Microstructural evolution of a commercial pure Ni processed by ambient and cryogenic rolling
LI Yan1, NI Song1, CHEN Gang2, SONG Min1
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. School of Materials Science and Engineering, Hunan University, Changsha 410082, China
Abstract:The hardness and microstructural evolutions of a commercial pure nickel subjected to rolling (thickness reduction is 20%, 40% and 60%, respectively) at room temperature and cryogenic temperature were investigated using transmission electron microscope (TEM), optical microscope and Vickers microhardness testing. The results show that, the dislocation slip dominates the deformation process at small strain when the sample is rolled at ambient temperature. As the strain increases, dislocation and twins appeared to coordinate the deformation. When the sample is rolled at cryogenic temperature, a larger density of dislocations and more twins can be observed at small strain, compared to the sample rolled at the ambient temperature. In addition, the grain refinement process of the cryogenically treated sample is much faster than the room temperature rolled sample because the interaction between dislocations and MBs/twins is more severe due to the low speed of dynamic recovery. Both samples have a sharp hardness increase at small strain, then the hardness increases softly with increasing the strain. The cryogenically treated sample always has a higher hardness due to a high density of the dislocations.
李艳, 倪颂, 陈刚, 宋旼. 纯镍室温轧制与液氮冷轧的微观结构演变[J]. 粉末冶金材料科学与工程, 2018, 23(6): 575-581.
LI Yan, NI Song, CHEN Gang, SONG Min. Microstructural evolution of a commercial pure Ni processed by ambient and cryogenic rolling. Materials Science and Engineering of Powder Metallurgy, 2018, 23(6): 575-581.
[1] ISLAMGALIEV R K, ALEXANDROW I V, VALIEV R Z.Bulk nanostructured materials from severe plastic deformation[J]. Progress in Material Science, 2000, 45(2): 103-189. [2] HEBESBERGER T, STUWE H P, VORHAUER A, et al.Structure of Cu deformed by high pressure torsion[J]. Acta Materialia, 2005, 53(2): 393-402. [3] CHINH N Q, SZONMMER P, CSANADI T, et al.Flow processes at low temperature in ultrafine-grained aluminum[J]. Materials Science and Engineering: A, 2006, 432(1/2): 326-334. [4] MAURY N, ZHILYEAV A P, LANGON T G, et al.A critical examination of pure tantalum processed by high-pressure torsion[J]. Materials Science and Engineering A, 2015, 638(19): 174-182. [5] ZHAO Henglv, NI Song, SONG Min, et al.Grain refinement and phase transition of commercial pure zirconium processed by cold rolling[J]. Materials Characterization, 2017, 129(7): 149-155. [6] WU Wenqian, NI Song, SONG Min, et al.Amorphization at twin-twin intersected region in FeCoCrNi high-entropy alloy subjected to high-pressure torsion[J]. Material Characterization, 2017, 127(5): 111-115. [7] YANG Xiaohui, NI Song, SONG Min.Partial dislocation emission in a superfine grained Al-Mg alloy subject to multi-axial compression[J]. Material Science and Engineering A, 2015, 641(22): 189-193. [8] WILSDORF D K.Fundamentals of cell and subgrain structures in historical perspective[J]. Scripta Metallurgica et Materialia, 1992, 27(8): 951-956. [9] WRONSKI S, BACROIX B.Microstructure evolution and grain refinement in asymmetrically rolled aluminium[J]. Acta Materialia, 2014, 76(15): 404-412. [10] LU Jinzhong, WU Liujun, SUN Guifang, et al.Microstructural response and grain refinement mechanism of commercially pure titanium subjected to multiple laser shock peening impacts[J]. Acta Materialia, 2017, 127(6): 252-266. [11] ZUO Jinrong, HOU Longgang, SHI Jintao, et al.The mechanism of grain refinement and plasticity enhancement by an improved thermomechanical treatment of 7055 Al alloy[J]. Materials Science and Engineering A, 2017, 702(23): 42-52. [12] LIAO Xiaozhou, HUANG Jun, ZHU Yuntian, et al.Nanostructures and deformation mechanisms in a cryogenically ball-milled Al-Mg alloy[J]. Philosophical Magazine, 2003, 83(26): 3065-3075. [13] MISHRA A, KAD B, GREGORI F, et al.Microstructural evolution in copper subjected to severe plastic deformation: Experiments and analysis[J]. Acta Materialia, 2007, 55(1): 13-28. [14] WANG Kai, TAO Nairong, LU Ke, et al.Plastic strain-induced grain refinement at the nanometer scale in copper[J]. Acta Materialia, 2006, 54(19): 5281-5291. [15] TAO Nairong, LU Ke.Nanoscale structural refinement via deformation twinning in face-centered cubic metals[J]. Scripta Materialia, 2009, 60(12): 1039-1043. [16] CAO Yang, WANG Yanbo, ZHU Yuntian, et al.Grain boundary formation by remnant dislocations from the de-twinning of thin nano-twins[J]. Scripta Materialia, 2015, 100(8): 98-101. [17] MEYERS M A, VOHRINGER O.The onset of twinning in metals: a constitutive description[J]. Acta Materialia, 2001, 49(19): 4025-4039 [18] CHEN Mingwei, MA E, HEMKER K J, et al.Deformation twinning in nanocrystalline aluminum[J]. Science, 2003, 300(5623): 1275-1277. [19] HEO T W, WANG Yi, BHATTACHARYA S, et al.A phase-field model for deformation twinning[J]. Philosophical Magazine Letters, 2011, 91(2): 110-121. [20] BAY B, HANSEN N, HUGHES DA, et al.Evolution of fcc deformation structures in polyship[J]. Acta Metal, 1992, 40(2): 205-219. [21] WANG Yinmin, JIAO Tong, MA E.Dynamic process for nanostructure deveopment in Cu after severe cryogenic rolling deformation[J]. Material Transaction, 2003, 44(10): 926-1934. [22] WANG Yinmin, MA E, SHENG H, et al.Nanocrystalline grain structure developed in commerical purity Cu by low-temperature cold rolling[J]. Journal of Materials Research, 2002, 17(12): 3004-3007. [23] HUGHES D A, HANSEN N.Microstructural evolution in Ni during rolling from intermediate to large strains[J]. Metal lurgical Transactions A, 1993, 24(9): 2022-2037. [24] LIU Qing, JENSEN D J, HANSEN N.Effect of grain orientation on deformation structure in cold-rolled polycrystalline aluminium[J]. Acta Materialia, 1998, 46(16): 5819-5838. [25] SHARBAF M, TOROGHINEIJAD M R.Nano-grained copper strip produced by accumulative roll bonding process[J]. Materials Science and Engineering A, 2008, 473(1/2): 28-33. [26] LU Lie, SHEN Yongfeng, CHEN Xianhua, et al.Ultrahigh strength and high electrical conductivity in copper[J]. Science, 2004, 304(5669): 422-426. [27] WANG Yanbo, LAVERNIA EJ, LIAO Xiaozhou, et al.The role of stacking faults and twin boundaries in grain refinement of a Cu-Zn alloy processed by high-pressure torsion[J]. Materials Science and Engineering A, 2010, 527(18/19): 4959-4966.