Fracture of bicrystal metal/ceramic interfaces: A study via the mechanism-based strain gradient crystal plasticity theory

A. Siddiq, S. Schmauder, Y. Huang

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

Two continuum mechanical models of crystal plasticity theory namely, conventional crystal plasticity theory and mechanism-based crystal plasticity theory, are used to perform a comparative study of stresses that are reached at and ahead of the crack tip of a bicrystal niobium/alumina specimen. Finite element analyses are done for a stationary crack tip and growing cracks using a cohesive modelling approach. Using mechanism-based strain gradient crystal plasticity theory the stresses reached ahead of the crack tip are found to be two times larger than the stresses obtained from conventional crystal plasticity theory. Results also show that strain gradient effects strongly depend on the intrinsic material length to the size of plastic zone ratio (l/R0). It is found that the larger the (l/R0) ratio, the higher the stresses reached using mechanism-based strain gradient crystal plasticity theory. An insight into the role of cohesive strength and work of adhesion in macroscopic fracture is also presented which can be used by experimentalists to design better bimaterials by varying cohesive strength and work of adhesion.

Original languageEnglish
Pages (from-to)665-689
Number of pages25
JournalInternational Journal of Plasticity
Volume23
Issue number4
Early online date21 Nov 2006
DOIs
Publication statusPublished - 1 Apr 2007

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Keywords

  • Cohesive model
  • Macro/micro fracture analysis
  • Mechanism-based strain gradient crystal plasticity
  • Metal/ceramic interface

ASJC Scopus subject areas

  • Mechanical Engineering

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