Grain-boundary resistivity versus grain size distribution in three-dimensional polycrystals

2006 ◽  
Vol 88 (14) ◽  
pp. 141920 ◽  
Author(s):  
G. Dezanneau ◽  
A. Morata ◽  
A. Tarancón ◽  
M. Salleras ◽  
F. Peiró ◽  
...  
2007 ◽  
Vol 558-559 ◽  
pp. 1183-1188 ◽  
Author(s):  
Peter Streitenberger ◽  
Dana Zöllner

Based on topological considerations and results of Monte Carlo Potts model simulations of three-dimensional normal grain growth it is shown that, contrary to Hillert’s assumption, the average self-similar volume change rate is a non-linear function of the relative grain size, which in the range of observed grain sizes can be approximated by a quadratic polynomial. In particular, based on an adequate modification of the effective growth law, a new analytical grain size distribution function is derived, which yields an excellent representation of the simulated grain size distribution.


2019 ◽  
Vol 87 (3) ◽  
Author(s):  
Abhilash Molkeri ◽  
Ankit Srivastava ◽  
Shmuel Osovski ◽  
Alan Needleman

Abstract The influence of grain size distribution on ductile intergranular crack growth resistance is investigated using full-field microstructure-based finite element calculations and a simpler model based on discrete unit events and graph search. The finite element calculations are carried out for a plane strain slice with planar grains subjected to mode I small-scale yielding conditions. The finite element formulation accounts for finite deformations, and the constitutive relation models the loss of stress carrying capacity due to progressive void nucleation, growth, and coalescence. The discrete unit events are characterized by a set of finite element calculations for crack growth at a single-grain boundary junction. A directed graph of the connectivity of grain boundary junctions and the distances between them is used to create a directed graph in J-resistance space. For a specified grain boundary distribution, this enables crack growth resistance curves to be calculated for all possible crack paths. Crack growth resistance curves are calculated based on various path choice criteria and compared with the results of full-field finite element calculations of the initial boundary value problem. The effect of unimodal and bimodal grain size distributions on intergranular crack growth is considered. It is found that a significant increase in crack growth resistance is obtained if the difference in grain sizes in the bimodal grain size distribution is sufficiently large.


2011 ◽  
Vol 172-174 ◽  
pp. 1128-1133 ◽  
Author(s):  
Eric A. Jägle ◽  
Eric J. Mittemeijer

The kinetics of phase transformations for which nucleation occurs on parent-micro-structure grain boundaries, and the resulting microstructures, were investigated by means ofgeometric simulations. The influences of parent microstructure grain-boundary area density,parent grain-size distribution and parent→product kinetics were analysed. Additionally, thesimulated kinetics were compared with predictions from two kinetic models, namely a modelproposed for spatially random nucleation and a model proposed for grain-boundary nucleation.It was found that the simulated transformed fraction as function of time lies in between the twomodel predictions for all investigated parent microstructures and parent→product kinetics.


1985 ◽  
Vol 63 (6) ◽  
pp. 716-718 ◽  
Author(s):  
S. Chandrasekhar ◽  
S. Martinuzzi ◽  
F. Z. Nataren

For low Zn concentrations i.e., x < 0.1, the performance of the Cd1−xZnxS–Cu2S solar cells can be improved by reducing the grain-boundary recombination. This has been achieved by growing well-oriented, homogeneous, ternary compound films.It was found that the Cd1−xZnxS films grown on the polycrystalline CdS films achieved the same larger grain size as that of the base layer. These films had fewer misorientations and had a unimodal grain-size distribution. There is a continuity in the crystallites from the CdS base to the Cd1−xZnxS overlayer, and the bifilms thus grown are less resistive than Cd1−xZnxS single layers.


1994 ◽  
Vol 34 (2) ◽  
pp. 186-190 ◽  
Author(s):  
Kiyotaka Matsuura ◽  
Youichi Itoh ◽  
Masayuki Kudoh ◽  
Tatsuya Ohmi ◽  
Kuniyoshi Ishii

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