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Morphology of Ni‐base superalloys via very small‐angle neutron scattering technique
Author(s) -
Aizawa K.,
Tomimitsu H.,
Tamaki H.,
Yoshinari A.
Publication year - 2000
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s0021889800000121
Subject(s) - superalloy , lamellar structure , materials science , creep , interphase , neutron scattering , small angle neutron scattering , scattering , turbine blade , scanning electron microscope , neutron , neutron diffraction , composite material , crystallography , optics , turbine , microstructure , crystal structure , nuclear physics , chemistry , thermodynamics , physics , genetics , biology
Very small‐angle neutron scattering (VSANS) was used to develop a nondestructive inspecting technique for predicting the residual life time of turbine blades made from single crystal Ni‐base superalloy. The VSANS curves, obtained from single crystalline CMSX‐4 samples with the various degrees of damage, clearly show the first order peak of the lamellar structure created by a sequence of γ and γ' phases in this material. The peak shifts in the direction of lower scattering vector magnitudes when the creep damage increases, which reflects a corresponding increase of the period of the lamellar structure. According to the VSANS data, the interphase distance in the samples increases gradually (but does not grow rapidly) with increasing creep damage when the latter is < 54% of the creep leading to rupture. Thus, the interphase distance is a sensitive parameter which can be used to describe the morphological changes in Ni‐base superalloys related to creep damage. The results are consistent with those obtained from scanning electron microscopy.