With the aim of testing further the conclusion (Wilman 1950
a
) that a new deformation process, rotational slip, occurs prominently when crystal surfaces are abraded unidirectionally, an approximately {110} face of a copper crystal was smoothed by electro-polishing, abraded along <11¯0> and examined by electron diffraction after various stages of etching. The immediate surface regions were heavily disorientated, but those slightly below the surface had mostly become rotated by about 35°, though a decreasing proportion was rotated by larger angles up to about 90°, about the cube edge lying in the surface and normal to the abrasion direction. When abrasion was along <001> or <112>, rotation occurred about <11¯0> and <11¯1> respectively. In iron, also, large rotation of parts of the crystal surface occurred when crystals were abraded parallel to either {100}, {110} or {111} planes which were normal or steeply inclined to the surface. The interpretation in terms of rotational slip on {001}, {110} or {111} planes is fully supported by previous metallographic observations of such rotated lamellae formed parallel to these planes in copper (and aluminium ) and iron, and by electron-diffraction evidence of the structure of beaten metal foils. It is pointed out that the deformation caused by the abrasion is analogous to the development of ‘deformation bands’.
Modelling the damage and deformation process in a plastic bonded explosive microstructure under tension using the finite element method
