1.National Engineering Research Center of Light Alloys Net Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China 2.State Key Laboratory of Metal Matrix Composite, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
Cite this article:
WU Guohua, TONG Xin, JIANG Rui, DING Wenjiang. Grain Refinement of As-Cast Mg-RE Alloys: Research Progress and Future Prospect. Acta Metall Sin, 2022, 58(4): 385-399.
Magnesium rare-earth (Mg-RE) alloy castings with a large size and complex structure exhibit versatile prospects in critical aircraft, aerospace, and defense fields owing to their ultralow density, excellent specific strength, and high-temperature resistance. The grain refinement of cast Mg-RE alloys can significantly improve their strength, plasticity, toughness, and casting performance, which are critical for expanding their applications. In this work, the grain refinement mechanism of Mg alloys by introducing RE elements and heterogeneous particles is first discussed based on the classical theory of constitutional supercooling and heterogeneous nucleation. Various grain refinement technologies for Mg-RE alloy casting using chemical and physical methods are comprehensively summarized. Further, the influence of grain refinement on the casting performance, mechanical properties, and corrosion properties of Mg-RE cast alloys is thoroughly discussed. Finally, the deficiencies and development trends of the current grain refinement of Mg-RE alloys are discussed from the point of actual application requirements.
Fund: National Natural Science Foundation of China(U2037601);National Natural Science Foundation of China(51821001);National Natural Science Foundation of China(51775334);Research Program of Joint Research Center of Advanced Spaceflight Technologies(USCAST-2020-31)
Table 1 Slope of the liquidus (m), solute partition coefficient (k), and growth restriction factor(Q) of RE elements in Mg alloys (concentration of solute element Ci = 1.0%, mass fraction)[21]
Fig.1 Dependence of grain size of Mg alloys on the Q of the RE elements[22] (a) measured curves(b) fitted curve of all data
Fig.2 Possible orientation relationships between Al2Y particles and α-Mg matrix calculated by edge to edge model (E2EM) (a)[26] and the relation between atom spacing mismatches and interface energy of Al2RE particles and α-Mg (b)[27] (γNS—interfacial energy between nucleant and solid Mg, γNL—interfacial energy between nucleant and liquid Mg, γSL—interfacial energy between solid Mg and liquid Mg, θc—contact angle at the interface between nucleant and solid Mg, γc—the difference between γNL and γNS)
Fig.3 Microstructure of the Zr halo in Mg alloy containing Zr (a)[22], changes of grain size (d) and eutectic phase's volume fraction (fV) with Zr content in the Mg-10Gd-3Y-xZr alloy (b)[36]
Fig.4 Microstructures of Mg-10Y alloy grain-refined by Al (a, b) and Zr (c, d)[26] (a, c) as-cast state (b, d) solution treated at 550oC for 48 h (e) Al-Y phase observed in the cast Mg-10Y-Al alloy
Fig.5 Microstructures of the Al2Y particle and its orientation relationship with α-Mg matrix[27] (a) SEM image (b) cross section of the Al2Y (c) TEM image showing the Al2Y/Mg interface with the selected area electron diffraction (SAED) pattern (d) HRTEM image of Al2Y/Mg interface close to F1 facet in Fig.5c
