Effect of large deformations on the microstructure of aluminium alloys

AlMg5 and AlCu4Zr alloys have been deformed in the range of true deformations ϕ=0.4–13.9 using the cyclic extrusion compression (CEC) method. In the entire range of the examined deformations a strong tendency to form microbands in the dislocation structure of the alloys has been observed. In the area of the microbands a strong misorientation of 60° occurred. Characteristic changes appearing as a result of the intersection of the microbands, leading to the formation of subgrain microstructure, have been observed. Similarly as in the microbands, large misorientation angles between the newly formed subgrains occurred. The nanometric dimensions of the newly formed subgrains and large misorientations angles in the alloys, plastically deformed above the conventional deformation range, indicated the tendency to form a microstructure typical for metallic nanomaterials.