Can slow-diffusing solute atoms reduce vacancy diffusion in advanced high-temperature alloys?

Goswami, Kamal Nayan; Mottura, Alessandro

doi:10.1016/j.msea.2014.08.054

Cited by 15 publications

(29 citation statements)

References 30 publications

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“…The Ni self-diffusion coefficient was also calculated and this has been plotted in Figure 3 as a function of temperature. The results completely overlap with our previous results from analytical formulations [11] as well as with the kMC simulations of Schuwalow et al [13]. Also, a correlation factor of 0.781 [47] was reproduced in pure Ni reaffirming the validity of the code.…”

Section: Kinetic Monte Carlo Resultssupporting

confidence: 86%

“…where R 2 (t) is the squared displacement of the vacancy (or solute atoms) from the initial state, N is the number of i atoms, t is the time elapsed, x v is the actual vacancy concentration [11] at temperature = T , while x sim v is the vacancy concentration used in the kMC simulation. R 2 (t) is calculated as…”

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

“…For all other calculations, besides the internal degrees of freedom of the supercells, the volume and the shape of the supercells were relaxed as well. The effective frequencies were calculated within the harmonic approximation as supported by VASP and have been presented in our previous work [11]. The cluster expansion was performed using the CASM code (Cluster-Assisted Statistical Mechanics) developed by the Van der Ven Research Group at the University of Michigan [27,28].…”

Section: Computational Detailsmentioning

confidence: 99%

“…Our previous work [11] was based on the use of an analytical model for vacancy diffusion developed by Manning [12] and indicated that small additions of slow-diffusing atoms in a Ni lattice do not reduce the diffusion rate of vacancies substantially. However, Manning's model is based on a number of simplifying assumptions which undermine the validity of the results.…”

Section: Introductionmentioning

confidence: 99%

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A kinetic Monte Carlo study of vacancy diffusion in non-dilute Ni-Re alloys

Goswami

Mottura

2019

Materials Science and Engineering: A

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Section: Kinetic Monte Carlo Resultssupporting

confidence: 86%

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

Section: Computational Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A kinetic Monte Carlo study of vacancy diffusion in non-dilute Ni-Re alloys

Goswami

Mottura

2019

Materials Science and Engineering: A

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“…Slow-diffusing atoms in the matrix were thought to hinder dislocation climb processes at the interface [11]. However, the reductions of the vacancy diffusion coefficient predicted from first-principle calculations is not large enough to provide the creep strengthening effect experimentally observed [12]. Such understanding could provide fundamental insight and allow the design of materials with improved properties, such as longer lifetimes or higher energy efficiency enabled by higher operational temperatures.…”

Section: Introductionmentioning

confidence: 99%

Modelling defects in Ni–Al with EAM and DFT calculations

Bianchini

Kermode

Vita

2016

Modelling Simul. Mater. Sci. Eng.

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We present detailed comparisons between the results of embedded atom model (EAM) and density functional theory (DFT) calculations on defected Ni alloy systems. We find that the EAM interatomic potentials reproduce low-temperature structural properties in both the γ and γ′ phases, and yield accurate atomic forces in bulk-like configurations even at temperatures as high as ∼1200 K. However, they fail to describe more complex chemical bonding, in configurations including defects such as vacancies or dislocations, for which we observe significant deviations between the EAM and DFT forces, suggesting that derived properties such as (free) energy barriers to vacancy migration and dislocation glide may also be inaccurate. Testing against full DFT calculations further reveals that these deviations have a local character, and are typically severe only up to the first or second neighbours of the defect. This suggests that a QM/MM approach can be used to accurately reproduce QM observables, fully exploiting the EAM potential efficiency in the MM zone. This approach could be easily extended to ternary systems for which developing a reliable and fully transferable EAM parameterisation would be extremely challenging e.g. Ni alloy model systems with a W or Re-containing QM zone.

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