等径角轧制AM60镁合金板材的显微组织与力学性能
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摘要
作为最轻的金属结构材料,镁合金特别是变形镁合金以其优异的综合性能表现出极其广阔的应用前景,高性能镁合金板材的研制已成为当今材料领域的研究热点。但常规轧制镁合金板材形成的强烈基面织构严重制约了镁合金板材的二次成形能力,因此,本文运用105o夹角模具采用等径角轧制工艺成功制备出AM60镁合金板材,分析了其经过等径角轧制之后微观组织和力学性能的变化,并对其进行了退火热处理,为制定合理的热处理工艺作参考。与普通轧制板材相比,研究结果表明:
(1)等径角轧制后,AM60镁合金板材中产生了大量的孪晶并且有细密排列的孪晶生成,晶粒得到了细化,平均晶粒度由10μm左右下降到5μm左右,晶粒形状不规则,为典型的大变形组织。
(2)等径角轧制后,AM60镁合金板材内晶粒c轴向轧制方向偏转了较大的角度,向非基面晶粒取向转变,改变了普通轧制板材强烈的(0002)基面织构,非基面织构的形成对板材二次成形有利。
(3)等径角轧制后,晶粒细化,细密孪晶生成以及非基面晶粒取向都对流变行为产生了影响,晶粒细化,晶界协调变形能力增加,强度增大,塑性得到提高,应变硬化能力大大加强,尤其是沿轧向方向;沿轧向和横向的抗拉强度分别由轧制前的222MPa和268MPa增加至轧制后的372MPa和380MPa;沿轧向和横向的屈服强度由轧制前的156MPa和188MPa分别增加至轧制后的260MPa和265MPa。
(4)退火处理后,晶粒趋向于均匀并等轴化,有条状晶粒出现,随着退火时间的延长,晶粒开始长大,孪晶逐渐消失,退火60分钟后,孪晶基本消失,条状晶粒趋于等轴化,晶界平直化,多为夹角约120°的三叉晶界,部分晶粒已经长大,但仍有细小晶粒存在。
(5)退火处理后,晶粒长大、细密孪晶逐渐消失以及位错密度下降使板材的抗拉强度和屈服强度降低,但是晶粒的均匀等轴化使板材的塑性增强,断裂延伸率大大提高;另外,退火处理后,各晶面衍射峰强度有所降低,但等径角轧制所形成非基面晶粒取向依然存在,并没有从根本上改变等径角轧制AM60镁合金的非基面晶粒取向;观察到300℃×30min退火处理效果较好。
Increase usage of magnesium components in the industries has propelled considerable research interest on the development of magnesium alloy,especially deformation magnesium alloy with excellent composite properties. However,the secondary deformation abilities are badly restricted by the (0002) basal texture of magnesium alloy sheets with normal rolling. Therefore,Mg-6%Al-0.5%Zn-0.5%Mn (AM60) alloy was subjected to Equal Channel Angular Rolling(ECAR)processing with 105omodul at 400℃. Microstructure observations and mechanical properties were carried out using optical microscope and tensile was tested. Annealing treatments were carried out with different periods. The study shows that
(1) Twins refinement are observed in AM60 magnesium alloy with ECAR and the grain size decreases. The grain size is 10μm and 5μm before and after ECAR. The grain shapes of ECAR AM60 magnesium alloy sheet are not regular. Typical severe plastic deformation microstructure appeares.
(2) It is found that the“c”axis orientation of the sheet processed by ECAR is changed and the crystal orientation evolves from (0002) basal plane orientation to non-basal plane. Non-basal texture of grains appeares. The existence of non-basal texture is advantageous to secondary deformation.
(3) The rheological behavior is affected by refined grains and non-basal texture. The rheological behavior after ECAR changes obviously especially along rolling direction. The grain boundary deformation ability gets enhanced after ECAR,strength and plasticity of ECAR AM60 sheets get enhanced too,the ultimate tensile strength increases from 222 to 372 MPa and the yield strength increases from 156 to 260 MPa along rolling direction,the ultimate tensile strength increases from 268 to 380 MPa and the yield strength increases from 188 to 265 MPa along transverse direction.
(4) Symmetrical axis grains and shape grains appeare after annealing treatment. Grains begin to grow up,twins begins to disappear with the annealing time going on. After 60 minutes annealing treatments,the grain boundary with 120o appears and shape grains begin to be symmetrical axis grains.
