Interfacial precipitation in {10 $\bar{1}$ 2} twin boundaries of a Mg-Gd-Zn-Zr alloy

doi:10.1016/j.jmst.2021.03.054

Abstract

Abstract:

Twinning and precipitation play important roles in deformation and strengthening of magnesium alloys. In this work, interfacial precipitation in {10$\bar{1}$2} twin boundaries (TBs) of a cold-stamped Mg-12Gd-1.2Zn-0.4Zr alloy was investigated using atomic-resolution high-angle annular dark-field scanning transmission electron microscopy. Extended periodic segregation of Gd + Zn atoms in the ~86.2° {10$\bar{1}$2} TBs with basal-prismatic facets and in the symmetric tilting TBs (obviously > 86.2°) frequently occurred, resulted in the formation of new interfacial phases, namely β_TB’ having a monoclinic structure in the TBs with two segregation layers and β_TB having a tetragonal structure in the TBs with three or more segregation layers. The formation of β_TB clearly accelerates peak-aging and improves the alloy's strength.

Key words: Magnesium alloys, Twinning, Scanning/transmission electron microscopy (STEM), Segregation, Interfacial precipitate

Zixiang Yan, Qiang Yang, Fanzhi Meng, Rui Ma, Rirong Bao, Xiaojuan Liu, Jian Meng, Xin Qiu. Interfacial precipitation in {10 $\bar{1}$ 2} twin boundaries of a Mg-Gd-Zn-Zr alloy[J]. J. Mater. Sci. Technol., 2021, 93: 103-109.

Figures/Tables 7

Fig. 1. Microstructures and mechanical properties. (a) Optical micrograph of the stamped sample and (b) age-hardening curves at 150 °C, (c) compression stress-strain curves of the stamped and unstamped samples in solution and peak-aging conditions, (d) low-magnified HAADF-STEM image and (e) corresponding HR-TEM image showing profuse {10$\bar{1}$2} twins in the stamped sample and clear solute segregation at TBs (For interpretation of the references to color in this figure, the reader is referred to the web version of this article.).

Fig. 2. Precipitates in grains. Bright-field TEM images showing the precipitates in (a,b) the stamped and (c,d) the unstamped samples, with beam direction parallel to (a,c) [11$\bar{1}$0]Mg and (b,d) [0001]Mg.

Fig. 3. EDS analysis of the twin boundaries. (a) HADDF-STEM image and (b) the corresponding EDS mappings of Mg, Gd, Zn and Zr (For interpretation of the references to color in this figure, the reader is referred to the web version of this article.).

Fig. 4. Ordered segregation of Gd + Zn atoms in TBs. (a) Atomic-resolution HAADF-STEM image showing periodic segregation of Gd + Zn atoms in the {10$\bar{1}$2} TB, which is schematically illustrated in (b).

Fig. 5. Expanded Gd + Zn segregation at steps of TBs. (a) Atomic-resolution HAADF-STEM images showing extended periodic segregation of solute atoms in the BP facets of {10$\bar{1}$2} TB near the twin tip, and the enlarged images showing the structures of the steps with height of (b) h and (d) h/2, indicated by purple and orange arrows, respectively, in (a), and schematically illustrated in (c) and (e), respectively (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.).

Fig. 6. Expanded Gd + Zn segregation in tilting TBs. Atomic-resolution HAADF-STEM images showing the extended periodic segregation of Gd + Zn atoms in the STTBs (a) without and (c) with BP facets, schematically illustrated in (b) and (d), respectively.

Fig. 7. Precipitates in TBs. Atomic-resolution HAADF-STEM images showing the structures of interfacial phases formed in the (a) STTBs and (c) CTBs, schematically illustrated in (b) and (d), respectively. The proposed (e) unreasonable and (f) reasonable crystal structures for the interfacial phases, named as βTB’ and βTB in this work.

