Squeeze Cast Mg-Zn Alloys for Bioapplications: Tensile Properties and Microstructure

Abstract:

In the past, Mg-Zn alloys prepared by a two-step manufacturing process of casting plus extrusion have been demonstrated to be a good candidate for biodegradable applications. But, studies on fabricating of Mg-Zn alloys with a single step process of squeeze casting capable of producing porosity-free Mg alloys, which can reduce the cost, are limited. In the present work, Zinc (Zn) addition varying from 1.0 up to 10.0 wt. % was introduced into liquid magnesium. The alloyed liquid was squeeze cast under an applied pressure of 90 MPa. The results of mechanical testing on the squeeze cast Mg-Zn alloys shows that Zn is an effective additive for enhancing their mechanical properties, specifically, tensile and yield strengths at room temperature, but reducing the elongation. While the Zn addition rises from 1.0 to 10.0 wt.%, the ultimate tensile and yield strengths increases to 181.0 MPa and 105.0 MPa from 140.7 MPa and 39.3 MPa, while the elongation-to-failure (e_f) decreases to 3.7% from 6.2%, respectively. The reveal of the as-cast grain structure by an optical microscope (OM) indicates that the high Zn content reduces grain sizes considerably. The microstructures analyzed by a scanning electron microscope (SEM) with the energy dispersive spectroscopy (EDS) show that the secondary MgZn phase forms once Zn is introduced in sufficient amount. The grain refinement and the massive presence of the secondary MgZn phase at the boundaries of the refined grains should be responsible to the enhancement of the strengths and the reduction in the elongation. The developed pressurized casting without employing secondary manufacturing processes such as extrusion or heat treatment exhibits its advantages to enhance the mechanical properties of the Mg alloys with high Zn content over conventional fabrication processes, since high Zn-containing Mg alloys have a long freezing range and tend to form microshrinkage porosity.

• Periodical: Key Engineering Materials (Volume 834)
• Pages: 169-176
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.834.169
• Online since: March 2020
• Authors: Anita Hu*, Xueyuan Nie, Henry Hu
• Keywords: Grain Structure, Intermetallics, Magnesium, Properties, Squeeze Casting, Zn Addition

References

[1] K. Kumar, R. S. Gill & U. Batra, Challenges and opportunities for biodegradable magnesium alloy implants, Materials Technology, Vol 33:2, 2018, 153-172.

DOI: 10.1080/10667857.2017.1377973

[2] H. Tapiero, K.D. Tew, Trace elements in human physiology and pathology: zinc and metallothioneins, Biomedicine and Pharmacotherapy, Vol 57, 2003, 399-411.

DOI: 10.1016/s0753-3322(03)00081-7

[3] K. Guan, B. Li, Q. Yang, X. Qiu, Z. Tian, D. Zhang, D. Zhang, X. Niu, W. Sun, X. Liu, J. Meng, Effects of 1.5 wt% samarium (Sm) addition on microstructures and tensile properties of a Mg−6.0Zn−0.5Zr alloy, Journal of Alloys and Compounds, Vol 735, 2018, 1737-1749.

DOI: 10.1016/j.jallcom.2017.11.315

[4] H. Du, Z. Wei, X. Liu, E. Zhang, Effects of Zn on the microstructure, mechanical property and bio-corrosion property of Mg–3Ca alloys for biomedical application, Materials Chemistry and Physics, Vol 125, 2011, 568-575.

DOI: 10.1016/j.matchemphys.2010.10.015

[5] E. Zhang, D. Yin, L. Xu, L. Yang, K. Yang, Microstructure, mechanical and corrosion properties and biocompatibility of Mg–Zn–Mn alloys for biomedical application, Materials Science and Engineering C, Vol 29, 2009, 987-993.

DOI: 10.1016/j.msec.2008.08.024

[6] L. Xu, G. Yu, E. Zhang, F. Pan, K. Yang, In vivo corrosion behavior of Mg‐Mn‐Zn alloy for bone implant application, Journal of Biomedical Materials Research Part A, Vol 83(3), 2007, 703-711.

DOI: 10.1002/jbm.a.31273

[7] D. Yin, E. Zhang, S. Zeng, Effect of Zn content on microstructure, mechanical properties and fracture behavior of Mg-Mn, China Foundry, Vol 6(1), 2009, 43-47.

