Electron Channeling Contrast Observations in Deformed Magnesium Alloys

In industrial metal-forming processes, quantitative and physical models are required to control and optimize the microstructure of the finished products. A detailed understanding of the behavior of polycrystalline materials during deformation processes is essential to develop such models. A number of instruments and analytical tools are available for deformation studies within the microscopy and microanalysis community. In a scanning electron microscope (SEM), the visualization and characterization of deformed microstructures are carried out with electron channeling contrast imaging (ECCI) and electron backscattered diffraction (EBSD). These SEM studies provide a nanoscale spatial resolution, a large field of view and statistically reliable information on a bulk specimen [1]. In this study, complex variations of backscattering intensity (IBSE) were observed in ECCI micrographs of magnesium (Mg) grains after the uniaxial hot compression test. The variations of IBSE across the ECCI micrographs were attributed to plastic deformation of the Mg grains [2]. Recovery, recrystallization and phase transformation processes occurred simultaneously during deformation at high temperature. The interactions between the three processes lead to a complex deformed microstructure consisting of dynamically recrystallized grains and precipitates. The deformed microstructure varied with different deformation variables such as temperature, strain rate and strain [3,4].