Corrosion behavior of biodegradable Mg–1%Zn–0.2%Ca alloy with ultrafine-grained structure

Objectives. The aim of this work is to investigate the corrosion resistance of ultrafine-grained magnesium alloy Mg–1%Zn–0.2%Ca processed by severe plastic deformation (SPD) methods, namely equal channel angular pressing combined with extrusion (ECAP-Ex) and circular simple shear extrusion (CSSE). In order to use such materials in the development of biocompatible implants, it becomes necessary to control their degradation rate.

Methods. To form an ultrafine-grained (UFG) structure, equal-channel angular pressing combined with extrusion (ECAP+Ex) and circular shear extrusion (CSSE) methods were used. Structural studies were conducted using X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). In order to confirm the reliability of this material for use in biodegradable medical implants, a gravimetric corrosion resistance study was carried out at 36.6°C over a long period (month).

Results. The use of ECAP-Ex processing led to the formation of an ultrafine-grained (UFG) structure in the alloy having a grain size of about 1 μm and the appearance of nanotwins, as well as the formation of highly dispersed Ca₂Mg₆Zn₃ nanoparticles 10 nm in a size with a volume fraction of 1%. The corrosion rate of the UFG samples was 3.8 mm/year. Following additional annealing at 175°C, the UFG alloy demonstrated a decrease in the corrosion rate to 0.9 mm/year as compared with coarse grained homogenized sample (4.8 mm/year). By way of comparison, the CSSE processing resulted in grain size reduction to 1 μm and a corrosion rate of 1.3 mm/year.

Conclusions. The study demonstrates that combining equal-channel angular pressing ECAP+ Ex and subsequent annealing at 175°C is an effective method for improving corrosion properties of the Mg–1%Zn–0.2%Ca alloy. By reducing the corrosion rate to 0.9 mm/year, the alloy becomes promising for medical applications such as biodegradable implants.

1. Valiev R.Z., Islamgaliev R.K., Alexandrov I.V. Bulk nanostructured materials from severe plastic deformation. Prog. Mater. Sci. 2000;45(2):103–189. https://doi.org/10.1016/S0079-6425(99)00007-9

2. Botkin A.V., Valiev R.Z., Volkova E.P., Khudododova G.D., Ebrahimi R. Effect of Preliminary Deformation on the Formation of Ultrafine-Grained Structure during Equal Channel Angular Pressing of Magnesium Alloys. Phys. Mesomech . 2024;27:678–686. https://doi.org/10.1134/S1029959924060055

3. Botkin A.V., Volkova E.P., Khudododova G.D., Kulyasova O.B., Islamgaliev R.K., Valiev R.Z. Research and development of magnesium alloy Mg–1%Zn–0.06%Ca for application in medicine. Nanoindustria = Nanoindustry. 2025;18(1):70–79 (in Russ.).

4. Zheng Y. Magnesium Alloys as Degradable Biomaterials . Boca Raton, FL USA: CRC Press; 2015, 600 p. https://doi.org/10.1201/b18932

5. Gorustovich A.A., Steimetz T., Cabrini R.L., Porto López J.M. Osteoconductivity of strontium-doped bioactive glass particles: A histomorphometric study in rats. J. Biomed. Mater. Res . 2010;92(1):232–237. https://doi.org/10.1002/jbm.a.32355

6. Seong J.W., Kim W.J. Mg-Ca binary alloy sheets with Ca contents of ≤ 1 wt.% with high corrosion resistance and high toughness. Corros. Sci . 2015;98:372–381. https://doi.org/10.1016/j.corsci.2015.05.068

7. Jin Y., Blawert C., Feyerabend F., Bohlen J., et al. Time-sequential corrosion behavior observation of micro-alloyed Mg–0.5Zn–0.2Ca alloy via a quasi_in situ_ approach. Corros. Sci . 2019;158:108096. https://doi.org/10.1016/j.corsci.2019.108096

8. Li Z., Gu X., Lou S., Zheng Y. The development of binary Mg–Ca alloys for use as biodegradable materials within bone. Biomaterials. 2008;29(10):1329–1344. https://doi.org/10.1016/j.biomaterials.2007.12.021

9. Merson D., Brilevski A., Myagkikh P., Tarkova A., Prokhorikhin A., Kretov E., Frolova T., Vinogradov A. The functional properties of Mg–Zn–X biodegradable magnesium alloys. Materials. 2020;13(3):544. https://doi.org/10.3390/ma13030544

10. Bakhsheshi R.H.R., Abdul K.M.R., Idris M.H., Farahany S. Relationship between the corrosion behavior and the thermal characteristics and microstructure of Mg–0.5Ca_x_ Zn alloys. Corros. Sci . 2012;64:184–197. https://doi.org/10.1016/j.corsci.2012.07.015

