Grain boundary sliding at low temperatures

Grain Boundary Sliding in Ice

It is well known that grain boundary processes intercrystdline sliding and grain boundary migration make an important contribution to high temperature deformation of polycrystalline materials, particularly for metals. More recently, these processes have been correlated with the atomic structure of the boundaries. Our goal is to study sliding and migration of ice boundaries, with respect to temp...

Boundary magnetism in liquid 3He at very low temperatures

The low-temperature magnetic susceptibility of normal and superfluid 3He confined between mylar foils spaced 40 p apart shows a large and field-dependent enhancement over the bulk Fermi liquid magnitude. The excess susceptibility disappears when the liquid is doped with 0.5 7; 4He. The reason for the excess is unknown. We also studied the proton resonance of the mylar substrate and obtained spi...

Phenomenology and Mechanism of Grain Boundary Sliding in Zinc Bicrystals

Denuded Zones, Diffusional Creep, and Grain Boundary Sliding

The appearance of denuded zones following low stress creep in particle-containing crystalline materials is both a microstructural prediction and observation often cited as irrefutable evidence for the Nabarro– Herring (N–H) mechanism of diffusional creep. The denuded zones are predicted to be at grain boundaries that are orthogonal to the direction of the applied stress. Furthermore, their dime...

Cooperative grain boundary sliding and migration process in nanocrystalline solids.

A new physical mechanism or mode of plastic deformation in nanocrystalline metals and ceramics is suggested and theoretically described. The mode represents the cooperative grain boundary (GB) sliding and stress-driven GB migration process. It is theoretically revealed that the new deformation mode is more energetically favorable than "pure" GB sliding and enhances the ductility of nanocrystall...