Annealing response of 3000 and 5000 series aluminum alloys
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I.
INTRODUCTION
THE thermomechanical
response of the Mg- and Mncontaining aluminum alloys is strongly dependent upon their hot-rolling history, tl-4] Small as-rolled subgrain size and pronounced deformation textures prior to the anneal are essential for the 45 to 0/90 deg earing shift during annealing. Low hot-rolling temperatures, high strain rates, large strains, and multipass rolling sequences are conditions appropriate for developing the preannealed substructure and texture conditions responsible for the 0/90 deg earing shift. A large (2 /~m or more) subgrain size, a significant spread in the deformation texture, and considerable randomness in textures in the hot-rolled strip transform upon annealing to either random or retained deformation textures and, hence, to residual 45 deg earing. A prior smaller (1/~m or less) subgrain size transforms not only to a larger proportion of cube textures but also to a finer recrystallized grain size. t21 This effect is enhanced by a high heating rate to the anneal temperature and is less pronounced in the presence of a large proportion of Mncontaining particles. Kitao e t al. iS} have examined the thermomechanical processing of 3004 alloy ingot after homogenization. The annealing response of the hot-rolled strip in generating cube textures and 0/90 deg earing increases with the total hot-rolling reduction prior to annealing. A small coldrolling reduction (about 15 pet) following hot rolling, but prior to the anneal, enhances the cube textures and the shift to 0/90 deg ears. However, further overlap of the cold-rolling textures on those produced by hot rolling gradually destroys the ability to develop the annealingH.D. MERCHANT, formerly with Continental Can Company, Norwalk, CT, is with Gould Electronics, Eastlake, OH 44095. J.G. MORRIS, Director of Light Metals Research Laboratories and Professor with the Department of Materials Science and Engineering, College of Engineering, is with the University of Kentucky, Lexington, KY 40506. Manuscript submitted April 21, 1989. METALLURGICALTRANSACTIONSA
induced 0/90 deg earing shift. There is an ingot homogenization temperature window (around 550 ~ within which the 0/90 deg shift is maximized. Superimposition of cold rolling over the hot-rolled structure may reduce or eliminate the annealing-induced 0/90 deg earing shift, as has been shown for the homogenized 3004 alloy, [5,61 or may show a variable response depending upon the hot-rolling exit temperature, as for the unhomogenized 5052 a l l o y . [6"7] Analyzing the textures into the cube (and near-cube) and the retained deformation components, the postanneal retained textures generally increase with the preanneal cold reduction. The cube textures, however, display a more complex response to annealing by either increasing (for 5052) or decreasing (for 3004) with the prior cold reduction. II.
OBJECTIVE,
MATERIALS AND PROCEDURE
The intent of this study is to examine the annealing response of Mn-free and Mn-bearing aluminum alloys. The states of alloys utilized are in industri
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