High temperature,high strain forging behaviour of binary Al–2Li alloy

Abstract

This investigation has demonstrated the utility of coupled computer simulation and constant strain rate, isothermal compression of double cone wedge tests within the dynamic recrystallisation regime, for predicting the influence of strain, strain rate and temperature on the high temperature, high strain forging behaviour of an annealed binary Al–2 wt-%Li alloy. Initially, experimentally determined true stress–true strain compression data were used to simulate isothermal forging of double cone compression specimens. At intermediate temperatures (673–773 K) and strain rates (0.01–0.001 s^-1), simulations predicted large gradients in strain across the specimen, the microstructural features in this case corresponding to both dynamic recovery and dynamic recrystallisation (DRX) within the specimen. At higher temperatures (773–823 K) and lower strain rates (0.0005–0.001 s^-1), simulations predicted a uniform strain distribution over the cross-section of the specimen, the microstructural observations correlating to DRX at lower strains and dynamic grain growth at high strain levels. Two models, one statistical, and the other phenomenological, were utilised to predict the grain size variation in the specimen as a function of strain. Both models showed excellent correlation with the experimentally measured grain size data.