Colloidal particles were sedimented onto patterned glass slides to grow three-dimensional bicrystals with a controlled structure. Three types of symmetric tilt grain boundaries between close-packed face-centered-cubic crystals were produced: Σ5(100),Σ17(100), and Σ3(110). The structure of the crystals and their defects were visualized by confocal microscopy, and characterized by simple geometri...

The mechanical behavior of bicrystalline aluminum nano-pillars under uniaxial compression reveals size effects, a stochastic stress– strain signature, and strain hardening. Pillar diameters range from 400 nm to 2 lm and contain a single, non-sigma high angle grain boundary oriented parallel to the pillar axes. Our results indicate that these bicrystalline pillars are characterized by intermitte...

A~~act-Semi~uantitative Auger Electron Spectroscopy (AES) on pure monophasic (Z~*)~.~(YO,.~~,,, was used to determine the chemical composition of the grain boundaries. Grain boundary enrichment with Y was observed with an enrichment factor of about 1.5. The difference in activation energy of the ionic conductivity of the grain boundary compared with the bulk can be explained by the Y segregatio...

Mixed atomistic and continuum methods offer the possibility of carrying out simulations of material properties at both larger length scales and longer times than direct atomistic calculations. The quasi-continuum method links atomistic and continuum models through the device of the finite element method which permits a reduction of the full set of atom-istic degrees of freedom. The present pape...

The impact of hydration on the transport properties of microcrystalline Sm(0.15)Ce(0.85)O(1.925) has been examined. Dense, polycrystalline samples were obtained by conventional ceramic processing and the grain boundary regions were found, by high resolution transmission electron microscopy, to be free of impurity phases. Impedance spectroscopy measurements were performed over the temperature ra...

We have used electron backscattered diffraction patterns to determine the misorientation of 201 adjacent pairs of grains in a magnesia polycrystal. The width and depth of the thermal grooves formed by these same grain boundaries were also measured by atomic force microscopy (AFM). By simulating the errors associated with the AFM observations and comparing our observations to existing data for m...

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...

In recent years, interface engineering of solid electrolytes has been explored to increase their ionic conductivity and improve the performance of solid oxide fuel cells and other electrochemical power sources. It has been observed that the ionic conductivity of epitaxially grown thin films of some electrolytes is dramatically enhanced, which is often attributed to effects (e.g. strain-induced ...

This paper describes a strategy for the measurement of boundary mobility using molecular dynamics (MD) simulations and its application to the migration of nominally flat h001i tilt grain boundaries in nickel, as described using an EAM potential. Determination of the driving force for boundary migration requires proper accounting for non-linear elastic effects for strains of the magnitude needed...