Microstructure and texture evolution during annealing of equiatomic CoCrFeMnNi high-entropy alloy P.P. Bhattacharjee a,⇑ , G.D. Sathiaraj a , M. Zaid a , J.R. Gatti a , Chi Lee b , Che-Wei Tsai b , Jien-Wei Yeh b,⇑ a Department of Materials Science and Engineering, Indian Institute of Technology Hyderabad, Ordnance Factory Estate, Yeddumailaram, 502205 AP, India b Department of Materials Science and Engineering, National Tsinghua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 30013, Taiwan article info Article history: Received 23 July 2013 Received in revised form 31 October 2013 Accepted 31 October 2013 Available online 8 November 2013 Keywords: High-entropy alloys Cold rolling Annealing Microstructure Texture abstract Evolution of microstructure and texture after heavy cold rolling and subsequent annealing in a wide tem- perature range was first studied in an FCC equiatomic CoCrFeMnNi high-entropy alloy (HEA). Development of a submicron-cell structure and a strong brass-type texture was observed after 90% cold rolling. An ultra- fine microstructure having average recrystallized grain size 1 lm with profuse annealing twins was observed after annealing at 650 °C. Remarkable resistance against grain coarsening was observed at least up to 800 °C. The mechanisms for these features were closely related with the distinct whole-solute matrix in HEAs. The recrystallization texture was characterized by the retention of deformation texture components similar to those of TWIP and 316 stainless steels. But notable differences exist. The S ({1 2 3}h634i) component is stronger than brass ({1 1 0}h112i) and Goss ({1 1 0}h001i), and strengthened with increasing annealing temperatures. Strong a-fiber (h110i//ND) components other than the deforma- tion components B S and G, and higher fraction of random components also develop. It could be attributed to profuse annealing twin formation due to the low stacking fault energy of the alloy. Ó 2013 Elsevier B.V. All rights reserved. 1. Introduction The conventional alloy design concept is essentially centered on using one principal element to which other alloying elements are added for improving desired properties. Recently, a new alloy de- sign concept has been introduced for developing novel materials which are equiatomic or near equiatomic multicomponent alloys having at least five elements [1]. These materials have been coined as high-entropy alloys (HEAs) due to their high configurational entropies associated with the mixing of a large number of elements at their random states: liquid or regular solid solution state. Although HEAs contain a large number of principal elements, the structure remains simple FCC, BCC or FCC + BCC in many instances [1,2]. HEAs have been successfully prepared by various processing routes including vacuum arc melting and casting [3–5], mechanical alloying [6,7], laser cladding [8], and powder metallurgy [9]. Poten- tial of these alloys in terms of various engineering applications such as wear and corrosion resistant parts [3,4] has already been recognized. Majority of the earlier investigations have focused on the alloy- ing effect, phase transformation and properties in various HEA sys- tems. More recently the deformation and annealing behavior of HEAs have also been studied and it is understood that appropriate thermo-mechanical treatments can enhance the properties of HEAs [10]. But, the evolution of texture during thermo-mechanical processing with heavy deformation and annealing has not been reported so far in HEA systems. In view of future structural applications involving the HEAs, the microstructure and texture evolution during deformation and recrystallization must be under- stood in depth for establishing the correlation between processing parameters and mechanical properties. Moreover, the effect of stacking fault energy (SFE) on microstructure and texture evolu- tion of such HEAs is also an academic issue and is required to be revealed and discussed. For the first time, the present work inves- tigates the microstructure and texture evolution during annealing of a cold-rolled equiatomic CoCrFeMnNi HEA. This alloy is a partic- ularly good candidate for the present study simply because it exhibits simple FCC structure in the whole temperature range of solid state [11,12]. The findings are believed to be applicable to other FCC HEAs. Besides, conventional FCC alloys with low SFE such as brass, stainless steel, and twinning-induced-plasticity (TWIP) steels are also compared to reveal their differences. 2. Experimental work The experimental equiatomic CoCrFeMnNi alloy was vacuum arc-melted from the starting elements with purities higher than 99.9% and cast into a slab of dimen- sions 10 mm  20mm  40mm. A small extra amount of Mn having higher vapori- zation was added to compensate its loss during arc-melting. The final composition was very close to equi-molar ratio. Rectangular samples were cut from the as-cast 0925-8388/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jallcom.2013.10.237 ⇑ Corresponding authors. Tel.: +91 40 2301 6069; fax: +91 40 2301 6032 (P.P. Bhattacharjee), tel.: +886 3 5719558; fax: +886 5 722366 (J.-W. Yeh). E-mail addresses: pinakib@iith.ac.in (P.P. Bhattacharjee), jwyeh@mx.nthu.edu.tw (J.-W. Yeh). Journal of Alloys and Compounds 587 (2014) 544–552 Contents lists available at ScienceDirect Journal of Alloys and Compounds journal homepage: www.elsevier.com/locate/jalcom