Effect of initial texture on texture evolution in 1050 Al alloys under simple shear
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6/28/03
6:50 PM
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Effect of Initial Texture on Texture Evolution in 1050 Al Alloys under Simple Shear JUN-HYUN HAN, KYU HWAN OH, and JAE-CHUL LEE The effect of the initial textures prior to dissimilar channel angular pressing (DCAP) on the texture evolution of the 1050 Al alloy sheets, processed by the continuous confined strip shearing (C2S2) process, were studied. The four different specimens, i.e., cold rolled, heat treated, warm rolled, and as-cast 1050 Al alloy sheets, having various initial textures were prepared using different thermomechanical routes. Although the major texture types were significantly affected by the initial textures prior to DCAP, DCAP always promoted both the 111//normal direction (ND) textures and the {001}110 rotated cube texture regardless of the initial texture status. Effects of the texture evolutions due to equal channel angular pressing (ECAP) on deep drawbility and planar anisotropy were analyzed based on the r¯ value and the r value determined from the measured pole figures. A feasibility for producing the 1050 Al alloy sheets having high deep drawbility and low planar anisotropy was demonstrated.
I. INTRODUCTION
EQUAL channel angular pressing (ECAP) is a process by which a large amount of shear strains can be imparted to the workpiece without any change in the cross-sectional area.[1,2,3] Very large strains can also be imposed to the workpiece through the multipass operation.[4] Therefore, this technique has been used as a means for producing materials having an ultrafine-grained structure.[5,6] In addition, considering simple shear is a dominant deformation mode in ECAP,[1] ECAP can be used as a technique for controlling textures of metallic materials. However, ECAP dealt in the earlier studies is neither continuous nor can it handle a long and thin strip. Such a feature of the conventional ECAP limits wider applications of this process for sheet production, although the process has a potential for enhancing formability of the metallic sheets with the fcc structure, in particular. Recently, Lee et al.[7] introduced a so-called continuous confined strip shearing (C2S2) process based on ECAP. The developed process not only enables shear-deforming metallic sheets in a continuous mode but also has a potential for producing Al alloy sheets with enhanced deep drawbility and reduced planar anisotropy. The newly developed process was termed dissimilar channel angular pressing (DCAP) to distinguish this technique from the conventional ECAP, and detailed explanations regarding the process are described elsewhere.[7] Saito and co-workers[8,9,10] have also proposed a shear deformation method called as the conshearing process having a concept similar to the present technique.
To date, several studies on the texture evolution in the Al alloys due to ECAP have been conducted. However, materials used in these studies are limited to those with the typical deformation or recrystallization textures. Cui and Ohori[11] observed that ECAP promoted the development of the {001}110
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