High temperature damage of Ni-base superalloy caused by the change of microtexture due to the strain-induced anisotropic diffusion of component elements

Hideo Miura, Ken Suzuki, Yamato Sasaki, Tomohiro Sano, Naokazu Murata

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

In order to assure the reliability of advanced gas turbine systems, it is very important to evaluate the damage of high temperature materials such as Ni-base superalloys under creep and fatigue conditions quantitatively. Since the micro texture of the gamma-prime (γ′) phase was found to vary during the creep damage process, it is possible, therefore, to evaluate the creep damage of this material quantitatively by measuring the change of the micro texture. The mechanism of the directional coarsening of γ′ phases of Ni-base superalloy under uni-axial strain at high temperatures, which is called rafting, was analyzed by using molecular dynamics (MD) analysis. The stress-induced anisotropic diffusion of Al atoms perpendicular to the finely dispersed γ/γ′ interface in the superalloy was observed clearly in a Ni(001)/Ni3Al(001) interface structure. The stress-induced anisotropic diffusion was validated by experiment using the stacked thin films structures which consisted of the (001) face-centered cubic (FCC) interface. The reduction of the diffusion of Al atoms perpendicular to the interface is thus, effective for improving the creep and fatigue resistance of the alloy. It was also found by MD analysis that the dopant elements in the superalloy also affected the strain-induced diffusion of Al atoms. Both palladium and tantalum were effective elements which restrain Al atoms from moving around the interface under the applied stress, while titanium and tungsten accelerated the strain-induced anisotropic diffusion, and thus, the rafting phenomenon.

Original languageEnglish
Title of host publicationEnergy Systems Analysis, Thermodynamics and Sustainability; Combustion Science and Engineering; Nanoengineering for Energy
PublisherAmerican Society of Mechanical Engineers (ASME)
Pages1649-1655
Number of pages7
EditionPARTS A AND B
ISBN (Print)9780791854907
DOIs
Publication statusPublished - 2011 Jan 1
EventASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011 - Denver, CO, United States
Duration: 2011 Nov 112011 Nov 17

Publication series

NameASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011
NumberPARTS A AND B
Volume4

Other

OtherASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011
CountryUnited States
CityDenver, CO
Period11/11/1111/11/17

ASJC Scopus subject areas

  • Mechanical Engineering

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