(5) Sheet strength decreases after annealing treatments,because grains grew up and twins refinement began to disappear. The decreased density of the locations makes the strength low too. Twins decreases but symmetrical axis grains appeares after annealing treatment. So,strength decreases,plasticity get enhanced more. The amounts of the twins decrease obviously but the non-basal orientation of the grains processed by ECAR changes little. The effect of annealing treatments with 30 minutes at 300℃is observed better in our results.
(1)等径角轧制后,AM60镁合金板材中产生了大量的孪晶并且有细密排列的孪晶生成,晶粒得到了细化,平均晶粒度由10μm左右下降到5μm左右,晶粒形状不规则,为典型的大变形组织。
(2)等径角轧制后,AM60镁合金板材内晶粒c轴向轧制方向偏转了较大的角度,向非基面晶粒取向转变,改变了普通轧制板材强烈的(0002)基面织构,非基面织构的形成对板材二次成形有利。
(3)等径角轧制后,晶粒细化,细密孪晶生成以及非基面晶粒取向都对流变行为产生了影响,晶粒细化,晶界协调变形能力增加,强度增大,塑性得到提高,应变硬化能力大大加强,尤其是沿轧向方向;沿轧向和横向的抗拉强度分别由轧制前的222MPa和268MPa增加至轧制后的372MPa和380MPa;沿轧向和横向的屈服强度由轧制前的156MPa和188MPa分别增加至轧制后的260MPa和265MPa。
(4)退火处理后,晶粒趋向于均匀并等轴化,有条状晶粒出现,随着退火时间的延长,晶粒开始长大,孪晶逐渐消失,退火60分钟后,孪晶基本消失,条状晶粒趋于等轴化,晶界平直化,多为夹角约120°的三叉晶界,部分晶粒已经长大,但仍有细小晶粒存在。
(5)退火处理后,晶粒长大、细密孪晶逐渐消失以及位错密度下降使板材的抗拉强度和屈服强度降低,但是晶粒的均匀等轴化使板材的塑性增强,断裂延伸率大大提高;另外,退火处理后,各晶面衍射峰强度有所降低,但等径角轧制所形成非基面晶粒取向依然存在,并没有从根本上改变等径角轧制AM60镁合金的非基面晶粒取向;观察到300℃×30min退火处理效果较好。
Increase usage of magnesium components in the industries has propelled considerable research interest on the development of magnesium alloy,especially deformation magnesium alloy with excellent composite properties. However,the secondary deformation abilities are badly restricted by the (0002) basal texture of magnesium alloy sheets with normal rolling. Therefore,Mg-6%Al-0.5%Zn-0.5%Mn (AM60) alloy was subjected to Equal Channel Angular Rolling(ECAR)processing with 105omodul at 400℃. Microstructure observations and mechanical properties were carried out using optical microscope and tensile was tested. Annealing treatments were carried out with different periods. The study shows that
(1) Twins refinement are observed in AM60 magnesium alloy with ECAR and the grain size decreases. The grain size is 10μm and 5μm before and after ECAR. The grain shapes of ECAR AM60 magnesium alloy sheet are not regular. Typical severe plastic deformation microstructure appeares.
(2) It is found that the“c”axis orientation of the sheet processed by ECAR is changed and the crystal orientation evolves from (0002) basal plane orientation to non-basal plane. Non-basal texture of grains appeares. The existence of non-basal texture is advantageous to secondary deformation.
(3) The rheological behavior is affected by refined grains and non-basal texture. The rheological behavior after ECAR changes obviously especially along rolling direction. The grain boundary deformation ability gets enhanced after ECAR,strength and plasticity of ECAR AM60 sheets get enhanced too,the ultimate tensile strength increases from 222 to 372 MPa and the yield strength increases from 156 to 260 MPa along rolling direction,the ultimate tensile strength increases from 268 to 380 MPa and the yield strength increases from 188 to 265 MPa along transverse direction.
(4) Symmetrical axis grains and shape grains appeare after annealing treatment. Grains begin to grow up,twins begins to disappear with the annealing time going on. After 60 minutes annealing treatments,the grain boundary with 120o appears and shape grains begin to be symmetrical axis grains.
(5) Sheet strength decreases after annealing treatments,because grains grew up and twins refinement began to disappear. The decreased density of the locations makes the strength low too. Twins decreases but symmetrical axis grains appeares after annealing treatment. So,strength decreases,plasticity get enhanced more. The amounts of the twins decrease obviously but the non-basal orientation of the grains processed by ECAR changes little. The effect of annealing treatments with 30 minutes at 300℃is observed better in our results.
