Journal article
Microstructural influence on small fatigue cracks in a ferritic-martensitic steel



Publication Details
Authors:
Brückner-Foit, A.; Motoyashiki, Y.; Sugeta, A.
Publication year:
2008
Journal:
Engineering Fracture Mechanics
Pages range:
768-778
Volume number:
75
Start page:
768
End page:
778
ISSN:
0013-7944

Abstract
Microstructure effects on fatigue crack initiation and propagation in ferritic-martensitic dual phase steel were investigated. Slip bands were formed in ferrite grains after several thousand cycles with ensuing crack initiation due to dislocation pile-up. Subsurface observations using a focused ion beam (FIB) and crystallographic analyses using electron backscatter diffraction (EBSD) measurements showed that crack initiation occurred as a result of the activation of a slip system having a high Schmid factor. Surface crack nucleation occurred quite frequently at ferrite/martensite and ferrite/ferrite boundaries, with crack propagation in the ferrite grains. This initiation mode can be attributed to the mismatch stresses at ferrite/martensite phase boundaries and at high angle grain boundaries. (C) 2007 Published by Elsevier Ltd.

Last updated on 2019-01-11 at 16:04