Materials Science Forum Vols.503-504(2006)pp.335-339 online at http://www.scientific.net C(2006)Trans Tech Publications,Switzerland Application of Twist Extrusion Viktor Varyukhin Yan Beygelzimer,Sergey Synkov and Dmitry Orlove Donetsk Physics Technology Institute of the NAS of Ukraine,72 R.Luxembourg St.,Donetsk, 83114,Ukraine. var@hpress.dipt.donetsk.ua,tean@an.dn.ua,orlov@donec.net Keywords:Twist Extrusion,powder,nanostructured materials,fragmentation,consolidation. Abstract.Twist Extrusion (TE)is a process of severe plastic deformation(SPD)being developed by us during recent 5 years.Upon this time we published few papers on mechanics of the process and influence of the TE processing on materials structure and properties.Here we reported some results on application of the twist extrusion processing and made few general conclusions. Peculiarities of Twist Extrusion Mode of TE functioning is obvious from the Fig.1. Fig.1.Scheme explains basic principle of twist extrusion processing In [1,2]it was shown that in first approximation each physical cross-section of a billet is deformed at the same way as thin disk under high pressure torsion(HPT)processing.At that,at the beginning it is realized torsion at some angle in one direction,and then re-torsion at the same angle in the opposite direction.I.e.the deformation is cyclic with amplitude of quasi-monotone part equals to a half of the full strain.For dies we use usually,the accumulated strain per pass is about 1.2 [2].Follow the billet's form does not changes during the treatment,it is possible to deform it over and over again in order to accumulate strain like this is done under ECAP processing. It is followed from the previous paragraph that TE is three-dimensional option of the HPT,in some terms.On the other hand,per se TE is equal channel extrusion,i.e.similar to ECAP.It is arisen the following question:what new this process can give and why one needs to concern oneself with it?From our point of view TE has a number of peculiarities in both stress-strain state and technological implementation which do this process attractive for both investigation and application. From the viewpoint of the stress-strain state of the specimen,there are four important properties: First,the simple shear plane in TE is perpendicular to the axis of the specimen,instead of being at 45-60 degrees as in ECAP.This allows us to obtain new structures and textures.Moreover, deformation by ECAP and TE in various combinations and regimes increases the number of possible deformation paths:besides paths achievable by ECAP only,one can obtain different combinations with paths achievable by TE (deformations in the same die and pipelined deformations through a die with oppositely twisted channels). Second,TE has the property that the deformation gradient is quite steep in the cross-section area, which makes TE similar to HPT.Note that this is not true for ECAP.There are still very few results about the effects of the deformation gradient on the structure and properties of materials,but there is enough evidence pointing to the fact that by increasing the gradient one can intensify grain refinement in metals and increase their ductility [3]
Application of Twist Extrusion Viktor Varyukhina , Yan Beygelzimerb , Sergey Synkov and Dmitry Orlovc 1 Donetsk Physics & Technology Institute of the NAS of Ukraine, 72 R. Luxembourg St., Donetsk, 83114, Ukraine. a var@hpress.dipt.donetsk.ua, b tean@an.dn.ua, c orlov@donec.net Keywords: Twist Extrusion, powder, nanostructured materials, fragmentation, consolidation. Abstract. Twist Extrusion (TE) is a process of severe plastic deformation (SPD) being developed by us during recent 5 years. Upon this time we published few papers on mechanics of the process and influence of the TE processing on materials structure and properties. Here we reported some results on application of the twist extrusion processing and made few general conclusions. Peculiarities of Twist Extrusion Mode of TE functioning is obvious from the Fig. 1. Fig. 1. Scheme explains basic principle of twist extrusion