Crack growth rate of inclined and deflected surface-cracks in round-bar specimens of copper processed by equal channel angular pressing under cyclic loading

•Cracks grew along the ECAP-shear plane, forming a 45° inclined/deflected crack.•The crack growth rate was discussed by the comparative-SIF,KV, under mixed mode.•Difference in crack growth rate between surface and inside specimen was clarified. For low-cycle fatigued, ultrafine grained copper, proce...

Full description

Saved in:
Bibliographic Details
Published in:Engineering fracture mechanics 2017-09, Vol.182, p.100-113
Main Authors: Goto, M., Yamamoto, T., Han, S.Z., Kim, S., Ahn, J-H., Kitamura, J., Iwamura, T., Lee, J.
Format: Article
Language:English
Subjects:
Copper
Crack growth rate
Crack propagation
Crack tips
Cracks
Cyclic loads
Deformation
Deformation mechanisms
Equal channel angular pressing
Fatigue
Fracture mechanics
Materials fatigue
Mixed mode
Round bars
Shear
Stress intensity factor
Stress intensity factors
Tips
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Cracks grew along the ECAP-shear plane, forming a 45° inclined/deflected crack.•The crack growth rate was discussed by the comparative-SIF,KV, under mixed mode.•Difference in crack growth rate between surface and inside specimen was clarified. For low-cycle fatigued, ultrafine grained copper, processed by equal channel angular pressing, a unique crack growth direction, either inclined at 45° or perpendicular to the loading direction, was observed around the circumference of round bar specimens. In addition, the perpendicular cracks showed a 45° deflected crack face toward the center of the specimens. To clarify the growth behavior of such inclined and deflected cracks, the role of the deformation mode at the crack-tip areas was discussed in terms of the surface damage caused by cyclic stressing and the mixed-mode deformation at the crack tips. The preexistent shear-bands/shear-cracks around the crack tips and the in-plane shear-mode deformation at the crack tips assisted the formation of shallow inclined- and deep deflected-cracks. To quantitatively estimate the severity of mechanical damage at the crack tips, the comparative stress intensity factor range under combined mode I, II and III conditions were calculated. The crack growth rate along the growth direction at the surface and bottom for inclined and deflected surface-cracks was discussed in terms of the comparative stress intensity factor range.
ISSN:0013-7944
1873-7315
DOI:10.1016/j.engfracmech.2017.07.024