Fig.6 SEM image of MgO particles in Mg melt with intensive melt shearing (a)[59] and HRTEM image of Zr adsorption layer at MgO/Mg interface (b)[60]
Fig.7 Average grain sizes of Mg-5Sm-xAl alloy with and without ultrasonic treatment (UT) (a), contribution rate of grain refinement (CRGR) by Al2Sm particles and UT (b)
Fig.8 OM images (a, b) and macro-photographs showing the effect of grain size on the hot tearing susceptibility (c, d) of Mg-4.5Zn-0.4Y (a, c) and Mg-4.5Zn-0.4Y-0.2Zr (b, d)[12]
1
Yang Y, Xiong X M, Chen J, et al. Research advances in magnesium and magnesium alloys world wide in 2020 [J]. J. Magnes. Alloy., 2021, 9: 705
2
Wu G H, Wang C L, Sun M, et al. Recent developments and applications on high-performance cast magnesium rare-earth alloys [J]. J. Magnes. Alloy., 2021, 9: 1
3
Xie J S, Zhang J H, You Z H, et al. Towards developing Mg alloys with simultaneously improved strength and corrosion resistance via RE alloying [J]. J. Magnes. Alloy., 2021, 9: 41
4
Peng Q M, Dong H W, Wang L D, et al. Microstructure and mechanical property of Mg-8.31Gd-1.12Dy-0.38Zr alloy [J]. Mater. Sci. Eng., 2008, A477: 193
5
Gao L, Chen R S, Han E H. Microstructure and strengthening mechanisms of a cast Mg-1.48Gd-1.13Y-0.16Zr (at.%) alloy [J]. J. Mater. Sci., 2009, 44: 4443
6
He S M, Zeng X Q, Peng L M, et al. Microstructure and strengthening mechanism of high strength Mg-10Gd-2Y-0.5Zr alloy [J]. J. Alloys Compd., 2007, 427: 316
7
Rong W, Wu Y J, Zhang Y, et al. Characterization and strengthening effects of γ′ precipitates in a high-strength casting Mg-15Gd-1Zn-0.4Zr (wt. %) alloy [J]. Mater. Charact., 2017, 126: 1
8
Zhang Y, Wu Y J, Peng L M, et al. Microstructure evolution and mechanical properties of an ultra-high strength casting Mg-15.6Gd-1.8Ag-0.4Zr alloy [J]. J. Alloys Compd., 2014, 615: 703
9
Yamada K, Hoshikawa H, Maki S, et al. Enhanced age-hardening and formation of plate precipitates in Mg-Gd-Ag alloys [J]. Scr. Mater., 2009, 61: 636
10
Tong X, Wu G H, Zhang L, et al. Microstructure and mechanical properties of repair welds of low-pressure sand-cast Mg-Y-RE-Zr alloy by tungsten inert gas welding [J]. J. Magnes. Alloy., 2020, 10: 180
11
Tong X, Zhang G Q, Wu G H, et al. Addressing the abnormal grain coarsening during post-weld heat treatment of TIG repair welded joint of sand-cast Mg-Y-RE-Zr alloy [J]. Mater. Charact., 2021, 176: 111125
12
Song J F, Pan F S, Jiang B, et al. A review on hot tearing of magnesium alloys [J]. J. Magnes. Alloy., 2016, 4: 151
13
Song J F, Wang Z, Huang Y D, et al. Effect of Zn addition on hot tearing behaviour of Mg-0. 5Ca-xZn alloys [J]. Mater. Des., 2015, 87: 157
14
Tong X, You G Q, Ding Y H, et al. Effect of grain size on low-temperature electrical resistivity and thermal conductivity of pure magnesium [J]. Mater. Lett., 2018, 229: 261
15
Johnsson M, Backerud L, Sigworth G K. Study of the mechanism of grain refinement of aluminum after additions of Ti-and B-containing master alloys [J]. Metall. Mater. Trans., 1993, 24A: 481
16
Greer A L, Bunn A M, Tronche A, et al. Modelling of inoculation of metallic melts: Application to grain refinement of aluminium by Al-Ti-B [J]. Acta Mater., 2000, 48: 2823
17
