Hall-Petch Relationship in an Al-Mg-Sc Alloy Subjected to ECAP

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Effect of extensive grain refinement on mechanical properties of an Al-Mg-Sc alloy subjected to equal-channel angular pressing (ECAP) at 300°C is considered in detail. It was shown that the Hall-Petch relationship with the coefficient, ky, of 0.2 MPa×m1/2 is valid in a wide strain range despite a great difference in deformation structures. Volume fraction of fine grains with an average size of ∼1 μm gradually increases with strain. It is caused by the fact that additive contributions of grain size strengthening and dislocation strengthening to the overall strengthening take place in this alloy. Upon ECAP the extensive grain refinement is accompanied by increasing dislocation density. Superposition of deformation and structural strengthening mechanisms provides achieving very high strength in the alloy. It was shown that ECAP at 300°C has no remarkable effect on a dispersion of coherent dispersoids. Al3(Sc,Zr), which gives a significant contribution to overall strength through dispersion strengthening. Contributions of different strengthening mechanisms to overall strength of the material are analyzed.

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120-125

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May 2014

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© 2014 Trans Tech Publications Ltd. All Rights Reserved

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[1] I.J. Polmear IJ, Light Alloys. From traditional alloys to nanocrystals. fourth ed., Butterworth-Heinemann/Elsevier, UK, 2006.

DOI: 10.1017/s000192400008670x

Google Scholar

[2] Yu.A. Filatov, V.I. Yelagin, V.V. Zakharov, New Al-Mg-Sc alloys, Mater.Sci.Eng. A280 (2000) 97–101.

DOI: 10.1016/s0921-5093(99)00673-5

Google Scholar

[3] J. Røyset, N. Ryum, Scandium in aluminium alloys, Intern.Mater.Rev. 50 (2005) 19-44.

Google Scholar

[4] R. Kaibyshev, A. Mogucheva, A. Dubyna, Strategy for achieving high strength in Al-Mg-Sc alloys by intense plastic straining, Mater. Sci. Forum 55 (2012) 706-709.

DOI: 10.4028/www.scientific.net/msf.706-709.55

Google Scholar

[5] K.-T. Park, J.H. Park, Y.S. Lee, W.J. Nam, Microstructures developed by compressive deformation of coarse grained and ultrafine grained 5083 Al alloys at 77 K and 298 K, Mater.Sci.Eng. A408 (2005) 102-109.

DOI: 10.1016/j.msea.2005.07.040

Google Scholar

[6] M.A. Munoz-Morris, C. G. Oca, D.G. Morris,Mechanical behaviour of dilute Al-Mg alloy processed by equal channel angular pressing, Scr.Mater. 48 (2003) 213-218.

DOI: 10.1016/s1359-6462(02)00501-8

Google Scholar

[7] R.Z. Valiev, N.A. Enikeev, M.Yu. Murashkin, V.U. Kazykhanov, X. Sauvage, On the origin of extremely high strength of ultrafine-grained Al alloys produced by severe plastic deformation, Scr. Mater. 63 (2010) 949–952.

DOI: 10.1016/j.scriptamat.2010.07.014

Google Scholar

[8] D.J. Lloyd, S.A. Court, Influence of grain size on tensile properties of Al-Mg alloys, Mater Sci Tech 19 (2003) 1349-1354.

DOI: 10.1179/026708303225006088

Google Scholar

[9] H. Hasegawa, S. Komura, A. Utsunomiya, Z. Horita, M. Furukawa, M. Nemoto, T.G. Langdon, Thermal stability of ultrafine-grained aluminum in the presence of Mg and Zr additions, Mater Sci Eng. A265 (1999) 188-196.

DOI: 10.1016/s0921-5093(98)01136-8

Google Scholar

[10] O. Sitdikov, T. Sakai, E. Avtokratova, R. Kaibyshev, K. Tsuzaki, Y. Watanabe, Microstructure behavior of Al-Mg-Sc alloy processed by ECAP at elevated temperature, Acta Mater. 56 (2008) 821-834.

DOI: 10.1016/j.actamat.2007.10.029

Google Scholar

[11] A. Mogucheva, E. Babich, B. Ovsyannikov, R. Kaibyshev, Microstructural evolution in a 5024 aluminum alloy processed by ECAP with and without back pressure, Mater.Sci.Eng. A560 (2013) 178–192.

DOI: 10.1016/j.msea.2012.09.054

Google Scholar

[12] H.W. Zhang, X. Huang, R. Pippan, N. Hansen, Thermal behavior of Ni (99.967% and 99.5% purity) deformed to an ultra-high strain by high pressure torsion, Acta Materialia 58 (2010) 1698–1707.

DOI: 10.1016/j.actamat.2009.11.012

Google Scholar

[13] H. Halim, D.S. Wilkinson, M. Niewczas, The Portevin-Le Chatelier (PLC) effect and shear band formation in an AA5754 alloy, Acta Mater. 55 (2007) 4151-4160.

DOI: 10.1016/j.actamat.2007.03.007

Google Scholar