{111}/{111} Near Singular Boundaries in a Dynamically Recrystallized Al-Zn-Mg-Cu Alloy Compressed at Elevated Temperature
LIU Guanghui1, WANG Weiguo1,2(), Rohrer Gregory S3, CHEN Song1,2, LIN Yan1,2, TONG Fang1, FENG Xiaozheng1, ZHOU Bangxin4
1.Institute of Grain Boundary Engineering, Fujian University of Technology, Fuzhou 350118, China 2.School of Materials Science and Technology, Fujian University of Technology, Fuzhou 350118, China 3.Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA15213 -3890, USA 4.Institute of Materials, Shanghai University, Shanghai 200072, China
Cite this article:
LIU Guanghui, WANG Weiguo, Rohrer Gregory S, CHEN Song, LIN Yan, TONG Fang, FENG Xiaozheng, ZHOU Bangxin. {111}/{111} Near Singular Boundaries in a Dynamically Recrystallized Al-Zn-Mg-Cu Alloy Compressed at Elevated Temperature. Acta Metall Sin, 2024, 60(9): 1165-1178.
Increasing the fraction of {111}/{111} near-singular boundaries ({111}/{111}-NSBs) has been reported as a primary solution to intergranular corrosion failure in Al-Zn-Mg-Cu alloys. The authors' previous work demonstrates that continuous static recrystallization resulting from a specific prestrain and annealing is conducive to the formation of {111}/{111}-NSBs in Al-Zn-Mg-Cu alloys. Therefore, the development of such boundaries in the alloys during dynamic recrystallization (DRX), particularly during discontinuous DRX (DDRX) and continuous DRX (CDRX) at elevated temperatures, should be elucidated. In the present work, an Al-Zn-Mg-Cu alloy containing 7.79%Zn, 1.53%Mg, and 1.68%Cu (mass fraction) was selected as the experimental material. A hot-rolled plate of the alloy was subjected to a two-stage solution treatment at 470oC for 12 h and 520oC for 6 h followed by cold rolling and recrystallization annealing. Three parallel samples cut from the recrystallized plate were compressed at 450, 480, and 520oC at a strain rate of 0.001 s-1 to a true strain of 1.20. The samples were water quenched immediately after the compression. Electron backscatter diffraction and grain boundary inter-connection measurement based on five-parameter analysis were performed to examine the microstructures and grain boundary character distributions of the compressed samples. The results indicate that the microstructures of the samples were uneven, exhibiting fine- and coarse-grained regions. Low-angle grain boundaries are dominant in the fine-grained regions, whereas high-angle grain boundaries are dominant in the coarse-grained regions. The fraction of {111}/{111}-NSBs increases with the compression temperature in fine- and coarse-grained regions. In the sample compressed at 520oC, the {111}/{111}-NSBs from the low-angle grain boundaries constitute 8.77% of all grain boundaries, while those from the high-angle grain boundaries constitute 4.53%. The stress-strain curves and the microstructures of the sample compressed at 450oC to a true strain of 0.36 show that primary DRX occurs at strains from 0.05 to 0.70. Furthermore, the coarse-grained microstructures and high-angle grain boundaries develop during the stage involving steady-state flow. When the strain increases from 0.70 to 1.20, secondary DRX (including DDRX and CDRX) occurs in some regions, leading to dramatic grain refinement and a sharp increase in flow stress. In this stage, CDRX intensifies with increasing compression temperature, and {111}/{111}-NSBs in the low-angle grain boundaries increase rapidly.
