808 Dislocation Dynamics Simulation of Plastic Deformation of Polycrystalline Metals

2011 ◽  
Vol 2011.24 (0) ◽  
pp. 240-241
Author(s):  
Taiki Kogure ◽  
Akiyuki TAKAHASHI
Keyword(s):  
Plastic Deformation ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Polycrystalline Metals

Plastic Deformation of Textured Zircaloy 2

2011 ◽  
Vol 702-703 ◽  
pp. 838-841
Author(s):  
Santosh Kumar Sahoo ◽  
V. D. Hiwarkar ◽  
Prita Pant ◽  
Indradev Samajdar ◽  
Karri V. Mani Krishna ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Residual Stresses ◽  
Room Temperature ◽  
Deformation Behaviour ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Distinct Class ◽  
Dislocation Interactions ◽  
Temperature Deformations ◽  
Grain Misorientation

The present study deals with deformation behaviour of textured Zircaloy 2 with two dominant orientations: basal and non-basal. During initial stages (20%), two distinct class of grains were observed – non-deforming/non-fragmenting grains and deforming/fragmenting grains. The so-called non- deforming/non-fragmenting grains remain equiaxed even after 50% of deformation. They also have insignificant in-grain misorientation developments and have more residual stresses. Dislocation dynamics simulation showed that the dislocation interactions/mobility is insignificant in basal orientations at room temperature deformations.

A study of the submicron indent-induced plastic deformation

1999 ◽  
Vol 14 (6) ◽  
pp. 2251-2258 ◽  
Author(s):  
C. F. Robertson ◽  
M. C. Fivel
Keyword(s):  
Plastic Deformation ◽  
Three Dimensional ◽  
Dislocation Nucleation ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Nanoindentation Test ◽  
Experimental Conditions ◽  
Discrete Dislocation Dynamics ◽  
Discrete Dislocation ◽  
Transmission Electron

A new method has been developed to achieve a better understanding of submicron indent-induced plastic deformation. This method combines numerical modeling and various experimental data and techniques. Three-dimensional discrete dislocation dynamics simulation and the finite element method (FEM) were used to model the experimental conditions associated with nanoindentation testing in fcc crystals. Transmission electron microscopy (TEM) observations of the indent-induced plastic volume and analysis of the experimental loading curve help in defining a complete set of dislocation nucleation rules, including the shape of the nucleated loops and the corresponding macroscopic loading. A validation of the model is performed through direct comparisons between a simulation and experiments for a nanoindentation test on a [001] copper single crystal up to 50 nm deep.

Grain Size Strengthening in Microcrystalline Copper: A Three-Dimensional Dislocation Dynamics Simulation

2009 ◽  
Vol 423 ◽  
pp. 25-32 ◽  
Author(s):  
Christophe de Sansal ◽  
Benoit Devincre ◽  
Ladislas P. Kubin
Keyword(s):  
Plastic Deformation ◽  
Mechanical Response ◽  
Initial Density ◽  
Three Dimensional ◽  
Dislocation Dynamics ◽  
Dynamics Simulation ◽  
Key Factors ◽  
Slip Mechanism ◽  
Dynamics Simulations ◽  
Dislocation Sources

This article reports on a study of the microstructure and mechanical response of copper polycrystals with grain sizes in the micrometer range. Three-dimensional dislocation dynamics simulations are used for the first time to investigate grain boundary strengthening and the Hall-Petch law. The methodology, which involves constructing a microcrystalline representative volume element with periodic boundary conditions, is briefly presented. Simulation results show that the initial density of dislocation sources and the cross-slip mechanism are two key factors controlling the heterogeneity of plastic deformation within the grains. At yield, the smaller the grains size, the more plastic deformation is heterogeneously distributed between grains and homogeneously distributed inside the grains. A size effect is reproduced and it is shown that the Hall-Petch exponent decreases from the very beginning of plastic flow and may reach a stable value at strains larger than the conventional proof stress.

Disorientations in dislocation structures: Formation and spatial correlation

2002 ◽  
Vol 17 (9) ◽  
pp. 2433-2441 ◽  
Author(s):  
Wolfgang Pantleon
Keyword(s):  
Plastic Deformation ◽  
Spatial Correlation ◽  
Distribution Functions ◽  
Scaling Behavior ◽  
Dislocation Dynamics ◽  
Slip Systems ◽  
Experimental Findings ◽  
Good Agreement

During plastic deformation, dislocation boundaries are formed and orientation differences across them arise. Two different causes lead to the formation of two kinds of deformation-induced boundaries: a statistical trapping of dislocations in incidental dislocation boundaries and a difference in the activation of slip systems on both sides of geometrically necessary boundaries. On the basis of these mechanisms, the occurrence of disorientations across both types of dislocation boundaries is modeled by dislocation dynamics. The resulting evolution of the disorientation angles with strain is in good agreement with experimental observations. The theoretically obtained distribution functions for the disorientation angles describe the experimental findings well and explain their scaling behavior. The model also predicts correlations between disorientations in neighboring boundaries, and evidence for their existence is presented.

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