Saturated dislocation structures of cyclic deformation Ni[110] single crystals

The cyclic deformation of Ni[110] single crystals has been investigated in tension-compression under total strain control. The slip systems found by slip trace analysis are (101)[111¯], (112)[111¯] and (213)[111¯]. Transmission electron microscopy (TEM) observations showed that at the saturation stage of cyclic deformation the characteristic features of the dislocation structure are dislocation tangles and bands located in definite orientations parallel to the intersections of the slip planes and the projective planes. It is suggested that the formation of dislocation bands is due to highly concentrated dislocations on the planes which constitute the coarse slip bands, producing high elastic strain fields in these planes. Under diffraction conditions these highly strained planes appear as thick and dark bands in TEM images.