A Modified Monte-Carlo Potts Model for Dynamic Recrystallization

2015 ◽  
Vol 1096 ◽  
pp. 280-287 ◽  
Author(s):  
Jian Fu ◽  
Bi You Peng ◽  
Bin Xie ◽  
Yi Gen Ye
Keyword(s):  
Monte Carlo ◽  
Dynamic Recrystallization ◽  
Potts Model ◽  
Metallic Materials ◽  
Stored Energy ◽  
Modified Model ◽  
Grain Sizes ◽  
Basic Characteristics ◽  
Evolution Modeling ◽  
The Relationship

In order to improve the microstructure evolution modeling of dynamic recrystallization (DRX) in agreement with physical experiment, a modified Monte-Carlo (MC) Potts model for simulating DRX process was proposed in this paper under the consideration of the inhomogeneous stored energy distribution related to grain sizes, the nucleation criteria related to critical dislocation density, the site energy change related to grain preferred-growth, the combination of macroscopic thermo-mechanical parameters and microscopic material parameters, and the relationship between MC calculation steps and real DRX time. The results show that the modified model can better simulate the basic characteristics of dynamic recrystallization of metallic materials during forging, which the recrystallized grains nucleate mainly in the deformed regions with high stored energy and preferentially grow up by merging adjacent deformed grains with high stored energy.

Simulation of Fabrication for Single-Phase Al2O3 Ceramic Tool Materials at Different Fabrication Pressure

2012 ◽  
Vol 499 ◽  
pp. 150-155 ◽  
Author(s):  
Bin Fang ◽  
Chuan Zhen Huang ◽  
Chong Hai Xu ◽  
Sheng Sun
Keyword(s):  
Monte Carlo ◽  
Microstructure Evolution ◽  
Potts Model ◽  
Single Phase ◽  
Two Dimensional ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Mean Grain Size ◽  
The Mean ◽  
The Relationship

The relationship between fabrication pressure and microstructure evolution is proposed. A computer simulation coupled with fabrication pressure for the hot-pressing process of single-phase ceramic tool materials has been developed, which uses a two-dimensional hexagon lattice model mapped from the realistic microstructure without considering the presence of pores. The fabrication of single-phase Al2O3 is simulated. The mean grain size of simulated microstructure by Monte Carlo Potts model integrated with fabrication pressure increases with an increase in fabrication pressure, which is consistent with the experiment results. It is shown that Monte Carlo Potts model coupled with fabrication pressure may simulate the microstructure evolution of single-phase ceramic tool materials.

Simulation of Fabrication for Al2O3 Ceramic Tool Materials

2012 ◽  
Vol 500 ◽  
pp. 537-543 ◽  
Author(s):  
Bin Fang ◽  
Chuan Zhen Huang ◽  
Hong Tao Zhu ◽  
Chong Hai Xu
Keyword(s):  
Grain Size ◽  
Monte Carlo ◽  
Microstructure Evolution ◽  
Potts Model ◽  
Single Phase ◽  
Ceramic Tool ◽  
Tool Materials ◽  
Fabrication Parameters

The new Monte Carlo Potts model that couples with fabrication parameters and considers pores and additives has been developed in order to simulate the fabrication of single-phase ceramics tool materials. The microstructure evolution for single-phase Al2O3 ceramic tool materials is simulated with the different technology parameters. At the same time, the single-phase Al2O3 ceramic tool materials are fabricated with the corresponding technology parameters. The errors of grain size between the simulated and the experimental is 12.1 and18.2%.

Characteristics of Dynamic Recrystallization during Hot Deformation for High Nitrogen Stainless Steels

2012 ◽  
Vol 715-716 ◽  
pp. 115-121
Author(s):  
Hai Wen Luo ◽  
Xu Dong Fang ◽  
Rui Zhen Wang ◽  
Zhan Yin Diao
Keyword(s):  
Dynamic Recrystallization ◽  
Stainless Steels ◽  
Hot Deformation ◽  
Strain Rates ◽  
Peak Strain ◽  
High Nitrogen ◽  
Flow Curves ◽  
Grain Sizes ◽  
Nitrogen Contents ◽  
High Nitrogen Stainless Steel

Dynamic recrystallization was studied for the stainless steels with nitrogen contents of 0.56% to 1.08% during hot deformation at temperatures of 900~1200 with strain rates ranging from 0.003 to 42 s-1. It was found that flow stress could increase remarkably with increasing nitrogen content. Flow curves during the deformation by 0.1~42/s at temperatures of 900~1200°C show a single peak, indicating the occurrence of dynamic recrystallization during deformation. The peak strain seems to decrease with increasing N content, suggesting that higher content of N facilitates dynamic recrystallization. The quenched microstructures were analyzed by optical microscopy, EBSD and TEM. The recrystallized grain sizes on the quenched specimens were measured and its dependence on temperature and strain rate was analyzed. At high temperature, continuously dynamically recrystallized microstructures were observed; whilst at low temperature, necklace-like partially recrystallized microstructures were found. Key words: High nitrogen stainless steel; dynamic recrystallization; stress-strain curves

The Processing of Ultrafine-Grained Materials Using High-Pressure Torsion

2007 ◽  
Vol 558-559 ◽  
pp. 1283-1294 ◽  
Author(s):  
Cheng Xu ◽  
Z. Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
High Pressure Torsion ◽  
Metallic Materials ◽  
Grain Sizes ◽  
Ultrafine Grained ◽  
Wide Range ◽  
Ultrafine Grained Materials ◽  
Thin Disks

It is now well-established that processing through the application of severe plastic deformation (SPD) leads to a significant reduction in the grain size of a wide range of metallic materials. This paper examines the fabrication of ultrafine-grained materials using high-pressure torsion (HPT) where this process is attractive because it leads to exceptional grain refinement with grain sizes that often lie in the nanometer or submicrometer ranges. Two aspects of HPT are examined. First, processing by HPT is usually confined to samples in the form of very thin disks but recent experiments demonstrate the potential for extending HPT also to bulk samples. Second, since the strains imposed in HPT vary with the distance from the center of the disk, it is important to examine the development of inhomogeneities in disk samples processed by HPT.

Modified Model for Static Behavior of Microcantilever Gas Sensor Adsorbed with Monolayer Molecules

2011 ◽  
Vol 415-417 ◽  
pp. 455-459
Author(s):  
Xiao Ming Wang ◽  
Fei Wang ◽  
Xue Zeng Zhao ◽  
Da Lei Jing
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Curvature Radius ◽  
Static Behavior ◽  
Neutral Layer ◽  
Modified Model ◽  
Adsorbed Molecules ◽  
Microcantilever Sensors ◽  
The Relationship ◽  
Layer Position

The modified static bending model of microcantilever with monolayer molecules has been established based on energy method, in which the change in neutral layer position caused by adsorption-induced stress has been considered. On this basis, we have analyzed the relationship between the bending curvature radius of a microcantilever with its thickness, Young’s modulus and molecule-molecule distance of adsorbed molecules when it is adsorbed with monolayer water molecules. Additionally, we have investigated the effect of change in neutral layer position on the static behavior of microcantilever sensors and have found that: 1) the bending curvature radius of microcantilever is affected by its Young’s modulus, thickness and distance of adsorbed molecules respectively; 2)the predicted error of bending curvature radius caused by the change in neutral layer position slightly increases with decreasing Young’s modulus and thickness, whereas the effect of distance between adsorbed molecules on the error is significant.

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