Effect of special rotational deformation on dislocation emission from interface collinear crack tip in nanocrystalline bi-materials

Abstract

The work is devoted to investigate the interaction between the special rotational deformation and interface collinear cracks in nanocrystalline bi-materials. As an illustrative example, the effect of the disclination quadrupole produced by the special rotational deformation on the emission of lattice dislocation from a finite interfacial crack tip in nanocrystalline bi-material is explored theoretically using the complex variable method. The complex form expression of dislocation force and the critical stress intensity factors for the first edge dislocation emission under remote mode I loadings and mode II loadings are deduced. And the influences of material properties, grain size, disclination strength, disclination location and orientation, special rotational deformation orientations, and crack length on the critical stress intensity factors are discussed in detail. The results show that the special rotational deformation and the relative shear modulus of the upper the lower half plane have great effect on the lattice dislocation emission from the interface collinear crack tip.

Analytical solution for the stress field of hierarchical defects: multiscale framework and applications

“…[15] and [16]. Much progress has also been made to analytically solve the problem of edge dislocation in front of blunt crack for nanocrystalline materials [17][18][19] . Recent work witnesses that the use of digital image correlation method is combined with analytical analysis for determining the stress field at blunt V-notch neighborhood [20][21] .…”

Deformation of Single Crystals, Polycrystalline Materials, and Thin Films: A Review

“…Until now, many models have been proposed to explain this phenomenon. The high resistance of some nanocrystalline materials to fracture is mostly attributed to special deformation modes, such as lattice dislocation slip [13,14], cross slip [15,16], coble creep [17,18], rotational deformation [19,20], grain boundary slip [21,22], grain boundary migration [23,24], and nanoscale twin deformation [25,26]. These special modes of plastic deformation not only release high stress concentrations but also hinder the nucleation of nanocracks; they can also slow down or organize the expansion of existing cracks.…”