processing In [1,2] it was shown that in first approximation each physical cross-section of a billet is deformed at the same way as thin disk under high pressure torsion (HPT) processing. At that, at the beginning it is realized torsion at some angle in one direction, and then re-torsion at the same angle in the opposite direction. I.e. the deformation is cyclic with amplitude of quasi-monotone part equals to a half of the full strain. For dies we use usually, the accumulated strain per pass is about 1.2 [2]. Follow the billet’s form does not changes during the treatment, it is possible to deform it over and over again in order to accumulate strain like this is done under ECAP processing. It is followed from the previous paragraph that TE is three-dimensional option of the HPT, in some terms. On the other hand, per se TE is equal channel extrusion, i.e. similar to ECAP. It is arisen the following question: what new this process can give and why one needs to concern oneself with it? From our point of view TE has a number of peculiarities in both stress-strain state and technological implementation which do this process attractive for both investigation and application. From the viewpoint of the stress-strain state of the specimen, there are four important properties: First, the simple shear plane in TE is perpendicular to the axis of the specimen, instead of being at 45-60 degrees as in ECAP. This allows us to obtain new structures and textures. Moreover, deformation by ECAP and TE in various combinations and regimes increases the number of possible deformation paths: besides paths achievable by ECAP only, one can obtain different combinations with paths achievable by TE (deformations in the same die and pipelined deformations through a die with oppositely twisted channels). Second, TE has the property that the deformation gradient is quite steep in the cross-section area, which makes TE similar to HPT. Note that this is not true for ECAP. There are still very few results about the effects of the deformation gradient on the structure and properties of materials, but there is enough evidence pointing to the fact that by increasing the gradient one can intensify grain refinement in metals and increase their ductility [3]. Materials Science Forum Vols. 503-504 (2006) pp. 335-339 online at http://www.scientific.net © (2006) Trans Tech Publications, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of the publisher: Trans Tech Publications Ltd, Switzerland, www.ttp.net. (ID: 195.58.224.45-01/10/06,22:51:58)
336 Nanomaterials by Severe Plastic Deformation Note that experiments done on Al-Mg-Sc-Zr alloys shown quite homogeneous distribution of grain size and microhardness within the billet cross-section [4]. Third,TE (unlike ECAP)is characterized by intense flows of material being deformed within cross-sections of the billet.This is very important when deforming powder materials since it intensifies consolidation processes. Finally,TE is also characterized by a significant nonmonotone change of specimen surface while the specimen goes through the die:Upon entering the twisted region,the surface expands (by 70- 80%),and it returns to its original size upon exiting the region.Such changes affect metal structure and could allow one to insert various alloying elements into surface layers of the billet. From the technological viewpoint,TE has the following properties: First,the size of terminating,distorted areas of the specimen is much smaller under TE than under ECAP [2],which is especially important when doing repeated runs. Second,TE can handle profile billets including those with the axial channel [1]. Third,TE can easily be performed on any standard extrusion equipment by putting a twist die in place of the standard die. Finally,TE (unlike ECAP)does not change the direction of the billet moving which allows one to embed TE into already existing industrial lines. The last two properties of TE were pointed out to us by Dr.Rack.We would like to thank Dr. Rack for valuable comments about TE. Due to the properties of mentioned above,TE seems very promising for obtaining UFG materials,both via metals'grain refinement and via powder consolidation.We have previously described(see,for example,[1-9])grain refinement under twist extrusion.In this paper,we show that twist extrusion allows one to refine strong coarse particles without fracture of metals.We also give examples of consolidation of powder with amorphous and nano-crystalline structure. Materials and Experimental procedure First material used for these experiments was Al-3 wt.