Texture evolution during room temperature ageing of silver processed by equal-channel angular pressing Sandip Ghosh Chowdhury, a,⇑ Jen} o Gubicza, b B. Mahato, a Nguyen Q. Chinh, b Zolta ´n Heged} us b and Terence G. Langdon c,d a Materials Science and Technology Division, CSIR National Metallurgical Laboratory, Jamshedpur 831007, India b Department of Material Physics, Eo ¨ tvo ¨ s Lora ´ nd University, Pa ´ zma ´ny Pe ´ter s. 1/A, H-1117 Budapest, Hungary c Departments of Aerospace and Mechanical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1453, USA d Materials Research Group, School of Engineering Sciences, University of Southampton, Southampton SO17 1BJ, UK Received 16 January 2011; revised 30 January 2011; accepted 7 February 2011 Available online 26 February 2011 The evolution of texture was investigated using silver samples processed by equal-channel angular pressing for different numbers of passes and stored at room temperature for up to 4 months. For 1 and 4 passes, only a slight texture intensity change was detected during storage. For 8 and 16 passes, there was a weakening of components A  2h and C h and the development of a strong A  1h com- ponent due to significant recrystallization in the severely deformed samples. Ó 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Keywords: Silver; Texture; ECAP; Recrystallization Grain growth and partial recrystallization have been reported for commercial purity Cu samples pro- cessed by equal-channel angular pressing (ECAP) and subsequently stored for long periods at room tempera- ture [1–5]. By comparison, there are only limited reports for materials having low stacking fault energies (SFEs). Specifically, considerable grain growth and changes in crystallographic texture were observed during room temperature storage of electrodeposited Ag [6] and there is also a report that Ag self-anneals several months after processing by ECAP [7]. It was shown that both recrystallization and recovery take place in Ag during self-annealing [7]. However, texture evolution will occur only in the presence of recrys- tallization where there is significant grain boundary movement. Accordingly, the present work was initiated to investigate the evolution of texture as a function of storage time when pure Ag is processed to very high strains up to a maximum of 16 ECAP passes. It is anticipated that a study of texture evolution may contrib- ute to an understanding of the processes occurring in self- annealing. High purity 99.995% Ag billets having lengths of 70 mm and diameters of 10 mm were annealed for 60 min at 741 K to give a grain size of 10 micron; the billets were subsequently processed through 1, 4, 8 and 16 passes of ECAP at room temperature following route B c . The ECAP die had an internal channel angle of U = 90 o and an outer arc of curvature of 20° at the intersection of the two parts of the channel. Full details on the ECAP processing were reported previously [7]. After ECAP, the samples were stored in air for 4 months at room temperature in order to study the stability of the texture. The texture analysis used Co Ka radiation and it was performed in the normal direction (ND) of the ECAP-processed billets corresponding to the Y plane using the standard notation for ECAP [8]. The texture was measured over an area of 10  10 mm 2 at the centre of the sample along a longitudinal section prepared by mechanical polishing, grinding and chemical etching. Four incomplete pole figures, {1 1 1}, {2 0 0}, {2 2 0} and {3 1 1}, were measured up to a reflection angle of 80 o . A weak {1 0 0} texture was present prior to ECAP. The evolution of texture was characterised through the orientation distribution function (ODF). The ODFs were calculated assuming triclinic sample symmetry due to the apparent monoclinic symmetry of the measured texture around the Z-axis in the TD direction as defined 1359-6462/$ - see front matter Ó 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.scriptamat.2011.02.005 ⇑ Corresponding author. Tel.: +91 657 2345007; fax: +91 657 2345213; e-mail addresses: sandipgc@gmail.com; sgc@nmlindia.org Available online at www.sciencedirect.com Scripta Materialia 64 (2011) 1007–1010 www.elsevier.com/locate/scriptamat