Electrical resistivity and grain boundaries in metals

The electrical resistivity measurements of a single grain boundary (GB) using Superconducting Quantum Interference Devices (SQUID) on zone-refined aluminum at 4.2 K have revealed that the intrinsic GB resistivity depends on the structure systematically. These give the following main conclusions: (1) GB resistivity is mainly caused by the electron scattering from the GB dislocation core region; and (2) a GB resistivity equation based on the primary dislocation model well explains the rotation angle dependence of specific GB resistivity for small-angle, large-angle and coincidence-related GBs, suggesting the good applicability of Read-Shockley model for these GBs, in consideration of the dislocation core overlap. The measurement on Al-Ag demonstrates that migrating GBs are associated with a much larger solute enhancement than equilibrium segregation. It suggests also that the solute resistivity becomes an order of magnitude smaller when segregated about GBs.