%Mg-0,3 wt.%Sc-0,15 wt.%Zr alloy! poured into a water-cooled copper mold and machined in 18x28x80 mm'bars.No thermal treatments or other processing were used before the TE processing.The TE was performed at elevated (280-300C)temperatures.The additional forced backpressure during the processing was about 200 MPa.It was performed 5 TE passes through 60 die for all the billets (accumulated equivalent strain e~5.8). Second material was oxygen-free high-purity copper powder2.The powder was produced via Plasma Rotating Electrode Process (PREP)in inert gas medium.Its fractional size was about 200 um;grain size (measured by X-ray diffraction technique)in the powder was 60-80 nm.The powder was pre-pressed in a copper can to 70%density.And twist extruded with the following parameters:temperature of deformation is 473 K;backpressure is about 200 MPa;true strain per pass is about 1.2 [2].Maximal pressure during the processing was about 1000-1300 MPa.It was performed the following processing of the billets: Billet I:Circle 28 mm in diameter>rectangle 18x28 mm2+1 TE pass; Billet II:Circle 28 mm in diameter>rectangle 18x28 mm2+2 TE passes; I The study was performed jointly with research group of Professor Milman from Frantcevich Institute for Problems of Materials Science,Kiev,Ukraine.Results of this research reported more in detail in paper [D.Orlov,A.Reshetov, A.Synkov,V.Varyukhin,D.Lotsko,O.Sirko,N.Zakharova,A.Sharovsky,V.Voropaiev,Yu.Milman and S.Synkov "Twist Extrusion as the Tool for Grain Refining in Al-Mg-Sc-Zr Alloys"//Proceedings of NATO ARW 'Nanostructured materials by high pressure severe plastic deformation',September 22-26,2004,Donetsk,Ukraine]. 2 The powder was supplied by group of Professor Firstov from Frantcevich Institute for Problems of Materials Science, Kiev,Ukraine
Note that experiments done on Al-Mg-Sc-Zr alloys shown quite homogeneous distribution of grain size and microhardness within the billet cross-section [4]. Third, TE (unlike ECAP) is characterized by intense flows of material being deformed within cross-sections of the billet. This is very important when deforming powder materials since it intensifies consolidation processes. Finally, TE is also characterized by a significant nonmonotone change of specimen surface while the specimen goes through the die: Upon entering the twisted region, the surface expands (by 70- 80%), and it returns to its original size upon exiting the region. Such changes affect metal structure and could allow one to insert various alloying elements into surface layers of the billet. From the technological viewpoint, TE has the following properties: First, the size of terminating, distorted areas of the specimen is much smaller under TE than under ECAP [2], which is especially important when doing repeated runs. Second, TE can handle profile billets including those with the axial channel [1]. Third, TE can easily be performed on any standard extrusion equipment by putting a twist die in place of the standard die. Finally, TE (unlike ECAP) does not change the direction of the billet moving which allows one to embed TE into already existing industrial lines. The last two properties of TE were pointed out to us by Dr. Rack. We would like to thank Dr. Rack for valuable comments about TE. Due to the properties of mentioned above, TE seems very promising for obtaining UFG materials, both via metals’ grain refinement and via powder consolidation. We have previously described (see, for example, [1-9]) grain refinement under twist extrusion. In this paper, we show that twist extrusion allows one to refine strong coarse particles without fracture of metals. We also give examples of consolidation of powder with amorphous and nano-crystalline structure. Materials and Experimental procedure First material used for these experiments was Al – 3 wt.