Statistical analysis of cleavage fracture ahead of sharp cracks and rounded notches

Journal Article · Sat Nov 01 00:00:00 EST 1986 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(86)90166-5· OSTI ID:6911325

Lin, T; Evans, A G; Ritchie, R O

Mechanisms of initiation and unstable propagation of transgranular cleavage cracks are compared for brittle fracture ahead of sharp cracks and rounded notches, e.g. for fatigue pre-cracks and Charpy V-notches, respectively, in standard toughness specimens. The comparison is made over a range of temperatures, from the lower shelf into the ductile/brittle transition region, for a single phase materials containing a known distribution of particles where weakest link statistics can be used to model the onset of catastrophic failure. Using linear and nonlinear elastic solutions for the stress distribution ahead of a sharp crack, and slip-line field solutions, modified for a power hardening material, for the rounded notch, statistical modelling is employed to define the critical dimensions ahead of the crack or notch tip where initial cracking events are most probable. The analysis provides an interpretation of the role of stress gradient in governing microscopic fracture behavior. Predictions are evaluated by comparison with experimental results on the low temperature flow, Charpy V-notch and plane strain fracture toughness behavior of a low carbon mild steel with simple ferrite/grain boundary carbide microstructures.

• Research Organization: Materials and Molecular Research Div., Lawrence Berkeley Lab. and Dept. of Materials Science and Mineral Engineering, Univ. of California, Berkeley, CA (US)
• OSTI ID: 6911325
• Journal Information: Acta Metall.; (United States), Vol. 34:11
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CARBON STEELS
CLEAVAGE
CRACK PROPAGATION
STRUCTURAL CHEMICAL ANALYSIS
BRITTLENESS
CARBIDES
CHARPY TEST
FATIGUE
FERRITE
FERRITIC STEELS
FRACTURE MECHANICS
FRACTURE PROPERTIES
FRACTURES
GRAIN BOUNDARIES
STATISTICS
ALLOYS
CARBON ADDITIONS
CARBON COMPOUNDS
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
FAILURES
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
MATERIALS TESTING
MATHEMATICS
MECHANICAL PROPERTIES
MECHANICAL TESTS
MECHANICS
MICROSTRUCTURE
STEELS
TESTING
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies