Frontier Materials & Technologies. 2015; : 18-24
ВЛИЯНИЕ РАВНОКАНАЛЬНОГО УГЛОВОГО ПРЕССОВАНИЯ НА СТРУКТУРУ И МЕХАНИЧЕСКИЕ СВОЙСТВА МАГНИЕВЫХ СПЛАВОВ Mg-Zn-Ca
https://doi.org/10.18323/2073-5073-2015-4-18-24Аннотация
Система Mg-Zn-Ca является одной из наиболее перспективных среди магниевых сплавов, рассматриваемых для потенциального применения в качестве медицинских имплантатов, в связи с его близким к идеальному отношением прочности к плотности при очень хорошей биосовместимости. Однако, несмотря на значительный прогресс в разработке биосовместимых магниевых сплавов, их технологическая пластичность до сих пор остается недостаточной, а многие их свойства – неизученными. С целью повышения пластичности в последнее время активно развиваются многочисленные методы управления структурой путем измельчения зерна и создания специального распределения избыточных фаз, основанные на применении термомеханической обработки, включающей интенсивную пластическую деформацию. В данной работе было исследовано влияние интенсивной пластической деформации методом равноканального углового прессования на структуру и свойства магниевых сплавов Mg-4Zn-0,16Ca и Mg-4Zn-0,56Ca.
Установлено, что увеличение содержания кальция в исходном состоянии ведет к увеличению объемной доли вторичных фаз. При этом в выделениях избыточных фаз содержатся повышенные концентрации основных легирующих элементов сплава – цинка и кальция.
После равноканального углового прессования даже при относительно высокой гомологической температуре деформации не удается получить однородную рекристаллизованную микроструктуру. Полученная микроструктура бимодальна, и в ней наряду с относительно мелкими зернами присутствуют крупные нерекриcталлизованные. Отмечаем, что для сплава Mg-4Zn-0,56Ca удалось достичь значительного повышения механических характеристик на растяжение до уровня лучших высокопрочных сплавов данного класса, что объясняется особенностями бимодальной структуры и, вероятно, особенностями кристаллографической текстуры.
Список литературы
1. Staiger M.P., Pietak A.M., Huadmai J., Dias G.J. Magnesium and its alloys as orthopedic biomaterials // Biomaterials. 2006. Vol. 27. № 9. P. 1728–1734.
2. Mathieu S., Rapin C., Steinmetz J., Steinmetz P.A. A corrosion study of the main constituent phases of AZ91 magnesium alloys // Corrosion Science. 2003. Vol. 45. № 12. P. 2741–2755.
3. Li L., Gao J., Wang Y. Evaluation of cyto-toxicity and corrosion behavior of alkali-heat-treated magnesium in simulated body fluid // Surface and Coatings Technology. 2004. Vol. 185. № 1. P. 92–98.
4. Chen J., Wang J., Han E., Dong J., Ke W. Corrosion behavior of AZ91D magnesium alloy in sodium sulfate solution // Materials and Corrosion. 2006. Vol. 57. № 10. P. 789–793.
5. Witte F. The history of biodegradable magnesium implants // Acta biomaterialia. 2010. Vol. 6. № 5. P. 1680–1692.
6. Zheng Y. Magnesium Alloys as Degradable Biomaterials. USA: CRC Press, 2015. 578 p.
7. Mani G., Feldman M.D., Patel D., Aqrawal C.M. Coronary stents: a materials perspective // Biomaterials. 2007. Vol. 28. № 9. P. 1689–1710.
8. Chino Y., Kobata M., Iwasaki H., Mabuchi M. Tensile Properties from Room Temperature to 673 K of Mg-0.9 mass% Ca Alloy Containing Lamella Mg2Ca // Materials Transactions. 2002. Vol. 43. № 10. P. 2643–2646.
9. Song G. Control of biodegradation of biocompatable magnesium alloys // Corrosion Science. 2007. Vol. 49. № 4. P. 1696–1701.
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13. Kocks U.F.D., Westlake G. The importance of twinning for the ductility of CPH polycrystals // Trans. Metall. Soc. AIME. 1967. Vol. 239. P. 1107–1109.
14. Dobatkin S.V., Estrin Y., Rokhlin L.L., Popov M.V., Lavopok R., Dobatkina T.V, Timofeev V.N., Nikitina N.I. Structure and properties of Mg-Al-Ca alloy after severe plastic deformation // Materials Science Forum. 2008. Vol. 584. P. 559–564.
15. Dobatkin S. V., Rokhlin L.L., Salishchev G.A., Kopylov V.I., Serebryany V.N., Stepanov N.D., Tarytina I.E., Kuroshev I.S., Martynenko N.S. Structure and properties of an Mg-0.3% ca magnesium alloy after multiaxial deformation and equal-channel angular pressing // Russian Metallurgy (Metally). 2014. Vol. 2014. № 11. P. 911–919.
