Mechanisms of amorphous-phase-dependent grain growth in two-phase nanocomposite films: A Monte Carlo analysis

2008 ◽  
Vol 92 (2) ◽  
pp. 021910 ◽  
Author(s):  
X. J. Hu ◽  
Z. J. Liu ◽  
Y. G. Shen
Keyword(s):  
Monte Carlo ◽  
Grain Growth ◽  
Amorphous Phase ◽  
Monte Carlo Analysis ◽  
Nanocomposite Films ◽  
Two Phase

Monte Carlo Simulation of Microstructure and Grain Growth in nc-Ti(N, B)/a-(TiB2, BN) Nanocomposite Films

2006 ◽  
Vol 312 ◽  
pp. 357-362 ◽  
Author(s):  
Yao Gen Shen ◽  
Z.J. Liu ◽  
Y.H. Lu ◽  
Chun Sheng Lu ◽  
Yiu Wing Mai
Keyword(s):  
Monte Carlo ◽  
Grain Growth ◽  
Photoelectron Spectroscopy ◽  
Nanocomposite Films ◽  
Two Phase ◽  
Unbalanced Magnetron Sputtering ◽  
Transmission Electron ◽  
Unbalanced Magnetron ◽  
Mean Grain Size ◽  
Good Agreement

A combination of high-resolution transmission electron microscopy and x-ray photoelectron spectroscopy are used to establish that Ti-B-N films with different boron concentrations prepared by reactive unbalanced magnetron sputtering exhibit a two-phase nanocomposite microstructure, showing nanocrystalline Ti(N, B) grains embedded in amorphous (TiB2, BN) matrices. Using Monte Carlo simulations and based on a simple model employing a kinetic grain growth theory, we also investigate the effects of the amorphous TiB2-BN phase on the microstructure evolution and grain growth in nanocrystalline-Ti(N, B). Our study demonstrates that the formation of such an amorphous phase at the grain boundary could hinder the growth of Ti(N, B) grains and the mean grain size shows an exponential decay with boron concentration, in good agreement with our experimental observations.

Simulations of Anisotropic Grain Growth Involving Two-Phase Nanocrystalline/Amorphous Systems Using Q-State Monte Carlo

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
J. B. Allen
Keyword(s):  
Monte Carlo ◽  
Grain Boundary ◽  
Grain Growth ◽  
Amorphous Phase ◽  
Volume Fraction ◽  
Critical Role ◽  
Boundary Surface ◽  
Binding Energies ◽  
Two Phase ◽  
Amorphous Systems

The present work incorporates an implementation of the two dimensional, Q-state Monte Carlo method to evaluate anisotropic grain growth in two-phase nanocrystalline/amorphous systems. Specifically, anisotropic grain boundaries are simulated via the use of surface energies and binding energies; the former attributable to the variation in grain orientation and assigned through a mapping process involving Wulff plots. The secondary, amorphous phase is randomly assigned to the lattice in accordance with a specified initial volume fraction. Among other findings, the results reveal that the grain boundary surface energy, as governed by the shape of the Wulff plot, plays a critical role in the resulting microstructure. Additionally, it was found that the addition of a secondary amorphous phase to an existing anisotropic grain boundary system evolves into primary grain microstructures characteristic of single phase isotropic systems.

scholarly journals Modified Monte Carlo approach for simulation of grain growth and Ostwald ripening in two-phase Zn–22Al alloy

2020 ◽  
Vol 9 (5) ◽  
pp. 9620-9631
Author(s):  
Hossein Mohammadi ◽  
Ali Reza Eivani ◽  
Seyed Hossein Seyedein ◽  
Manojit Ghosh
Keyword(s):  
Monte Carlo ◽  
Grain Growth ◽  
Ostwald Ripening ◽  
Two Phase ◽  
Monte Carlo Approach

3D MС Simulation of Grain Growth Kinetics and the Zener Limit in Polycrystals

2014 ◽  
Vol 598 ◽  
pp. 8-12
Author(s):  
K.R. Phaneesh ◽  
Anirudh Bhat ◽  
Gautam Mukherjee ◽  
Kishore T. Kashyap
Keyword(s):  
Monte Carlo ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Large Scale ◽  
Volume Fraction ◽  
Growth Exponent ◽  
Cube Root ◽  
Second Phase ◽  
Two Phase ◽  
Second Phase Particles

Large scale Potts model Monte Carlo simulation was carried on 3-dimensional square lattices of 1003 and 2003 sizes using the Metropolis algorithm to study grain growth behavior. Simulations were carried out to investigate both growth kinetics as well as the Zener limit in two-phase polycrystals inhibited in growth by second phase particles of single-voxel size. Initially the matrices were run to 10,000 Monte Carlo steps (MCS) to check the growth kinetics in both single phase and two-phase poly-crystals. Grain growth exponent values obtained as a result have shown to be highest (~ 0.4) for mono-phase materials while the value decreases with addition of second phase particles. Subsequently the matrices were run to stagnation in the presence of second phase particles of volume fractions ranging from 0.001to 0.1. Results obtained have shown a cube root dependence of the limiting grain size over the particle volume fraction thus reinforcing earlier 3D simulation efforts. It was observed that there was not much difference in the values of either growth kinetics or the Zener limit between 1003 and 2003 sized matrices, although the results improved mildly with size.

Probabilistic Leak Before Break Using the R6 Methodology

2020 ◽  
Author(s):  
Peter Gill
Keyword(s):  
Monte Carlo ◽  
Nuclear Reactor ◽  
Probabilistic Method ◽  
Limit Load ◽  
Monte Carlo Analysis ◽  
Two Phase ◽  
Weld Residual Stress ◽  
Circumferential Defects ◽  
Further Development ◽  
Leak Before Break

Abstract The integrity of a component in a safety critical industry is determined by carrying out Engineering Critical Assessments (ECA). These are designed to provide a conservative estimate of the life of a component based on conservative inputs/methodology. It is becoming increasingly apparent that for many applications these methods are overly conservative. The only physical way to really assess the reliability of a component is by producing many thousands, if not millions of a specific component and calculating a failure probability based on testing/OPEX. This is simply not feasible for the components in, for example, a nuclear reactor, and probabilistic techniques are becoming increasingly important as a means to understand the reliability of a component. This information can then be used to assess risk and inform inspection programmes. Typically a probabilistic method relies on assigning distributions to various input parameters and evaluating a probability integral, usually by Monte-Carlo analysis. A previous PVP paper developed Monte Carlo methods using the R6 fracture mechanics procedure. Although providing good insight into the likelihood of failure, these analyses were simplified and not readily applied to realistic plant situations. Further development would enable much more of the technology contained within R6 to be applied within probabilistic software. The following new features of the software are presented in this paper: • the latest K and limit load solutions from R6 for through wall circumferential defects • Simplified V factor approach to account for secondary stresses • two phase flow (water) based on the latest SQUIRT methodology • global bending, through wall bending, weld residual stress This enables a full probabilistic leak detection calculation for circumferential through wall cracks in pipes. Examples of probabilistic Leak-before-Break calculations for PWR pipework are presented in the paper.

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