Grain boundary sliding during ambient-temperature creep in hexagonal close-packed metals

摘要: Even at ambient temperature or less, below their 0.2% proof stresses all hexagonal close-packed metals and alloys show creep behaviour because they have dislocation arrays lying on a single slip system with no tangled inside each grain. In this case, lattice dislocations move without obstacles pile-up in front of grain boundary. Then these must be accommodated the boundary to continue deformation. Atomic force microscopy revealed occurrence sliding (GBS) ambient-temperature region. Lattice rotation 5° was observed near boundaries by electron backscatter diffraction pattern analyses. Because an extra low apparent activation energy 20 kJ/mol, conventional diffusion processes are not activated. To accommodate piled-up processes, absorbed through slip-induced GBS mechanism.