X-ray topographic observation of dislocation multiplication by cross-slip in Cu crystals

Highly perfect 99-999% copper crystals were studied under increasing tensile stress at room temperature, using the Borrmann transmission X-ray topography technique. Fresh dislocations were produced at a resolved shear stress of 1-5 g/mm2. The nucleation of several half-loops by the same sources gives rise to pile-ups. The local stress resulting from the pile-ups is sufficient to occasion cross-slip, giving rise to multiplication. On the basis of the observations, a model of the multiplication mechanism is proposed.