Papers by Keyword: Equal Channel Angular Extrusion (ECAE)

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Authors: Wei Neng Tang, Hong Yan, Rong Shi Chen, En Hou Han
Abstract: Superplastic deformation (SPD) behaviors of two fine-grained materials produced by ECAE and hot rolling methods have been contrastively studied in this paper. It is found that the optimum superplastic condition in as-ECAEed material was at 350°C and 1.7×10-3s-1 with elongation to failure about 800%; while in as-rolled material, the largest elongation to failure about 1000% was obtained at 480°C and 5.02×10-4s-1. Microstructure observation showed that grain evolution and cavitation behavior were different in these two materials during superplastic deformation. The controlled mechanisms for superplasticity, i.e. grain boundary sliding (GBS), dislocation creep and diffusional creep, at different deformation conditions were discussed in terms of strain rate sensitivity coefficient, stress exponent and activity energy.
Authors: Traian Canta, Dan Frunză, Eniko Szilagyi, Magdalena Lungu
Abstract: The paper presents the experimental results on an aluminum alloy and a silver alloy processed by equal channel angular extrusion in order to refine the grains. Two type of extrusion dies have been used for experimental works: one with fixed walls and the other one with movable walls in order to reduce the friction during extrusion process. The new concept of the die consists in simultaneously pressing of two samples in one entering channel with two opposite exit channels. The channel geometry, friction contact, strain rate, extrusion load and micro structure aspects are presented.
Authors: Satyam Suwas, André Eberhardt, László S. Tóth, Jean-Jacques Fundenberger, Thierry Grosdidier
Abstract: The amount of stored energy of cold work for the processing routes A and Bc of Equal Channel Angular Extrusion (ECAE) process has been measured using differential scanning calorimetry. The study is preceded by the effect of amount of ECAE deformation on materials of different stacking fault energies, namely Cu and Ag. The results indicate that the different processing routes have significant effect on the stored energy, which is likely to affect the grain refinement process.
Authors: K. Short, Richard Wuhrer, G. Collins, Wing Yiu Yeung
Authors: Rustam Kaibyshev, Taku Sakai, Ilya Nikulin, F. Musin
Authors: Majid Vaseghi, Ali Karimi Taheri, Ji Hoon Yoo, Soo Hyun Joo, Hyoung Seop Kim
Abstract: Equal channel angular pressing is an outstanding method for imposing large plastic deformation to metallic materials without any decreasing in cross section area of as processed samples. In this paper, the effect of working temperature, ram speed and the number of passes on the formation of adiabatic shear bands in Al6061 during equal channel angular pressing was investigated. Billets of the alloy were processed up to four passes via route BC from room temperature to 200oC with two ram speeds using a die that imparts an effective strain of ~1.1 per pass. The results have demonstrated that the onset of the adiabatic shear banding in this alloy strongly depends on the ram speed: more frequently observed at the higher ram speed than the lower speed. Although the geometry of the macroscopic view of shear band is similar in all cases, the development of bands depends on the number of passes as well as processing temperature.
Authors: R. Lupoi, F.H. Osman (1)
Abstract: The Channel Angular Extrusion (CAE) technique is a process, in which a deformable solid material is led to yielding through the intersection of inclined channels. Compared to classic plastic deformation, the process is technically simple but the material experiences, instantly, large plastic deformation. The deformation occurs locally and high internal stresses develop during the process. In most cases the process is used for grain size refinement. Equal Channel Angular Extrusion (ECAE) is a special case where the intersecting channels are of equal cross sections. In this paper, an analytical study of the internal stresses and those developed along CAE tools is presented. A deformation model is introduced for the general process of channel extrusion in which the intersecting channels are not necessarily equal. The procedure splits the material at the intersection of the channels into two zones; one causes the deformation while the other remains rigid. The analysis is also applied to the particular case of ECAE, and the results are compared with those obtained from a finite element analysis and the overall experimental pressure.
Authors: Gang Wang, Shi Ding Wu, Yan Dong Wang, Ya Ping Zong, Claude Esling, Liang Zuo
Abstract: Equal channel angular extrusion (ECAE) is an effective means of producing ultrafine-grained materials with extraordinary mechanical properties. Texture evolution and microstructure in pure copper single crystals processed by ECAE for up to five passes via route C are investigated to understand mechanisms of plastic deformation and grain refinement during ECAE. The experimental textures after the third pass ECAE process recovers that after one pass ECAE process. The main textures approaches a stable one after four passes of ECAE process via Route C while the intensity of main texture components decreases gradually. Local TEM-OIM measurements shows that grain subdivision in ECAE-processed samples occurs with the formation of many low angle grain boundaries.
Authors: Ben Aour, Fahmi Zaïri, M. Naït-Abdelaziz, J.M. Gloaguen, J.M. Lefebvre
Abstract: Plastic deformation of polypropylene (PP) resulting from equal channel angular extrusion (ECAE) process was investigated in a 135° die. A phenomenological elastic-viscoplastic constitutive model was identified and coupled with the three-dimensional finite element (FE) method in order to predict the different processing parameters governing the deformation behaviour of PP during the extrusion. An optimal agreement between FE results and experimental data was obtained for a friction coefficient of 0.2. A detailed three-dimensional FE analysis of stress-strain field distribution was then carried out. The effects of both the number of extrusion passes and the processing routes were experimentally highlighted. The results show that the pressing force decreases with the increase of the number of extrusion passes and reaches its saturation state rapidly for routes A and C while, for routes BA and BC, it requires a high number of passes.
Authors: Satyam Suwas, Dong Ik Kim
Abstract: The paper deals with the evolution of recrystallization texture during annealing of Equal Channel Angular Extrusion (ECAE) processed copper with different deformation texture that may evolve as a result of different routes of ECAE. The deformation and recrystallization texture components have been separated and corresponding texture analysis has been carried out. An attempt has been made to understand the origin of recrystallization texture.
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