Hongxiang Li, ShengLi Guo, Jianjun Zhang, Peng Du, Shengpu Liu
April 30, 2019
An 6201Al alloy was rolled at room temperature (RT), liquid nitrogen and alcohol mixed temperature (LAT) and liquid nitrogen temperature (LNT). The effect of the rolling temperature on microstructure and mechanical properties was investigated by means of hardness measurements, tensile tests, optical microscopy (OM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Microstructural observations reveal that the dislocation tangles and dislocation density increased with decreasing rolling temperature. The dislocation accumulation was enhanced, and the formation of dislocation tangles and cells occurred during deformation under low rolling temperature. The substructures of the rolled sample at LAT and LNT are similar, consisting of dislocation cells, high dislocation density with networks, dislocation array, dislocation tangles and subgrains. Compared with rolled samples at RT and LAT, the rolled samples at LNT presented strengthened hardness and strength. The improvement of mechanical properties contributes to the fine substructures and accumulation of higher dislocation density during low temperature rolling. In addition, with decreasing rolling temperature, the average dimple size decreased.