16. Serebryany V.N. Texture, Microstructure, and Ductility of Mg-Al-Zn Alloy after Equal Channel Angular Pressing // Materials Science Forum. 2010. Vol. 633. P. 365–372.
17. Nugmanov D.R., Sitdikov O.S., Markushev M.V. Texture and anisotropy of yield strength in multistep isothermally forged Mg-5.8 Zn-0.65 Zr alloy // IOP Conference Series: Materials Science and Engineering. 2015. Vol. 82. № 1. P. 012099.
18. Nugmanov D.R., Sitdikov O.S., Markushev M.V. About fine-grain structure forming in bulk magnesium alloy MA14 under multidirectional isothermal forging // Bas. Problelm in Materials Science. 2012. № 9. P. 230.
19. Nugmanov D.R., Sitdikov O.S., Markushev M.V. Structure of magnesium alloy MA14 after multistep isothermal forging and subsequent isothermal rolling // The Physics of Metals and Metallography. 2015. Vol. 116. № 10. P. 993–1001.
20. Lu Y. Microstructure and degradation behaviour of Mg-Zn (-Ca) alloys. Birmingham: University of Birmingham, 2014. 215 p.
21. Bakhsheshi‐Rad H.R., Hamzah E., Lotfabadi A.F., Daroonparvar V., Yajid M.A.M., Islam M.M. Microstructure and bio‐corrosion behavior of Mg–Zn and Mg–Zn–Ca alloys for biomedical applications // Materials and Corrosion. 2014. Vol. 65. № 12. P. 1178–1187.
22. Ma E. Eight routes to improve the tensile ductility of bulk nanostructured metals and alloys // JOM. 2006. Vol. 58. № 4. P. 49–53.
23. Zhang B., Hou Y., Wang X., Wang Y., Geng L. Mechanical properties, degradation performance and cytotoxicity of Mg–Zn–Ca biomedical alloys with different compositions // Materials Science and Engineering: C. 2011. Vol. 31. № 8. P. 1667–1673.
24. Hofstetter J., Becker M., Martinelli E., Weinberg A.M., Mingler B., Kilian H., Pogatscher S., Uggowitzer P.J., Löffler J.F. High-strength low-alloy (HSLA) Mg–Zn–Ca alloys with excellent biodegradation performance // JOM. 2014. Vol. 66. № 4. P. 566–572.
Frontier Materials & Technologies. 2015; : 18-24
THE INFLUENCE OF EQUAL CHANNEL ANGULAR PRESSING ON THE STRUCTURE AND MECHANICAL PROPERTIES OF MAGNESIUM Mg-Zn-Ca ALLOYS
https://doi.org/10.18323/2073-5073-2015-4-18-24Abstract
Due to its close to the ideal straight-to-density ratio and good biocompatibility, the Mg-Zn-Ca system is the advanced alloy among the magnesium alloys, which are considered for the potential use as the medical implants. However, despite the significant progress in the development of biocompatible magnesium alloys, their technological plasticity is still insufficient and many of their properties are still uninvestigated. In order to increase the plasticity, various methods of structure management by means of grain refining and creation of special proeutectoid constituent distribution are being actively developed lately, which are based on the application of thermomechanical processing including the severe plastic deformation. In this paper, the authors studied the influence of severe plastic deformation using the method of equal channel angular pressing on the structure and properties of Mg-4Zn-0,16Ca and Mg-4Zn-0,56Ca magnesium alloys.
It was found that the increase of calcium content in the initial state leads to the increase of second phases volume fraction. At the same time, the proeutectoid constituent precipitate contains the elevated concentration of the major alloying elements – zinc and calcium.
After the equal channel angular pressing, even at a relatively high homologous deformation temperature, it is impossible to obtain a uniform recrystallized microstructure. The obtained microstructure is bimodal; it consists of relatively fine grains and large non-recrystallized grains. The authors notice that the Mg-4Zn-0,56Ca alloy exhibits the significant increase in tensile mechanical properties to the level of the top-ranking high-strength alloys of this class. It can be explained by the peculiarities of the bimodal grain structure and, probably, by the peculiarities of the crystallographic texture.
References
1. Staiger M.P., Pietak A.M., Huadmai J., Dias G.J. Magnesium and its alloys as orthopedic biomaterials // Biomaterials. 2006. Vol. 27. № 9. P. 1728–1734.
2. Mathieu S., Rapin C., Steinmetz J., Steinmetz P.A. A corrosion study of the main constituent phases of AZ91 magnesium alloys // Corrosion Science. 2003. Vol. 45. № 12. P. 2741–2755.
3. Li L., Gao J., Wang Y. Evaluation of cyto-toxicity and corrosion behavior of alkali-heat-treated magnesium in simulated body fluid // Surface and Coatings Technology. 2004. Vol. 185. № 1. P. 92–98.
4. Chen J., Wang J., Han E., Dong J., Ke W. Corrosion behavior of AZ91D magnesium alloy in sodium sulfate solution // Materials and Corrosion. 2006. Vol. 57. № 10. P. 789–793.
