Dislocation Networks in Crystals

application/pdfThe conditions to make dislocation networks exist with sufficient life time were examined. It was found that the hexagonal plane network formed parallel to {113} planes was relatively more stable than others, for instance {111} type in a face-centred cubic crystal. This prediction came only from a local maintenance of mechanical balance at a node. The space arrangements of those networks have certain intimate connection with their persistence in crystals. A reasonable estimation of the density of dislocations in annealed crystal from the present picture gave 2×10^6 cm/cm^3, which was fairly smaller than usually accepted values. The motion of dislocation network of {113} type under externally applied small stress was studied, which gave an alternative explanation for the micro-creep. The order of magnitude of the micro-creep rate could be satisfactorily accounted for. A number of jogs formed along dislocation lines during the motion of networks account for the increase of critical shear stress of crystals after micro-creep. The orientation dependence of such a micro-creep hardening predicted theoretically showed a fair agreement with experiments.紀要類(bulletin)1600328 bytesdepartmental bulletin pape