Control of texture and earing in aluminium alloy AA 8011A-H14 closure stock

摘要

The development of crystallographic texture during the thermo-mechanical processing of aluminium sheet results in the formation of pronounced plastic anisotropy, including the well-known earing phenomenon. In the present study we track the evolution of texture, microstructure and the resulting earing profiles in Al alloy AA 8011A during down-stream processing to final-gauge sheet in temper H14. This processing, which includes two interannealings, followed by a mild final temper rolling pass, was designed for providing minimum earing for earing-critical packaging applications. Besides the experimental characterization of microstructure, texture and earing along the standard process chain, means to optimize the earing behaviour are addressed. This includes changes in the homogenization practice, possible omission of one of the two interannealings and variation of the interannealing gauge. The resulting earing properties are discussed in the light of the interplay of deformation and recrystallization with the resultant texture changes along the process chain.