Papers by Author: J.P. Lee

Abstract: The evolution of annealing textures and microstructures in the aluminum alloy 3103, which was subjected to deformation by either cold rolling or equal channel angular rolling (ECAR), was investigated. Samples of AA 3103 sheets were repeatedly deformed by ECAR up to six passes. In addition, AA 3103 was cold rolled to the same hardness level of the ECARed samples. Upon annealing, the cold rolled sample was recrystallized by the discontinuous recrystallization which gave rise to the formation of the cube texture and large grains bigger than 30 µm. In contrast, the ECARed sample was recrystallized by extended recovery which led to the formation of ultra-fine grains having a size smaller than 3.5 µm.

Abstract: The evolution of texture and microstructure during the equal channel angular rolling (ECAR) and subsequent annealing in aluminum alloy 3003 sheets was investigated. The tools of ECAR were designed to provide a constant shear deformation of the order of 0.5 per passage while preserving the original sheet shape. Samples of the aluminum alloy 3003 sheets were repeatedly deformed by ECAR up to twelve passages. Shear textures developed after the first passage of ECAR. However, the intensity of shear texture components decreased with increasing number of ECAR passages. After a large number of ECAR passages, a random texture developed at the expense of shear texture components. Observations by TEM and EBSD revealed that the degree of misorientations within the deformed grains increased with increasing number of ECAR passages. After recrystallization annealing, samples deformed by ECAR displayed pronounced {111}//ND fiber orientations. The annealed sheets comprising of ultra-fine grains were successfully produced in the samples deformed by a large number of ECAR passages.