Effect of deformation temperature on mechanical properties of ultrafine grained Al–Mg alloys processed by rolling

Aluminum–Magnesium (Al 5083) alloy was subjected to cryorolling (CR) and cryorolling followed by warm rolling (WR) in order to investigate the changes in mechanical behavior and microstructure evolution in the present work. Al alloy specimens were first cryorolled up to 50% thickness reduction followed with warm rolling at 100 °C, 145 °C, 175 °C and 200 °C till to achieve total 90% thickness reduction. The final microstructure of all conditions were analyzed and compared through transmission electron microscopy (TEM), Electron back scattered diffraction (EBSD), and X-ray diffraction (XRD) techniques to investigate the effect of WR deformation temperatures on mechanical properties. The mechanical behavior of the processed samples were evaluated through hardness and tensile tests performed at room temperature. An increase in yield strength (522 MPa), ultimate tensile strength (539 MPa) and ductility (6.8%) was observed in WR specimens at 175 °C, hardness also increases to (146 HV) as compared to CR samples. These samples were annealed in temperature range from 150 °C to 300 °C to investigate their thermal stability. The CR samples exhibited severely deformed structure with high dislocation density network while cryorolled followed by warm rolled (WR) samples has shown formation of ultrafine grains associated with dynamic recovery. At elevated temperature of 200 °C, WR samples showed decrease in strength accompanied with increase in elongation due to dominant dynamic recovery effect led to reduction in dislocation density.