StJohn D H, Qian M, Easton M A, et al. The interdependence theory: The relationship between grain formation and nucleant selection [J]. Acta Mater., 2011, 59: 4907
18
Bramfitt B L. The effect of carbide and nitride additions on the heterogeneous nucleation behavior of liquid iron [J]. Metall. Mater. Trans., 1970, 1B: 1987
19
Zhang M X, Kelly P M, Easton M A, et al. Crystallographic study of grain refinement in aluminum alloys using the edge-to-edge matching model [J]. Acta Mater., 2005, 53: 1427
20
Easton M A, StJohn D H. A model of grain refinement incorporating alloy constitution and potency of heterogeneous nucleant particles [J]. Acta Mater., 2001, 49: 1867
21
Ali Y, Qiu D, Jiang B, et al. Current research progress in grain refinement of cast magnesium alloys: A review article [J]. J. Alloys Compd., 2015, 619: 639
22
Sun M. Study on grain refinement behavior of Mg-Gd-Y magnesium alloy by zirconium [D]. Shanghai: Shanghai Jiao Tong University, 2012
Yuan G Y, Liu Z L, Wang Q D, et al. Microstructure refinement of Mg-Al-Zn-Si alloys [J]. Mater. Lett., 2002, 56: 53
25
Lu L, Dahle A K, StJohn D H. Grain refinement efficiency and mechanism of aluminium carbide in Mg-Al alloys [J]. Scr. Mater., 2005, 53: 517
26
Qiu D, Zhang M X, Taylor J A, et al. A new approach to designing a grain refiner for Mg casting alloys and its use in Mg-Y-based alloys [J]. Acta Mater., 2009, 57: 3052
27
Qiu D, Zhang M X. The nucleation crystallography and wettability of Mg grains on active Al2Y inoculants in an Mg-10wt% Y Alloy [J]. J. Alloys Compd., 2014, 586: 39
28
Qian M. Heterogeneous nucleation on potent spherical substrates during solidification [J]. Acta Mater., 2007, 55: 943
29
Sun M, Easton M A, Stjohn D H, et al. Grain refinement of magnesium alloys by Mg-Zr master alloys: The role of alloy chemistry and Zr particle number density [J]. Adv. Eng. Mater., 2013, 15: 373
30
Qiu D, Zhang M X. Effect of active heterogeneous nucleation particles on the grain refining efficiency in an Mg-10wt.%Y cast alloy [J]. J. Alloys Compd., 2009, 488: 260
31
StJohn D H, Easton M A, Qian M, et al. Grain refinement of magnesium alloys: A review of recent research, theoretical developments, and their application [J]. Metall. Mater. Trans., 2013, 44A: 2935
32
StJohn D H, Ma Q, Easton M A, et al. Grain refinement of magnesium alloys [J]. Metall. Mater. Trans., 2005, 36A: 1669
33
Qian M, Das A. Grain refinement of magnesium alloys by zirconium: Formation of equiaxed grains [J]. Scr. Mater., 2006, 54: 881
34
Zhang D Y, Qiu D, Zhu S M, et al. Grain refinement in laser remelted Mg-3Nd-1Gd-0.5Zr alloy [J]. Scr. Mater., 2020, 183: 12
35
Emley E F. Principles of Magnesium Technology [M]. Oxford: Pergamon Press, 1966: 126
36
Pang S. Study on solidification behavior and grain refining mechanism of sand-cast Mg-Gd-Y alloys [D]. Shanghai: Shanghai Jiao Tong University, 2015
Qian M, StJohn D H. Grain nucleation and formation in Mg-Zr alloys [J]. Int. J. Cast Met. Res., 2009, 22: 256
39
Sun M, Wu G H, Wang W, et al. Effect of Zr on the microstructure, mechanical properties and corrosion resistance of Mg-10Gd-3Y magnesium alloy [J]. Mater. Sci. Eng., 2009, A523: 145
40
Qian M, Zheng L, Graham D, et al. Settling of undissolved zirconium particles in pure magnesium melts [J]. J. Light Met., 2001, 1: 157
