Under the framework of crystal slip theory,a θ model that can describe the anisotropic creep of Ni-base single crystal(SC) alloy was built by the θ mapping method to the crystal directional problem of Ni-base single crystal turbine bladecreep.

The rate-dependent crystallographic finite element program was implemented for the analysis of the elastic-plastic stress fields near grain boundary(GB) in anisotropic bicrystals and tricrystals,taking the different crystallographic orientations,geometry GB and physical GB into consideration.

As the grain sizes are decreased,the transition of deformation mechanism from partial dislocation emission from grain boundaries and twinning to grain boundary sliding and grain rotation in face-centered-cubic nano-crystalline metals is summarized.

The following grain size effects are analyzed; on the contributions of various mechanisms including diffusion creep,grain boundary sliding and dislocation creep to the total strain, and on the grain boundary sliding which is a dominant mechanism in superplastic deformation.

For the latter,there are two different types,attributed to liquid phase at grain boundary and grain boundary sliding respectively.

It can be predicated that local crystalline slip systems are responsible for the formation of the kink band.