Influence of Initial Heat Treatment on the Microhardness Evolution of an Al-Mg-Sc Alloy Processed by High-Pressure Torsion

Abstract:

An Al-3% Mg-0.2% Sc alloy was subjected to annealing or solution treatment and further processed by HPT at room temperature. Microhardness measurements were taken along the middle-sections of the discs and they demonstrated that a very substantial hardening is achieved during HPT processing regardless of the initial heat treatment. Hardness values of ~200 Hv were recorded at the edge of the samples although the microhardness distribution remained inhomogeneous along the diameters of the discs after 20 turns of high-pressure torsion. In addition, the microhardness of the solution treated Al-Mg-Sc samples continued to increase with the equivalent strain imposed by the anvils even after 30 turns of HPT processing whereas the hardness at the edges of the annealed discs saturated after 10 turns. These differences in the hardness evolution are attributed to the higher Mg content in solid solution in the case of the solution treated samples and its influence on delaying the recovery rate of this aluminium alloy.

• Periodical: Materials Science Forum (Volume 879)
• Pages: 1471-1476
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.879.1471
• Online since: November 2016
• Authors: Pedro Henrique R. Pereira*, Yi Huang, Terence G. Langdon
• Keywords: Aluminum Alloy, Hardness, High-Pressure Torsion, Homogeneity, Severe Plastic Deformation (SPD)

References

[1] T.G. Langdon, Twenty-five years of ultrafine-grained materials: Achieving exceptional properties through grain refinement, Acta Mater. 61 (2013) 7035-7059.

DOI: 10.1016/j.actamat.2013.08.018

[2] A.P. Zhilyaev, T.G. Langdon, Using high-pressure torsion for metal processing: fundamentals and applications, Prog. Mater. Sci. 53 (2008) 893–979.

DOI: 10.1016/j.pmatsci.2008.03.002

[3] R.B. Figueiredo, P.R. Cetlin, T.G. Langdon, Using finite element modeling to examine the flow processes in quasi-constrained high-pressure torsion, Mater. Sci. Eng. A528 (2011) 8198-8204.

DOI: 10.1016/j.msea.2011.07.040

[4] P.H.R. Pereira, R.B. Figueiredo, P.R. Cetlin, T.G. Langdon, An examination of the elastic distortions of anvils in high-pressure torsion, Mater. Sci. Eng. A631 (2015) 201-208.

DOI: 10.1016/j.msea.2015.02.052

[5] S. Komura, Z. Horita, M. Furukawa, M. Nemoto, T.G. Langdon, An evaluation of the flow behavior during high strain rate superplasticity in an Al-Mg-Sc alloy, Metall. Mater. Trans. A 32A (2001) 707-716.

DOI: 10.1007/s11661-001-1006-9

[6] G. Sakai, Z. Horita, T.G. Langdon, Grain refinement and superplasticity in an aluminum alloy processed by high-pressure torsion, Mater. Sci. Eng. A393 (2005) 344-351.

DOI: 10.1016/j.msea.2004.11.007

[7] Y. Harai, K. Edalati, Z. Horita, T.G. Langdon, Using ring samples to evaluate the processing characteristics in high-pressure torsion, Acta Mater. 57 (2009) 1147-1153.

DOI: 10.1016/j.actamat.2008.10.046

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

DOI: 10.1016/j.scriptamat.2010.07.014

[9] J. Gubicza, N.Q. Chinh, Z. Horita, T.G. Langdon, Effect of Mg addition on microstructure and mechanical properties of aluminum, Mater. Sci. Eng. A387-389 (2004) 55-59.

DOI: 10.1016/j.msea.2004.03.076

[10] G. Horváth, N.Q. Chinh, J. Gubicza, J. Lendvai, Plastic instabilities and dislocation densities during plastic deformation in Al-Mg alloys, Mater. Sci. Eng. A445-446 (2007) 186-192.

DOI: 10.1016/j.msea.2006.09.019

[11] T. Morishige, T. Hirata, T. Uesugi, Y. Takigawa, M. Tsujikawa, K. Higashi, Effect of Mg content on the minimum grain size of Al-Mg alloys obtained by friction stir processing, Scripta Mater. 64 (2011) 355-358.

DOI: 10.1016/j.scriptamat.2010.10.033

[12] K. Edalati, D. Akama, A. Nishio, S. Lee, Y. Yonenaga, J.M. Cubero-Sesin, Z. Horita, Influence of dislocation–solute atom interactions and stacking fault energy on grain size of single-phase alloys after severe plastic deformation using high-pressure torsion, Acta Mater. 69 (2014).

DOI: 10.1016/j.actamat.2014.01.036

[13] K. Dám, P. Lejček, A. Michalcová, In situ TEM investigation of microstructural behaviour of superplastic Al-Mg-Sc alloy, Mater. Charact. 76 (2013) 69-75.

DOI: 10.1016/j.matchar.2012.12.005

[14] R.Z. Valiev, Yu.V. Ivanisenko, E.F. Rauch, B. Baudelet, Structure and deformation behaviour of Armco iron subjected to severe plastic deformation, Acta Mater. 44 (1996) 4705-4712.

DOI: 10.1016/s1359-6454(96)00156-5

[15] F. Wetscher, A. Vorhauer, R. Stock, R. Pippan, Structural refinement of low alloyed steels during severe plastic deformation, Mater. Sci. Eng. A387-389 (2004) 809-816.

DOI: 10.1016/j.msea.2004.01.096

[16] F. Wetscher, R. Pippan, S. Sturm, F. Kauffmann, C. Scheu, G. Dehm, TEM investigations of the structural evolution in a pearlitic steel deformed by high-pressure torsion, Metall. Mater. Trans. A 37A (2006) 1963-(1968).

DOI: 10.1007/s11661-006-0138-3

[17] M. Kawasaki, Different models of hardness evolution in ultrafine-grained materials processed by high-pressure torsion, J. Mater. Sci. 49 (2014) 18-34.

DOI: 10.1007/s10853-013-7687-9

[18] M. Kawasaki, S.N. Alhajeri, C. Xu, T.G. Langdon, The development of hardness homogeneity in pure aluminum and aluminum alloy disks processed by high-pressure torsion, Mater. Sci. Eng. A529 (2011) 345-351.

DOI: 10.1016/j.msea.2011.09.039

[19] M. Kawasaki, T.G. Langdon, The significance of strain reversals during processing by high-pressure torsion, Mater. Sci. Eng. A498 (2008) 341-348.

DOI: 10.1016/j.msea.2008.08.021

[20] B.B. Straumal, B. Baretzky, O.A. Kogtenkova, A.B. Straumal, A.S. Sidorenko, Wetting of grain boundaries in Al by the solid Al3Mg2 phase, J. Mater. Sci. 45 (2010) 2057-(2061).

DOI: 10.1007/s10853-009-4014-6

[21] X. Sauvage, N. Enikeev, R. Valiev, Y. Nasedkina, M. Murashkin, Atomic-scale analysis of the segregation and precipitation mechanisms in a severely deformed Al–Mg alloy, Acta Mater. 72 (2014) 125-136.

DOI: 10.1016/j.actamat.2014.03.033