[8] B. Zhang, Y. Hou, X. Wang, Y. Wang, L. Geng, Mechanical properties, degradation performance and cytotoxicity of Mg–Zn–Ca biomedical alloys with different compositions, Materials Science and Engineering C, Vol 31, 2011, 1667–1673.

DOI: 10.1016/j.msec.2011.07.015

[9] E. Zhang, L. Yang, J. Xu, H. Chen, Microstructure, mechanical properties and bio-corrosion properties of Mg–Si(–Ca, Zn) alloy for biomedical application, Acta Biomaterialia, Vol 6, 2010, 1756-1762.

DOI: 10.1016/j.actbio.2009.11.024

[10] E. Zhang, L. Xu, G. Yu, F. Pan, K. Yang, In vivo evaluation of biodegradable magnesium alloy bone implant in the first 6 months implantation, Journal of Biomedical Materials Research Part A, Vol 90(3), 2009, 882-893.

DOI: 10.1002/jbm.a.32132

[11] H. Ibrahim, N. S. Moghaddam, M. Elahinia, Mechanical and In Vitro Corrosion Properties of a Heat-Treated Mg-Zn-Ca-Mn Alloy as a Potential Bioresorbable Material, Advances in Metallurgical and Material Engineering, Vol 1(1), 2017, 1-7.

DOI: 10.36959/508/392

[12] Y. F. Zheng, X. N. Gu, F. Witte, Biodegradable metals, Materials Science and Engineering R, Vol 77, 2014, 1-34.

[13] M. Mezbahul-Islam, A. O. Mostafa, and M. Medraj, Essential magnesium alloys binary phase diagrams and their thermochemical data, Journal of Materials, Vol 2014, 2014, Article ID 704283, http://dx.doi.org/10.1155/2014/704283, 33 pages.

DOI: 10.1155/2014/704283

[14] H. Okamoto, Supplemental literature review of binary phase diagrams: Cs-In, Cs-K, Cs-Rb, Eu-In, Ho-Mn, K-Rb, Li-Mg, Mg-Nd, Mg-Zn, Mn-Sm, O-Sb, and Si-Sr, Journal of Phase Equilibria and Diffusion, Vol. 34, 2013, 251–263.

DOI: 10.1007/s11669-013-0233-2

[15] L. Fang, X. Zhang, L. Ren, H. Hu, X. Nie and J. Tjong, Effect of Ni addition on tensile properties of squeeze cast Al alloy A380. Advances in Materials and Processing Technologies. Vol 4(2), 2018.200-209.

DOI: 10.1080/2374068x.2017.1411746

[16] X. Zhang, L. Fang, H. Hu, X. Nie, and J. Tjong, Determination of Metal/die Interfacial Heat Transfer Coefficients in Squeeze Casting of Wrought Aluminum Alloy 7075 with Variations in Section Thicknesses and Applied Pressures. Journal of Heat Transfer, Vol 139, 2017, 022101-1-022101-9.

DOI: 10.1115/1.4034855

[17] J. Zhou, L. Ren, X. Geng, L. Fang, H. Hu, As-cast magnesium AM60-based hybrid nanocomposite containing alumina fibres and nanoparticles: microstructure and tensile behavior. Materials Science & Engineering A, 2017, In Press.

DOI: 10.1016/j.msea.2017.10.070

[18] M. Masoumi, H. Hu, Influence of Applied Pressure on Microstructure and Tensile Properties of Squeeze Cast Magnesium Mg-Al-Ca alloy, Materials Science and Engineering A, Vol 528(10-11), 2011, 3589-3593.

DOI: 10.1016/j.msea.2011.01.032

[19] S. Cai, T. Lei, N. Li, F. Feng, Effects of Zn on microstructure, mechanical properties and corrosion behavior of Mg–Zn alloys, Materials Science and Engineering C, Vol 32, 2012, 2570-2577.

DOI: 10.1016/j.msec.2012.07.042

[20] T. J. Collins, ImageJ for microscopy,, BioTechniques, 2007, vol. 43, no. 1, pp. S25-S30.

DOI: 10.2144/000112517

[21] J. Hu and X. Nie, Effect of nanostructure oxide coatings on tensile properties of cast pure magnesium, Advanced Materials Research, Vol 1088, 2015, 18-22.

DOI: 10.4028/www.scientific.net/amr.1088.18