Fig.1 Orientation imaging microscopy (OIM) images (a, d, g), grain boundary network (GBN) maps (b, e, h), and the magnifications of the fine-grained regions as marked by the squares in Figs.1b, e, and h (c, f, i) for the samples A (a-c), B (d-f), and C (g-i) compressed at 450, 480, and 520oC, respectively (In Figs.1b, e, and h, red arrows point at the fine grains aggregated at the initial grain boundaries; the areas framed by the red dotted lines are the coarse-grained regions, the areas framed by the green dotted lines are the fine-grained regions)
Fig.2 Misorientation distribution (MD) maps of the reconstructed grain boundaries in the samples A (a), B (b), and C (c)
Sample
Rotation axis
NB
LF / %
NF / %
A
<001>
1340
2.50
2.52
<011>
3450
5.72
6.49
<012>
5593
10.20
10.52
<013>
5332
9.96
10.03
<111>
2594
4.92
4.88
<112>
6443
12.07
12.12
<113>
5545
10.59
10.43
<122>
7432
14.10
13.98
B
<001>
1349
2.40
2.44
<011>
3385
6.07
6.12
<012>
5620
10.08
10.16
<013>
5636
10.24
10.19
<111>
2804
5.03
5.07
<112>
6682
12.28
12.08
<113>
5846
10.58
10.57
<122>
7710
14.04
13.94
C
<001>
1371
2.73
2.60
<011>
3316
6.30
6.29
<012>
5484
10.21
10.40
<013>
5299
9.99
10.05
<111>
2573
4.79
4.88
<112>
6306
12.06
11.96
<113>
5505
10.59
10.44
<122>
7318
13.83
13.88
Table 1 Grain boundary (GB) statistics after-filtration according to the 8 low Miller index rotation axes in the samples A-C
Fig.3 MD maps of grain boundaries with specific rotation axis for the samples A-C (a) rotation around <001> (b) rotation around <011> (c) rotation around <012> (d) rotation around <013> (e) rotation around <111> (f) rotation around <112> (g) rotation around <113> (h) rotation around <122>
Fig.4 Five parameter grain boundary plane distributions of the low-angle grain boundary (LAGB) groups containing {111}/{111} near singular boundaries ({111}/{111}-NSB) in the sample C (A projection onto (001); MRD—multiple of random distribution) (a) <00>/10° (b) <011>/5° (c) <011>/10° (d) <012>/5° (e) <012>/10° (f) <013>/5° (g) <013>/10° (h) <111>/10° (i) <112>/5° (j) <112>/10° (k) <122>/5° (l) <122>/10°
Fig.5 Five parameter grain boundary plane distributions of the high-angle grain boundary (HAGB) groups containing {111}/{111}-NSB in the sample C (A projection onto (001)) (a) <111>/20° (b) <111>/25° (c) <111>/45° (d) <111>/50° (e) <111>/60° (f) <112>/15° (g) <112>/20° (h) <112>/25° (i) <122>/15° (j) <122>/25° (k) <122>/30° (l) <122>/35°
Fig.6 Weighted Gaussian misorientation distribution curves of two grain boundary groups containing {111}/{111}-NSBs in the sample C (FWHM—full width half maximum) (a) <111>/10° (b) <111>/45°
Sample
Misorientation
<uvw>/θ
Pi
%
Mi
Wi
(°)
Fi
%
F
%
A
<012>/5°
1.16
1.90
1.70
0.62
4.18
<013>/5°
1.11
1.64
2.01
0.58
<111>/5°
0.42
1.86
2.13
0.22
<111>/10°
0.71
1.85
2.09
0.37
<113>/10°
2.13
1.32
1.83
1.11
<122>/10°
2.49
1.37
2.11
1.28
B
<011>/5°
0.66
1.69
1.94
0.35
4.87
<011>/10°
1.11
1.43
2.00
0.58
<112>/5°
1.33
1.55
2.17
0.69
<013>/5°
1.31
1.30
1.78
0.68
<111>/5°
0.44
1.85
1.82
0.23
<111>/10°
0.73
1.61
2.29
0.38
<122>/5°
1.40
1.44
1.98
0.72
<122>/10°
2.39
1.57
