Computer simulation of motion of screw dislocation in model B.C.C. lattices. I. Effect of inter-atom-row potential on Peierls stress

Motion of screw dislocations in b.c.c. lattices at 0 °K has been computer-simulated by applying shear stress on the {110} plane of a model crystal block, using systematically varied interaction potentials between atom rows parallel to the Burgers vector. For all the potentials used, the core of the dislocation moved in a zigzag way alternately on two {110} planes, and the resultant slip trace was the twinning-{112} plane. The Peierls stress changed sensitively with the change of the inter-atom-row potential, and the dependence of the former on the latter was not consistent with what is predicted from the Peierls-Na-barro model. The Peierls stresses calculated ranged from 0.002 to 0.03μ (μ shear modulus) and covered those estimated for various b.c.c. metals from experiments.