Effect of differential speed rolling strain on microstructure and mechanical properties of nanostructured 5052 Al alloy

The present work reported the influence of differential speed rolling (DSR) strain on microstructure and mechanical properties of the nanostructured 5052 Al alloy. As the amount of DSR strain increased, the deformed microstructure developed from the band-like structure of the elongated grains after one-pass DSR (approximate to 0.4) into the nanostructure of the equiaxed grains whose mean size of approximate to 700 nm after four-pass DSR (approximate to 1.6). This was attributed to the fact that, by a sample rotation of 180 degrees along the longitudinal axis, the macro shear deformation formed by one-pass DSR was intersected with that by two-pass DSR. From the microhardness contour maps of the DSR-deformed samples, the microhardness values and their uniformity were improved with increasing amount of DSR strain. Tensile test results showed that, as the amount of DSR strain increased, the tensile strength increased significantly while sacrificing tensile ductility and strain hardenability. Such mechanical response of the nanostructured 5052 Al alloy was discussed in relation to microstructure evolution during DSR. (C) 2012 Elsevier B. V. All rights reserved.