Dislocation arrangements and deformation bands were studied in a single crystal which had been fatigued at a strain amplitude of 0.008. The results showed that primary slip-bands formed after 2 x 104 cycles, and were associated with a relatively homogeneous small plastic strain. Secondary slip-bands did not operate during cyclic deformation. Deformation bands with a width of 50μm were homogeneously distributed over the whole surface of the crystal and were perpendicular to the primary slip-bands. Dislocation patterns within the primary slip-bands often consisted of irregular structures which did not exhibit persistent features. The results indicated that the primary slip-bands were not typical persistent slip bands. The microstructures within the deformation bands could be classified into 2 types. One type consisted of regular 100% ladder-like parallel persistent slip bands. The other type was full of dislocation walls that were parallel to the deformation-band direction, and had not previously been reported. Crystallographic analysis of the deformation bands showed that the habit-plane of the latter bands should correspond to (¯101). On the basis of these observations, it was suggested that the formation of deformation bands could be attributed to a local regularization of dislocation walls within primary slip bands.

Dislocation Arrangements and Crystallographic Characterization of Deformation Band in Fatigued Copper Single Crystal. Z.F.Zhang, Z.G.Wang, S.X.Li: Philosophical Magazine Letters, 2000, 80[8], 525-33