scholarly journals Effects of crack tip geometry on dislocation emission and cleavage: A possible path to enhanced ductility

1997 ◽  
Vol 55 (10) ◽  
pp. 6211-6221 ◽  
Author(s):  
J. Schiøtz ◽  
L. M. Canel ◽  
A. E. Carlsson
Keyword(s):  
Crack Tip ◽  
Dislocation Emission ◽  
Crack Tip Geometry

Effect of Crack Blunting on the Ductile-Brittle Response of Crystalline Materials

1998 ◽  
Vol 539 ◽  
Author(s):  
D.M. Lipkin ◽  
G.E. Beltz ◽  
L.L. Fischer
Keyword(s):  
Crack Tip ◽  
Dislocation Nucleation ◽  
Crack Advance ◽  
Dislocation Emission ◽  
Crystalline Materials ◽  
Self Consistent ◽  
Crack Blunting ◽  
Cohesive Stresses ◽  
Crack Tip Geometry ◽  
Crack Tip Blunting

AbstractWe propose a self-consistent criterion for crack propagation versus dislocation emission, taking into account the effects of crack-tip blunting. Continuum concepts are used to evaluate the evolving competition between crack advance and dislocation nucleation as a function of crack- tip curvature. This framework is used to classify crystals as intrinsically ductile or brittle in terms of the unstable stacking energy, the surface energy, and the peak cohesive stresses achieved during opening and shear of the atomic planes. We find that ductile-brittle criteria based on the assumption that the crack is ideally sharp capture only two of the four possible fracture regimes. One implication of the present analysis is that a crack may initially emit dislocations, only to reinitiate cleavage upon reaching a sufficiently blunted crack-tip geometry.

Atomistic Study of Cleavage and Dislocation Emission in NiAl

1994 ◽  
Vol 364 ◽  
Author(s):  
M. Ludwig ◽  
P. Gumbsch
Keyword(s):  
Finite Element ◽  
Mixed Mode ◽  
Crack Tip ◽  
Mode I ◽  
Crack Plane ◽  
Dislocation Emission ◽  
Dislocation Generation ◽  
Embedded Atom ◽  
Atomistic Study ◽  
Eam Potential

AbstractThe atomistic processes during fracture of NiAl are studied using a new embedded atom (EAM) potential to describe the region near the crack tip. To provide the atomistically modeled crack tip region with realistic boundary conditions, a coupled finite element - atomistic (FEAt) technique [1] is employed. In agreement with experimental observations, perfectly brittle cleavage is observed for the (110) crack plane. In contrast, cracks on the (100) plane either follow a zig-zag path on (110) planes, or emit dislocations. Dislocation generation is studied in more detail under mixed mode I/II loading conditions.

Crack-tip dislocation emission arrangements for equilibrium—III. Application to large applied stress intensities

1992 ◽  
Vol 40 (11) ◽  
pp. 2883-2894 ◽  
Author(s):  
P.G. Marsh ◽  
W. Zielinski ◽  
H. Huang ◽  
W.W. Gerberich
Keyword(s):  
Applied Stress ◽  
Crack Tip ◽  
Dislocation Emission

scholarly journals Direct Observation of Dislocation Emission from a Crack Tip in YSZ

Materia Japan ◽  
2005 ◽  
Vol 44 (12) ◽  
pp. 998-998
Author(s):  
Takeo Sasaki ◽  
Satoshi Tanaka ◽  
Takahisa Yamamoto ◽  
Katsuyuki Matsunaga ◽  
Yuichi Ikuhara
Keyword(s):  
Direct Observation ◽  
Crack Tip ◽  
Dislocation Emission
Sign in / Sign up

Export Citation Format

Share Document