41
Qian M, Hildebrand Z C G, StJohn D H. The loss of dissolved zirconium in zirconium-refined magnesium alloys after remelting [J]. Metall. Mater. Trans., 2009, 40A: 2470
42
Qian M, StJohn D H, Frost M T, et al. Grain refinement of pure magnesium using rolled Zirmax master alloy (Mg-33.3Zr) [J]. Magnes. Technol., 2003, 2003: 215
43
Wang C Q, Sun M, Zheng F Y, et al. Improvement in grain refinement efficiency of Mg-Zr master alloy for magnesium alloy by friction stir processing [J]. J. Magnes. Alloy., 2014, 2: 239
44
Viswanathan S, Saha P, Foley D, et al. Engineering a more efficient zirconium grain refiner for magnesium [A]. Magnesium Technology 2011 [M]. Cham: Springer, 2011: 559
45
Sun M, Wu G H, Dai J C, et al. Grain refinement behavior of potassium fluozirconate (K2ZrF6) salts mixture introduced into Mg-10Gd-3Y magnesium alloy [J]. J. Alloys Compd., 2010, 494: 426
46
Tong X, Wu G H, Zhang L, et al. Achieving low-temperature Zr alloying for microstructural refinement of sand-cast Mg-Gd-Y alloy by employing zirconium tetrachloride [J]. Mater. Charact., 2020, 171: 110727
47
Tong X, You G Q, Wang Y C, et al. Effect of ultrasonic treatment on segregation and mechanical properties of as-cast Mg-Gd binary alloys [J]. Mater. Sci. Eng., 2018, A731: 44
48
Wu G H, Tong X, Sui H M, et al. Research status and prospect of melt treatment of magnesium-rare earth alloy [J]. Foundry, 2021, 70: 1
Dai J C, Easton M A, Zhang M X, et al. Effects of cooling rate and solute content on the grain refinement of Mg-Gd-Y alloys by aluminum [J]. Metall. Mater. Trans., 2014, 45A: 4665
50
Wang C L, Dai J C, Liu W C, et al. Effect of Al additions on grain refinement and mechanical properties of Mg-Sm alloys [J]. J. Alloys Compd., 2015, 620: 172
51
Jiang Z T, Jiang B, Zeng Y, et al. Role of Al modification on the microstructure and mechanical properties of as-cast Mg-6Ce alloys [J]. Mater. Sci. Eng., 2015, A645: 57
52
Chang H W, Qiu D, Taylor J A, et al. The role of Al2Y in grain refinement in Mg-Al-Y alloy system [J]. J. Magnes. Alloy., 2013, 1: 115
53
Dai J C. Study on the effects of Al and trace elements on grain refinement behavior, microstructure and mechanical properties of Mg-Gd(-Y) alloys [D]. Shanghai: Shanghai Jiao Tong University, 2014
Jiang Z T, Meng X, Jiang B, et al. Grain refinement of Mg-3Y alloy using Mg-10Al2Y master alloy [J]. J. Rare Earths, 2021, 39: 881
55
Tong X, You G Q, Luo J C, et al. Rapid cooling effect during solidification on macro- and micro-segregation of as-cast Mg-Gd alloy [J]. Prog. Nat. Sci., 2021, 31: 68
56
Tong X, You G Q, Yao F J, et al. Segregation behavior and its regulating process in as-cast magnesium alloy containing heavy rare earth [J]. J. Rare Earths, doi: 10.1016/j.jre.2021.08.009
57
Izumi S, Yamasaki M, Kawamura Y. Relation between corrosion behavior and microstructure of Mg-Zn-Y alloys prepared by rapid solidification at various cooling rates [J]. Corros. Sci., 2009, 51: 395
58
Fan Z, Wang Y, Xia M, et al. Enhanced heterogeneous nucleation in AZ91D alloy by intensive melt shearing [J]. Acta Mater., 2009, 57: 4891
59
Peng G S, Wang Y, Fan Z. Competitive heterogeneous nucleation between Zr and MgO particles in commercial purity magnesium [J]. Metall. Mater. Trans., 2018, 49A: 2182