11. Martynenko N., Anisimova N., Rybalchenko G., Lukyanova E., Rybalchenko O., Shchetinin I., Babayeva G., Pashinzeva N.V., Gorbenko A., Temralieva D., Kiselevskiy M., Andreev V., Dobatkin S. Effect of warm rotary swaging on the mechanical and operational properties of the biodegradable Mg–1%Zn–0.6%Ca alloy. J. Magnesium Alloys. 2025:13(5): 2252–2266. https://doi.org/10.1016/j.jma.2025.03.019

12. Zhang C., Guan S., Wang L., Zhu S., Chang L. The microstructure and corrosion resistance of biological Mg–Zn–Ca alloy processed by high-pressure torsion and subsequently annealing. J. Mater. Res. 2017;32:1061–1072. https://doi.org/10.1557/jmr.2017.55

13. Zhang C.Z., Zhu S.J., Wang L.G., Guo R.M., Yue G.C., Guan S.K. Microstructures and degradation mechanism in simulated body fluid of biomedical Mg–Zn–Ca alloy processed by high pressure torsion . Mater. Des . 2016;96:54–62. https://doi.org/10.1016/j.matdes.2016.01.072

14. Parfenov E.V., Kulyasova O.B., Mukaeva V.R., Mingo B., Farrakhov R.G., Cherneikina Y.V., Yerokhin A., Zheng Y.F., Valiev R.Z. Influence of ultra-fine grain structure on corrosion behaviour of biodegradable Mg–1Ca alloy. Corros. Sci . 2020;163:108303. https://doi.org/10.1016/j.corsci.2019.108303

15. Zhang E., Yang L. Microstructure, mechanical properties and bio-corrosion properties of Mg–Zn–Mn–Ca alloy for biomedical application. Mater. Sci. Eng. A . 2008;497(1-2): 111–118. https://doi.org/10.1016/j.msea.2008.06.019

16. Tong L.B., Zheng M.Y., Cheng L.R., Zhang D.P., Kamado S., Meng J., Zhang H.J. Influence of deformation rate on microstructure, texture and mechanical properties of indirect extruded Mg–Zn–Ca alloy. Mater. Charact. 2015;104:66–72. https://doi.org/10.1016/j.matchar.2014.09.020

17. Rezvani A., Bagherpour E., Ebrahimi R. Circular simple shear extrusion as an alternative to simple shear extrusion technique. Iranian J. Sci. Technol. Trans. Mech. Eng. 2020;44(1): 193–201. https://doi.org/10.1007/s40997-018-0257-7

18. Botkin A.V., Volkova E.P., Kulyasova O.B., Valiev R.Z. Modeling and experimental study of combined SPD processing of magnesium alloys to obtain rodshaped samples ultrafine-grained structure. Russian Journal of Biomechanics. 2026;30(1):84–96 (in Russ.) https://doi.org/0.15593/RJBiomech/2026.1.08

19. Lutterotti L., Matthies S., Wenk H.-R., Schultz A., Richardson J. Combined Texture and Structure Analysis of Deformed Limestone from Time-of-Flight Neutron Diffraction Spectra. J. Appl. Phys. 1997;81:594–600. https://doi.org/10.1063/1.364220

20. Tong L.B., Zheng M.Y., Cheng L.R., Zhang D.P., Kamado S., Meng J., Zhang H.J. Influence of deformation rate on microstructure, texture and mechanical properties of indirect extruded Mg–Zn–Ca alloy. Mater. Charact . 2015;104:66–72. https://doi.org/10.1016/j.matchar.2014.09.020

21. Zhang E., Yang L. Microstructure, mechanical properties and bio-corrosion properties of Mg–Zn–Mn–Ca alloy for biomedical application. Mater. Sci. Eng. A. 2008;497: 111–118. https://doi.org/10.1016/j.msea.2008.06.019

22. Südholz A.D., Kirkland N.T., Buchheit R.G., Birbilis N. Electrochemical Properties of Intermetallic Phases and Common Impurity Elements in Magnesium Alloys. Electrochem. Solid-Stat. Lett. 2011;14(2):5. https://doi.org/10.1149/1.3523229

23. Zhao S., Tayyebi M., Yarigarravesh M., Hu G. A review of magnesium corrosion in bio-applications: mechanism, classification, modeling, in-vitro , and in-vivo experimental testing, and tailoring Mg corrosion rate. J. Mater. Sci . 2023;58:12158–12181. https://doi.org/10.1007/s10853-023-08782-z

24. Khudododova G.D., Ishmukhamedova G.M., Kulyasova O.B., Parfenov E.V., Islamgaliev R.K., Valiev R.Z. Corrosion resistance of ultrafine-grained Mg–1Zn and Mg–1Zn–0.2Ca magnesium alloys subjected to high pressure torsion. Materials. Technologies. Design . 2024;6(4-19):21–28 (in Russ.). https://doi.org/10.54708/26587572_2024_641921

25. Khudododova G.D., Kulyasova O.B., Islamgaliev R.K. Strength and corrosion resistance of the UFG Mg–Zn–Ca alloy. Nanoindustria = Nanoindustry. 2022;15(7-8):426–433 (in Russ.). https://doi.org/10.22184/1993-8578.2022.15.7-8.426.433