相关论文: Atomic size effect in impurity indued grain bounda…
Grain boundaries often exhibit ordered atomic structures. Increasing amounts of evidence have been provided by transmission electron microscopy and atomistic computer simulations that different stable and metastable grain boundary…
The role of grain size in determining fracture toughness in metals is incompletely understood with apparently contradictory experimental observations. We study this grain-size dependence computationally by building a model that combines the…
The effect of grain size on the flow strength of FCC polycrystals was analyzed by means of computational homogenization. The mechanical behavior of each grain was dictated by a dislocation-based crystal plasticity model in the context of…
We have performed four-probe electrical transport measurements on solitary highly crystalline wires of semimetallic bismuth with aspect ratios up to 60 at room and at cryogenic temperatures. By proper choice of the substrate material and…
Nanostructures have the immense potential to supplant the traditional metallic structure as they show enhanced mechanical properties through strain hardening. In this paper, the effect of grain size on the hardening mechanism of Al-Cu…
While it is known that alloy components can segregate to grain boundaries (GBs), and that the atomic mobility in GBs greatly exceeds the atomic mobility in the lattice, little is known about the effect of GB segregation on GB diffusion.…
It is a conventional wisdom that symmetry breakdown at grain boundaries in crystals introduces volume expansion and there has been no confirmed evidence of volume contraction at a grain boundary in any kind of crystals. We report surprising…
The study of grain size effects in ferroelectric ceramics has attracted great research interest over the last 50 years. Although different theoretical models have been proposed to account for the variation in structure and properties with…
Grain boundaries can exist as different grain boundary phases (also called complexions) with individual atomic structures. The thermodynamics of these defect phases in high-angle grain boundaries were studied mostly with atomistic and phase…
Milling of brittle materials shows a lower limit in size reduction, below which grinding cannot proceed further. Experimentally, the smallest particle size is determined by the milling media energy, and it is time-independent. Rittinger's…
Our ab initio study suggests that boron segregation to the Sigma 5(310)[001] grain boundary should strengthen the boundary up to 1.5 ML coverage (15.24 at/nm^2). The maximal effect is observed at 0.5 ML and corresponds to boron atoms…
In Part I of this set of two papers, a model of mesoscopic plasticity is developed for studying initial-boundary value problems of small scale plasticity. Here we make qualitative, finite element method-based computational predictions of…
The effects of micro-alloying element, vanadium, on a bcc Fe \Sigma 3(111)[1-10] symmetric tilt grain boundary strength are studied using density functional theory calculations. The lowest energy configuration of the grain boundary…
Grain boundaries, the two-dimensional (2D) defects between differently oriented crystals, control mechanical and transport properties of materials. Our fundamental understanding of grain boundaries is still incomplete even after nearly a…
To investigate the barrier effect of grain boundaries on the propagation of avalanche-like plasticity at the atomic-scale, we perform three-dimensional molecular dynamics simulations by using simplified polycrystal models including…
Light elements play an important role in influencing the macroscale properties of engineering alloys through grain boundary (GB) segregation phenomena. However, the scarcity and scattered nature of ab initio datasets for light elements in…
Hydrogen embrittlement is a prime cause of several degradation effects in metals. Since grain boundaries (GBs) act efficiently as sinks for hydrogen atoms, H is thought to segregate in these regions, affecting the local formation of…
The size-segregation of granular materials, a process colloquially known as the Brazil Nut Effect, has generally been thought to proceed faster the greater the size difference of the particles. We experimentally investigate sheared…
Quantum size effects on the permittivity of metal nanoparticles are investigated using the quantum box model. Explicit upper and lower bounds are derived for the permittivity and relaxation rates due to quantum confinement effects. These…
Nanoparticles were predicted to exhibit unique physical properties due to quantum size effects, but their identification remains difficult. According to Kubo's theory, the gap size is inversely correlated with both the density of states at…