Effects of velocity ratios and strain paths on the microstructures and mechanical properties of Al-Li alloy during asymmetric rolling
摘要
In this work, the asymmetric rolling (ASR) is employed to improve the formability of 2195 Al-Li alloy, which has been widely used in the aerospace and automobile fields. The microstructures and mechanical properties of 2195 Al-Li alloy in ASR under different velocity ratios and strain paths are explored through experimental characterization. Compared with conventional rolling, ASR can effectively refine the grain. As the velocity ratio increases, the average grain size gradually decreases, and the surface grain contacted with the faster roll is finer, which can be attributed to more severe shear deformation. The complex strain path will increase the shear component. Under the same velocity ratio, the grain refinement effect of double-direction asymmetrical rolling is more significant. Moreover, the shear component generated by ASR causes some textures to deviate or split from the ideal positions. Most of the recrystallization textures are eliminated. During ASR, the rolling texture of the surface in contact with the faster roll tends to evolve into the shear texture. In terms of improving the uniformity of microstructure, adjusting the velocity ratio is more effective than changing the strain path. The grain size and texture of the top and inner layers of the ASR sheet with a velocity ratio of 1.8 are closer. These findings provide theoretical guidance for achieving high-performance manufacturing of Al-Li alloy components.