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Investigation of small crack behaviour under cyclic loading in a dual phase steel with an FIB tomography technique
Author(s) -
MOTOYASHIKI Y.,
BRÜCKNERFOIT A.,
SUGETA A.
Publication year - 2007
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2007.01130.x
Subject(s) - electron backscatter diffraction , materials science , martensite , focused ion beam , microstructure , grain boundary , ferrite (magnet) , composite material , slip (aerodynamics) , dual phase steel , scanning electron microscope , diffraction , metallurgy , optics , ion , physics , quantum mechanics , thermodynamics
Damage accumulation is investigated in the early stage of fatigue life in a ferritic martensitic dual phase steel. Microcrack initiation and propagation are influenced by microstructure, such as grain boundaries, grain orientation and/or phase distribution morphology. The dominant crack initiation pattern is one in which microcracks are generated in a ferrite grain along slip bands inclined at a certain angle with respect to the loading direction. Subsurface observation with a focused ion beam (FIB) device and additional crystallographic characterization by means of the electron backscatter diffraction (EBSD) technique show that a slip system having a high Schmid factor value is activated and results in a crack nucleus. The FIB tomography technique with the help of EBSD measurement allows a three‐dimensional investigation of small crack behaviour to be performed.