References 58

[1]	F. Wang, Y. Gu, R.J. McCabe, L. Capolungo, J.A. El-Awady, S.R. Agnew, Acta Mater., 195(2020), pp. 13-24.
[2]	S.R. Agnew, J.F. Nie, Scr. Mater., 63(2010), pp. 671-673.
[3]	L.R. Xiao, X.F. Chen, Y. Cao, H. Zhou, X.L. Ma, D.D. Yin, B. Ye, X.D. Han, Y.T. Zhu, Scr. Mater., 177(2020), pp. 69-73.
[4]	Q. Yang, S. Lv, P. Qin, F. Meng, X. Qiu, X. Hua, K. Guan, W. Sun, X. Liu, J. Meng, Mater. Des., 190(2020), Article 108566.
[5]	B.Y. Liu, F. Liu, N. Yang, X.B. Zhai, L. Zhang, Y. Yang, B. Li, J. Li, E. Ma, J.F. Nie, Z.W. Shan, Science, 365(2019), pp. 73-75.
[6]	D. Zhang, H. Wen, M.A. Kumar, F. Chen, L. Zhang, I.J. Beyerlein, J.M. Schoenung, S. Majajan, E.J. Lavernia, Acta Mater., 120(2016), pp. 75-85.
[7]	M.R. Barnett, Mater. Sci. Eng. A, 464(2007), pp. 1-7.
[8]	J. Bohlen, M.R. Nürnberg, J.W. Senn, D. Letzig, S.R. Agnew, Acta Mater., 55(2007), pp. 2101-2112.
[9]	S. Lyu, R. Zheng, W. Xiao, Y. Huang, S. Gavras, N. Hort, G. Li, C. Ma, Mater. Sci. Eng. A, 760(2019), pp. 426-430.
[10]	J.F. Nie, Y.M. Zhu, J.Z. Liu, X.Y. Fang, Science, 340(2013), pp. 957-960.
[11]	J.W. Christian, S. Mahajan, Prog. Mater. Sci., 39(1995), pp. 1-157.
[12]	Q. Yu, L. Qi, K. Chen, R.K. Mishra, J. Li, A.M. Minor, Nano Lett., 12(2012), pp. 887-892.
[13]	Q. Peng, Y. Sun, J. Wang, Q. Zu, M. Yang, H. Fu, Acta Mater., 192(2020), pp. 60-66.
[14]	H. Su, X. Zhou, S. Zheng, D. Wu, R. Chen, H. Ye, Z. Yang, Scr. Mater., 187(2020), pp. 113-118.
[15]	J. Wang, J.M. Molina-Aldareguia, J. LLorca, Acta Mater., 188(2020), pp. 215-227.
[16]	J. Wang, S.K. Yadav, J.P. Hirth, C.N. Tome, I.J. Beyerlein, Mater. Res. Lett., 1(2013), pp. 126-132.
[17]	J. Wang, J.P. Hirth, C.N. Tome, Acta Mater., 57(2009), pp. 5521-5530.
[18]	N. Stanford, R.K.W. Marceau, M.R. Barnett, Acta Mater., 82(2015), pp. 447-456.
[19]	Zhao X, Chen H, Wilson N, Liu Q, J.F. Nie, Nat. Commun., 10 (2019), p.3243
[20]	H. Zhou, G.M. Cheng, X.L. Ma, W.Z. Xu, S.N. Mathaudhu, Q.D. Wang, Y.T. Zhu, Acta Mater., 95(2015), pp. 20-29.
[21]	Y.M. Zhu, S.W. Xu, J.F. Nie, Acta Mater., 143(2018), pp. 1-12.
[22]	X.F. Chen, L.R. Xiao, Z.G. Ding, W. Liu, Y.T. Zhu, X.L. Wu, Scr. Mater., 178(2020), pp. 193-197.
[23]	M.S. Hooshmand, M. Ghazisaeidi, Acta Mater., 188(2020), pp. 711-719.
[24]	L. Li, Z. Li, A.K. da Silva, Z. Peng, H. Zhao, B. Gault, D. Raabe, Acta Mater., 178(2019), pp. 1-9.
[25]	M. Saadati, R.A. Khosroshahi, G. Ebrahimi, M. Jahazi, Mater. Sci. Eng. A, 706(2017), pp. 142-152.
[26]	L.R. Xiao, Y. Cao, S. Li, H. Zhou, X.L. Ma, L. Mao, X.C. Sha, Q.D. Wang, Y.T. Zhu, X.D. Han, Acta Mater., 162(2019), pp. 214-225.
[27]	D. Guan, J. Nutter, J. Sharp, J. Gao, W.M. Rainforth, Scr. Mater., 138(2017), pp. 39-43.
[28]	S.H. Lu, R.S.Chen D.Wu, E.-.H. Han, Mater. Des., 191(2020), Article 108600.
[29]	T.T.T. Trang, J.H. Zhang, J.H. Kim, A. Zargaran, J.H. Hwang, B.C. Suh, N.J. Kim, Nat. Commun., 9 (2018), p.2522.
