J. Mater. Sci. Technol. ›› 2019, Vol. 35 ›› Issue (9): 2058-2063.DOI: 10.1016/j.jmst.2019.05.013
• Orginal Article • Previous Articles Next Articles
Lifeng Zhanga, Shangyi Maa, Weizhen Wangba, Zhiqing Yanga*(), Hengqiang Yea
Received:
2018-09-18
Revised:
2018-11-05
Accepted:
2018-11-05
Online:
2019-09-20
Published:
2019-07-26
Contact:
Yang Zhiqing
About author:
1 These authors contributed equally to this work.
Lifeng Zhang, Shangyi Ma, Weizhen Wang, Zhiqing Yang, Hengqiang Ye. Atomic structure and enhanced thermostability of a new structure MgYZn4 formed by ordered substitution of Y for Mg in MgZn2 in a Mg-Zn-Y alloy[J]. J. Mater. Sci. Technol., 2019, 35(9): 2058-2063.
Fig. 1. Low-magnification HAADF-STEM images showing morphology of plate-like phases in as-cast (a, b) and annealed at 625 K for 1 h (c) samples of Mg-3.6Zn-0.6Y alloy. The inset in Fig. 1c is Zn and Y profiles of EDXS line-scanning along the red line. The yellow arrow in Fig. 1c points to a newly formed IQC precipitate, which will not be discussed in the present paper. (d-h) Electron micro-diffraction patterns of plate-like precipitates recorded along [0001]α, [10$\bar{1}$0]α, [11$\bar{2}$0]α, [01$\bar{1}$0]α and [2$\bar{11}$0]α zone axes, respectively.
Fig. 2. (a and b) Atomic-resolution HAADF-STEM images of C14 MgZn2 recorded along the 〈11$\bar{2}$0〉 and 〈10$\bar{1}$0〉 zone axes, respectively. The insets are the corresponding atomic projections and simulated images. (c-f) Atomic-resolution HAADF-STEM images of plate-like phase recorded along [11$\bar{2}$0]P, [01$\bar{1}$0]P, [$\bar{1}$2$\bar{1}$0]P and [10$\bar{1}$0]P zone axes, respectively.
Fig. 3. (a) Schematic diagram showing the substitution of heavy atoms for Mg in a 2 × 2×1 MgZn2 supercell. (b) [0001] projection of the 2 × 2×1 supercell with a red rectangular outlining a reduced unit cell of MgYZn4. (c) Unit cell of MgYZn4. Arrows “d” - “g” in (b) and (c) indicate the four observation directions of atomic-resolution imaging. The zone axes indicated by “d” - “g” which are respectively [11$\bar{2}$0]P, [01$\bar{1}$0]P, [$\bar{1}$2$\bar{1}$0]P and [10$\bar{1}$0]P in the four-number miller indices for hexagonal structures become [110], [310], [100] and [010], respectively, in the three-number miller indices for the orthorhombic MgYZn4. (d-g) Simulated images for orthorhombic MgYZn4 along zone axes [110], [310], [100] and [010], respectively.
Structure | Ef |
---|---|
Mg4Zn8 | -0.152 |
Mg3Zn9 | -0.139 |
Mg3YZn8 | -0.173 |
MgYZn4 | -0.313 |
Table 1 Formation energy Ef (eV/atom) for structures formed by substitution of Zn or Y for Mg in MgZn2.
Structure | Ef |
---|---|
Mg4Zn8 | -0.152 |
Mg3Zn9 | -0.139 |
Mg3YZn8 | -0.173 |
MgYZn4 | -0.313 |
Atom | Wyckoff position | x/a | y/b | z/c |
---|---|---|---|---|
Mg | 4g | 0 | 0.15934 | 0.93678 |
Y | 4g | 0.5 | 0.32860 | 0.05781 |
Zn1 | 8h | 0.74528 | 0.41880 | 0.74757 |
Zn2 | 4g | 0.5 | 0.17351 | 0.74362 |
Zn3 | 2d | 0.5 | 0 | 0.5 |
Zn4 | 2b | 0.5 | 0 | 0 |
Table 2 Wyckoff position and coordinates of atoms in MgYZn4, according to atom positions in the structure model after first-principles relaxation. The a and c axes of MgYZn4 are arbitrarily set parallel to those of C14 MgZn2, and the space group is thus described as Pmnn which is equivalent to Pnnm.