%Mg – 0,3 wt.%Sc – 0,15 wt.%Zr alloy1 poured into a water-cooled copper mold and machined in 18x28x80 mm3 bars. No thermal treatments or other processing were used before the TE processing. The TE was performed at elevated (280-300ºC) temperatures. The additional forced backpressure during the processing was about 200 MPa. It was performed 5 TE passes through 60º die for all the billets (accumulated equivalent strain е≈5.8). Second material was oxygen-free high-purity copper powder2 . The powder was produced via Plasma Rotating Electrode Process (PREP) in inert gas medium. Its fractional size was about 200 µm; grain size (measured by X-ray diffraction technique) in the powder was 60-80 nm. The powder was pre-pressed in a copper can to 70% density. And twist extruded with the following parameters: temperature of deformation is 473 K; backpressure is about 200 MPa; true strain per pass is about 1.2 [2]. Maximal pressure during the processing was about 1000-1300 MPa. It was performed the following processing of the billets: Billet I: Circle 28 mm in diameter → rectangle 18x28 mm2 + 1 TE pass; Billet II: Circle 28 mm in diameter → rectangle 18x28 mm2 + 2 TE passes; 1 The study was performed jointly with research group of Professor Milman from Frantcevich Institute for Problems of Materials Science, Kiev, Ukraine. Results of this research reported more in detail in paper [D. Orlov, A. Reshetov, A. Synkov, V. Varyukhin, D. Lotsko, O. Sirko, N. Zakharova, A. Sharovsky, V. Voropaiev, Yu. Milman and S. Synkov “Twist Extrusion as the Tool for Grain Refining in Al-Mg-Sc-Zr Alloys” // Proceedings of NATO ARW ‘Nanostructured materials by high pressure severe plastic deformation’, September 22-26, 2004, Donetsk, Ukraine]. 2 The powder was supplied by group of Professor Firstov from Frantcevich Institute for Problems of Materials Science, Kiev, Ukraine. 336 Nanomaterials by Severe Plastic Deformation
Materials Science Forum Vols.503-504 337 Billet III:Circle 28 mm in diameter->rectangle 18x28 mm2+3 TE passes->Circle 12 mm in diameter. And third material was amorphous ribbon of ALs6NiCo2Gd6 alloy.The rapidly quenched ribbons were produced by planar flow casting of melt onto a rotating copper wheel using a quartz nozzle in atmosphere of pure helium.The resultant fully ductile ribbons had a width of 15 mm and thickness of 40-60 um thick.The melt-spun ribbons without preliminary milling were placed into copper cans and cold compacted to about 73%of theoretical density and then cans were sealed.The die having a twist channel with a rectangular cross-section 18x28 mm2 and a twist line angle B of 60,true strain per pass is about 1.2 [2],was used(Fig.1).The die and the can were preheated to the selected temperature during about 15 min prior to extrusion and then extruded with back-pressure applied to outlet part of the channel.During first extrusion pass the can with compacted ribbon changed its cross section and its size remained unchanged during subsequent passes.From five to seven extrusion passes were conducted in several experiments at temperatures 458-573 K and applied pressures ranged between 1150-1700 MPa.3 Results and discussions In the poured Al-Mg-Sc-Zr ingots it was registered by SEM(Superprobe-733)precipitation of primary intermetallic Al3(Sc,Zr)fibers with size up to 1-2 um in diameter and length up to 30 um along the billets'axis.As a result of the processing,all the particles were fragmented and had orientations similar to generatrix of slope of the twist line (Fig.2).No voids were observed at precipitate-matrix border. 