论文信息 - The influence of the interatomic force law and of kinks on the propagation of brittle cracks

The influence of the interatomic force law and of kinks on the propagation of brittle cracks

Abstract Cracks in brittle crystals can be lattice-trapped, as dislocations are by the Peierls barrier. Previous estimates of the range of loads within which a crack will not propagate more than one atomic spacing have varied greatly. The author's earlier computer model is extended to examine the effects of varying the shape of the interatomic force law and of the introduction of kinks in the crack edge. The system studied is a (111) cleavage crack in silicon, with edge either parallel to [OT1], or at a small angle to this direction, so that a series of kinks forms. The boundary conditions, being derived from a general continuum theory solution containing variable terms dependent on the core conditions, are ‘flexible’, allowing free motion of the crack inside the crystallite. The numerical relaxation method allows energy minima or saddle points to be located, thus making possible the calculation of migration activation energies. Several non-central interatomic force laws are employed, all matched to the e...

J. E. Sinclair

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