2.12
1.24
C
<001>/10°
0.59
1.52
1.85
0.31
8.77
<011>/5°
0.54
1.59
1.69
0.29
<011>/10°
1.09
2.33
1.80
0.59
<012>/5°
1.18
1.51
2.01
0.61
<012>/10°
2.14
1.53
1.90
1.11
<013>/5°
1.25
1.31
2.26
0.64
<013>/10°
2.18
1.34
2.08
1.12
<111>/10°
0.71
1.74
1.80
0.37
<112>/5°
1.41
1.34
1.84
0.73
<112>/10°
2.23
1.49
2.10
1.15
<122>/5°
1.20
2.01
1.40
0.65
<122>/10°
2.32
1.48
2.02
1.20
Table 2 Statistics of the {111}/{111}-NSBs within the LAGB in the samples A-C
Fig.7 Relative frequency of {111}/{111}-NSB from the LAGB and HAGB in samples A-C
Sample
Misorientation
<uvw>/θ
Pi
%
Mi
Wi
(°)
Fi
%
F
%
A
<111>/15°
0.47
2.27
2.25
0.25
2.54
<111>/20°
0.34
1.98
1.79
0.18
<111>/35°
0.34
2.06
1.65
0.19
<111>/40°
0.30
1.32
2.05
0.16
<111>/45°
0.41
1.40
1.77
0.21
<112>/20°
1.04
1.42
1.88
0.54
<122>/20°
0.96
1.57
2.05
0.50
<122>/40°
0.99
1.24
2.15
0.51
B
<111>/25°
0.32
2.40
2.33
0.17
3.69
<111>/30°
0.27
1.55
1.44
0.14
<111>/35°
0.33
1.74
1.87
0.17
<111>/40°
0.36
1.53
1.57
0.19
<111>/50°
0.87
1.45
1.89
0.23
<111>/55°
0.52
2.35
2.07
0.28
<112>/15°
1.60
1.30
2.01
0.84
<1 2>/25°
0.84
1.22
2.06
0.43
<112>/30°
0.72
1.62
2.07
0.37
<122>/35°
0.77
1.25
2.06
0.39
<122>/40°
0.93
1.46
2.02
0.48
C
<111>/20°
0.30
2.30
1.96
0.16
4.53
<111>/25°
0.28
2.09
1.72
0.15
<111>/45°
0.42
1.72
1.95
0.22
<111>/50°
0.49
2.22
1.73
0.26
<111>/60°
0.36
1.88
2.17
0.19
<112>/15°
1.44
1.25
2.07
0.74
<112>/20°
0.97
1.29
2.09
0.50
<112>/25°
0.79
1.36
2.07
0.41
<122>/15°
1.20
1.35
2.04
0.62
<122>/25°
0.71
1.36
1.87
0.37
<122>/30°
0.92
1.36
1.74
0.48
<122>/35°
0.82
1.51
1.91
0.43
Table 3 Statistics of the {111}/{111}-NSBs within the HAGB in the samples A-C
Fig.8 Load-displacement (a) and stress-strain (b) curves of samples A-C
Fig.9 OIM images (a, c) and GBN maps (b, d) of the Al-Zn-Mg-Cu alloy compressed at 450oC with a strain rate 0.001 s-1 and true strain 0.36 (The area framed by the red dotted line in Fig.9b is the region where grains begin to refine) (a, b) compression plane (c, d) cross section
Fig.10 Kernel average misorientations (KAM) maps of fine-grained regions in samples A (a), B (b), and C (c)
Fig.11 GBN maps of HAGB and LAGB with different rotation angles in samples A (a), B (b), and C (c)
Fig.12 Overlapped {111} pole figure trace analyses for the {111}/{111}-NSBs from the LAGB and HAGB in samples A (a-d), B (e-h), and C (i-l) (a, b) <1>/5.7° (c, d) <1>/48.4° (e, f) <1>/6.2° (g, h) <111>/46.1° (i, j) <11>/8.2° (k, l) <11>/17.6°
Fig.13 Area fractions of continuous dynamic recrystallization (CDRX) (ƒCDRX) and discontinuous dynamic recrystallization (DDRX) (ƒDDRX) versus compressing temperatures for Al alloys (Compressed with a strain rate 0.001 s-1 and true strain 1.2)
Fig.14 Area fractions of CDRX and DDRX versus compressing strain rate for Al alloys (Compressed at 520oC with true strain 1.2)
1
Georgantzia E, Gkantou M, Kamaris G S. Aluminium alloys as structural material: A review of research [J]. Eng. Struct., 2021, 227: 111372
2
Aamir M, Giasin K, Tolouei-Rad M, et al. A review: Drilling performance and hole quality of aluminium alloys for aerospace applications [J]. J. Mater. Res. Technol., 2020, 9: 12484