250Lm 0.5m Fig.2 SEM image of Al3(Sc,Zr)fibers Fig.3 Optical microscopy image compacted Cu fragmented by twist extrusion.The arrow shows powder,Billet III,by twist extrusion direction of extrusion The obtained Cu billets with maximal density (measured by Archimedes technique)of 99.6% (Table 1).It was observed there substantial increase in microhardness,decrease in electrical resistivity and grain size in dependence on accumulated strain (Table 1).The optical microscopy of Billet III show full consolidation of the Cu powder by TE processing (Fig.3).Tensile and compression tests data showed that mechanical properties of the billets obtained are similar to properties of solid one.For example,yield stress of Billet III was 450 MPa. The experiments for TE of amorphous ribbon of ALs6NisCo2Gd6 alloy showed that fully dense billets have been obtained by TE at temperatures >523 K.Fig.4 shows the microstructure of the etched sample consolidated via three twist extrusion passes at 523 K.The voids and cracks have not 3 The experimental procedure and results obtained are described more detailed in paper [V.N.Varyukhin,V.I.Tkatch, V.V.Maslov,Y.Y.Beygelzimer,S.G.Synkov,V.K.Nosenko,S.G.Rassolov,A.S.Synkov,V.I.Krysov,V.A.Mashira "Consolidation of amorphous AlsoNiCo Gd melt-spun ribbons by twist extrusion"//this proceedings book]
Billet III: Circle 28 mm in diameter → rectangle 18x28 mm2 + 3 TE passes → Circle 12 mm in diameter. And third material was amorphous ribbon of AL86Ni6Co2Gd6 alloy. The rapidly quenched ribbons were produced by planar flow casting of melt onto a rotating copper wheel using a quartz nozzle in atmosphere of pure helium. The resultant fully ductile ribbons had a width of 15 mm and thickness of 40-60 µm thick. The melt-spun ribbons without preliminary milling were placed into copper cans and cold compacted to about 73% of theoretical density and then cans were sealed. The die having a twist channel with a rectangular cross-section 18×28 mm2 and a twist line angle β of 60º, true strain per pass is about 1.2 [2], was used (Fig. 1). The die and the can were preheated to the selected temperature during about 15 min prior to extrusion and then extruded with back-pressure applied to outlet part of the channel. During first extrusion pass the can with compacted ribbon changed its cross section and its size remained unchanged during subsequent passes. From five to seven extrusion passes were conducted in several experiments at temperatures 458-573 K and applied pressures ranged between 1150-1700 MPa.3 Results and discussions In the poured Al-Mg-Sc-Zr ingots it was registered by SEM (Superprobe-733) precipitation of primary intermetallic Al3(Sc,Zr) fibers with size up to 1-2 µm in diameter and length up to 30 µm along the billets’ axis. As a result of the processing, all the particles were fragmented and had orientations similar to generatrix of slope of the twist line (Fig. 2). No voids were observed at precipitate-matrix border. Fig. 2 SEM image of Al3(Sc,Zr) fibers fragmented by twist extrusion. The arrow shows direction of extrusion Fig. 3 Optical microscopy image compacted Cu powder, Billet III, by twist extrusion The obtained Cu billets with maximal density (measured by Archimedes technique) of 99.6% (Table 1). It was observed there substantial increase in microhardness, decrease in electrical resistivity and grain size in dependence on accumulated strain (Table 1). The optical microscopy of Billet III show full consolidation of the Cu powder by TE processing (Fig. 3). Tensile and compression tests data showed that mechanical properties of the billets obtained are similar to properties of solid one. For example, yield stress of Billet III was 450 MPa. The experiments for TE of amorphous ribbon of AL86Ni6Co2Gd6 alloy showed that fully dense billets have been obtained by TE at temperatures ≥ 523 K. Fig. 4 shows the microstructure of the etched sample consolidated via three twist extrusion passes at 523 K. The voids and cracks have not 3 The experimental procedure and results obtained are described more detailed in paper [V.N. Varyukhin, V.I. Tkatch, V.V. Maslov , Y. Y. Beygelzimer, S.G. Synkov, V.K. Nosenko, S.G. Rassolov, A.S. Synkov, V.I. Krysov, V.A. Mashira “Consolidation of amorphous Al86Ni6Co2Gd6 melt-spun ribbons by twist extrusion” // this proceedings book]. Materials Science Forum Vols. 503-504 337
