Mouvements des boucles de discloations glissiles précédant la formation des lignes de glissement, dans les `rubans' de cuivre

An elastic deformation wave initiates loops on edges and steps of a crystallographically perfect ribbon (copper whisker). Multiple loops move and intersect on two glide-plane families normal to the plane of the whisker and the tensions produced in this way probably move loops on two other plane families parallel to the axis of the ribbon. It is assumed that these loops meet Lomer-Cottrell dislocations, which were originally formed, normal to the ribbon surface, and Frank-Read sources are created. To increase the contrast of the Lang method topograms, the plate is kept dark in vacuum during the exposure.