Grain Boundary Structure in ARB Processed Copper
Grain boundary structures in the Accumulative roll-bonding (ARB) processed copper (ARB-Cu) have been studied. The grain boundary structures were observed by high-resolution transmission electron microscopy (HRTEM). In order to clarify the difference between the grain boundaries in ARB-Cu and equilibrium boundaries, calculated atomic structure of symmetric tilt grain boundaries with <110> common axis (<110> symmetric tilt grain boundary; <110> STGB) in Cu were used. The near 14° boundary in the ARB-Cu could be described by the dislocation model, but the dense dislocation region existed near the grain boundary. The high angle boundaries in ARB-Cu could be described by the structural units which were obtained by molecular dynamics (MD) simulation. Furthermore, in the 2 cycles and 6 cycles ARB-Cu (2cARB-Cu and 6cARB-Cu), the deformation twin boundaries could be observed and described by the structural unit. Therefore, it was concluded that the grain boundary structure in the ARB-Cu was not much different from the normal equilibrium grain boundary and explained by conventional dislocation and structural unit models.
K. Ikeda et al., "Grain Boundary Structure in ARB Processed Copper", Materials Science Forum, Vols. 503-504, pp. 925-930, 2006