Published online by Cambridge University Press: 26 February 2011
The large elongations associated with superplasticity are observed only in materials with fine grain sizes. An Al-Li alloy processed thermomechanically to develop a fine grain size exhibits superplastic characteristics and large elongations to failure of up to ∼900%. Measurements at large elongations reveal that the grain boundary sliding contribution to superplastic deformation is ∼75%. Microstructural inspection of superplastically deformed specimens reveals also the occurrence of extensive cavitation.