Study of Strain characterization and microstructure evolution under compression stress in Al-Li alloy

Abstract

Abstract:The strain variation and microstructure evolution of 2060-T8 alloy during bending are investigated by Micro-hardness point method (MHPM) and Digital Image Correlation (DIC), electron backscattered diffraction (EBSD). Experimental result shows DIC method can be used to characterize the strain micro-region on average and it can also represent the local strain tensor in the micro-region compared to the traditional MHPM. The strain is unevenly distributed in grains due to the mis-orientation between the adjacent grains difference, the mis-orientation has a blocking effect on the slip of dislocations during deformation in polycrystalline sample. The result shows the mis-orientation between adjacent grains is smaller with larger strain, while the mis-orientation between adjacent grains is larger with smaller strain. The degree of grain division in the process of deformation is related to the strain in this region, a new microstructure such as band structure is observed in grains with larger strain.