Effect of Grain Boundary Characters on Grain Boundary Sliding during Superplastic Deformation

On grain boundary wetting during deformation

We use numerical experiments to analyze the kinetics of grain boundary wetting in polycrystalline aggregates under the influence of an external applied shear stress. Grain boundary wetting is driven by the stress concentration at the tip of the fluid front. The extent of wetting of favorably oriented grain boundaries depends on the fluid mobility number b, which is defined as the ratio of the r...

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...

Coupling grain boundary motion to shear deformation

Molecular dynamics (MD) simulations confirm that normal grain boundary (GB) motion must often be coupled to tangential translation of grains and will then produce shear deformation of the lattice traversed by the GB. Conversely, shear stresses applied to a GB can induce its normal motion. Using [001] symmetrical tilt GBs in copper as a model, the coupling factor b between the GB motion and grai...

Effect of Grain-Boundary Phase

Two types of hot-pressed silicon nitride, one having an amorphous grain-boundary phase (6 wt% yttria, 3 wt% alumina) and the other having a predominantly crystalline grain-boundary phase (8 wt% yttria, 1 wt% alumina), were tested on a split Hopkinson pressure bar with a momentum trap, such that, in each test, the sample was subjected to a single predefined stress pulse and then recovered withou...

Effect of Grain Boundary Engineering on Microstructural Stability During Annealing