338 Nanomaterials by Severe Plastic Deformation detected in the structure while the separate ribbons without any structural features at the boundaries may be identified.The measurements of microhardness exhibited maximum value(5500 MPa)after temperature processing of 523 K (Fig.5).It is essentially higher than Hu of the as-prepared amorphous ribbons,but lower than the maximum value achieved in the partially crystallized ribbons.It means that the regimes of TE processing of the melt-spun ribbons may be optimized to enhance the microhardness of the compacted billets.Nevertheless,the microhardness achieved in the twist extruded AlsoNisCo2Gd6 samples is higher than the hardness of the material obtained by the ECAP processing of the semi-amorphous AlgsNioY2.sLa2.5 alloy powder [10].The sizes of Al- nanocrystals in samples consolidated at 513-523 K estimated from the X-ray analysis data are 13+ 1 nm while the volume fraction of nanocrystalline phase is ranged between 40-50%. Billets conditions Relative density [% Microhardness [MPa] Grain size nm Prepressing 69.0 80 Billet I 99.2 950 35 Billet II 99.6 1150 50 BilletⅢ 99.2 1050 45 Table 1.Relative density,microhardness and averaged grain size (measured by X-ray diffraction technique)of Cu powder processed by twist extrusion 550 81。 Al (Ni,Co)Gd E 500 08是 5 0.6 450 0.4 3 400 1,4 0.2 ●、 3500- Extrusions 0.0 300350400450500550 Extrusion temperature (K) Fig.4.Optical micrograph of the five-pass TE Fig.5.Microhardness of the Als6NiCo2Gd6 ribbons compacted at 513 K.x1000 amorphous ribbons before and after consolidation (left axis)and the volume fraction of crystallized in the compacted samples (right axis)as function of the extrusion temperature. Numbers represent the number of TE passes Conclusions In the paper it was shown peculiarities of twist extrusion technique.Based on these peculiarities it was demonstrated attractiveness of TE for enhancement possibilities of SPD processing. We have previously described (see,for example,[1-9])grain refinement in metals under twist extrusion.In this paper,we have shown that twist extrusion allows one to refine strong coarse particles without fracture of metals.We also give examples of consolidation of powder with amorphous and nano-crystalline structure
detected in the structure while the separate ribbons without any structural features at the boundaries may be identified. The measurements of microhardness exhibited maximum value (5500 MPa) after temperature processing of 523 K (Fig. 5). It is essentially higher than Hµ of the as-prepared amorphous ribbons, but lower than the maximum value achieved in the partially crystallized ribbons. It means that the regimes of TE processing of the melt-spun ribbons may be optimized to enhance the microhardness of the compacted billets. Nevertheless, the microhardness achieved in the twist extruded Al86Ni6Co2Gd6 samples is higher than the hardness of the material obtained by the ECAP processing of the semi-amorphous Al85Ni10Y2.5La2.5 alloy powder [10]. The sizes of Alnanocrystals in samples consolidated at 513-523 K estimated from the X-ray analysis data are 13 ± 1 nm while the volume fraction of nanocrystalline phase is ranged between 40-50%. Billets conditions Relative density [%] Microhardness [MPa] Grain size [nm] Prepressing 69.0 --- 80 Billet I 99.2 950 35 Billet II 99.6 1150 50 Billet III 99.2 1050 45 Table 1. Relative density, microhardness and averaged grain size (measured by X-ray diffraction technique) of Cu powder processed by twist extrusion 300 350 400 450 500 550 350 400 450 500 550 0.0 0.2 0.4 0.6 0.8 1.0 Microhardness (kgf/mm 2 ) Extrusion temperature (K) Al86(Ni,Co)8Gd6 Ribbons Extrusions 3 4 5 4 1 Volume density of crystals Fig. 4. Optical micrograph of the five-pass TE ribbons compacted at 513 K. ×1000 Fig. 5. Microhardness of the Al86Ni6Co2Gd6 amorphous ribbons before and after consolidation (left axis) and the volume fraction of crystallized in the compacted samples (right axis) as function of the extrusion temperature. Numbers represent the number of TE passes Conclusions In the paper it was shown peculiarities of twist extrusion technique. Based on these peculiarities it was demonstrated attractiveness of TE for enhancement possibilities of SPD processing. We have previously described (see, for example, [1-9]) grain refinement in metals under twist extrusion. In this paper, we have shown that twist extrusion allows one to refine strong coarse particles without fracture of metals. We also give examples of consolidation of powder with amorphous and nano-crystalline structure. 338 Nanomaterials by Severe Plastic Deformation
