Investigation of Ca in the Microstructural Evolution and Porosity Analysis of ZK60 Alloy in As-Cast and Extruded Conditions

Document Type : Research Paper

Authors

1 Imam Khomeini International, University, Qazvin, Qazvin, Iran

2 School of Metallurgy and Materials Engineering, University of Tehran, Tehran, Iran

Abstract

This research work has been carried out to study the effect of different Ca contents (0.5, 1.0, 1.5, 2.0 and 3.0) on the microstructure and porosity content of ZK60 alloys. The samples were examined by using optical and scanning electron microscopy (SEM) to evaluate the modification efficiency of the alloy with different Ca concentrations. The cast specimens were modified, homogenized and extruded at 350 °C at an extrusion ratio of 12:1. The experimental results showed that the addition of Ca brings about the precipitation of a new phase and refines the as-cast grains. It was also found that the presence of Ca at higher concentrations (>2 wt. %) results in the formation of hard Ca-rich intermetallics segregated in cell boundaries. Hot-extrusion was found to be powerful in breaking the eutectic network and changing the size and morphology of Ca-rich intermetallic phase. By applying the extrusion process and increasing Ca concentration (up to 2.0 wt. %), the porosity percentage decreased from 13.62% to 6.34% and 7.11% to 3.89% for ZK60 and ZK60+3%Ca alloys, respectively.

Keywords

References

  [1] K. Yu, W. Li, J. Zhao, Z. Ma, R. Wang, Plastic deformation behaviors of a Mg–Ce–Zn–Zr alloy, Scripta Materialia, 48 (2003) 1319-1323.
[2] A. Lou, M. O. Pekguleryuz, J. Mater, Cast magnesium alloys for elevated temperature applications, Journal of Materials Science, 29 (1994) 5259–5271.
[3] B. L. Mordike, T. Ebert, Magnesium properties-applications-potential, Materials Science and Engineering, A 302 (2001) 37-45.
[4] A. Sanschagrin, R. Tremblay, R. Angers, Mechanical properties and microstructure of new magnesium-lithium base alloys, Materials Science and Engineering, A 220 (1996) 69-77.
[5] I. J. Polmear, Magnesium alloys and applications, Materials Science and Technology, 10 (1994) 1-16.
[6] I. J. Polmear, Recent Developments in Light Alloys, Metallurgical and Materials Transactions, JIM 37 (1996) 12.
[7] F. S. Pan, J. Zhang, J. F. Wang, M. B. Yang, e. H. Han, R. S. Chen, Key R&D activities for development of new types of wrought magnesium alloys in China, Transactions of Nonferrous Metals Society of China, 20 (2010) 1249-1258.
[8] H. T. Zhou, Z. D. Zhang, C. M. Liu, Q. W. Wang, Effect of Nd and Y on the microstructure and mechanical properties of ZK60 alloy, Materials Science and Engineering, A 445–446 (2007) 1-6.
[9] M. A. Chunjiang, L. Manping, W. U. Guohua, D. Wengjiang, Z.H.U. Yanping, Tensile properties of extruded ZK60–RE alloys, Materials Science and Engineering, A 349 (2003) 207–212.
[10] C. J. Bettles, M. A. Gibson, Current wrought magnesium alloys, Strengths and weaknesses. JOM 57 (2005) 46-49.
[11] M. Vogel, O. Kraft, E. Arzt, Effect of Ca additions on the creep behavior of magnesium die-cast alloy ZA85, Metallurgical and Materials Transactions, A 36 (2005) 1713–1719.
[12] P. M. Jardim, G. Solorzano, J. B. Vander Sande, Second phase formation in melt-spun Mg-Ca-Zn alloys, Materials Science and Engineering, A 381 (2004) 196–205.
[13] D. W. Kim, B. C. Suh, M. S. Shim, J. H. Bae, D. H. Kim, N. Kim, Texture Evolution in Mg-Zn-Ca Alloy Sheets, Metallurgical and Materials Transactions A, 44 (2013) 2950–2961.
[14] M. Yuasa, N. Miyazawa, M. Hayashi, M. Mabuchi, Y. Chino,  Effects of group II elements on the cold stretch formability of Mg-Zn alloys , Acta Materialia, 83 (2015) 294–303.
[15] Y. Chino, X. S. Huang, K. Suzuki, M. Mabuchi, Influence of aluminum content on the texture and sheet formability of AM series magnesium alloys, Materials Science and Engineering A, 633 (2015) 144-153.
[16] A. Luo, A. Sachdev, Microstructure and Mechanical Properties of Magnesium-Aluminum-Manganese Cast Alloys, International Journal of Metal casting, 4(2010) 51–59.
[17] Erenilton Pereira da Silva; Larissa Fernandes Batista; Bruna Callegari; Ricardo Henrique Buzolin; Fernando Warchomicka; Guillermo Carlos Requena; Pedro Paiva Brito; Haroldo Cavalcanti Pinto, Solution and ageing heat treatments of ZK60 magnesium alloys with rare earth additions produced by semi-solid casting, Materials Research, 17 (2014) 1516-1439.
[18] M. Paliwal, I. H. Jung, J. Microstructural evolution in Mg–Zn alloys during solidification: An experimental and simulation study, Journal of Crystal Growth, 394 (2014) 28–38.
[19] M. Mezbahul-Islam, A. O. Mostafa, M. Medraj, Essential Magnesium Alloys Binary Phase Diagrams and Their Thermochemical Data, Journal of Materials, (2014).
[20] P. Ghosh, M. Mezbahul-Islam, M. Medraj, Critical assessment and thermodynamic modeling of Mg–Zn, Mg–Sn, Sn–Zn and Mg–Sn–Zn systems, Calphad, 36 (2012) 28–43.
[21] X. Gao, J. F. Nie, Scr. Structure and thermal stability of primary intermetallic particles in an Mg–Zn casting alloy, Scripta Materialia, 57 (2007) 655–658.
Iranian Journal of Materials Forming
Volume 6, Issue 1
April 2019
Pages 24-31

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