The motion and dynamic interaction of dislocations in lithium and sodium

Abstract

In-situ transmission electron microscopy observations have been made of the motion and interaction of dislocations in lithium. Under a thermally induced stress, dislocation segments observed at room temperature are often seen to bow out in a manner consistent with the shapes of dislocations predicted by anisotropic elasticity calculations of the dislocation line tension. Both attractive and repulsive dislocation interactions have been observed, lending further support to the importance of forest dislocation intersection as the rate controlling mechanism to dislocation motion above one fifth of the absolute melting temperature of the alkali metals. The formation of a Saada-type attractive dislocation reaction has been dynamically recorded in lithium. Attractive reactions have also been observed in sodium.