Tensile properties of cross cryo-rolled and room temperature rolled 6063 Al alloy

In the present work, 6063 Al alloy was subjected to cross cryo-rolling (XCR) at liquid nitrogen and room temperature for producing the ultrafine grained Al alloy. The XCR and cross room temperature rolling (XRTR) were performed by doing a reduction of 90%. The mechanical properties were investigated by measuring the hardness and tensile properties of investigated alloys. The increases in the average ultimate tensile strength (332 MPa), yield strength (300 MPa), and ductility (11.66%) of the XCR sample were observed as compared to the XRTR sample. The increase in the strength of the XCR sample was due to the extensive dislocation strengthening as compared to the XRTR sample. The increase in the ductility of the XCR sample was due to the softening mechanism dominated during the rolling. The microstructural properties were reported with the help of transmission electron microscopy (TEM), scanning electron microscopy and X-ray diffraction analysis and correlated with the mechanical properties. The TEM investigation revealed that XCR promotes the formation of heavily deformed sub-grains, dislocation tangles, and fragmented initial grains. The presence of dislocations inside the XRTR sample was low as compared to the XCR sample. It was observed that cross rolling at liquid nitrogen temperature further helped in the accumulation of a large number of dislocations and further improved the strength of 6063 Al alloy by suppressing the dislocations annihilations.