3
Jiang L, Zhang Z H, Fu H D, et al. Corrosion behavior and mechanism of Al-Zn-Mg-Cu alloy based on the characterization of the secondary phases [J]. Mater. Charact., 2022, 189: 111974
4
Zhang Z G, Ma X W, Zhang C S, et al. Effect of stress-aging treatment on the mechanical and corrosion properties of Al-Zn-Mg-Cu alloy [J]. Mater. Sci. Eng., 2022, A838: 142791
5
Wang X D, Pan Q L, Wang W Y, et al. Effects of pre-strain and aging treatments on the mechanical property and corrosion resistance of the spray formed ultra-high strength Al-Zn-Mg-Cu alloy [J]. Mater. Charact., 2022, 194: 112381
6
Peng X Y, Li Y, Xu G F, et al. Effect of precipitate state on mechanical properties, corrosion behavior, and microstructures of Al-Zn-Mg-Cu alloy [J]. Met. Mater. Int., 2018, 24: 1046
7
Rao A C U, Vasu V, Govindaraju M, et al. Stress corrosion cracking behaviour of 7xxx aluminum alloys: A literature review [J]. Trans. Nonferrous Met. Soc. China, 2016, 26: 1447
8
Yang W C, Ji S X, Zhang Q, et al. Investigation of mechanical and corrosion properties of an Al-Zn-Mg-Cu alloy under various ageing conditions and interface analysis of η′ precipitate [J]. Mater. Des., 2015, 85: 752
9
Lin Y C, Zhang J L, Liu G, et al. Effects of pre-treatments on aging precipitates and corrosion resistance of a creep-aged Al-Zn-Mg-Cu alloy [J]. Mater. Des., 2015, 83: 866
10
Xiao Y P, Pan Q L, Li W B, et al. Influence of retrogression and re-aging treatment on corrosion behaviour of an Al-Zn-Mg-Cu alloy [J]. Mater. Des., 2011, 32: 2149
11
Jiang J T, Xiao W Q, Yang L, et al. Ageing behavior and stress corrosion cracking resistance of a non-isothermally aged Al-Zn-Mg-Cu alloy [J]. Mater. Sci. Eng., 2014, A605: 167
12
Yan J F, Hodge A M. Study of β precipitation and layer structure formation in Al 5083: The role of dispersoids and grain boundaries [J]. J. Alloys Compd., 2017, 703: 242
13
Alabbad B, Tin S. Effect of grain boundary misorientation on η phase precipitation in Ni-base superalloy 718Plus [J]. Mater. Charact., 2019, 151: 53
doi: 10.1016/j.matchar.2019.02.038
14
Aust K T. Grain boundary engineering [J]. Can. Metall. Q., 1994, 33: 265
15
Wang W G, Cai C H, Rohrer G S, et al. Grain boundary inter-connections in polycrystalline aluminum with random orientation [J]. Mater. Charact., 2018, 144: 411
16
Lee D S, Ryoo H S, Hwang S K. A grain boundary engineering approach to promote special boundaries in Pb-base alloy [J]. Mater. Sci. Eng., 2003, A354: 106
17
Liu Z Q, Wang W G. Study on Σ3 boundaries in an cold rolled and recrystallized Al-Cu alloy [J]. J. Chin. Electr Microsc. Soc., 2018, 37: 232
Du A H, Wang W G, Gu X F, et al. The dependence of precipitate morphology on the grain boundary types in an aged Al-Cu binary alloy [J]. J. Mater. Sci., 2021, 56: 781
19
Wang Z P, Wang W G, Rohrer G S, et al. {111}/{111} near singular boundaries in an Al-Zn-Mg-Cu Alloy recrystallized after rolling at different temperatures [J]. Acta Metall. Sin., 2023, 59: 947
王宗谱, 王卫国, Rohrer G S 等. 不同温度轧制Al-Zn-Mg-Cu合金再结晶后的{111}/{111}近奇异晶界 [J]. 金属学报, 2023, 59: 947