引文
[1] N Ogawa, M Shiomi, K Osakada. Forming limit of magnesium alloy at elevated temperatures for precision forging[J]. International Journal of Machine Tools and Manufacture, 2002, 42(5): 607-614
[2] Tsuji N, Toyoda T, Minamino Y, et al. Microstructural change of ultrafine-grained aluminum during high-speed plastic deformation[J]. Materials Science and Engineering, 2003, A350(1-2): 108-116
[3] Costa A L M, Reis A C C, Kestens L, et al. Ultra grain refinement and hardening of IF-steel during accumulative roll-bonding[J]. Materials Science and Engineering, 2005, A406(1-2): 279-285
[4] 管仁国, 李俊鹏, 赵金力, 等. 叠轧深变形制备超细晶 Al-21%Mg 合金[J]. 材料与冶金学报, 2005, 4(1): 65-69
[5] Lee S H, Saito Y, Tsuji N, et al. Role of shear strain in ultragrain refinement by accumulative roll-bonding (ARB) process[J]. Scripta Materialia, 2002, 46(4): 281-285
[6] Tsuji N, Saito Y, Lee S, et al. ARB (Accumulative Roll-Bonding) and other new Techniques to Produce Bulk Ultrafine Grained Materials[J]. Advanced Engineering Materials, 2005, 5(5): 338-344
[7] Kamikawa N, Tsuji N, Minamino Y. Microstructure and texture through thickness of ultralow carbon IF steel sheet severely deformed by accumulative roll-bonding[J]. Science and Technology of Advanced Materials, 2004, 5(1-2): 163-172
[8] Tsuji N, Saito Y, Utsunomiya H, et al. Ultra-Fine Grained Bulk Steel Produced by Accumulative Roll-Bonding (ARB) Process[J]. Scripta Materialia, 1999, 40(7): 795-800
[9] Islamgaliev R K, Yunusova N F, Sabirov I N, et al. Deformation behavior of nanostructured aluminum alloy processed by severe plastic deformation[J]. Materials Science and Engineering, 2001, A319-321(1): 877-881
[10] Sakai G, Horita Z, Langdon T G. Grain refinement and superplasticity in an aluminum alloy processed by high-pressure torsion[J]. Materials Science and Engineering, 2005, A393(1-2): 344-351
[11] Vorhauer A, Pippan R. On the homogeneity of deformation by high pressuretorsion[J]. Scripta Materialia, 2004, 51(9): 921-925.
[12] Hebesberger T, Stüwe H P, Vorhauer A, et al. Structure of Cu deformed by high pressure torsion[J]. Acta Materialia, 2005, 53(2): 393-402.
[13] Segal V M, Reznikov V I, Drobyshevski A E, et al. Plastic metal working by simple shear[J]. Metally, 1981, 1(1): 115-123
[14] Iwahashi Y, Wang J T, Horita Z J, et al. Principle of Equal-Channel Angular Pressing for the Processing of Ultra-fine Grained Materials[J]. Scripta Materialia, 1996, 35(2): 143-146
[15] Furukawa M, Horita Z J, Langdon T G. Factors influencing the shearing patterns in equal-channel angular pressing[J]. Materials Science and Engineering, 2002, A332(1-2): 97-109
[16] Segal V M. Materials processing by simple shear[J]. Materials Science and Engineering, 1995, A197(2): 157-164
[17] Yamashit A, Horit Z J, Langdon T G. Improving the mechanical properties of magnesium and a magnesium alloy through severe plastic deformation[J]. Materials Science and Engineering, 2001, A300(1-2): 142-147
[18] Conrad H, Jung K. On the strain rate sensitivity of the flow stress of ultrafine-grained Cu processed by equal channel angular extrusion (ECAE) [J]. Scripta Materialia, 2005, 53(5): 581-584
[19] Sastry S M L, Mahapatra R N. Grain refinement of intermetallics by severe plastic deformation[J]. Materials Science and Engineering, 2001, A329-331(1): 872-877
[20] Saito N, Mabuchi M, Nakanishi M, et al. Microstructure and mechanical properties of SUS304L stainless steel processed by equal channel angular extrusion[J]. Journal of Materials Science Letters, 2000, 19(1): 2091-2093
[21] Nakashima K, Horita Z J, Nemoto M, et al. Influence of Channel Angle on the Development of Ultrafine Grains in Equal-Channel Angular Pressing[J]. Acta Materialia, 1998, 46(5): 1589-1599
[22] Mishra A, Kad B K, Gregori F, et al. Microstructural evolution in copper subjected to severe plastic deformation: Experiments and analysis[J]. Acta Materialia, 2007, 55(1): 13-28
[23] Su C W, Lu L, Lai M O. A model for the grain refinement mechanism in equal channel angular pressing of Mg alloy from microstructural studies[J]. Materials Science and Engineering, 2006, A434(1-2): 227-236
[24] Mishin O V, Gertsman V Y, Valiev R Z, et al. Grain boundary distribution andtexture in ultrafine-grained copper produced by severe plastic deformation[J]. Scripta Materialia, 1996, 35(7): 873-878
[25] Saito Y, Utsunomiya H, Suzuki H, et al. Improvement in the r-Value of Aluminum Strip by a Continuous Shear Deformation Process[J]. Scripta Materialia, 2000, 42(12): 1139-1144
[26] Utsunomiya H, Hatsuda K, Sakai T, et al. Continuous grain refinement of aluminum strip by Conshearing[J]. Materials Science and Engineering, 2004, A372(1-2): 199-206.