[30]	Z.R. Zeng, Y.M. Zhu, S.W. Xu, M.Z. Bian, C.H.J. Davies, N. Birbilis, J.F. Nie, Acta Mater., 105(2016), pp. 479-494.
[31]	C.D. Barrett, A. Imandoust, H. El Kadiri, Scr. Mater., 146(2018), pp. 46-50.
[32]	T. Homma, N. Kunito, S. Kamado, Scr. Mater., 61(2009), pp. 644-647.
[33]	S.Z. Wu, T. Nakata, G.Z. Tang, C. Xu, X.J. Wang, X.W. Li, X.G. Qiao, M.Y. Zheng, L. Geng, S. Kamado, G.H. Fan, J. Mater. Sci. Technol., 73(2021), pp. 66-75.
[34]	C. Huang, C. Liu, S. Jiang, Y. Wan, Y. Gao, Mater. Sci. Eng. A, 807(2021), Article 140853.
[35]	Q. Yang, S. Lv, Z. Yan, X. Hua, X. Qiu, J. Meng, Mater. Des., 201(2021), Article 109482.
[36]	K. Wang, J. Wang, X. Dou, Y. Huang, N. Hort, S. Gavras, S. Liu, Y. Cai, J. Wang, F. Pan, J. Mater. Sci. Technol., 52(2020), pp. 72-82.
[37]	N. Su, X. Xue, H. Zhou, Y. Wu, Q. Deng, K. Yang, Q. Chen, B. Chen, L. Peng, Mater. Charact., 165(2020), Article 110396.
[38]	F. Zhang, Y. Ren, Z. Yang, H. Su, Z. Lu, C. Tan, H. Peng, K. Watanabe, B. Li, M.R. Barnett, M. Chen, Acta Mater., 188(2020), pp. 203-214.
[39]	G. Li, J. Zhang, R. Wu, S. Liu, B. Song, Y. Jiao, Q. Yang, L. Hou, J. Alloy. Compd., 777(2019), pp. 1375-1385.
[40]	Y. Zhang, Wei Rong, Y. Wu, L. Peng, J.F. Nie, N. Birbilis, J. Alloy. Compd., 777(2019), pp. 531-543.
[41]	Z. Tian, Q. Yang, K. Guan, Z.Y. Cao, J. Meng, Rare Met.(2020), 10.1007/s12598-020-01510-5, https://doi.org/
[42]	A. Sanaty-Zadeh, A.A. Luo, D.S. Stone, Acta Mater., 94(2015), pp. 294-306.
[43]	G. Garces, M.A. Munoz-Morris, D.G. Morris, J.A. Jimenez, P. Perez, P. Adeva, Intermetallics, 55(2014), pp. 167-176.
[44]	X.H. Shao, Q.Q. Jin, Y.T. Zhou, H.J. Yang, S.J. Zheng, B. Zhang, Q. Chen, X.L. Ma, Mater. Sci. Eng. A, 779(2020), Article 139109.
[45]	C. He, Z. Li, H. Chen, N. Wilson, J.F. Nie, Nat. Commun., 12 (2021), p.722.
[46]	J. Tu, X.Y. Zhang, Z.M. Zhou, C. Huang, Mater. Charact., 110 (2015), p.39.
[47]	Q. Sun, X.Y. Zhang, Y. Ren, J. Tu, Q. Liu, Scr. Mater., 90-91 (2014), p.41.
[48]	D. Hull, D.J. Bacon, Elsevier Ltd.(2011), pp. 109-112.
[49]	Y. Guo, B. Liu, W. Xie, Q. Luo, Q. Li, Scri. Mater., 193(2021), pp. 127-131.
[50]	Q. Luo, Y. Guo, B. Liu, Y. Feng, J. Zhang, Q. Li, K. Chou, J. Mater. Sci. Technol., 44(2020), pp. 171-190.
[51]	J. Wang, I.J. Beyerlein, C.N. Tome, Int. J. Plast., 56 (2014), p.156.
[52]	Y. Li, B. Hu, B. Liu, A. Nie, Q. Gu, J. Wang, Q. Li, Acta Mater., 187(2020), pp. 51-65.
[53]	Y. Guo, Q. Luo, B. Liu, Q. Li, Scr. Mater., 178(2020), pp. 422-427.
[54]	M.A. Easton, M.A. Gibson, D. Qiu, S.M. Zhu, J. Grobner, R. Schmid-Fetzer, J.F. Nie, M.X. Zhang, Acta Mater., 60(2012), pp. 4420-4430.
[55]	Y. Pang, D. Sun, Q. Gu, K.C. Chou, X. Wang, Q. Li, Cryst. Growth Des., 16(2016), pp. 2404-2415.
[56]	Y. Pang, Q. Li, Scr. Mater., 130(2017), pp. 223-228.
[57]	X. Xia, A. Sanaty-Zadeh, C. Zhang, A.A. Luo, D.S. Stone, CALPHAD, 60(2018), pp. 58-67.
[58]	J. Wei, C. Liu, Y. Wan, J. Shao, X. Han, G. Zhang, Mater. Charact., 167(2020), Article 110523.