5. Witte F. The history of biodegradable magnesium implants // Acta biomaterialia. 2010. Vol. 6. № 5. P. 1680–1692.
6. Zheng Y. Magnesium Alloys as Degradable Biomaterials. USA: CRC Press, 2015. 578 p.
7. Mani G., Feldman M.D., Patel D., Aqrawal C.M. Coronary stents: a materials perspective // Biomaterials. 2007. Vol. 28. № 9. P. 1689–1710.
8. Chino Y., Kobata M., Iwasaki H., Mabuchi M. Tensile Properties from Room Temperature to 673 K of Mg-0.9 mass% Ca Alloy Containing Lamella Mg2Ca // Materials Transactions. 2002. Vol. 43. № 10. P. 2643–2646.
9. Song G. Control of biodegradation of biocompatable magnesium alloys // Corrosion Science. 2007. Vol. 49. № 4. P. 1696–1701.
10. Tapiero H., Tew K. D. Trace elements in human physiology and pathology: zinc and metallothioneins // Biomedicine & Pharmacotherapy. 2003. Vol. 57. № 9. P. 399–411.
11. Zhang S., Zhang X., Zhao C., Li J., Song Y., Xie C., Tao H., Zhang Y., He Y., Jiang Y., Bian Y. Research on an Mg–Zn alloy as a degradable biomaterial // Acta Biomaterialia. 2010. Vol. 6. № 2. P. 626–640.
12. Luo A., Pekguleryuz M.O. Cast magnesium alloys for elevated temperature applications // Journal of Materials Science. 1994. Vol. 29. № 20. P. 5259–5271.
13. Kocks U.F.D., Westlake G. The importance of twinning for the ductility of CPH polycrystals // Trans. Metall. Soc. AIME. 1967. Vol. 239. P. 1107–1109.
14. Dobatkin S.V., Estrin Y., Rokhlin L.L., Popov M.V., Lavopok R., Dobatkina T.V, Timofeev V.N., Nikitina N.I. Structure and properties of Mg-Al-Ca alloy after severe plastic deformation // Materials Science Forum. 2008. Vol. 584. P. 559–564.
15. Dobatkin S. V., Rokhlin L.L., Salishchev G.A., Kopylov V.I., Serebryany V.N., Stepanov N.D., Tarytina I.E., Kuroshev I.S., Martynenko N.S. Structure and properties of an Mg-0.3% ca magnesium alloy after multiaxial deformation and equal-channel angular pressing // Russian Metallurgy (Metally). 2014. Vol. 2014. № 11. P. 911–919.
16. Serebryany V.N. Texture, Microstructure, and Ductility of Mg-Al-Zn Alloy after Equal Channel Angular Pressing // Materials Science Forum. 2010. Vol. 633. P. 365–372.
17. Nugmanov D.R., Sitdikov O.S., Markushev M.V. Texture and anisotropy of yield strength in multistep isothermally forged Mg-5.8 Zn-0.65 Zr alloy // IOP Conference Series: Materials Science and Engineering. 2015. Vol. 82. № 1. P. 012099.
18. Nugmanov D.R., Sitdikov O.S., Markushev M.V. About fine-grain structure forming in bulk magnesium alloy MA14 under multidirectional isothermal forging // Bas. Problelm in Materials Science. 2012. № 9. P. 230.
19. Nugmanov D.R., Sitdikov O.S., Markushev M.V. Structure of magnesium alloy MA14 after multistep isothermal forging and subsequent isothermal rolling // The Physics of Metals and Metallography. 2015. Vol. 116. № 10. P. 993–1001.
20. Lu Y. Microstructure and degradation behaviour of Mg-Zn (-Ca) alloys. Birmingham: University of Birmingham, 2014. 215 p.
21. Bakhsheshi‐Rad H.R., Hamzah E., Lotfabadi A.F., Daroonparvar V., Yajid M.A.M., Islam M.M. Microstructure and bio‐corrosion behavior of Mg–Zn and Mg–Zn–Ca alloys for biomedical applications // Materials and Corrosion. 2014. Vol. 65. № 12. P. 1178–1187.
22. Ma E. Eight routes to improve the tensile ductility of bulk nanostructured metals and alloys // JOM. 2006. Vol. 58. № 4. P. 49–53.
23. Zhang B., Hou Y., Wang X., Wang Y., Geng L. Mechanical properties, degradation performance and cytotoxicity of Mg–Zn–Ca biomedical alloys with different compositions // Materials Science and Engineering: C. 2011. Vol. 31. № 8. P. 1667–1673.
24. Hofstetter J., Becker M., Martinelli E., Weinberg A.M., Mingler B., Kilian H., Pogatscher S., Uggowitzer P.J., Löffler J.F. High-strength low-alloy (HSLA) Mg–Zn–Ca alloys with excellent biodegradation performance // JOM. 2014. Vol. 66. № 4. P. 566–572.
