Evolution of Nanostructure in Al 1050 Sheet Deformed by Cryo-cross-rolling

Cryo-cross-rolling (CCR) is a new process that combines the properties of cross-rolling and cryo-rolling. In this study, an Al 1050 sheet was reduced up to 95% of its thickness by rolling in vertical directions for ten passes at cryogenic temperature. This process creates high dislocation density and a nano-subgrain structure. The transmission electron microscopy (TEM) and x-ray diffraction (XRD) analyses show that the grain size is almost 180 nm and the crystallite size is about 47 nm in CCR sample. Scanning electron microscopy observations of fracture surfaces show that the ductility of Al 1050 decreases under the CCR process. The hardness of the sample increased significantly in this process. The results of TEM and XRD performed on crystallite size were in conformity with each other. The strength of specimens was increased and their ductility was decreased by the application of this process.