NON-ELASTIC DEFORMATION OF POLYCRYSTALS WITH A LIQUID BOUNDARY PHASE

摘要

A conceptual view is taken to understand the deformation behavior of a polycrystal with a liquid (or a quasi-elastic) boundary phase. The analysis is based on the theories of liquid adhesives, the fracture of liquids and the concepts of fracture mechanics. It is shown that boundary separation rather than boundary sliding is the step that controls the deformation rate. Using this principal result, it is shown that the deformation behavior of a polycrystalline material with a viscous boundary phase is controlled by the flow characteristics, the volume content of the boundary phase and the microstructure features of the polycrystal (viz., voids, solid inclusions and cracks). Polycrystalline materials with a viscous boundary phase will exhibit a much greater rate of deformation in tension than in compression. (Author)