An as-cast high purity coarse-grained aluminum was deformed by dynamic equal channel angular pressing (D-ECAP) at high strain rate for one pass at room temperature.The twins formed during extrusion were studied with electron backscatter diffraction.The results show that deformation twins and annealing twins can be synthesized simultaneously in the coarse-grained aluminum via D-ECAP, which can be differentiated by their morphology, Kernel average misorientation (KAM) and the misorientation between adjacent grains.Due to the high strain rate and large shear deformation of D-ECAP, deformation twins with size of several hundred microns can be formed in aluminum with high stacking fault energy, and their shapes are lenticular.The twin boundaries deviate from ∑3 60°〈111〉 orientation relationship as a result of subsequent deformation, and the KAM values are mainly between 0.6°-1.8°.The high strain rate shear deformation contributes to the formation of abundant stacking fault, intricate dislocation patterns, and high deformation stored energy, and thus the ensuing temperature rise facilitates the formation of annealing twins.The morphology of annealing twins is irregular, but the orientation relationship of annealing twin boundaries is more close to ∑3 60°〈111〉 and the KAM values of annealing twins are mainly between 0.2°-0.5°.
刘敬勇, 卢磊, 钟政烨. 高应变速率下等径角挤压高纯粗晶铝中的形变孪晶与退火孪晶[J]. 材料工程, 2021, 49(4): 89-94.
Jing-yong LIU, Lei LU, Zheng-ye ZHONG. Deformation twins and annealing twins in high purity coarse-grained aluminum by equal channel angular pressing at high strain rate. Journal of Materials Engineering, 2021, 49(4): 89-94.
SONG G S , JI K S , ZHANG S H . Cyclic torsion of AZ31 magnesium alloy rod and its effect on mechanical property[J]. Journal of Materials Engineering, 2019, 47 (9): 46- 54.
2
LU L , SHEN Y , CHEN X , et al. Ultrahigh strength and high electrical conductivity in copper[J]. Science, 2004, 304 (5669): 422- 426.
doi: 10.1126/science.1092905
LU L , LU K . Metallic materials with nano-scale twins[J]. Acta Metallurgica Sinica, 2010, 46 (11): 1422- 1427.
4
HUNTER A , BEYERLEIN I J . Stacking fault emission from grain boundaries: material dependencies and grain size effects[J]. Materials Science and Engineering: A, 2014, 600, 200- 210.
doi: 10.1016/j.msea.2014.02.030
DONG M H , HAN P D , ZHANG C L , et al. First-principles study of stacking fault energy and deformation twin energy in Al-Mg alloys[J]. Acta Metallurgica Sinica, 2011, 47 (5): 573- 577.
6
HAN W , CHENG G , LI S , et al. Deformation induced microtwins and stacking faults in aluminum single crystal[J]. Physical Review Letters, 2008, 101 (11): 115505.
doi: 10.1103/PhysRevLett.101.115505
LIU M P , WANG J , JIANG T H , et al. Stacking faults and deformation twins in Al-Mg alloys subjected to high pressure torsion[J]. The Chinese Journal of Nonferrous Metals, 2014, 24 (6): 1383- 1392.
8
CAO B , DAPHALAPURKAR N P , RAMESH K T . Ultra-high-strain-rate shearing and deformation twinning in nanocrystalline aluminum[J]. Meccanica, 2015, 50 (2): 561- 574.
doi: 10.1007/s11012-014-9952-7
9
ZHAO F , WANG L , FAN D , et al. Macrodeformation twins in single-crystal aluminum[J]. Physical Review Letters, 2016, 116 (7): 075501.
doi: 10.1103/PhysRevLett.116.075501
10
HAN W , ZHANG Z , WU S , et al. Combined effects of crystallographic orientation, stacking fault energy and grain size on deformation twinning in fcc crystals[J]. Philosophical Magazine, 2008, 88 (24): 3011- 3029.
doi: 10.1080/14786430802438168
11
YAMAGUCHI D , HORITA Z , NEMOTO M , et al. Significance of adiabatic heating in equal-channel angular pressing[J]. Scripta Materialia, 1999, 41 (8): 791- 796.