Materials Science Forum Vols.503-504 339 References [1]Beygelzimer Y.,Orlov D.and Varyukhin V.:Ultrafine Grained Materials II;Ed.By Y.T.Zhu, T.G.Langdon,R.S.Mishra,S.L.Semiatin,M.J.Saran,T.C.Lowe.TMS (The Minerals,Metals Materials Society)(2002).p.297. [2]Y.Beygelzimer,V.Varyukhin,D.Orlov,S.Synkov:Twist extrusion -process for strain accumulation (Donetsk:TEAN 2003)[In Russian] [3]Beygelzimer Y.:Mechanics of Materials V.37(2005)(in press) [4]D.Orlov,A.Reshetov,A.Synkov,V.Varyukhin,D.Lotsko,O.Sirko,N.Zakharova, A.Sharovsky,V.Voropaiev,Yu.Milman and S.Synkov:Proceedings of NATO ARW 'Nanostructured materials by high pressure severe plastic deformation',September 22-26, 2004,Donetsk,Ukraine (2004) [5]Beygelzimer Y.,Varyukhin V.,Orlov D.,Efros B.,Stolyarov V.and Salimgareyev H.: Ultrafine Grained Materials II;Ed.By Y.T.Zhu,T.G.Langdon,R.S.Mishra,S.L.Semiatin, M.J.Saran,T.C.Lowe.TMS(The Minerals,Metals Materials Society),(2002)p.43 [6]D.V.Orlov,V.V.Stolyarov,H.Sh.Salimgareyev,E.P.Soshnikova,A.V.Reshetov, Ya.Ye.Beygelzimer,S.G.Synkov and V.N.Varyukhin:Ultrafine Grained Materials III;Ed.by Y.T.Zhu,T.G.Langdon,R.Z.Valiev,S.L.Semiatin,D.H.Shin,and T.C.Lowe.(TMS (The Minerals,Metals Materials Society)(2004)p.457 [7]V.V.Stolyarov,Ya.E.Beigel'zimer,D.V.Orlov,and R.Z.Valiev:The Physics of Metals and Metallography,Vol.99,No.2(2005)p.204 [8]Y.Beygelzimer,V.Varyukhin,D.Orlov,S.Synkov,A.Spuskanyuk,Y.Pashinska: Nanomaterials by severe plastic deformation.Edited by Zehetbauer MJ,Valiev RZ Weinheim, Germany:Wiley-VCH;(2004)p.511 [9]Beygelzimer Y.,Orlov D.:Defect and Diffusion Forum,V.208-209(2002)p.311 [10]O.N.Senkov,D.B.Miracle,J.M.Scott,S.V.Senkova:J.Alloys and Compounds Vol.365 (2004),p.126
References [1] Beygelzimer Y., Orlov D. and Varyukhin V.: Ultrafine Grained Materials II; Ed. By Y.T.Zhu, T.G.Langdon, R.S.Mishra, S.L.Semiatin, M.J.Saran, T.C.Lowe. TMS (The Minerals, Metals & Materials Society) (2002). p.297. [2] Y. Beygelzimer, V. Varyukhin, D. Orlov, S. Synkov: Twist extrusion – process for strain accumulation (Donetsk: TEAN 2003) [In Russian] [3] Beygelzimer Y.: Mechanics of Materials V.37 (2005) (in press) [4] D. Orlov, A. Reshetov, A. Synkov, V. Varyukhin, D. Lotsko, O. Sirko, N. Zakharova, A. Sharovsky, V. Voropaiev, Yu. Milman and S. Synkov: Proceedings of NATO ARW ‘Nanostructured materials by high pressure severe plastic deformation’, September 22-26, 2004, Donetsk, Ukraine (2004) [5] Beygelzimer Y., Varyukhin V., Orlov D., Efros B., Stolyarov V. and Salimgareyev H.: Ultrafine Grained Materials II; Ed. By Y.T. Zhu, T.G.Langdon, R.S.Mishra, S.L.Semiatin, M.J.Saran, T.C.Lowe. TMS (The Minerals, Metals & Materials Society), (2002) p.43 [6] D.V. Orlov, V.V. Stolyarov, H.Sh. Salimgareyev, E.P. Soshnikova, A.V. Reshetov, Ya.Ye. Beygelzimer, S.G. Synkov and V.N. Varyukhin: Ultrafine Grained Materials III; Ed. by Y.T. Zhu, T.G. Langdon, R.Z. Valiev, S.L. Semiatin, D.H. Shin, and T.C. Lowe. (TMS (The Minerals, Metals & Materials Society) (2004) p.457 [7] V. V. Stolyarov, Ya. E. Beigel’zimer, D. V. Orlov, and R. Z. Valiev: The Physics of Metals and Metallography, Vol. 99, No. 2 (2005) p. 204 [8] Y. Beygelzimer, V. Varyukhin, D. Orlov, S. Synkov, A. Spuskanyuk, Y. Pashinska: Nanomaterials by severe plastic deformation. Edited by Zehetbauer MJ, Valiev RZ Weinheim, Germany: Wiley-VCH; (2004) p.511 [9] Beygelzimer Y., Orlov D.: Defect and Diffusion Forum, V. 208-209 (2002) p.311 [10]O.N. Senkov, D.B. Miracle, J.M. Scott, S.V. Senkova: J. Alloys and Compounds Vol. 365 (2004), p. 126 Materials Science Forum Vols. 503-504 339