Atomic scale investigation of grain boundary structure role on intergranular deformation in aluminium

I. Adlakha, M. Bhatia, M. Tschopp, Kiran Solanki

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

The role that grain boundary (GB) structure plays on the directional asymmetry of an intergranular crack (i.e. cleavage behaviour is favoured along one direction, while ductile behaviour along the other direction of the interface) was investigated using atomistic simulations for aluminium 〈1 1 0〉 symmetric tilt GBs. Middle-tension (M(T)) and Mode-I crack propagation specimens were used to evaluate the predictive capability of the Rice criterion. The stress–strain response of the GBs for the M(T) specimens highlighted the importance of the GB structure. The observed crack tip behaviour for certain GBs (Σ9 (2 2 1), Σ11 (3 3 2) and Σ33 (4 4 1)) with the M(T) specimen displayed an absence of directional asymmetry which is in disagreement with the Rice criterion. Moreover, in these GBs with the M(T) specimen, the dislocation emission from a GB source at a finite distance ahead of the crack tip was observed rather than from the crack tip, as suggested by the Rice criterion. In an attempt to understand discrepancy between the theoretical predictions and atomistic observations, the effect of boundary conditions (M(T), Mode-I and the edge crack) on the crack tip events was examined and it was concluded that the incipient plastic events observed were strongly influenced by the boundary conditions (i.e. activation of dislocation sources along the GB, in contrast to dislocation nucleation directly from the crack tip). In summary, these findings provide new insights into crack growth behaviour along GB interfaces and provide a physical basis for examining the role of the GB character on incipient event ahead of a crack tip and interface properties, as an input to higher scale models.

Original languageEnglish (US)
JournalPhilosophical Magazine
DOIs
StateAccepted/In press - Sep 27 2014

Fingerprint

crack tips
grain boundaries
aluminum
rice
cracks
asymmetry
edge cracks
boundary conditions
scale models
crack propagation
cleavage
plastics
nucleation
activation
predictions
simulation

Keywords

  • directional anisotropy
  • dislocation
  • fracture
  • grain boundary

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Atomic scale investigation of grain boundary structure role on intergranular deformation in aluminium. / Adlakha, I.; Bhatia, M.; Tschopp, M.; Solanki, Kiran.

In: Philosophical Magazine, 27.09.2014.

Research output: Contribution to journalArticle

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