Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/28165
Title: A Discrete Dislocation Study of Thin Film Interfacial Fracture
Authors: CHNG CHIA-K'AI, AUDREY
Keywords: Dislocations; Plastic; Mechanical Properties - Fracture; Thin Films; Computer Simulation; Size Effects
Issue Date: 10-Apr-2008
Source: CHNG CHIA-K'AI, AUDREY (2008-04-10). A Discrete Dislocation Study of Thin Film Interfacial Fracture. ScholarBank@NUS Repository.
Abstract: Fracture at the interface of micrometer-thick metal films and an elastic substrate is studied using a two-dimensional discrete dislocation (DD) framework. Quantitative agreement is observed between DD and experimental fracture toughness over a range of film thickness at small (<60MPa) levels of residual stress, this quantitative agreement buttressed by quantitative agreement between DD 0.2%-offset yield strength and continuum-derived yield strengths.The effect of significant (~300MPa) residual stress on fracture toughness is also observed within the DD model, although the magnitude of these effects appears to be larger than that observed experimentally. DD fracture toughness also exhibits the appropriate trends with variation in cohesive strength, intrinsic fracture energy, and mode mixity.Overall, appropriate size effects are shown to emerge naturally within the DD model without any ad-hoc assumptions through the complex interplay of the dislocation plasticity, small-scale boundary conditions, and crack fields that are the key phenomena controlling thin film interfacial fracture.
URI: http://scholarbank.nus.edu.sg/handle/10635/28165
Appears in Collections:Ph.D Theses (Open)

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