[27] Lee J C, Seok H K, Han J H, et al. Controlling the textures of the metal strips via the continuous confined strip shearing (C2S2) process[J]. Materials Research Bulletin, 2001, 36(1): 997-1004
[28] Suh J Y, Han J H, Oh K H, et al. Effect of deformation histories on texture evolution during equal-channel and dissimilar-channel angular pressing[J]. Scripta Materialia, 2003, 49(2): 185-190
[29] Nam C Y, Han J H, Chung Y H, et al. Effect of precipitates on microstructural evolution of 7050 Al alloy sheet during equal channel angular rolling[J], Materials Science and Engineering, 2003, A347(1-2): 253-257
[30] Lee J C, Seok H K, Suh J Y. Microstructural evolutions of the Al strip prepared by cold rolling and continuous equal channel angular pressing[J]. Acta Materialia, 2002, 50(16): 4005-4019
[31] Lee J C, Seok H K, Suh J Y, et al. Structural evolution of a strip-cast Al alloy sheet Processed by continuous equal-channel angular pressing[J]. Metallurgical and Materials Transactions, 2002, A33(1): 665-673
[32] Park J W, Kim J W, Chung Y H, Grain refinement of steel plate by continuous equal-channel angular process[J]. Scripta Materialia, 2004, 51(2): 181-184
[33] Han J H, Huh M Y, Suh J Y, et al. Controlling the textures of the Al alloy sheet via dissimilar channel angular pressing[J]. Materials Science and Engineering, 2005, A394(1-2): 60-65
[34] Qin J N, Han J H, Zhang G D, et al. Characteristic of textures evolution induced by equal channel angular pressing in 6061 aluminum sheets[J]. Scripta Materialia, 2004, 51(2): 185-189
[35] Qin J N, Zhang D, Zhang G D, et al. Effect of temperature on texture formation of 6061 aluminum sheet in equal-channel angular pressing[J]. Materials Science and Engineering, 2005, A408(1-2): 79-84
[36] Chaudhury P K, Cherukuri B, Srinivasan R. Scaling up of equal channel angularpressing (ECAP) and its effect on mechanical properties, microstructure, and hot workability of Al 6061[J]. Materials Science and Engineering, 2005, A410-411(1): 316-318.
[37] Raab G J, Valiev R Z, Lowe T C, et al. Continuous processing of ultrafine grained Al by ECAP-Conform[J]. Materials Science and Engineering, 2004, A382(1-2): 30-34
[38] Del Valle J A, Carreno F, Ruano O A. Influence of texture and grain size on work hardening and ductility in magnesium-based alloys processed by ECAP and rolling[J]. Acta Materialia, 2006, 54(16): 4247-4259
[39] Lapovok R, Thomson P F, Cottam R, et al. The effect of grain refinement by warm equal channel angular extrusion on room temperature twinning in magnesium alloy ZK60[J]. Journal of Materials Science, 2005, 40(1): 1699-1708
[40] Mabuchi M, Iwasaki H, Yanase K, et al. Low temperature superplasticity in an AZ91 Magnesium alloy processed by ECAE[J]. Scripta Materialia, 1997, 36(6): 681-686
[41] Horita Z, Furukawa M, Nemoto M, et al. Superplastic forming at high strain rates after severe plastic deformation[J]. Acta Materialia, 2000, 48(14): 3633-3640
[42] Yoshida Y, Cisar L, Kamado S, et al. Effect of Microstructural Factors on Tensile Properties of an ECAE-Processed AZ31 Magnesium Alloy[J]. Materials Transactions, 2003, 44(4): 468-475
[43] Koike J. New Deformation Mechanisms in Fine-Grain Mg Alloys[J]. Materials Science Forum, 2003, 419-422(1): 189-194
[44] 吉田雄, Cisar C, 鎌土重晴ら. ECAE 加工した AZ31 マグネシウム合金の引張特性及ぼすミクロ組織因子の影响[J]. 軽金属, 2002, 52(11): 559-565
[45] Mukai T, Yamanoi M, Watanabe H, et al. Ductility enhancement in AZ31 magnesium alloy by controlling its grain structure[J]. Scripta Materialia, 2001, 45(1): 89-94
[46] Kim H K, Kim W J. Microstructural instability and strength of an AZ31 Mg alloy after severe plastic deformation[J]. Materials Science and Engineering, 2004, A385(1-2): 300-308