60
Peng G S, Wang Y, Chen K H, et al. Improved Zr grain refining efficiency for commercial purity Mg via intensive melt shearing [J]. Int. J. Cast Met. Res., 2017, 30: 374
61
Chen X R, Jia Y H, Le Q C, et al. The interaction between in situ grain refiner and ultrasonic treatment and its influence on the mechanical properties of Mg-Sm-Al magnesium alloy [J]. J. Mater. Res. Technol., 2020, 9: 9262
62
Zhang L, Li Y L. Research progress on grain refining methods of magnesium alloy [J]. Foundry, 2019, 68: 1195
张 玲, 李英龙. 镁合金晶粒细化方法研究进展 [J]. 铸造, 2019, 68: 1195
63
Nagasivamuni B, Wang G, StJohn D H, et al. Effect of ultrasonic treatment on the alloying and grain refinement efficiency of a Mg-Zr master alloy added to magnesium at hypo- and hyper-peritectic compositions [J]. J. Cryst. Growth, 2019, 512: 20
64
Atamanenko T V, Eskin D G, Zhang L, et al. Criteria of grain refinement induced by ultrasonic melt treatment of aluminum alloys containing Zr and Ti [J]. Metall. Mater. Trans., 2010, 41A: 2056
65
Wang G, Wang Q, Easton M A, et al. Role of ultrasonic treatment, inoculation and solute in the grain refinement of commercial purity aluminium [J]. Sci. Rep., 2017, 7: 9729
66
Wu G H, Chen Y S, Ding W J. Current research and future prospect on microstructures controlling of high performance magnesium alloys during solidification [J]. Acta Metall. Sin., 2018, 54: 637
Qiu Y F, Gao D M, Chen L, et al. Effects of pulsed electric current on solidification structure and mechanical properties of AZ91 magnesium alloy [J]. Spec. Cast. Nonferrous Alloys, 2007, 27: 633
Lan J, Yang Y, Li X. Microstructure and microhardness of SiC nanoparticles reinforced magnesium composites fabricated by ultrasonic method [J]. Mater. Sci. Eng., 2004, A386: 284
69
Zi B T, Ba Q X, Cui J Z, et al. Effect of strong pulsed electromagnetic field on metal's solidified structure [J]. Aсtа Phys. Sin., 2000, 49: 1010
Sterzel R, Dahlmann E, Langsdorf A, et al. Preparation of Zn-Mg-rare earth quasicrystals and related crystalline phases [J]. Mater. Sci. Eng., 2000, A294-296: 124
71
Misra A K. A novel solidification technique of metals and alloys: Under the influence of applied potential [J]. Metall. Trans., 1985, 16A: 1354
72
Wang B, Yang Y S, Zhou J X, et al. Effect of the pulsed magnetic field on the solidification and mechanical properties of Mg-Gd-Y-Zr alloy [J]. Rare Met. Mater. Eng., 2009, 38: 519
Zhang L, Zhou W, Hu P H, et al. Microstructural characteristics and mechanical properties of Mg-Zn-Y alloy containing icosahedral quasicrystals phase treated by pulsed magnetic field [J]. J. Alloys Compd., 2016, 688: 868
74
Chang Z Y, Wu Y J, Heng X W, et al. Characterization of microstructure and nanoscale phase in Mg-15Gd-1Zn (wt.%) alloy fabricated by rotating magnetic field casting [J]. Mater. Charact., 2020, 170: 110660
75
Hu S P, Chen L P, Zhou Q, et al. Research progress in effects of physical fields on solidified structure of metals [J]. Spec. Cast. Nonferrous Alloys, 2018, 38: 717
Wang L, Wang N, Provatas N. Liquid channel segregation and morphology and their relation with hot cracking susceptibility during columnar growth in binary alloys [J]. Acta Mater., 2017, 126: 302
77
