Precipitation of Helium along Dislocations in Aluminum

Abstract

Helium was generated in an Al‐0.1 at. % Li alloy by transmutation of the Li⁶ atoms during neutron irradiation. During subsequent heating of the specimens, the helium appeared to precipitate in the form of small ``bubbles.'' On using a dislocation etchant it was found that (a) the regions of largest dislocation density also contained the highest cavity density, (b) in some regions each dislocation etch pit was associated with a cavity, and (c) in other regions a series of cavities appeared to delineate the track of a dislocation. It is believed that the helium precipitates along the dislocations in the form of continuous or semicontinuous cylindrical cavities.