Abstract: 1420Al-Li alloy was used to explore the best deformation results including high elongation, uniform, and fine-grain structure by changing deformation temperature and strain rate. The results showed that, on the condition of deflection temperature T=480℃ and strain rate  =3×10-4s-1, 1420 Al-Li alloy showed good superplasticity, of which the maximum elongation δ=550％ and the minimum flow stress σ=1.9MPa. Furthermore, the grain microstructure was isometric and fine after superplastic deformation through metallurgical analysis and TEM microstructure observation. Besides, the re-crystallization grains appeared which could promote the super-plastic deformation process during the deformation.

Key words: re-crystallization, strain rate, elongation, 1420 Al-Li alloy, super-plastic deformation, flow stress