Hot compressive deformation behavior and microstructural evolution of the spray-formed 1420 Al–Li alloy

Abstract

The 1420 Al–Li alloy has been widely used in the aerospace field. To investigate the hot workability of the alloy, a series of hot compression tests were carried out on the spray-formed alloy in the temperature range of 300°C–450 °C with strain rates of 0.0001s−1-10s−1. First, an improved Johnson-Cook model was developed by considering the coupling effect of strain, strain rate, and temperature, and the prediction error of the model was reduced to 5.3 %. Subsequently, processing maps with various strains were established. In addition, the microstructural evolution under various deformation conditions was systematically studied using the electron backscatter diffraction (EBSD) technique. The alloy exhibited uniform deformation under the synergistic effect of the continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX) mechanisms. Finally, the feasible hot working windows were identified as 425°C–450°C and 0.01s−1-0.1s−1 based on processing maps and microstructural evolution results. This work could offer comprehensive guidance for the hot working process of 1420 Al–Li alloy from both the macro and the micro aspects.