Dislocation enhancement and inhibition induced by films on crack surfaces

Journal Article · Mon Aug 01 04:00:00 EDT 1983 · Acta Metall.; (United States)

DOI:https://doi.org/10.1016/0001-6160(83)90187-6· OSTI ID:6141083

Paskin, A; Dienes, G J; Sieradzki, K; Som, D K

Computer simulations were used to study the propagation of cracks coated with thin solid films in a 2D triangular Lennard-Jones solid. The key parameter investigated was the mismatch in the interatomic distances of the film and the substrate (the eleastic moduli were kept the same). The major result is that ''Large Film Atoms,'' i.e. interatomic distance in the film larger than in the substrate, promote dislocation generation at the film-substrate interface while ''Small Film Atoms'' inhibit dislocation formation and promote brittle fracture in an otherwise ductile material. The critical applied load to cause fracture decreased significantly with increasing film thickness. These results are in qualitative agreement with some currently available experimental data. A model was developed which explains the simulation results in terms of the residual stresses resulting from the ''atomic size'' mismatch of film and substrate. The fact that cracks propagated brittly in the substrate after the film was ruptured is explained in terms of a model for dynamic embrittlement.

• Research Organization: Queens College of CUNY, Flushing, NY
• OSTI ID: 6141083
• Journal Information: Acta Metall.; (United States), Journal Name: Acta Metall.; (United States) Vol. 31:8; ISSN AMETA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ATOM TRANSPORT
BRITTLENESS
COATINGS
COMPUTERIZED SIMULATION
CRACK PROPAGATION
CRACKS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DISLOCATIONS
DYNAMICS
ELEMENTS
EMBRITTLEMENT
FILMS
FRACTURE MECHANICS
INTERFACES
LINE DEFECTS
MECHANICAL PROPERTIES
MECHANICS
METALLURGY
METALS
NEUTRAL-PARTICLE TRANSPORT
PHYSICAL METALLURGY
RADIATION TRANSPORT
RESIDUAL STRESSES
SIMULATION
STRESSES
SUBSTRATES