[47] Doege E, Dr?der K. Sheet metal forming of magnesium wrought alloys — formability and process technology[J]. Journal of Materials Processing Technology, 2001, 115(1): 14-19
[48] 程永奇. AZ31 镁合金板材等径角轧制及冲压性能研究[D]: 长沙湖南大学博士论文, 2007: 15-39
[49] Yoshida Y, Cisar L, Kamado S, et al.Texture development of AZ31 magnesium alloy during ECAE processing[J]. Materials Science Forum, 2003, 419-422(1): 533-538
[50] Segal V M. Slip line solutions, deformation mode and loading history during equal channel angular extrusion[J]. Materials Science and Engineering, 2003, A345(1-2): 36-46
[51] Luis Pérez C J. On the correct selection of the channel die in ECAP processes[J]. Scripta Materialia, 2004, 50(3): 387-393
[52] Galiyev A, Sitdikov O, Kaibyshev R. Deformation behavior and controlling mechanisms for plastic flow of magnesium and magnesium alloy[J]. Materials Transactions, 2003, 44 (4): 426-435
[53] Barnett M R. Influence of deformation conditions and texture on the high temperature flow stress of magnesium AZ31[J]. Journal of Light Metals, 2001, 1(3): 167-177
[54] 郭强, 张辉, 陈振华, 等. AZ31 镁合金的高温热压缩流变应力行为的研究[J].湘潭大学自然科学学报, 2004, 26(3): 108-111.
[55] Lin J, Lin D L, Mao D L. Mechanical properties and microstructure of AZ31 Mg alloy processed by two-step equal channel angular extrusion[J]. Materials Letters, 2005, 59(18): 2267-2270
[56] 丁水,于彦东,张凯锋,等. MB15 镁合金板材的超塑性能研究[J]. 锻压技术, 2003, 28(3): 44-46
[57] Mukai T, Matsuoka S, Miyamoto S, et al. Effects of extrusion conditions on microstructure and mechanical properties of AZ31B magnesium alloy extrusions[J]. Journal of Materials Processing Technology, 2003, 141(2): 207-212
[58] 黄光胜,汪凌云,范永革. AZ31B 镁合金挤压工艺研究[J]. 金属成形工艺, 2002, 20(5): 11-14
[59] Oishi Y, Kawabe N, Hoshima A, et al. Development of High Strength Magnesium Alloy Wire[J]. SEI Technical Review, 2003, 56(6): 54-58
[60] Pérez-Prado M T, Ruano O A. Texture evolution during annealing of magnesium AZ31 alloy[J]. Scripta Materialia, 2002, 46(2): 149-155
[61] 杨平,任学平,赵祖德. AZ31 镁合金热成形及退火过程的组织与织构[J]. 材料热处理学报, 2003, 24(4): 12-16
[62] J?ger A, Luká? P, G?rtnerová V, et al. Influence of annealing on the microstructure of commercial Mg alloy AZ31 after mechanical forming[J]. Materials Science and Engineering, 2006, A432(1-2): 20-25
[63] Wagner F, Bozzolo N, Van Landuyt O, et al. Evolution of recrystallization texture and microstructure in low alloyed titanium sheets[J]. Acta Materialia, 2002, 50(5): 1245-1259
[64] Koike J, Kobayashi T, Mukai T, et al. The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys[J]. Acta Materialia, 2003, 51(7): 2055-2065
[65] Huang Z W, Yoshida Y, Cisar L, et al. Microstructures and Tensile Properties of Wrought Magnesium Alloys Processed by ECAE[J]. Materials Science Forum, 2003, 419-422(1): 243-248
[66] 王占学. 塑性加工金属学[M]. 北京: 冶金工业出版社, 1991: 231
[67] 钟家湘,郑秀华,刘颖. 金属学教程[M]. 北京:北京理工大学出版社, 1995: 304
[2] Tsuji N, Toyoda T, Minamino Y, et al. Microstructural change of ultrafine-grained aluminum during high-speed plastic deformation[J]. Materials Science and Engineering, 2003, A350(1-2): 108-116
[3] Costa A L M, Reis A C C, Kestens L, et al. Ultra grain refinement and hardening of IF-steel during accumulative roll-bonding[J]. Materials Science and Engineering, 2005, A406(1-2): 279-285
[4] 管仁国, 李俊鹏, 赵金力, 等. 叠轧深变形制备超细晶 Al-21%Mg 合金[J]. 材料与冶金学报, 2005, 4(1): 65-69
[5] Lee S H, Saito Y, Tsuji N, et al. Role of shear strain in ultragrain refinement by accumulative roll-bonding (ARB) process[J]. Scripta Materialia, 2002, 46(4): 281-285
[6] Tsuji N, Saito Y, Lee S, et al. ARB (Accumulative Roll-Bonding) and other new Techniques to Produce Bulk Ultrafine Grained Materials[J]. Advanced Engineering Materials, 2005, 5(5): 338-344
