The nature of grown-in dislocations and dislocation multiplication sources were studied by means of X-ray topography. A number of grown-in dislocations in monocrystalline plates were found, following long-term cyclic annealing, to penetrate the large surfaces without any nodes. Those dislocations had Burgers vectors with a strong edge component. Segments of grown-in dislocations acted as surface multiplication sources at shear stresses of less than 100kPa. The stress was in good agreement with that which was deduced from the observed length of a single-ended multiplication source. A further increase in stress activated new sources and also the cross-slip of screw dislocations onto neighboring slip planes. The crystal became covered with rows of multiplied dislocations before reaching its macroscopic yield point. A series of topographs which corresponded to an incrementally increasing stress clearly revealed the dislocation multiplication process.

Y.Miura, F.Higuchi, H.Era: Philosophical Magazine A, 1995, 71[6], 1363-73