Dislocation-free zone model of fracture

Journal Article · Tue Dec 01 04:00:00 EST 1981 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.328692· OSTI ID:6064366

Chang, S; Ohr, S M

Recent observations by electron microscopy have shown that a dislocation-free zone (DFZ) is present between the crack tip and the linear pileup of dislocations in the plastic zone. A singular integral equation is formulated to describe the equilibrium configuration of the dislocations. The distribution function of the dislocations is obtained in terms of elliptic integrals. The condition of compatibility and the elastic stress intensity factor at the crack tip are also derived. At the crack tip the stress varies as 1/..sqrt..r. It is found that the stress intensity factor K is approximately a function of the length of the DFZ, whereas the externally applied stress approximately determines the length of the plastic zone. Based on the mechanism of dislocation generation at the crack tip proposed by Rice and Thomson, it is shown that the formation of the DFZ is anticipated when the stress intensity factor K is less than a critical stress intensity factor K/sub g/ defined for a spontaneous generation of dislocations. The magnitude of K/sub g/ relative to the critical stress intensity factor for brittle fracture K/sub c/ determines the brittle-ductile nature of a material.

• Research Organization: Computer Sciences Division, Union Carbide Corporation, Nuclear Division, Oak Ridge, Tennessee 37830
• OSTI ID: 6064366
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 52:12; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

656000* -- Condensed Matter Physics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BRITTLE-DUCTILE TRANSITIONS
CONFIGURATION
CRACKS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DATA
DISLOCATIONS
DISTRIBUTION FUNCTIONS
ELASTICITY
ELECTRON MICROSCOPY
EQUATIONS
EQUILIBRIUM
FAILURES
FRACTURES
FUNCTIONS
INFORMATION
INTEGRAL EQUATIONS
INTEGRALS
LINE DEFECTS
MECHANICAL PROPERTIES
MICROSCOPY
NUMERICAL DATA
STRESSES
STRUCTURAL MODELS
TENSILE PROPERTIES
THEORETICAL DATA
ZONES