[7] Kamikawa N, Tsuji N, Minamino Y. Microstructure and texture through thickness of ultralow carbon IF steel sheet severely deformed by accumulative roll-bonding[J]. Science and Technology of Advanced Materials, 2004, 5(1-2): 163-172
[8] Tsuji N, Saito Y, Utsunomiya H, et al. Ultra-Fine Grained Bulk Steel Produced by Accumulative Roll-Bonding (ARB) Process[J]. Scripta Materialia, 1999, 40(7): 795-800
[9] Islamgaliev R K, Yunusova N F, Sabirov I N, et al. Deformation behavior of nanostructured aluminum alloy processed by severe plastic deformation[J]. Materials Science and Engineering, 2001, A319-321(1): 877-881
[10] Sakai G, Horita Z, Langdon T G. Grain refinement and superplasticity in an aluminum alloy processed by high-pressure torsion[J]. Materials Science and Engineering, 2005, A393(1-2): 344-351
[11] Vorhauer A, Pippan R. On the homogeneity of deformation by high pressuretorsion[J]. Scripta Materialia, 2004, 51(9): 921-925.
[12] Hebesberger T, Stüwe H P, Vorhauer A, et al. Structure of Cu deformed by high pressure torsion[J]. Acta Materialia, 2005, 53(2): 393-402.
[13] Segal V M, Reznikov V I, Drobyshevski A E, et al. Plastic metal working by simple shear[J]. Metally, 1981, 1(1): 115-123
[14] Iwahashi Y, Wang J T, Horita Z J, et al. Principle of Equal-Channel Angular Pressing for the Processing of Ultra-fine Grained Materials[J]. Scripta Materialia, 1996, 35(2): 143-146
[15] Furukawa M, Horita Z J, Langdon T G. Factors influencing the shearing patterns in equal-channel angular pressing[J]. Materials Science and Engineering, 2002, A332(1-2): 97-109
[16] Segal V M. Materials processing by simple shear[J]. Materials Science and Engineering, 1995, A197(2): 157-164
[17] Yamashit A, Horit Z J, Langdon T G. Improving the mechanical properties of magnesium and a magnesium alloy through severe plastic deformation[J]. Materials Science and Engineering, 2001, A300(1-2): 142-147
[18] Conrad H, Jung K. On the strain rate sensitivity of the flow stress of ultrafine-grained Cu processed by equal channel angular extrusion (ECAE) [J]. Scripta Materialia, 2005, 53(5): 581-584
[19] Sastry S M L, Mahapatra R N. Grain refinement of intermetallics by severe plastic deformation[J]. Materials Science and Engineering, 2001, A329-331(1): 872-877
[20] Saito N, Mabuchi M, Nakanishi M, et al. Microstructure and mechanical properties of SUS304L stainless steel processed by equal channel angular extrusion[J]. Journal of Materials Science Letters, 2000, 19(1): 2091-2093
[21] Nakashima K, Horita Z J, Nemoto M, et al. Influence of Channel Angle on the Development of Ultrafine Grains in Equal-Channel Angular Pressing[J]. Acta Materialia, 1998, 46(5): 1589-1599
[22] Mishra A, Kad B K, Gregori F, et al. Microstructural evolution in copper subjected to severe plastic deformation: Experiments and analysis[J]. Acta Materialia, 2007, 55(1): 13-28
[23] Su C W, Lu L, Lai M O. A model for the grain refinement mechanism in equal channel angular pressing of Mg alloy from microstructural studies[J]. Materials Science and Engineering, 2006, A434(1-2): 227-236
[24] Mishin O V, Gertsman V Y, Valiev R Z, et al. Grain boundary distribution andtexture in ultrafine-grained copper produced by severe plastic deformation[J]. Scripta Materialia, 1996, 35(7): 873-878
[25] Saito Y, Utsunomiya H, Suzuki H, et al. Improvement in the r-Value of Aluminum Strip by a Continuous Shear Deformation Process[J]. Scripta Materialia, 2000, 42(12): 1139-1144
[26] Utsunomiya H, Hatsuda K, Sakai T, et al. Continuous grain refinement of aluminum strip by Conshearing[J]. Materials Science and Engineering, 2004, A372(1-2): 199-206.