doi: 10.1016/S1359-6462(99)00233-X
12
KAPOOR R , NEMATN S . Determination of temperature rise during high strain rate deformation[J]. Mechanics of Materials, 1998, 27 (1): 1- 12.
doi: 10.1016/S0167-6636(97)00036-7
13
PEROCHEAU F , DRIVER J . Slip system rheology of Al-1% Mn crystals deformed by hot plane strain compression[J]. International Journal of Plasticity, 2002, 18 (2): 185- 202.
doi: 10.1016/S0749-6419(00)00075-9
14
LUGO N , LLORCA N , CABRERA J , et al. Microstructures and mechanical properties of pure copper deformed severely by equal-channel angular pressing and high pressure torsion[J]. Materials Science and Engineering: A, 2008, 477 (1/2): 366- 371.
15
BRANDON D . The structure of high-angle grain boundaries[J]. Acta Metallurgica, 1966, 14 (11): 1479- 1484.
doi: 10.1016/0001-6160(66)90168-4
16
LOU C , ZHANG X , DUAN G , et al. Characteristics of twin lamellar structure in magnesium alloy during room temperature dynamic plastic deformation[J]. Journal of Materials Science & Technology, 2014, 30 (1): 41- 46.
17
LIN H P , CHEN Y C , CHEN D , et al. Effect of cold deformation on the recrystallization behavior of FePd alloy at the ordering temperature using electron backscatter diffraction[J]. Materials Characterization, 2014, 94, 138- 148.
doi: 10.1016/j.matchar.2014.05.018
18
LU H , SIVAPRASAD P , DAVIES C H J . Treatment of misorientation data to determine the fraction of recrystallized grains in a partially recrystallized metal[J]. Materials Characterization, 2003, 51 (5): 293- 300.
doi: 10.1016/j.matchar.2004.01.005
19
JIN Y , LIN B , BERNACKI M , et al. Annealing twin development during recrystallization and grain growth in pure nickel[J]. Materials Science and Engineering: A, 2014, 597, 295- 303.
doi: 10.1016/j.msea.2014.01.018
20
CHEN M , MA E , HEMKER K J , et al. Deformation twinning in nanocrystalline aluminum[J]. Science, 2003, 300 (5623): 1275- 1277.
doi: 10.1126/science.1083727
21
GRAY G T Ⅲ . High-strain-rate deformation: mechanical behavior and deformation substructures induced[J]. Annual Review of Materials Research, 2012, 42, 285- 303.
doi: 10.1146/annurev-matsci-070511-155034
MISZCZYK M M , PAUL H , DRIVER J H , et al. Recrystallization nucleation in stable aluminium-base single crystals: crystallography and mechanisms[J]. Acta Materialia, 2017, 125, 109- 124.
doi: 10.1016/j.actamat.2016.11.054
24
CAHOON J R , LI Q Y , RICHARDS N L . Microstructural and processing factors influencing the formation of annealing twins[J]. Materials Science and Engineering: A, 2009, 526 (1/2): 56- 61.
25
WANG W , BRISSET F , HELBERT A , et al. Influence of stored energy on twin formation during primary recrystallization[J]. Materials Science and Engineering: A, 2014, 589, 112- 118.
doi: 10.1016/j.msea.2013.09.071
26
FIELD D P , EAMES R C , LILLO T M . The role of shear stress in the formation of annealing twin boundaries in copper[J]. Scripta Materialia, 2006, 54 (6): 983- 986.
doi: 10.1016/j.scriptamat.2005.11.037
27
MAHAJAN S , PANDE C , IMAM M , et al. Formation of annealing twins in fcc crystals[J]. Acta Materialia, 1997, 45 (6): 2633- 2638.
doi: 10.1016/S1359-6454(96)00336-9
28
UPMANYU M , SROLOVITZ D , SHVINDLERMAN L , et al. Misorientation dependence of intrinsic grain boundary mobility: simulation and experiment[J]. Acta Materialia, 1999, 47 (14): 3901- 3914.
doi: 10.1016/S1359-6454(99)00240-2
29
JIN Z H , GUMBSCH P , ALBE K , et al. Interactions between non-screw lattice dislocations and coherent twin boundaries in face-centered cubic metals[J]. Acta Materialia, 2008, 56 (5): 1126- 1135.
doi: 10.1016/j.actamat.2007.11.020