(C)-COMPONENT DISLOCATIONS IN ZIRCONIUM ALLOYS

Dislocations with 〈c〉-component Burgers vectors have been found in abundance near deformation twins, and to a lesser extent near grain boundary junctions, in deformed Zircaloy-2 and Zircaloy-4. Both pure 〈c〉 and 〈c + a〉 dislocations have been identified by TEM contrast experiments. The segments of 〈c〉-component dislocations tend to be long, straight, and to lie on either basal or pyramidal planes. It is suggested that these dislocations are generated in order to maintain compatibility between crystallites which differ significantly in their ability to accommodate an imposed deformation by 〈a〉-slip. The manner in which 〈c〉-component dislocations can alter the partitioning of irradiation-produced point defects, and their influence on irradiation growth are discussed. © 1979.