Influence of heat treatment on microstructure and electrochemical behaviors of Mg-Zn binary alloys prepared by gas-phase alloying technique

Abstract

Mg-Zn binary alloys fabricated by the gas-phase alloying technique under vacuum condition were investigated in the state of initial state and after heat treatment for the microstructure and electrochemical behaviors. Different from the traditional Mg-Zn alloys preparation methods, alloys prepared by gas-phase alloying have a large number of intermetallic compounds, such as MgZn, Mg₇Zn₃ and MgZn₂. After solution treatment, the boundary of the eutectic disappeared and the size of α-Mg increased from 100 μm to 150 μm. At the same time, the value of the resistance of charge transfer increased, which indicates that the resistance of the charge transfer and the corrosion resistance of the alloys increased. After artificial aging treatment, the distribution of α-Mg was more uniform and its size was reduced to about 50 μm, and there was new eutectic structure formed. The newly formed eutectic structure forms galvanic cells with the alloy matrix, which makes the corrosion resistance of the alloy weaken.

Keywords

gas-phase alloying / Mg-Zn alloy / heat treatment / Ringer’s solution / electrochemical behavior

References

[1] PanF-s, YangM-b, ChenX-hua. A review on casting magnesium alloys: Modification of commercial alloys and development of new alloys. Journal of Materials Science & Technology, 2016, 32(12): 1211-1221

[2] RadhaR, SreekanthD. Insight of magnesium alloys and composites for orthopedic implant applications–A review. Journal of Magnesium and Alloys, 2017, 5(3): 286-312

[3] YangG-q, PengX-d, YangY, LiM-l, WeiG-b, ShaoH-y, WangBao. Microstructure and mechanical properties of as-cast and extruded Mg-8Li-3Al-0.7Si alloy. Journal of Central South University, 2018, 25(4): 764-771

[4] NaveM D, DahleA K, StjohnD H. The role of zinc in the eutectic solidification of magnesium-aluminium-zinc alloys. The Minearls, Metals and Materials Society, 2000

[5] WanP, TanL-l, YangKe. Surface modification on biodegradable magnesium alloys as orthopedic implant materials to improve the bio-adaptability: A review. Journal of Materials Science & Technology, 2016, 32(9): 827-834

[6] YouZ-y, ZhangY-h, ChengW-l, ZhangJ-s, WeiY-hui. Effect of heat-treatment on the microstructures and mechanical properties of Mg-10Zn-5Al-0.1Sb-xCu magnesium alloy. Journal of Wuhan University of Technology-Mater Sci Ed, 2013, 28(4): 834-839

[7] AtrensA, LiuM, AbidinN I Z. Corrosion mechanism applicable to biodegradable magnesium implants. Materials Science and Engineering B, 2011, 176(20): 1609-1636

[8] SinghalA, SkandanG, WangA, GlumcaN, KearB H, HuntR D. On nanoparticle aggregation during vapor phase synthesis. Nanostructured Materials, 1999, 11(4): 545-552

[9] SimchiA, AhmadiR, ReihaniS S, MahdaviA. Kinetics and mechanisms of nanoparticle formation and growth in vapor phase condensation process. Materials & Design, 2007, 28(3): 850-856

[10] AkbariM K, DerakhshanR, MirzaeeO. A case study in vapor phase synthesis of Mg–Al alloy nanoparticles by plasma arc evaporation technique. Chemical Engineering Journal, 2015, 259(290): 918-926

[11] ZhongG-x, ZhangQ-f, JiangS-m, YuG-qiang. Effect of the process parameters on the microstructure and corrosion resistance of Zn-Mg alloy coatings prepared via acombined PVD and reaction-diffusion process. Surface and Coatings Technology, 2016, 306(25): 418-427

[12] ZhangR-y, KhalizovA, WangL, HuM, XuWen. Nucleation and growth of nanoparticles in the atmosphere. Chemical Reviews, 2012, 112(3): 1957-2011

[13] JiangY, LiuM, YangY-m, GuanD-g, ChenJ-z, TuM-jing. The hydrogen mechanism study in preparing nanonickel by plasma arc spraying method. Rare Met Mater Eng, 2005, 34: 475-478

[14] DaiY-n, YangBinThe vacuum metallurgy of nonferrous metals, 2000, Beijing, Metallurgical Industry Press(in Chinese)

[15] VerissimoNATH, LiaC, BritoC, Afonso, ConradoR, SpinelliJ E, CheungN, GarciaA. Microstructure characterization of a directionally solidified Mg-12wt.% Zn alloy: Equiaxed dendrites, eutectic mixture and type/morphology of intermetallic. Materials Chemistry and Physics, 2018, 204: 105-131

[16] VidaT A, BritoC, LimaT S, SpinelliJ E, CheungN, GarciaA. Near-eutectic Zn-Mg alloys: Interrelations of solidification thermal parameters, microstructure length scale and tensile/corrosion properties. Current Applied Physics, 2019, 19(5): 582-598

[17] PoundG M. Selected values of evaporation and condensation coefficients for simple substances. Journal of Physical & Chemical Reference Data, 1972, 1(1): 135-146

[18] NemecM, JagerA, TesarK, GartnerovaV. Influence of alloying element Zn on the microstructural, mechanical and corrosion properties of binary Mg-Zn alloys after severe plastic deformation. Materials Characterization, 2017, 134: 69-75

[19] YanY, CaoH-w, KangY-j, YuK, XiaoT, LuoJ, DengY-w, FangH-j, XiongH-q, DaiY-long. Effects of Zn concentration and heat treatment on the microstructure, mechanical properties and corrosion behavior of as-extruded Mg-Zn alloys produced by powder metallurgy. Journal of Alloys and Compounds, 2017, 693: 1277-1289

[20] JameshM, KumarS, NarayananT S N S. Corrosion behavior of commercially pure Mg and ZM21 Mg alloy in Ringer’s solution–long term evaluation by EIS. Corrosion Science, 2011, 53(2): 645-654

[21] CaoF-y, ShiZ-m, HofetetterJ, UggowitzerP J, SongG-l, LiuM, AtrensA. Corrosion of ultra-high-purity Mg in 3.5% NaCl solution saturated with Mg(OH)₂. Corrosion Science, 2013, 75: 78-99

[22] SongY-w, HanE-h, ShanD-y, YimC D, YouB S. The effect of Zn concentration on the corrosion behavior of Mg–xZn alloys. Corrosion Science, 2012, 65: 322-330

[23] JiaH-m, FengX-h, YangY-sheng. Effect of crystal orientation on corrosion behavior of directionally solidified Mg-4wt.% Zn alloy. Journal of Materials Science & Technology, 2018, 34(7): 1229-1235

[24] YangJ, PengJ, NybergE A, PanF-sheng. Effect of Ca addition on the corrosion behavior of Mg–Al–Mn alloy. Applied Surface Science, 2016, 369: 92-100

[25] XuH, WuZ-q, WangX-r, ZhangX, RenJ-p, ShiY, WangZ-p, WangL-w, LiuC-hua. Corrosion mechanism and corrosion model of Mg-Y alloy in NaCl solution. Journal of Wuhan University of Technology-Mater Sci Ed, 2016, 31(5): 1048-1062

[26] SongY-w, HanE-h, ShanD-y, YimC D, YouB S. The role of second phases in the corrosion behavior of Mg–5Zn alloy. Corrosion Science, 2012, 60: 238-245

[27] MandalM, MoonA P, DeoG, MendisC L, MondalK. Corrosion behavior of Mg–2.4Zn alloy micro-alloyed with Ag and Ca. Corrosion Science, 2014, 78: 172-182