Analysis of Crystallographic Textures in Aluminum Plates Processed by Equal Channel Angular Extrusion
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annel angular extrusion (ECAE) has been shown to be an efficient technique for producing submicrocrystalline and nanostructured materials.[1] While the effect of processing route on the microstructure and texture development in ECAE-deformed rods and bars has been investigated in a large number of publications,[2–6] only a few studies have been carried out for establishing this effect for ECAE-processed plates, for which new routes, different from those proposed for rod or bar samples, can be utilized.[7–11] In a recent work on AA1050 plates deformed by 8 ECAE passes either without rotation between passes (route A) or with 90 deg sequential rotations about the plate normal ND (route BChNDi),[11] it was found that the microstructure obtained via route BChNDi was more refined than that obtained via route A. The extent of refinement in these plates was nevertheless less significant than that in a rod sample extruded with 90 deg inter-pass rotations about the extrusion direction, ED (route BChEDi).[11] The effect of the processing route on texture evolution in ECAE plates was investigated by Ferrasse et al.[9,10] However, these authors considered a large number of orientation fibers differing from the shear-type fibers commonly adopted for characterizing
SAIYI LI, Professor, is with the Key Laboratory of Nonferrous Metal Materials Science and Engineering of the Ministry of Education, School of Materials Science and Engineering, Central South University, Changsha 410083, P.R. China. Contact [email protected] OLEG V. MISHIN, Senior Scientist, is with the Danish-Chinese Center for Nanometals, Section for Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark. Manuscript submitted October 29, 2013. METALLURGICAL AND MATERIALS TRANSACTIONS A
ECAE textures,[2–6] which complicates a comparison of textures in their plate samples with those in rod samples described in many other publications. To better compare the general tendencies of texture evolution during ECAE of plates with those of rod samples, a modeling and experimental investigation of textures formed by ECAE has, therefore, been carried out and is described in the present work for commercial purity aluminum. A recrystallized AA1050 plate with an average grain size of ~50 lm and a pronounced cube texture was used as a starting material. Samples with dimensions of 15 9 75 9 75 mm3 were subjected to 8 ECAE passes either via route A or route BChNDi, at room temperature, using a 90 deg die with a sharp outer corner and a sliding floor, and using an anti-seize lubricant.[11] Since during ECAE the rectangular cuboid shape of the initial sample was distorted by shear, the leading end of the route BChNDi sample had to be trimmed after the first pass in order to reinsert the 90 deg-rotated sample into the die. For the subsequent passes via route BChNDi, the end was only slightly ground between passes. To enable a direct comparison with these plate samples, a rod sample with a dimension of 15 9 15 9 75 m
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