Dynamical Behavior of Dislocations in the Primary Slip Systems of Body-Centered Cubic Crystals

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Abstract
The general analysis of uniformly moving dislocations in anisotropic media is applied to investigate the dynamical behavior of dislocations in the primary slip systems of body-centered cubic crystals. Both edge and screw dislocations on the {110}, {112}, and {123} slip planes are considered; in each case, the Burgers vector of the dislocation lies along a 〈111〉 direction. Numerical solutions are obtained for the force exerted by a uniformly moving dislocation on a parallel dislocation of similar type on the same slip plane. The bcc elements treated are niobium, molybdenum, vanadium, tungsten, tantalum, iron, potassium, sodium, and lithium. Calculated values of the limiting velocities both of edge and screw dislocations are presented, as well as the threshold velocities for the interaction of two edge or two screw dislocations. These calculations determine, for each slip system in each of the elements listed, the extent of the velocity range of anomalous behavior in which two like dislocations attract rather than repel each other.