Sistaninia M, Terzi S, Phillion A B, et al. 3-D granular modeling and in situ X-ray tomographic imaging: A comparative study of hot tearing formation and semi-solid deformation in Al-Cu alloys [J]. Acta Mater., 2013, 61: 3831
78
Huang Y G. Study on the fluidity and hot tearing behavior of Mg-Gd-Y-Zr alloys [D]. Shanghai: Shanghai Jiao Tong University, 2009
黄玉光. Mg-Gd-Y-Zr合金的热裂和流动性研究 [D]. 上海: 上海交通大学, 2009
79
Kamga K H, Larouche D, Bournane M, et al. Hot tearing of aluminum-copper B206 alloys with iron and silicon additions [J]. Mater. Sci. Eng., 2010, A527: 7413
80
Lin S, Aliravci C, Pekguleryuz M O. Hot-tear susceptibility of aluminum wrought alloys and the effect of grain refining [J]. Metall. Mater. Trans., 2007, 38A: 1056
81
Liu J W, Kou S. Crack susceptibility of binary aluminum alloys during solidification [J]. Acta Mater., 2016, 110: 84
82
Hatami N, Babaei R, Dadashzadeh M, et al. Modeling of hot tearing formation during solidification [J]. J. Mater. Process. Technol., 2008, 205: 506
83
Li J l, Chen R S, Ma Y Q, et al. Characterization and prediction of microporosity defect in sand cast WE54 alloy castings [J]. J. Mater. Sci. Technol., 2014, 30: 991
84
Yin H, Liu Z L, Liu X Q, et al. Effects of Al addition on the microstructure and mechanical properties of Mg-4Y alloys [J]. Mater. Sci. Technol., 2017, 33: 2188
85
Dai J C, Zhu S M, Easton M A, et al. Heat treatment, microstructure and mechanical properties of a Mg-Gd-Y alloy grain-refined by Al additions [J]. Mater. Sci. Eng., 2013, A576: 298
86
Gao L, Chen R S, Han E H. Effects of rare-earth elements Gd and Y on the solid solution strengthening of Mg alloys [J]. J. Alloys Compd., 2009, 481: 379
87
Li Y L, Wu G H, Chen A T, et al. Effects of Gd and Zr additions on the microstructures and high-temperature mechanical behavior of Mg-Gd-Y-Zr magnesium alloys in the product form of a large structural casting [J]. J. Mater. Res., 2015, 30: 3461
88
Ralston K D, Birbilis N, Davies C H J. Revealing the relationship between grain size and corrosion rate of metals [J]. Scr. Mater., 2010, 63: 1201
89
Song G L, StJohn D. The effect of zirconium grain refinement on the corrosion behaviour of magnesium-rare earth alloy MEZ [J]. J. Light Met., 2002, 2: 1
90
Zhang L L, Zhang J S, Zhao R, et al. Effect of microalloyed Al on microstructure and corrosion behaviors of as-cast Mg-Zn-Y-Mn alloys [J]. Adv. Eng. Mater., 2021, 23: 2000587
91
Wang L S, Jiang J H, Yuan T, et al. Recent progress on corrosion behavior and mechanism of Mg-RE based alloys with long period stacking ordered structure [J]. Met. Mater. Int., 2020, 26: 551
92
Wang L S, Jiang J H, Liu H, et al. Microstructure characterization and corrosion behavior of Mg-Y-Zn alloys with different long period stacking ordered structures [J]. J. Magnes. Alloy., 2020, 8: 1208
93
Cao F Y, Zheng D J, Song G L, et al. The corrosion behavior of Mg5Y in nominally distilled water [J]. Adv. Eng. Mater., 2018, 20: 1700986
94
Qian M, StJohn D H, Frost M T. Effect of soluble and insoluble zirconium on the grain refinement of magnesium alloys [J]. Mater. Sci. Forum, 2003, 419-422: 593
95
Ben-Hamu G, Eliezer D, Shin K S, et al. The relation between microstructure and corrosion behavior of Mg-Y-RE-Zr alloys [J]. J. Alloys Compd., 2007, 431: 269
