On the Activation Energies Observed in Al-based Materials Deformed at Ultrahigh Temperatures

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

Detail(s)

Original languageEnglish
Pages (from-to)545-550
Journal / PublicationMaterials Science Forum
Volume357-359
Online published15 Jan 2001
Publication statusPublished - 2001
Externally publishedYes

Conference

TitleSuperplasticity in Advanced Materials (ICSAM-2000)
PlaceUnited States
CityOrlando, FL
Period1 - 4 August 2000

Abstract

This study examines the exceptionally high activation energies estimated from data obtained from various composites exhibiting high strain rate superplasticity and loaded at ultrahigh temperatures near or slightly above the solidus. It is shown that the activation energies for the 6061 composite and for Al 6061 and 1050 alloys are below 200 kJ/mol at temperatures lower than the incipient melting temperature, Ti, but they become significantly higher at temperatures near or slightly above Ti and this increase is independent of the alloy system, the grain size, whether the material is superplastic and the dominant deformation mechanism at T<Ti. There is a transition from plastic flow in a solid state to a viscous-like flow behavior in the Al-6061 systems at T>610°C and in the Al-1050 alloy at T>650°C. It is concluded that the high values of Qt have no physical meaning in terms of the rate-controlling diffusive species.

Research Area(s)

  • Activation Energy, Al Alloy, Al Composites, Deformation Mechanisms

Citation Format(s)

On the Activation Energies Observed in Al-based Materials Deformed at Ultrahigh Temperatures. / Lou, B.Y.; Wang, T.D.; Huang, J.C. et al.
In: Materials Science Forum, Vol. 357-359, 2001, p. 545-550.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review