MECHANICAL PROPERTIES AND STRUCTURE EVOLUTION OF THE AZ91 MAGNESIUM ALLOY AFTER HOT ROLLING AND ANNEALING

Authors

  • Bartosz Sułkowski AGH University of Science and Technology Faculty of Non-ferrous Metals
  • Grzegorz Boczkal AGH University of Science and Technology Faculty of Non-ferrous Metals

DOI:

https://doi.org/10.7494/mafe.2015.41.3.143

Keywords:

magnesium AZ91, hot rolling, texture, annealing, mechanical properties

Abstract

The AZ91 magnesium alloy was processed up to 87.5% of total thickness reduction in several thermodynamic routes, consisted of hot rolling and intermediate annealing. The hot-rolling process was performed at a high strain rate equal to 1.6 s−1 and at a temperature of 430°C. The intermediate annealing was performed at 430°C for 15 minutes after each route. It was found that, during hot rolling, the hardness of the material increased from 32 HV to 40 HV, and the structure investigations showed a huge amount of twins formed inside the grains (which were not observed after annealing). Tensile tests have shown strong anisotropy in mechanical properties of the “as-rolled” samples dependent on the orientation between tension direction (TD) and rolling direction (RD). The samples with TD perpendicular to RD proved higher ultimate tensile strength (UTS) and (on the other hand) worse plastic properties as compared to the samples with TD parallel to RD. The annealing has an effect on the reduction of mechanical properties anisotropy. X-ray investigations have shown texture changes from the basal type with the additional (0001) <1120> component for “as-rolled” samples to the texture with the main (0001) <1010> component for annealed samples. The texture changes had a great impact on the anisotropy of mechanical properties of the investigated AZ91 magnesium alloy.

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References

Kainer K.U. (ed.): Magnesium Alloys and their Applications. Wiley-VCH Verlag GmbH, Weinheim, Germany 2000

Krystian M., Zehetbauer M.J., Kropik H., Mingler B., Krexner G.: Hydrogen storage properties of bulk nanostructured ZK60 Mg alloy processed by Equal Channel Angular Pressing. Journal of Alloys and Compounds, 509, 1 (2011), S449–S455, doi:10.1016/j.jallcom.2011.01.029

Chen Y., Xu Z., Smith C., Sankar J.: Recent advances on the development of magnesium alloys for biodegradable implants. Acta Biomaterialia, 10, 11 (2014) S4561–S4573, doi:10.1016/j.actbio.2014.07.005

Kainer K.U. (ed.): Magnesium – Alloys and Technology. WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2003

Kelly W.E.: Technical Report: The Plastic Deformation of Magnesium. The University of Michigan, Ann Arbor 1967

Zeng Z.R., Bian M.Z., Xu S.W., Davies C.H.J., Birbilis N., Nie J.F.: Texture evolution during cold rolling of dilute Mg alloys. Scripta Materialia, 108 (2015), 6–10

Zhang Z.: The formation of double peaks in the basal texture during ambient extrusion of an AZ31 magnesium alloy. Materials Letters, 116 (2014), 131–134

Huang X., Suzuki K., Saito N.: Textures and stretch formability of Mg-6Al-1Zn magnesium alloy sheets rolled at high temperatures up to 793 K. Scripta Materialia, 60, 8 (2009), 651–654

Tong L.B., Li X., Zhang D.P., Cheng L.R., Meng J., Zhang H.J.: Dynamic recrystallization and texture evolution of Mg-Y-Zn alloy during hot extrusion process. Materials Characterization, 92 (2014), 77–83

Ono N., Nowak R., Miura S.: Effect of deformation temperature on HallPetch relationship registered for polycrystalline magnesium. Materials Letters, 58, 1–2 (2003), 39–43

Chino Y., Lee J.-S., Sassa K., Kamiya A., Mabuchi M.: Press formability of a rolled AZ31 Mg alloy sheet with controlled texture. Materials Letters, 60, 2 (2006), 173–176

Zhu S.Q., Yan H.G., Chen J.H., Wu Y.Z., Liu J.Z., Tian J.: Effect of twinning and dynamic recrystallization on the high strain rate rolling process. Scripta Materialia, 63, 10 (2010), 985–988

Sulkowski B., Palka P.: Deformation behaviors of AZ61 magnesium alloy systematic rolled and annealed at 450°C. Kovové Materiály 2016, in press

Mostaed E., Fabrizi A., Dellasega D., Bonollo F., Vedani M.: Microstructure, mechanical behavior and low temperature superplasticity of ECAP processed ZM21 Mg alloy. Journal of Alloys and Compounds, 638 (2015), 267–276

ASM Handbook, Joseph R. Davis (Manager of Handbook Development). USA, 1990

Wua H.-Y., Yan J.-Ch., Tsai H.-H., Chiu Ch.-H., Zhou G.-Z., Lin Ch.-F.: Tensile flow and strain-hardening behaviors of dual-phase Mg-Li-Zn alloy thin sheets. Materials Science and Engineering A, 527, 27–28 (2010), 7197–7203

del Valle J.A., Pérez-Prado M.T., Ruano O.A.: Texture evolution during large-strain hot rolling of the Mg AZ61 alloy. Materials Science and Engineering A, 355, 1–2 (2003), 68–78

Ion S.E., Humphreys F.J., White S.H.: Dynamic recrystallisation and the development of microstructure during the high temperature deformation of magnesium. Acta Metallurgica, 30, 10 (1982), 1909–1919

Foley D.C., Al-Maharbi M., Hartwig K.T., Karaman I., Kecskes L.J., Mathaudhu S.N.: Grain refinement vs. crystallographic texture: Mechanical anisotropy in a magnesium alloy. Scripta Materialia, 64, 2 (2011), 193–196

Cepeda-Jiménez C.M., Molina-Aldareguia J.M., Carreño F., Pérez-Prado M.T.: Prominent role of basal slip during high-temperature deformation of pure Mg polycrystals. Acta Materialia, 85 (2015), 1–13

Wang Y.N., Huang J.C.: Texture analysis in hexagonal materials. Materials Chemistry and Physics, 81, 1 (2003), 11–26

Graff S., Brocks W., Steglich D.: Yielding of magnesium: From single crystal to polycrystalline aggregates. International Journal of Plasticity 23, 12 (2007) 1957–1978

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Published

2016-03-23

How to Cite

Sułkowski, B., & Boczkal, G. (2016). MECHANICAL PROPERTIES AND STRUCTURE EVOLUTION OF THE AZ91 MAGNESIUM ALLOY AFTER HOT ROLLING AND ANNEALING. Metallurgy and Foundry Engineering, 41(3), 143. https://doi.org/10.7494/mafe.2015.41.3.143

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