisms of nanocrystalline pure Al and Al-Mg binary alloys. Voronoi tessellation was used to fully create a three dimensional polycrystalline model with a grain size of 10 nm, while hybrid Monte Carlo and molecular dynamic simulations were used to achieve both mechanical and chemical equilibrium in nanocrystalline Al-5 at. % Mg. The results of tensile tests show an improved strength, including the yield strength and ultimate strength, through doping 5 at.% Mg into nanocrystalline aluminum. The results of atomic structures clearly reveal the multiple strengthening mechanisms related to doping in Al-Mg alloys. At the early deformation stage, up to an applied strain of 0.2, the strengthening mechanism of dopants exhibits as dopant pinning grain boundary (GB) migration. However, at the late deformation stage, which is close to failure of nanocrystalline materials, dopants can prohibit the initiation of intergranular cracks and also impede propagation of existing cracks along the GBs, thus improving the flow stress of Al-Mg alloy.

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Thermal Stability and S‐Phase Evolution in Ultrafine‐Grained Al−Mg−Li Alloy Produced by Equal‐Channel Angular Pressing

2021

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Ultrafine‐grained (UFG) aluminum alloys produced by severe plastic deformation demonstrate high mechanical properties but low thermal stability, which can negatively affect their service characteristics. Herein, the thermal stability of structure and S‐phase (Al2LiMg) evolution in UFG Al−5.5Mg−2.2Li−0.12Zr alloy produced by equal‐channel angular pressing (ECAP) are studied during heating and direct annealing. It is found that the UFG structure with an average grain size of about 1 μm formed by ECAP is preserved at up to 410 °C (≈0.7 T m), with a significant decrease in dislocation density (from 5 × 109 to 3 × 108 cm−2) and the fraction of low‐angle grain boundaries (from 20% to 5%) at 380 °C. The dissolution of metastable semicoherent SI‐phase particles located within grains at 330 °C is accompanied by a corresponding increase in Mg content in solid solution. The transfer of Mg atoms from solid solution to grain boundaries at 380 °C with subsequent coalescent growth of SII particles leads to an increase in the volume fraction (from 3% to 12%) and size of the particles and to recrystallization in UFG Al−Mg−Li alloy at 415 °C.

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Grain boundary segregation and intermetallic precipitation in coarsening resistant nanocrystalline aluminum alloys

Cited by 104 publications

References 60 publications

Review of thermo‐kinetic correlation during grain growth in nanocrystalline materials

Review of thermo‐kinetic correlation during grain growth in nanocrystalline materials

Atomistic Study of the Effect of Magnesium Dopants on the Strength of Nanocrystalline Aluminum

Thermal Stability and S‐Phase Evolution in Ultrafine‐Grained Al−Mg−Li Alloy Produced by Equal‐Channel Angular Pressing

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