Atomic-Scale Mechanism of Crack-Tip Plasticity: Dislocation Nucleation and Crack-Tip Shielding

Journal Article · Fri Aug 01 00:00:00 EDT 1997 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.79.1309· OSTI ID:664458

Cleri, F; Wolf, D; Phillpot, S R ^[1]; Cleri, F ^[2]; Yip, S ^[3]

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1. Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)
2. Divisione Materiali Avanzati, ENEA, Centro Ricerche Casaccia, 00100 Roma A.D. (Italy)
3. Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

By isolating the process of dislocation emission from a crack tip under an applied tensile stress, we extract from a molecular dynamics simulation the atomic-level displacement and stress fields on the activated slip plane before and after the nucleation event. The stress-displacement relations so obtained provide a direct link with recent continuum descriptions of brittle versus ductile behavior in crack propagation. Crack-tip shielding by the emitted dislocations is demonstrated, as is the role of surface steps in dislocation nucleation and crack-tip blunting. {copyright} {ital 1997} {ital The American Physical Society}

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 664458
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 7 Vol. 79; ISSN 0031-9007; ISSN PRLTAO
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
BRITTLENESS
CRACK PROPAGATION
DISLOCATIONS
MATERIALS
MOLECULAR DYNAMICS METHOD
NUCLEATION
PLASTICITY
SIMULATION
STRESSES