Effect of Warm Rolling on Microstructure and Mechanical Properties of 6061 Aluminum Alloy Cast-Rolled Sheet

The effect of different warm rolling temperatures and cumulative reductions on microstructure and mechanical properties of 6061 aluminum alloy sheet rolled by twin-roll casting was studied. Multi-scale characterization techniques were employed to study the microstructures of cast-rolled and warm-rolled sheets. The mechanical properties such as hardness, strength and elongation were also measured. The results show that the cast-rolled 6061 alloy mainly contains heat-resistant phase Al0.7Fe3Si0.3, Al9Fe0.84Mn2.16Si, and a small number of strengthening phase Mg2Si. With increasing the rolling passes, the shape of second phases gradually changes from a mesh and a sheet shape to a line shape along the rolling direction, and finally b6comes a fine granular shape. After warm rolling, the amount of new precipitates Al0.5Fe3Si0.5 and Mg2Si increases. Additionally, the hardness linearly increases with increasing the reduction, and the maximum slope (2.421 14) of hardness curves is found at the warm rolling temperature of 370 degrees C. At this temperature, fine AlFeSi precipitates and Mg2Si phases are uniformly dispersed in the alloy, the highest hardness of similar to 842 MPa is obtained for plate, and the tensile strength, yield strength and elongation are 209.34 MPa, 79.09 MPa and 20.11% respectively.