Hexagonal close-packed metals and alloys show significant creep behavior at ambient temperature, even below their 0.2% proof stresses. That creep behavior arose from linearly aligned dislocation arrays in a single slip system without any dislocation cuttings. These dislocation arrays pile up at grain boundary because of violation of von Mises' condition. Therefore, grain boundary sliding must accommodate the piled-up dislocations. Electron back-scattering diffraction analyses and atomic force microscope observations here revealed an accommodation mechanism in ambient temperature creep region. Lattice rotation occurred near grain boundaries during creep, as revealed by electron back-scattering diffraction analyses, indicating the pile up of lattice dislocations there. Grain boundary sliding during creep was revealed by atomic force microscope observations.

Grain Boundary Sliding Induced by Lattice Dislocation Activity during Ambient Temperature Creep in HCP Metals. T.Matsunaga, T.Kameyama, E.Sato: IOP Conference Series - Materials Science and Engineering, 2009, 3[1], 012014