In-depth analysis of grain structure of heavily-deformed multilayered composites by electron backscattered...

The variation of texture, grain size, grain boundaries, and hardness of the composite layers has been examined at different deformation passes and regions of the Cu (matrix)-Mg (reinforcement) composite and the Mg (matrix)-Cu (reinforcement) composite. The multilayered composites were processed by the accumulative roll bonding (ARB) method. With the rise of ARB passes, the layers became wavy, then necked, and were finally broken into smaller layers. Rolling texture and shear texture were the predominant textures in the rolled composites. The rolling texture grew with increasing ARB pass. Also, the intensity of the shear texture increased in regions closer to the surfaces. Furthermore, a grain size decrement was observed in all layers, even though the Cu layer in the Cu/Mg/Cu and the Mg layer in the Mg/Cu/Mg showed finer grains than when these layers were used as inner layers. Additionally, the grain sizes gradually increased from near-surface regions to near-center regions. Based on kernel average misorientation (KAM) images, more evident strain was accumulated near boundaries in regions closer to the surfaces. Furthermore, the hardness measurements showed a reduction from the composite's surface to the composite's center, although all matrix and reinforcing layers showed an increase in hardness with increasing ARB pass.