[27] Lee J C, Seok H K, Han J H, et al. Controlling the textures of the metal strips via the continuous confined strip shearing (C2S2) process[J]. Materials Research Bulletin, 2001, 36(1): 997-1004
[28] Suh J Y, Han J H, Oh K H, et al. Effect of deformation histories on texture evolution during equal-channel and dissimilar-channel angular pressing[J]. Scripta Materialia, 2003, 49(2): 185-190
[29] Nam C Y, Han J H, Chung Y H, et al. Effect of precipitates on microstructural evolution of 7050 Al alloy sheet during equal channel angular rolling[J], Materials Science and Engineering, 2003, A347(1-2): 253-257
[30] Lee J C, Seok H K, Suh J Y. Microstructural evolutions of the Al strip prepared by cold rolling and continuous equal channel angular pressing[J]. Acta Materialia, 2002, 50(16): 4005-4019
[31] Lee J C, Seok H K, Suh J Y, et al. Structural evolution of a strip-cast Al alloy sheet Processed by continuous equal-channel angular pressing[J]. Metallurgical and Materials Transactions, 2002, A33(1): 665-673
[32] Park J W, Kim J W, Chung Y H, Grain refinement of steel plate by continuous equal-channel angular process[J]. Scripta Materialia, 2004, 51(2): 181-184
[33] Han J H, Huh M Y, Suh J Y, et al. Controlling the textures of the Al alloy sheet via dissimilar channel angular pressing[J]. Materials Science and Engineering, 2005, A394(1-2): 60-65
[34] Qin J N, Han J H, Zhang G D, et al. Characteristic of textures evolution induced by equal channel angular pressing in 6061 aluminum sheets[J]. Scripta Materialia, 2004, 51(2): 185-189
[35] Qin J N, Zhang D, Zhang G D, et al. Effect of temperature on texture formation of 6061 aluminum sheet in equal-channel angular pressing[J]. Materials Science and Engineering, 2005, A408(1-2): 79-84
[36] Chaudhury P K, Cherukuri B, Srinivasan R. Scaling up of equal channel angularpressing (ECAP) and its effect on mechanical properties, microstructure, and hot workability of Al 6061[J]. Materials Science and Engineering, 2005, A410-411(1): 316-318.
[37] Raab G J, Valiev R Z, Lowe T C, et al. Continuous processing of ultrafine grained Al by ECAP-Conform[J]. Materials Science and Engineering, 2004, A382(1-2): 30-34
[38] Del Valle J A, Carreno F, Ruano O A. Influence of texture and grain size on work hardening and ductility in magnesium-based alloys processed by ECAP and rolling[J]. Acta Materialia, 2006, 54(16): 4247-4259
[39] Lapovok R, Thomson P F, Cottam R, et al. The effect of grain refinement by warm equal channel angular extrusion on room temperature twinning in magnesium alloy ZK60[J]. Journal of Materials Science, 2005, 40(1): 1699-1708
[40] Mabuchi M, Iwasaki H, Yanase K, et al. Low temperature superplasticity in an AZ91 Magnesium alloy processed by ECAE[J]. Scripta Materialia, 1997, 36(6): 681-686
[41] Horita Z, Furukawa M, Nemoto M, et al. Superplastic forming at high strain rates after severe plastic deformation[J]. Acta Materialia, 2000, 48(14): 3633-3640
[42] Yoshida Y, Cisar L, Kamado S, et al. Effect of Microstructural Factors on Tensile Properties of an ECAE-Processed AZ31 Magnesium Alloy[J]. Materials Transactions, 2003, 44(4): 468-475
[43] Koike J. New Deformation Mechanisms in Fine-Grain Mg Alloys[J]. Materials Science Forum, 2003, 419-422(1): 189-194
