DISLOCATION BEHAVIOR IN ALKALINE EARTH FLUORIDES.
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MASS
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A brief review of the basic approaches in the area of dislocation dynamics and a review of some of the past work in this field is presented. Studies of the mobilities of both edge and screw dislocations in CaF2 and BaF2 are discussed. It is shown that in pure CaF2 and BaF2 the mobility of screw dislocations apparently depends on the concentration of non-symmetrical impurities ie Nd3. The observed behavior of edge dislocations in CaF2 as a function of impurity level is rationalized on the basis of a change from an intrinsic to extrinsic drag mechanism. Evidence for this change is presented. Etch trails associated with mobile screw dislocations in the alkaline earth fluorides are discussed. Author