High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys

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High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys. / Titus, Michael S.; Mottura, Alessandro; Viswanathan, G. Babu; Suzuki, Akane; Mills, Michael J.; Pollock, Tresa M.

In: Acta Materialia, Vol. 89, 01.05.2015, p. 423–437.

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Titus, Michael S. ; Mottura, Alessandro ; Viswanathan, G. Babu ; Suzuki, Akane ; Mills, Michael J. ; Pollock, Tresa M. / High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys. In: Acta Materialia. 2015 ; Vol. 89. pp. 423–437.

Bibtex

@article{c0dcbf55808641f0b2abe84c90623b5a,
title = "High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys",
abstract = "Local chemical fluctuations in the vicinity of superlattice intrinsic stacking faults (SISFs) have been observed via high resolution energy dispersive X-ray spectroscopy (EDS) mapping in new single crystal Co- and CoNi-base superalloys containing γ′-(L12) precipitates. The SISFs were formed during high temperature tensile creep at 900 °C. Chemical fluctuations were found to greatly influence the SISF energy, which was calculated from density functional theory in Co3(Al, Ta, W) compounds at 0 K. The local SISF structure was found to be comprised of four D019 (0001) planes that were enriched in W and Ta, as revealed by high resolution scanning transmission electron microscopy (HRSTEM) imaging and EDS mapping. The precipitates were determined to accommodate up to 22% of the plastic deformation accrued during an interrupted creep test to 0.6% creep strain. The driving forces for segregation are discussed, and new models for shearing of the ordered precipitates are proposed.",
keywords = "Cobalt alloys, High temperature creep, Scanning transmission electron microscopy, Energy dispersive X-ray spectroscopy, Stacking faults",
author = "Titus, {Michael S.} and Alessandro Mottura and Viswanathan, {G. Babu} and Akane Suzuki and Mills, {Michael J.} and Pollock, {Tresa M.}",
year = "2015",
month = may,
day = "1",
doi = "10.1016/j.actamat.2015.01.050",
language = "English",
volume = "89",
pages = "423–437",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - High resolution energy dispersive spectroscopy mapping of planar defects in L12-containing Co-base superalloys

AU - Titus, Michael S.

AU - Mottura, Alessandro

AU - Viswanathan, G. Babu

AU - Suzuki, Akane

AU - Mills, Michael J.

AU - Pollock, Tresa M.

PY - 2015/5/1

Y1 - 2015/5/1

N2 - Local chemical fluctuations in the vicinity of superlattice intrinsic stacking faults (SISFs) have been observed via high resolution energy dispersive X-ray spectroscopy (EDS) mapping in new single crystal Co- and CoNi-base superalloys containing γ′-(L12) precipitates. The SISFs were formed during high temperature tensile creep at 900 °C. Chemical fluctuations were found to greatly influence the SISF energy, which was calculated from density functional theory in Co3(Al, Ta, W) compounds at 0 K. The local SISF structure was found to be comprised of four D019 (0001) planes that were enriched in W and Ta, as revealed by high resolution scanning transmission electron microscopy (HRSTEM) imaging and EDS mapping. The precipitates were determined to accommodate up to 22% of the plastic deformation accrued during an interrupted creep test to 0.6% creep strain. The driving forces for segregation are discussed, and new models for shearing of the ordered precipitates are proposed.

AB - Local chemical fluctuations in the vicinity of superlattice intrinsic stacking faults (SISFs) have been observed via high resolution energy dispersive X-ray spectroscopy (EDS) mapping in new single crystal Co- and CoNi-base superalloys containing γ′-(L12) precipitates. The SISFs were formed during high temperature tensile creep at 900 °C. Chemical fluctuations were found to greatly influence the SISF energy, which was calculated from density functional theory in Co3(Al, Ta, W) compounds at 0 K. The local SISF structure was found to be comprised of four D019 (0001) planes that were enriched in W and Ta, as revealed by high resolution scanning transmission electron microscopy (HRSTEM) imaging and EDS mapping. The precipitates were determined to accommodate up to 22% of the plastic deformation accrued during an interrupted creep test to 0.6% creep strain. The driving forces for segregation are discussed, and new models for shearing of the ordered precipitates are proposed.

KW - Cobalt alloys

KW - High temperature creep

KW - Scanning transmission electron microscopy

KW - Energy dispersive X-ray spectroscopy

KW - Stacking faults

UR - http://www.sciencedirect.com/science/article/pii/S1359645415000634

U2 - 10.1016/j.actamat.2015.01.050

DO - 10.1016/j.actamat.2015.01.050

M3 - Article

VL - 89

SP - 423

EP - 437

JO - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

ER -