The excellent deep drawability of interstitial free steel(IF steel)is closely related to its texture formed during recrystallization.The nucleation process of cold rolled IF steel at the early stage of recrystallization was investigated by electron back scattered diffraction(EBSD).The characteristics of the microstructure after deformation and the orientation of nucleation were observed.The results show that the deformed microstructure with 80% reduction could be subdivided into two groups.These two types of microstructure were characterized by their orientation and internal local misorientations.The nuclei withγ-orientation preferred to form in deformed bands with γ-orientation and at the boundaries between deformed grains with different orientations.The recrystallized grains with{111}<110>orientation appeared firstly in deformed matrix with{111}<112>orientation and consumed the matrix with {111}<112>to grow up,while the recrystallized grains with{111}<112>orientation were observed secondly in deformed matrix with{111}<110> orientation and consumed matrix with{111}<110>to grow up.
The evolution of the grain structures in AA2195 Al-Li alloy plate warm-rolled by 80% reduction during recrystallization annealing at 500 ℃ was investigated by electron backscatter diffraction, scanning electron microscopy and transmission electron microscopy. It is found that the elongated grain structures are caused by the lamellar distribution of recrystallization nucleation sites, being lack of large second phase particles (>1 μm), and dispersive coherent particles (such as δ′ and β′) concentrated in planar bands. The recrystallization process may be separated into three stages: firstly, recrystallization nucleation occurs heterogeneously, and the nuclei are concentrated in some planar zones parallel to rolling plane. Secondly, the grain boundaries interacted with small particles concentrate in planar bands, which is able to result in the elongated grain structures. The rate of the grain growth is controlled by the dissolution of these small particles. Thirdly, after most of small particles are dissolved, their hindrance to migration of the grain boundaries fades away, and the unrecrystallized zones are consumed by adjacent recrystallized grains. The migration of high angle grain boundaries along normal direction leads a gradual transformation from the elongated grains to the nearly equiaxed, which is driven by the tension of the grain boundaries.
The evolution of the microstructure and texture with strain during compression at 150℃ of the magnesium alloy AZ31 has been investigated using the electron backscattered diffraction (EBSD) technique. The initial samples were chosen to have a strong basal plane texture with the crystal c-axes perpendicular to the compression direction. The EBSD data provide evidence concerning the relative activity of both {10-12} extension twinning and slip, and suggest that non-basal slip is important in samples deformed to a strain of more than 0.2. The relative contributions of the twinning and the slip during deformation have been discussed based on the results above.
