In the case of a loaded crack in an homogeneous solid, we know works by Samuels and Roberts (1989) and George and Michot (1993): most of the dislocations are generated on planes cutting the crack front at one point. Also the works of Ohr and Chang (1981, 1982, 1983, 1985) gave some crucial informations on the behaviour of dislocations ahead of the crack-tip, in particular the existence of a dislocation-free zone between the crack and the generated dislocations.

But for the interface crack in a bi-material pair, I do not have a clear idea. Could someone give some informations?

References:

Ohr, S.M. (1985). An electron microscope study of crack tip deformation and its impact on the dislocation theory of fracture. Materials Science and Engineering 72, 1-35.

Samuels, J. and Roberts, S.G. (1989). The brittle-ductile transition in silicon. I. Experiments. Proceedings, Royal Society London A421, 1-23.

George, A. and Michot, G. (1993). Dislocation loops at crack tips: nucleation and growth- an experimental study in silicon. Materials Science and Engineering A164, 118-134.

Patrick, if you would say what is your system: are the Bi-metals are both FCC or BCC, do they form any intermetallics, having a complex system and trying to figure out how it would affect the dislocation front without even telling how the crack is oriented is hopeless task from my point of view.

We welcome any system of  bi-material pair  and applied loading (mixed or not).