TY - JOUR
T1 - Slip delocalization and diffusion mediated carbide formation during fatigue of a nickel-base superalloy
AU - Gu, Yejun
AU - Stinville, Jean Charles
AU - Callahan, Patrick G.
AU - Echlin, McLean P.
AU - Pollock, Tresa M.
AU - El-Awady, Jaafar A.
N1 - Funding Information:
The authors gratefully acknowledge the support of GE Global Research, AFOSR/AFRL for sponsoring Center of Excellence on Integrated Materials Modeling (CEIMM ? Grant FA9550-12?1-0445) and the Air Force Center of Excellence (Grant FA9550-12?1-0445) and US Department of Energy Basic Energy Sciences Grant DE-SC0018901. Y. Gu and J. A. El-Awady gratefully acknowledge the support of the Office of Naval Research through grant number N00014-18-1-2858. P. G. Callahan acknowledges NRL for support under the auspices of the ONR. The authors also appreciate useful discussions with J. Laflen and A. Loghin.
Funding Information:
The authors gratefully acknowledge the support of GE Global Research, AFOSR/AFRL for sponsoring Center of Excellence on Integrated Materials Modeling (CEIMM – Grant FA9550-12–1-0445) and the Air Force Center of Excellence (Grant FA9550-12–1-0445) and US Department of Energy Basic Energy Sciences Grant DE-SC0018901. Y. Gu and J. A. El-Awady gratefully acknowledge the support of the Office of Naval Research through grant number N00014-18-1-2858. P. G. Callahan acknowledges NRL for support under the auspices of the ONR. The authors also appreciate useful discussions with J. Laflen and A. Loghin.
Publisher Copyright:
© 2020 Elsevier Ltd
PY - 2021/4
Y1 - 2021/4
N2 - Fatigue crack initiation at high temperatures occurs at microscopic fatigue shear bands that form near twin boundaries in polycrystalline nickel-base superalloys that contain minimal metallurgical defects. The associated dislocation sub-structure is complex and dependent on thermal and mechanical conditions. Here we show the formation of fine-scale carbide precipitates along these fatigue shear bands in a nickel-base superalloy during fatigue above 650 °C. The formation of carbide precipitates is studied using calculations of bulk and pipe diffusion. The contribution of pipe diffusion is observed to be critical in the formation of fine-scale carbides and occurs coincident with the delocalization of slip during fatigue.
AB - Fatigue crack initiation at high temperatures occurs at microscopic fatigue shear bands that form near twin boundaries in polycrystalline nickel-base superalloys that contain minimal metallurgical defects. The associated dislocation sub-structure is complex and dependent on thermal and mechanical conditions. Here we show the formation of fine-scale carbide precipitates along these fatigue shear bands in a nickel-base superalloy during fatigue above 650 °C. The formation of carbide precipitates is studied using calculations of bulk and pipe diffusion. The contribution of pipe diffusion is observed to be critical in the formation of fine-scale carbides and occurs coincident with the delocalization of slip during fatigue.
KW - Bulk and pipe diffusion
KW - Carbide precipitation
KW - Coherent twin boundary
KW - Microscopic fatigue shear band
KW - Persistent slip band
KW - René 88DT nickel-base superalloy
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U2 - 10.1016/j.ijfatigue.2020.106077
DO - 10.1016/j.ijfatigue.2020.106077
M3 - Article
AN - SCOPUS:85100006200
SN - 0142-1123
VL - 145
JO - International Journal of Fatigue
JF - International Journal of Fatigue
M1 - 106077
ER -