doi: 10.11900/0412.1961.2022.00027
20
Luo L, Liu Z Y, Bai S, et al. Hot deformation behavior considering strain effects and recrystallization mechanism of an Al-Zn-Mg-Cu alloy [J]. Materials, 2020, 13: 1743
21
Li B, Chu Z J, Du Y, et al. Hot deformation behavior and dynamic recrystallization kinetics of a novel sc and zr modified ultra-high-strength Al-Zn-Mg-Cu alloy [J]. J. Mater. Eng. Perform., 2020, 29: 7774
22
Ashrafizadeh S M, Eivani A R, Jafarian H R, et al. Improvement of mechanical properties of AA6063 aluminum alloy after equal channel angular pressing by applying a two-stage solution treatment [J]. Mater. Sci. Eng., 2017, A687: 54
23
Xu C L, Huang J W, Jiang F Q, et al. Dynamic recrystallization and precipitation behavior of a novel Sc, Zr alloyed Al-Zn-Mg-Cu alloy during hot deformation [J]. Mater. Charact., 2022, 183: 111629
24
Rohrer G S, Saylor D M, E 1 Dasher B, et al. The Distribution of Internal Interfaces in Polycrystals [J]. Ze. Metall., 2004, 95: 197
25
Saylor D M, Eldasher B S, Adams B L, et al. Measuring the five-parameter grain-boundary distribution from observations of planar sections [J]. Metall. Mater. Trans., 2004, 35A: 1981
26
Beladi H, Rohrer G S. The distribution of grain boundary planes in interstitial free steel [J]. Metall. Mater. Trans., 2013, 44A:115
27
Wang W G, Du A H, Yang X M, et al. Quantitative determination of grain boundary inter-connections [P]. Chin Pat, 202011173146.8, 2021
Yang X M, Wang W G, Gu X F. The near singular boundaries in BCC iron [J]. Philos. Mag., 2022, 102: 440
29
Wright S I, Larsen R J. Extracting twins from orientation imaging microscopy scan data [J]. J. Microsc., 2002, 205: 245
30
Yu Y N. Principles of Metallography [M]. 2nd Ed., Beijing: Metallurgical Industry Press, 2013: 970
余永宁. 金属学原理 [M]. 第2版. 北京: 冶金工业出版社, 2013: 970
31
Sun B, Zhang T B, Song L, et al. Microstructural evolution and dynamic recrystallization of a nickel-based superalloy PM EP962NP during hot deformation at 1150oC [J]. J. Mater. Res. Technol, 2022, 18: 1436
32
Humphreys F J, Hatherly M. Recrystallization and related annealing phenomena [M]. Oxford: Elsevier, 2012: 428
33
Zhang J J, Yi Y P, He H L, et al. Kinetic model for describing continuous and discontinuous dynamic recrystallization behaviors of 2195 aluminum alloy during hot deformation [J]. Mater. Charact., 2021, 181: 111492
34
Zhang J J, Yi Y P, Huang S Q, et al. Dynamic recrystallization mechanisms of 2195 aluminum alloy during medium/high temperature compression deformation [J]. Mater. Sci. Eng., 2021, A804: 140650
35
Winther G, Huang X, Godfrey A, et al. Critical comparison of dislocation boundary alignment studied by TEM and EBSD: Technical issues and theoretical consequences [J]. Acta Mater., 2004, 52: 4437
36
Zhao J H, Deng Y L, Tang J G. Grain refining with DDRX by isothermal MDF of Al-Zn-Mg-Cu alloy [J]. J. Mater. Res. Technol., 2020, 9: 8001
37
Tang J G, Yi Y P, He H L, et al. Hot deformation behavior and microstructural evolution of the Al-Cu-Li alloy: A study with processing map [J]. J. Alloys Compd., 2023, 934: 167755