[44] 吉田雄, Cisar C, 鎌土重晴ら. ECAE 加工した AZ31 マグネシウム合金の引張特性及ぼすミクロ組織因子の影响[J]. 軽金属, 2002, 52(11): 559-565
[45] Mukai T, Yamanoi M, Watanabe H, et al. Ductility enhancement in AZ31 magnesium alloy by controlling its grain structure[J]. Scripta Materialia, 2001, 45(1): 89-94
[46] Kim H K, Kim W J. Microstructural instability and strength of an AZ31 Mg alloy after severe plastic deformation[J]. Materials Science and Engineering, 2004, A385(1-2): 300-308
[47] Doege E, Dr?der K. Sheet metal forming of magnesium wrought alloys — formability and process technology[J]. Journal of Materials Processing Technology, 2001, 115(1): 14-19
[48] 程永奇. AZ31 镁合金板材等径角轧制及冲压性能研究[D]: 长沙湖南大学博士论文, 2007: 15-39
[49] Yoshida Y, Cisar L, Kamado S, et al.Texture development of AZ31 magnesium alloy during ECAE processing[J]. Materials Science Forum, 2003, 419-422(1): 533-538
[50] Segal V M. Slip line solutions, deformation mode and loading history during equal channel angular extrusion[J]. Materials Science and Engineering, 2003, A345(1-2): 36-46
[51] Luis Pérez C J. On the correct selection of the channel die in ECAP processes[J]. Scripta Materialia, 2004, 50(3): 387-393
[52] Galiyev A, Sitdikov O, Kaibyshev R. Deformation behavior and controlling mechanisms for plastic flow of magnesium and magnesium alloy[J]. Materials Transactions, 2003, 44 (4): 426-435
[53] Barnett M R. Influence of deformation conditions and texture on the high temperature flow stress of magnesium AZ31[J]. Journal of Light Metals, 2001, 1(3): 167-177
[54] 郭强, 张辉, 陈振华, 等. AZ31 镁合金的高温热压缩流变应力行为的研究[J].湘潭大学自然科学学报, 2004, 26(3): 108-111.
[55] Lin J, Lin D L, Mao D L. Mechanical properties and microstructure of AZ31 Mg alloy processed by two-step equal channel angular extrusion[J]. Materials Letters, 2005, 59(18): 2267-2270
[56] 丁水,于彦东,张凯锋,等. MB15 镁合金板材的超塑性能研究[J]. 锻压技术, 2003, 28(3): 44-46
[57] Mukai T, Matsuoka S, Miyamoto S, et al. Effects of extrusion conditions on microstructure and mechanical properties of AZ31B magnesium alloy extrusions[J]. Journal of Materials Processing Technology, 2003, 141(2): 207-212
[58] 黄光胜,汪凌云,范永革. AZ31B 镁合金挤压工艺研究[J]. 金属成形工艺, 2002, 20(5): 11-14
[59] Oishi Y, Kawabe N, Hoshima A, et al. Development of High Strength Magnesium Alloy Wire[J]. SEI Technical Review, 2003, 56(6): 54-58
[60] Pérez-Prado M T, Ruano O A. Texture evolution during annealing of magnesium AZ31 alloy[J]. Scripta Materialia, 2002, 46(2): 149-155
[61] 杨平,任学平,赵祖德. AZ31 镁合金热成形及退火过程的组织与织构[J]. 材料热处理学报, 2003, 24(4): 12-16
[62] J?ger A, Luká? P, G?rtnerová V, et al. Influence of annealing on the microstructure of commercial Mg alloy AZ31 after mechanical forming[J]. Materials Science and Engineering, 2006, A432(1-2): 20-25
[63] Wagner F, Bozzolo N, Van Landuyt O, et al. Evolution of recrystallization texture and microstructure in low alloyed titanium sheets[J]. Acta Materialia, 2002, 50(5): 1245-1259
[64] Koike J, Kobayashi T, Mukai T, et al. The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys[J]. Acta Materialia, 2003, 51(7): 2055-2065
[65] Huang Z W, Yoshida Y, Cisar L, et al. Microstructures and Tensile Properties of Wrought Magnesium Alloys Processed by ECAE[J]. Materials Science Forum, 2003, 419-422(1): 243-248
[66] 王占学. 塑性加工金属学[M]. 北京: 冶金工业出版社, 1991: 231
[67] 钟家湘,郑秀华,刘颖. 金属学教程[M]. 北京:北京理工大学出版社, 1995: 304