DOI: 10.1002/adem.201000254 Production of Ultrafine Grained AlMnFe Samples by Confined Channel Die Pressing as Compared to Equal Channel Angular Pressing** By Rolf Berghammer * , Weiping Hu, Arman Hasani and Gu ¨nter Gottstein There is a large variety of severe plastic deformation (SPD) techniques. Amongst the most established ones are equal channel angular pressing (ECAP) and high pressure torsion (HPT). Although these processes are widely used there are a few drawbacks. For ECAP high forces are needed and therefore, the die cracks occasionally. In comparison, confined channel die pressing (CCDP) is a fast and easy process to obtain high degrees of deformation. The confined channel die has a simple geometry and therefore, can be manufactured very easily. However, CCDP can merely fabricate homogeneous ultrafine grained (UFG) structures within a relatively small volume from the central area of the sample, since the strain distribution in the sample is inhomogeneous. The purpose of the current investigation was to evaluate the efficiency for producing UFG material by comparing the microstructures and mechanical properties of the samples subjected to CCDP and ECAP processing. Experimental An Al–1.0Mn–0.6Fe alloy was melt processed from Al, Mn, and Fe with a purity of 99.99%. Two different heat treatments were applied in order to obtain material with different initial states. One batch of samples was quenched down from the melt so that most alloying elements were supersaturated in solid solution. The other batch of samples was subsequently cold rolled to generate more nucleation sites for precipitation by increasing the dislocation density and then annealed at 440 8C for 2 h to precipitate (Mn,Fe)Al 6 particles with a size of about 100 nm. The grain size of the as-quenched material was in the range about 1 mm whereas the thermomechanically treated material had a grain size of several hundred micrometres. CCDP was carried out in a confined channel die, as shown in Figure 1. When being pressed the sample can expand in one direction only as the channel width and the breadth of the sample are the same. With the height of the sample and the width of the channel being identical the geometry of the sample after pressing is the same as prior to pressing, so the process can be repeated for many passes. The geometry of the sample was 9  9  12 mm 3 . Between passes the sample was rotated about its transversal and longitudinal direction by 908, so the sample was pressed in turn along its x, y, and z axes which is referred to as Route II. For ECAP (Fig. 2) a sample with a geometry of 10  10  120 mm 3 was inserted into the die which consisted of two channels of the same cross-section which intersect under F ¼ 908. The sample was deformed by shear at the intersection of the channels. As the cross-section of the samples keeps unchanged during pressing they can be reinserted into the die and pressed for several times. Samples in this study were processed by route B C i.e., with a rotation of 908 around the longitudinal axes of the sample between passes. The equivalent strain in the central area of a CCDP sample [Fig. 1(b)] was e  0.77 per pass [1] . In comparison, during ECAP with an inner angle F ¼ 908 and an outer angle C between 08 and 308 e  1 per pass [2] . The samples were deformed to up to 16 passes both by ECAP and CCDP. The microstructure was characterized by optical microscopy and SEM/EBSD. Mechanical properties were determined at room temperature by tensile tests with a strain rate 5  10 4 s 1 . COMMUNICATION [*] R. Berghammer, Dr. W. Hu, Prof. G. Gottstein Institute of Pyhsical Metallurgy and Metal Physics, RWTH Aachen University Kopernikusstrasse 14, 52056 Aachen, (Germany) E-mail: berghammer@imm.rwth-aachen.de Dr. A. Hasani Laboratoire de Physique et Me´canique des Mate´riaux, Universite Paul Verlaine – Metz, Ile du Saulcy, 57045 Metz Cedex 01, (France) [**] The Authors gratefully acknowledge financial support from the Deutsche Forschungsgemeinschaft for the project HU 821/1. Ultrafine grained material was produced by equal channel angular pressing and confined channel die pressing. Microstructure and mechanical properties of the obtained samples were compared. The different effects on microstructure evolution and mechanical properties from both processes are discussed. 232 wileyonlinelibrary.com ß 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ADVANCED ENGINEERING MATERIALS 2011, 13, No. 4