Abstract
The conditions for dislocation emission from a crack tip, as well as crack propagation under mode I, are analyzed for bcc iron both with the Rice model based on the Peierls-Nabarro framework and a molecular dynamic technique including virial stresses. The atomistic results with a pair potential agree satisfactorily with the continuum prediction on load conditions for dislocation emission. Crack extension in atomistic simulations is observed when normal virial stress at the crack tip exceeds cohesive strength of the potential.

Key words
crack tip, molecular dynamics, iron, Rice model, Peierls-Nabarro framework, molecular dynamic technique, virial stresses, dislocation emission

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