Preparation of bulk nanolaminated aluminum alloy with high strength

Bulk nanolaminated (NL) structures were obtained in a low alloying commercial aluminum alloy 5052, via a two-step process: grain refinement firstly by equal-channel angular pressing (ECAP) and secondly by liquid nitrogen rolling (LNR). The microstructure and the properties including hardness, tensile properties and thermal stability were characterized. The results show that the average lamellar spacing of the NL structure is similar to 49 nm with high dislocation density (similar to 6.4 x 10(14) m (-2)) and high strength (sigma(0.2) approximate to 515 MPa). Decrease of lattice parameter of the 1 , ECAP 8P + LNR sample, calculated from XRD data, unveils strong segregation of Mg to the lamellar boundaries. Close analysis indicates, although solid solution strengthening, grain boundary strengthening and dislocation strengthening accounts most of the high strength, strengthening related to salute segregation to lamellir boundaries during deformation process may also play an important role for this high strength.