Atom | Wyckoff position | x/a | y/b | z/c |
---|---|---|---|---|
Mg | 4g | 0 | 0.15934 | 0.93678 |
Y | 4g | 0.5 | 0.32860 | 0.05781 |
Zn1 | 8h | 0.74528 | 0.41880 | 0.74757 |
Zn2 | 4g | 0.5 | 0.17351 | 0.74362 |
Zn3 | 2d | 0.5 | 0 | 0.5 |
Zn4 | 2b | 0.5 | 0 | 0 |
|
[1] | L.Y. Zhao, H. Yan, R.S. Chen, En-Hou Han. Orientations of nuclei during static recrystallization in a cold-rolled Mg-Zn-Gd alloy [J]. J. Mater. Sci. Technol., 2021, 60(0): 162-167. |
[2] | Chunduo Dai, Tianliang Zhao, Cuiwei Du, Zhiyong Liu, Dawei Zhang. Effect of molybdenum content on the microstructure and corrosion behavior of FeCoCrNiMox high-entropy alloys [J]. J. Mater. Sci. Technol., 2020, 46(0): 64-73. |
[3] | Shuo Wang, Chi Zhang, Xin Li, Houbing Huang, Junsheng Wang. First-principle investigation on the interfacial structure evolution of the δ'/θ'/δ' composite precipitates in Al-Cu-Li alloys [J]. J. Mater. Sci. Technol., 2020, 58(0): 205-214. |
[4] | Yanke Liu, Yulong Cai, Chenggang Tian, Guoliang Zhang, Guoming Han, Shihua Fu, Chuanyong Cui, Qingchuan Zhang. Experimental investigation of a Portevin-Le Chatelier band in Ni‒Co-based superalloys in relation to γʹ precipitates at 500 ℃ [J]. J. Mater. Sci. Technol., 2020, 49(0): 35-41. |
[5] | Qiang Lu, Kai Li, Haonan Chen, Mingjun Yang, Xinyue Lan, Tong Yang, Shuhong Liu, Min Song, Lingfei Cao, Yong Du. Simultaneously enhanced strength and ductility of 6xxx Al alloys via manipulating meso-scale and nano-scale structures guided with phase equilibrium [J]. J. Mater. Sci. Technol., 2020, 41(0): 139-148. |
[6] | Shun Zhang, Yong Sun, Ruizhi Wu, Xiang Wang, Xiao-Bo Chen, Carlos Fernandez, Qiuming Peng. Coherent interface strengthening of ultrahigh pressure heat-treated Mg-Li-Y alloys [J]. J. Mater. Sci. Technol., 2020, 51(0): 79-83. |
[7] | Y.H. Gao, L.F. Cao, J. Kuang, J.Y. Zhang, G. Liu, J. Sun. Dual effect of Cu on the Al3Sc nanoprecipitate coarsening [J]. J. Mater. Sci. Technol., 2020, 37(0): 38-45. |
[8] | Zhengliang Liu, Shenglong Zhu, Mingli Shen, Yixuan Jia, Wen Wang, Fuhui Wang. Microstructure and cavitation erosion behavior of sputtered NiCrAlTi coatings with and without N incorporations [J]. J. Mater. Sci. Technol., 2020, 54(0): 211-222. |
[9] | Xiaoxiao Wei, Li Jin, Fenghua Wang, Jing Li, Nan Ye, Zhenyan Zhang, Jie Dong. High strength and ductility Mg-8Gd-3Y-0.5Zr alloy with bimodal structure and nano-precipitates [J]. J. Mater. Sci. Technol., 2020, 44(0): 19-23. |
[10] | Weiyi Wang, Qinglin Pan, Geng Lin, Xiaoping Wang, Yuqiao Sun, Xiangdong Wang, Ji Ye, Yuanwei Sun, Yi Yu, Fuqing Jiang, Jun Li, Yaru Liu. Microstructure and properties of novel Al-Ce-Sc, Al-Ce-Y, Al-Ce-Zr and Al-Ce-Sc-Y alloy conductors processed by die casting, hot extrusion and cold drawing [J]. J. Mater. Sci. Technol., 2020, 58(0): 155-170. |
[11] | Kaustubh Bawane, Kathy Lu. Microstructure evolution of nanostructured ferritic alloy with and without Cr3C2 coated SiC at high temperatures [J]. J. Mater. Sci. Technol., 2020, 43(0): 126-134. |
[12] | Tao Yuan, Xin Song, Xianglong Zhou, Wentao Jia, Munzali Musa, Jingdong Wang, Tianyu Ma. Role of primary Zr-rich particles on microstructure and magnetic properties of 2:17-type Sm-Co-Fe-Cu-Zr permanent magnets [J]. J. Mater. Sci. Technol., 2020, 53(0): 73-81. |
[13] | Wenyin Xue, Jinhua Zhou, Yongfeng Shen, Weina Zhang, Zhenyu Liu. Micromechanical behavior of a fine-grained China low activation martensitic (CLAM) steel [J]. J. Mater. Sci. Technol., 2019, 35(9): 1869-1876. |
[14] | Guangyu Liu, Shohreh Khorsand, Shouxun Ji. Electrochemical corrosion behaviour of Sn-Zn-xBi alloys used for miniature detonating cords [J]. J. Mater. Sci. Technol., 2019, 35(8): 1618-1628. |
[15] | Shude Ji, Shiyu Niu, Jianguang Liu. Dissimilar Al/Mg alloys friction stir lap welding with Zn foil assisted by ultrasonic [J]. J. Mater. Sci. Technol., 2019, 35(8): 1712-1718. |
Viewed | ||||||
Full text |
|
|||||
Abstract |
|
|||||