Grain Refinement and Texture Evolution of Mg-1Zn-1Gd Alloy in Equal Channel Angular Pressing

The effect of equal channel angular pressing (ECAP) on the microstructure and texture, as well as dynamic recrystallization behavior of Mg-1Zn-1Gd alloy (wt%) was investigated. The results show that after the equal channel angular pressing at 350 degrees C, the microstructures of these samples are composed of fine recrystallized grains, and there are a large number of homogeneously distributed equiaxed grains in the matrix. Upon 8 passes, the uniform ultra-fine grain structure with an average grain size of 3.6 mu m is obtained. The mechanism of the discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) leads to grain refinement. The micro texture was analyzed through electron backscatter diffraction (EBSD) technique. It is revealed that after 4 passes of ECAP, a strong basal texture is achieved (multiple random distribution similar to 19.76). With increasing the extrusion passes, the grain on the basal planes of extruded alloy sheet is mainly elongated along the extrusion direction, the orientation distribution changes from concentrated state to decentralized state. The texture is weakened and the maximum is 15.66. Finally, the texture is related to the plane anisotropy of the Mg-1Zn-1Gd alloy.