Evolution of Texture and Microstructure in AA 3004 Sheets during Continuous Confined Strip Shearing Deformation and Subsequent Annealing

摘要

A new deformation process termed "continuous confined strip shearing" (CCSS) has been developed for shear deformation of metallic sheets. The tools of CCSS were designed to provide a constant shear deformation of the order of 0.5 per pass while preserving the original sheet shape. In order to clarify the evolution of texture and microstructure during CCSS, strips of the aluminum alloy AA3004 were deformed by CCSS in up to three passes. FEM results indicated that CCSS provides a quite uniform shear deformation at thickness layers close to the strip center, although the deformation is not homogeneous in the die channel, in particular at the surface layers. The rolling texture of the initial sheet decreased during CCSS, and preferred orientations along two fibers developed. However, with an increasing number of CCSS passes the deformation texture did not develop further. The evolution of annealing textures depended on the number of CCSS passes. A strong {112}<110> component in the deformation texture led to the formation of a strong {111}<112> orientation in the annealing texture. Observations by TEM and EBSD revealed the formation of very fine grains of ～1.0 μm after CCSS.