Ultrafine-Grained Structure Produced by FSW and ECAP in Al-Mg-Sc-Zr Alloy: Comparison

Abstract:

The Al-5.4Mg-0.2Sc-0.1Zr alloy with initial coarse grained structure and containing coherent nanoscale Al₃(Sc,Zr) particles with an average size of ~9 nm was subjected to equal channel angular pressing (ECAP) at temperatures ranging from 300 to 450°C up to a total strain of ~12 and friction stir processing (FSP) with the rotation speed ranging from 350 to 800 rpm. ECAP led to the formation of a uniform microstructure with an average grain size of ~ 0.9 μm. Increasing deformation temperature leads to a slight increase in the average grain size to 1.4 μm and coarsening of Al₃(Sc,Zr) precipitates to 13 nm. FSP with a tool rotation speed of 350, 500, 650, 800 rpm and traveling speed of 75 mm/min led to the formation of fully recrystallized uniform microstructures with an average grain size of ~1.6, 1.9, 2.7 and 2.9 μm, respectively. The coarsening of Al₃(Sc,Zr) dispersoids from 9 to 27 nm occurred under FSP but most of them retained coherency with the matrix.

• Periodical: Materials Science Forum (Volumes 838-839)
• Pages: 379-384
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.838-839.379
• Online since: January 2016
• Authors: Vladislav Kulitskiy*, Sergey Malopheyev, Yulia Buranova, Sergiy V. Divinski, Gerhard Wilde, Rustam Kaibyshev
• Keywords: Aluminium Alloy, Equal Channel Angular Pressing, Friction Stir Welding, Ultrafine Grained Microstructure

References

[1] Yu.A. Filatov, V.I. Yelagin, V.V. Zakharov, New Al–Mg–Sc alloys, Mater. Sci. Eng. A 280 (2000) 97-101.

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

[2] J. Røyset, N. Ryum, Scandium in aluminium alloys, Inter. Mater. Rev 50 (2005) 19–44.

[3] F. Musin, R. Kaibyshev, Y. Motohashi, G. Itoh, Superplastic Behavior and Microstructure Evolution in a Commercial Al-Mg-Sc Alloy Subjected to Intense Plastic Straining, Metall. Mater. Trans. 35A (2004) 2383-2392.

DOI: 10.1007/s11661-006-0218-4

[4] Z. Horita, M. Furukawa, M. Nemoto, A. J. Barnes, T. G. Langdon, Superplastic Forming at High Strain Rates After Severe Plastic Deformation, Acta Mater. 48 (2000) 3633-3640.

DOI: 10.1016/s1359-6454(00)00182-8

[5] S. Ota, H. Akamatsu, K. Neishi, M. Furukawa, Z. Horita, T.G. Langdon, Low-temperature superplasticity in aluminum alloys processed by equal-channel angular pressing, Mater. Trans. 43 (2002) 2364-2369.

DOI: 10.2320/matertrans.43.2364

[6] F.C. Liu and Z.Y. Ma, Achieving exceptionally high superplasticity at high strain rates in a micrograined Al–Mg–Sc alloy produced by friction stir processing, Scr. Mater. 59 (2008) 882–885.

DOI: 10.1016/j.scriptamat.2008.06.035

[7] F.C. Liu, Z.Y. Ma, L.Q. Chen, Low-temperature superplasticity of Al–Mg–Sc alloy produced by friction stir processing, Scr. Mater. 60 (2009) 968–971.

DOI: 10.1016/j.scriptamat.2009.02.021

[8] Z.Y. Ma, F.C. Liu, R.S. Mishra, Superplastic deformation mechanism of an ultrafine-grained aluminum alloy produced by friction stir processing, Acta Mater. 58 (2010) 4693–4704.

DOI: 10.1016/j.actamat.2010.05.003

[9] R. Valiev, T. Langdon, Principles of equal-channel angular pressing as a processing tool for grain refinement Prog. Mater. Sci. 51 (2006) 881–981.

DOI: 10.1016/j.pmatsci.2006.02.003

[10] P. Threadgill, A. Leonard, H. Shercliff, P. Withers, Friction stir welding of aluminium alloys, Int. Mater. Rev. 54 (2009) 49–93.

DOI: 10.1179/174328009x411136

[11] S. Malopheyev, V. Kulitskiy, S. Mironov, D. Zhemchuzhnikova, R. Kaibyshev, Friction-stir welding of an Al–Mg–Sc–Zr alloy in as-fabricated and work-hardened conditions, Mater. Sci. Eng. A 600 (2014) 159–170.

DOI: 10.1016/j.msea.2014.02.018