Strain Rate Sensitivity of Ultrafine Grained Aluminium Alloy AA6061

Abstract:

The strain rate sensitivity of the aluminium alloy AA6061 has been investigated in a conventional grain sized (CG) state and in two different ultrafine grained (UFG) conditions processed by Equal Channel Angular Pressing (ECAP) for 2 and 6 passes at 100o C. Strain rate jump tests in compression were performed at different temperatures and the strain-rate sensitivity exponent m was determined. The tests were accomplished by microstructural investigations before and after compression testing in CG and UFG conditions. It is shown that all UFG microstructures exhibit strongly increased strain-rate sensitivity (SRS) compared to the CG state. The SRS increases with increasing temperature and is more pronounced for the UFG material processed using 6 ECAP passes. The microstructural investigations show a rather high stability of the grain structure for the UFG conditions up to 250o C. The results are discussed with respect to the relevant deformation mechanisms.

• Periodical: Materials Science Forum (Volumes 584-586)
• Pages: 741-747
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.584-586.741
• Online since: June 2008
• Authors: Aferdita Vevecka-Priftaj, Andreas Böhner, Johannes May, Heinz Werner Höppel, Matthias Göken
• Keywords: Equal-Channel Angular Pressing (ECAP), Severe Plastic Deformation (SPD), Strain Rate Sensitivity (SRS), Ultra Fine Grained Metal

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