Mechanical properties and structure evolution of the AZ91 magnesium alloy after hot rolling and annealing

• Autorzy: Sułkowski B. , Boczkal G.

Identyfikatory

DOI

10.7494/mafe.2015.41.3.143

Warianty tytułu

PL

Właściwości mechaniczne oraz struktura stopu AZ91 po walcowaniu na gorąco i wyżarzaniu

• Języki publikacji: EN

Abstrakty

EN

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 onthe orientation between tension direction (TD) and rolling direction (RD). The samples with TD perpendicular to RD provedhigher 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.

PL

Stop magnezu AZ91 był walcowany na gorąco ze zgniotem 87.5% w kilku operacjach walcowania-wyżarzania. Walcowanie na gorąco było przeprowadzone w temperaturze 430°C z prędkością odkształcenia 1.6 s−1. Wyżarzanie międzyoperacyjne przeprowadzano w temperaturze 430°C przez 15 minut. Po walcowaniu twardość stopu AZ91 wzrosła od wartości 32 HV do wartości 40 HV, a obserwacje struktury wykazały obecność wewnątrz ziaren dużej liczby bliźniaków. Po przeprowadzeniu wyżarzania (15 minut, 430°C) nie zaobserwowano obecności bliźniaków. Wyniki badań z próby rozciągania wykazały silną anizotropię własności mechanicznych w zależności od ułożenia kierunku rozciągania (KR) próbek wtórnych względem kierunku walcowania (KW).Przeprowadzone wyżarzanie spowodowało zmniejszenie anizotropii właściwości mechanicznych w badanym materiale. Przeprowadzone badania rentgenowskie wykazały zmiany w teksturze z typu bazalnego z dodatkowym komponentem (0001) <1120>dla próbek po walcowaniu na typ tekstury z głównym komponentem (0001) <1010> dla próbek wyżarzanych. Zmiany tekstury miały silny wpływ na zaobserwowaną anizotropię właściwości mechanicznych badanego stopu AZ91 po walcowaniu na gorąco i wyżarzaniu.

Słowa kluczowe

EN

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

PL

stop magnezu AZ91; walcowanie na gorąco; tekstura; właściwości mechaniczne

• Wydawca: AGH University of Science and Technology Press
• Czasopismo: Metallurgy and Foundry Engineering
• Rocznik: 2015
• Tom: Vol. 41, no. 3
• Strony: 143--151
• Opis fizyczny: Bibliogr. 22 poz., rys., tab., wykr.

Twórcy

autor

Sułkowski B.

• AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Material Engineering and Non-Ferrous Metals, Krakow, Poland

autor

Boczkal G.

• AGH University of Science and Technology, Faculty of Non-Ferrous Metals, Department of Material Engineering and Non-Ferrous Metals, Krakow, Poland

Bibliografia

• [1] Kainer K.U. (ed.): Magnesium Alloys and their Applications. Wiley-VCH Verlag GmbH, Weinheim, Germany 2000
• [2] 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
• [3] 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
• [4] Kainer K.U. (ed.): Magnesium – Alloys and Technology. WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2003
• [5] Kelly W.E.: Technical Report: The Plastic Deformation of Magnesium. The University of Michigan, Ann Arbor 1967
• [6] 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
• [7] 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
• [8] 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
• [9] 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
• [10] 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
• [11] 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
• [12] 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
• [13] Sulkowski B., Palka P.: Deformation behaviors of AZ61 magnesium alloy systematic rolled and annealed at 450°C. Kovové Materiály 2016, in press
• [14] 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
• [15] ASM Handbook, Joseph R. Davis (Manager of Handbook Development). USA, 1990
• [16] 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
• [17] 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
• [18] 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
• [19] 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
• [20] 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
• [21] Wang Y.N., Huang J.C.: Texture analysis in hexagonal materials. Materials Chemistry and Physics, 81, 1 (2003), 11–26
• [22] Graff S., Brocks W., Steglich D.: Yielding of magnesium: From single crystal to polycrystalline aggregates. International Journal of Plasticity 23, 12 (2007) 1957–1978