Computer Simulation of Grain Growth in Polycrystalline Aggregates

1982 ◽  
Vol 21 ◽  
Author(s):  
M. P. Anderson ◽  
D. J. Srolovitz ◽  
G. S. Grest ◽  
P. S. Sahni
Keyword(s):  
Grain Growth ◽  
Chemical Properties ◽  
Predictive Ability ◽  
Grain Morphology ◽  
Catalytic Efficiency ◽  
Second Phase ◽  
Controllable Factors ◽  
Polycrystalline Aggregates ◽  
Grain Growth Kinetics ◽  
Physical And Chemical

The physical and chemical properties of materials are determined in part by microstructure. Grain orientation and size in polycrystalline aggregates affect, for example, yield strength, catalytic efficiency, chemisorption, physisorption, fracture and a host of other properties. The final grain morphology is often determined by thermal processing, addition of a second phase, deformation, etc. However, in order to effectively tailor the microstructure for specific applications, the mechanism and kinetics of grain growth must be known. Unfortunately, present theories predict grain growth kinetics (1–3) which often differ from experimental observation, have little predictive ability with respect to microstructure and are not easily generalized to account for experimentally controllable factors.

Grain Growth during Annealing: Experiments and Modelling

2012 ◽  
Vol 715-716 ◽  
pp. 611-616 ◽  
Author(s):  
M. Candic ◽  
Bao Hui Tian ◽  
Christof Sommitsch
Keyword(s):  
Grain Growth ◽  
Second Phase ◽  
Excellent Correlation ◽  
Grain Sizes ◽  
Second Phase Particles ◽  
Different Temperatures ◽  
Grain Growth Kinetics ◽  
Parameter Approach ◽  
Annealing Experiments ◽  
Two Parameter

In the present work, for the description of grain coarsening, a probabilistic and a deterministic 2D cellular automaton simulation setup were developed. The results of the simulation have been validated by solution annealing experiments of austenitic stainless steel 304L (Fe-18Cr-8Ni) at different temperatures and times. Both cellular automata models show an excellent correlation between the experimental determined data and grain growth kinetics based upon considerations of temperature and second phase particles. Additionally, a two parameter approach of the probabilistic model was implemented, resulting in determining the grain sizes limiting normal and abnormal grains and accurate description of grain growth.

Evaluation of grain growth exponent by Monte Carlo simulation in polycrystalline materials

2021 ◽  
pp. 2150024
Author(s):  
P. Rajendra ◽  
K. R. Phaneesh ◽  
C. M. Ramesha ◽  
Madeva Nagaral ◽  
V Auradi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Grain Growth ◽  
Growth Exponent ◽  
Polycrystalline Materials ◽  
Second Phase ◽  
2D Simulation ◽  
Second Phase Particles ◽  
The Matrix ◽  
Grain Growth Kinetics

In metallurgy, the microstructure study is very important to evaluate the properties and performances of a material. The Monte Carlo method is applied in so many fields of Engineering Science and it is a very effective method to examine the topology of the computer-simulated structures and exactly resembles the static behavior of the atoms. The effective 2D simulation was performed to understand the grain growth kinetics, under the influence of second phase particles (impurities) is a base to control the microstructure. The matrix size and [Formula: see text]-states are optimized. The grain growth exponent was investigated in a polycrystalline material using the [Formula: see text]-state Potts model under the Monte Carlo simulation. The effect of particles present within the belly of grains and pinning on the grain boundaries are observed. The mean grain size under second phase particles obeys the square root dependency.

Effect of SiO2 and Y2O3 additives on the anisotropic grain growth of dense mullite

2000 ◽  
Vol 15 (3) ◽  
pp. 718-726 ◽  
Author(s):  
T. Huang ◽  
M. N. Rahaman ◽  
T-I Mah ◽  
T. A. Parthasarathay
Keyword(s):  
Fracture Toughness ◽  
Grain Growth ◽  
Average Length ◽  
Stoichiometric Composition ◽  
Second Phase ◽  
Transmission Electron ◽  
Indentation Fracture Toughness ◽  
Grain Growth Kinetics ◽  
Mullite Powder

Mullite powder with a nearly stoichiometric composition was doped with 1.5–5 wt% SiO2 or 0.5–1.0 wt% Y2O3 and hot pressed at 1525–1550 °C to produce almost fully dense materials. The effect of the additives on the grain growth of the dense systems was investigated during subsequent annealing at temperatures above that of the eutectic (∼1590 °C) for the SiO2–Al2O3 system. The average length and width of the grains were measured by image analysis of polished and etched sections. At 1750 °C, anisotropic grain growth was relatively rapid, leading to the formation of rodlike grains. Compared to the undoped mullite, the addition of SiO2 and Y2O3 produced a small reduction in the grain growth kinetics. Transmission electron microscopy revealed that the glassy second phase was concentrated at the three-grain junctions or distributed inhomogeneously at the grain boundaries. For the materials annealed at 1750 °C, the indentation fracture toughness at room temperature increased from 2.0 to 2.5 MPa m1/2 for the undoped mullite to values as high as 4.0–4.5 MPa m1/2 for the doped mullite. The implications of the data for enhancing the fracture toughness of mullite by the in situ development of a microstructure of elongated grains are considered.

