Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys: density-functional theory calculations

H. Hasan; P. Mlkvik; P.D. Haynes; V.A. Vorontsov

doi:10.1016/j.mtla.2019.100555

Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys: density-functional theory calculations

H. Hasan, P. Mlkvik, P.D. Haynes, V.A. Vorontsov

Design, Manufacturing And Engineering Management

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Abstract

Generalised stacking fault energy surfaces (Γ-surfaces) are calculated for Co-Al-W-based and Ni-Al-based superalloys from first-principles calculations. A Special Quasi-random Structure is employed in the calculation of the ternary compound, Co ₃(Al,W). Phase field simulations are used to compare dislocation cores present in Co-based and Ni-based superalloys. The higher planar fault energies of the Co-based system lead to a more constricted dislocation which can have implications on both the bowing of dislocations as well as cross-slip. Additionally, planar fault energies of various L1 ₂ compounds are compared to explain observed segregation pathways in both types of superalloy. Both the planar fault energies and the segregation pathways are discussed within the context of strengthening mechanisms in superalloys.

Original language	English
Article number	100555
Number of pages	13
Journal	Materialia
Volume	9
Early online date	5 Dec 2019
DOIs	https://doi.org/10.1016/j.mtla.2019.100555
Publication status	Published - 31 Mar 2020

Funding

HH would like to gratefully acknowledge funding from the EPSRC Centre for Doctoral Training on Theory and Simulation of Materials at Imperial College London under grant number EP/L015579/1 . VAV would like to acknowledge support from Rolls-Royce plc and Imperial College London under the Imperial College Research Fellowship scheme. Calculations were performed at the Imperial College Research Computing Service, doi: 10.14469/hpc/2232 .

Keywords

superalloys
density functional theory
stacking fault energy
phase field simulation
dislocations

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10.1016/j.mtla.2019.100555

Hasan-etal-Materialia-2019-Generalised-stacking-fault-energy-of-Ni-Al-and-Co-Al-W-superalloysAccepted author manuscript, 6.08 MBLicence: CC BY-NC-ND 4.0

Cite this

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title = "Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys: density-functional theory calculations",

abstract = "Generalised stacking fault energy surfaces (Γ-surfaces) are calculated for Co-Al-W-based and Ni-Al-based superalloys from first-principles calculations. A Special Quasi-random Structure is employed in the calculation of the ternary compound, Co 3(Al,W). Phase field simulations are used to compare dislocation cores present in Co-based and Ni-based superalloys. The higher planar fault energies of the Co-based system lead to a more constricted dislocation which can have implications on both the bowing of dislocations as well as cross-slip. Additionally, planar fault energies of various L1 2 compounds are compared to explain observed segregation pathways in both types of superalloy. Both the planar fault energies and the segregation pathways are discussed within the context of strengthening mechanisms in superalloys. ",

keywords = "superalloys, density functional theory, stacking fault energy, phase field simulation, dislocations",

author = "H. Hasan and P. Mlkvik and P.D. Haynes and V.A. Vorontsov",

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T1 - Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys

T2 - density-functional theory calculations

AU - Hasan, H.

AU - Mlkvik, P.

AU - Haynes, P.D.

AU - Vorontsov, V.A.

PY - 2020/3/31

Y1 - 2020/3/31

N2 - Generalised stacking fault energy surfaces (Γ-surfaces) are calculated for Co-Al-W-based and Ni-Al-based superalloys from first-principles calculations. A Special Quasi-random Structure is employed in the calculation of the ternary compound, Co 3(Al,W). Phase field simulations are used to compare dislocation cores present in Co-based and Ni-based superalloys. The higher planar fault energies of the Co-based system lead to a more constricted dislocation which can have implications on both the bowing of dislocations as well as cross-slip. Additionally, planar fault energies of various L1 2 compounds are compared to explain observed segregation pathways in both types of superalloy. Both the planar fault energies and the segregation pathways are discussed within the context of strengthening mechanisms in superalloys.

AB - Generalised stacking fault energy surfaces (Γ-surfaces) are calculated for Co-Al-W-based and Ni-Al-based superalloys from first-principles calculations. A Special Quasi-random Structure is employed in the calculation of the ternary compound, Co 3(Al,W). Phase field simulations are used to compare dislocation cores present in Co-based and Ni-based superalloys. The higher planar fault energies of the Co-based system lead to a more constricted dislocation which can have implications on both the bowing of dislocations as well as cross-slip. Additionally, planar fault energies of various L1 2 compounds are compared to explain observed segregation pathways in both types of superalloy. Both the planar fault energies and the segregation pathways are discussed within the context of strengthening mechanisms in superalloys.

KW - superalloys

KW - density functional theory

KW - stacking fault energy

KW - phase field simulation

KW - dislocations

UR - https://www.journals.elsevier.com/materialia

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DO - 10.1016/j.mtla.2019.100555

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JO - Materialia

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ER -

Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys: density-functional theory calculations

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Generalised stacking fault energy of Ni-Al and Co-Al-W superalloys: density-functional theory calculations

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