Formation of a submicrocrystalline structure upon dynamic deformation of aluminum alloys

Light and electron microscopy and X-ray diffraction were used to study the microstructure and phase composition of the bulk samples of the multicomponent Al-based alloys (Al-3003 and Al-5556) produced by the method of dynamic channel angular pressing (DCAP). The relation between the geometry of channels, pressure in the sample, high rate mode of loading, and specific features of the microstructure arising in metal under investigation are stated. It was established that even after one DCAP pass, material hardening occurred and the grain size radically decreased to less than 0.5 μm. The microhardness increased from the initial value by a factor of 1.5–2. It was discovered that the structure becomes fragmented and consists of grains with a developed substructure and displays a high density of dislocations after one pass. With increasing number of passes, the fraction of the grains separated by high-angle grain boundaries increases and the density of dislocations decreases.