Correlations among ‘special’ and ‘general’ grain boundaries are studied on two-dimensional networks, by examining the configurational entropy of boundary structures as well as percolation thresholds. Consideration of crystallographic constraints at various length scales reveals that higher-order constraints play a role in boundary connectivity and network structure. Implications for grain bound...

Polycrystalline ceramic/single-walled carbon nanotube (SWNT) composites possess unique grain boundaries, containing 1D tortuous SWNTs bundles that form 2D tangled embedded nets. This unprecedented grain-boundary structure allows tailoring of multifunctional ceramic/SWNTs composites with unique combinations of desirable mechanical (toughness, strength, creep) and transport (electrical, thermal) ...

The effects of grain-boundary chemistry on the mechanical properties of a high-purity silicon nitride ceramics were investigated, with specific emphasis on the role of oxygen. Variations in the grain-boundary oxygen content, through control of oxidizing heat treatments and sintering additives, was found to result in a transition in fracture mechanism from transgranular to intergranular fracture...

Grain boundary structure and grain boundary segregation in stoichiometric and Ni-rich compositions of NiAl are studied by molecular statics and grand-canonical Monte-Carlo simulations in conjunction with an embedded-atom potential. Significant Ni segregation is found at the R = 3(1 1 1) and R = 3(2 1 1) grain boundaries, with segregation isotherms showing a saturation effect. The amount of Ni s...

A phase-field model is developed for predicting the polarization switching and domain structure evolution under an applied electric field in ferroelectric polycrystals. The model takes into account realistic grain structures as well as various energetic contributions, including elastic energy, electrostatic energy, and domain wall energy. A hysteresis loop – average polarization as a function o...