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Microstructural changes during creep of CMSX‐4 single crystal Ni base superalloy at 750°C
Author(s) -
DUBIEL B. T.,
CZYRSKAFILEMONOWICZ A.
Publication year - 2010
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.2009.03261.x
Subject(s) - creep , materials science , superalloy , dislocation creep , dislocation , burgers vector , microstructure , single crystal , stress (linguistics) , metallurgy , ultimate tensile strength , stacking fault , deformation (meteorology) , composite material , crystallography , linguistics , chemistry , philosophy
Summary TEM studies of creep tested CMSX‐4 nickel‐base single crystal superalloy were performed to analyse a microstructure evolution during creep at temperature 750°C, and uniaxial tensile stress of 675 MPa. Microstructural analyses were focused mainly on examination of dislocation configurations during primary and secondary creep stages of high temperature deformation. At such low temperature and high stress creep deformation proceed by cutting of γ′ particles by dislocations. It was found that primary creep is initiated by movement of dislocations with Burgers vector a/2 <110> in the γ phase. The second type of dislocations active at primary creep stage are extended dislocation ribbons with overall a<112> Burgers vector, separated by superlattice stacking faults, cutting both the γ and γ′ phases. The movement of the dislocation ribbons is inhibited at secondary creep stage by dislocation networks formed at γ−γ′ interfaces.