scholarly journals Comparative Catalytic Evaluation of Nano-ZrOx Promoted Manganese Catalysts: Kinetic Study and the Effect of Dopant on the Aerobic Oxidation of Secondary Alcohols

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Mohamed E. Assal ◽  
Mufsir Kuniyil ◽  
Mujeeb Khan ◽  
Mohammed Rafi Shaik ◽  
Abdulrahman Al-Warthan ◽  
...  
Keyword(s):  
Reaction Time ◽  
Specific Activity ◽  
Aerobic Oxidation ◽  
Chemical Properties ◽  
High Specific Activity ◽  
Catalytic Efficiency ◽  
Manganese Carbonate ◽  
Spectroscopic Techniques ◽  
Oxidation Of Alcohols ◽  
Physical And Chemical

This work reports the zirconia (ZrOx) nanoparticles doped MnCO3 catalysts prepared by facile and simple coprecipitation technique and the synthesis of zirconia-manganese carbonate [X% ZrOx–MnCO3] (where X% = 0–7%) catalyst which upon calcination at 400°C is converted to zirconia-manganese dioxide [1% ZrOx–MnO2] and when calcined at 500°C is converted to zirconia-manganic trioxide [1% ZrOx–Mn2O3]. A comparative catalytic study was performed to investigate the catalytic efficiency between carbonate and oxides for the selective oxidation of 1-phenylethanol by using molecular O2 as a clean oxidant. The influence of several parameters such as w/w% of ZrOx, reaction time, calcination temperature, catalyst amount, and reaction temperature has been thoroughly examined using oxidation of 1-phenylethanol as a model substrate. The 1% ZrOx–MnCO3 precalcined at 300°C exhibited the best catalytic efficiency. It was found that ZrOx nanoparticles also play an essential role in enhancing the effectiveness of the catalytic system for the aerobic oxidation of alcohols. Furthermore, the physical and chemical properties of synthesized catalysts were evaluated by microscopic and spectroscopic techniques. An extremely high specific activity of 40 mmol·g−1·h−1 with a 100% conversion of oxidation product and selectivity of >99% was achieved within extremely short reaction time (6 min).

Grain growth kinetics and microstructures of the high Tc GdBa2Cu3O7−δ superconductor

1992 ◽  
Vol 7 (12) ◽  
pp. 3194-3201 ◽  
Author(s):  
M.W. Shin ◽  
T.M. Hare ◽  
A.I. Kingon ◽  
C.C. Koch
Keyword(s):  
Aspect Ratio ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Boundary Energy ◽  
Growth Exponent ◽  
Second Phase ◽  
High Tc ◽  
Microstructure Observation ◽  
Grain Aspect Ratio ◽  
Grain Growth Kinetics

Grain growth in the GdBa2Cu3O7−δ high Tc superconductor was investigated. The composition Gd1.09Ba1.91Cu3O7−δ, within the solid solubility region, was selected for the present grain growth study. Differential thermal analysis did not reveal any thermal event except the incongruent melting point, which is indicative of the absence of a liquid second phase during grain growth. The final densities of isothermally annealed samples ranged from 91.3% to 93.7% of theoretical density. The microstructure observation showed a greater grain aspect ratio in this material than in YBa2Cu3O7−δ. The average grain aspect ratio was about 4.7. A very low grain growth exponent of 0.07 was found in the isothermal annealing temperature range from 965 °C to 1020 °C. By comparison with the results on the YBa2Cu3O7−δ system previously reported, it was concluded that the grain growth kinetics in these materials are strongly controlled by the anisotropy of the grain boundary energy. The activation energy of grain growth was calculated to be about 77 kJ/mole.

scholarly journals Grain growth kinetics for B2O3-doped ZnO ceramics

2015 ◽  
Vol 33 (2) ◽  
pp. 220-229 ◽  
Author(s):  
Berat Yuksel ◽  
T. Osman Ozkan
Keyword(s):  
Activation Energy ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Liquid Phase Sintering ◽  
Growth Exponent ◽  
Second Phase ◽  
Growth Activation ◽  
Doped Zno ◽  
Grain Growth Kinetics ◽  
Zno Ceramics

AbstractGrain growth kinetics in 0.1 to 2 mol % B2O3-added ZnO ceramics was studied by using a simplified phenomenological grain growth kinetics equation Gn = K0 · t · exp(-Q/RT) together with the physical properties of sintered samples. The samples, prepared by conventional ceramics processing techniques, were sintered at temperatures between 1050 to 1250 °C for 1, 2, 3, 5 and 10 hours in air. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 0.1 mol % B2O3-doped ZnO ceramics were found to be 2.8 and 332 kJ/mol, respectively. By increasing B2O3 content to 1 mol %, the grain growth exponent value (n) and the activation energy decreased to 2 and 238 kJ/mol, respectively. The XRD study revealed the presence of a second phase, Zn3B2O6 formed when the B2O3 content was > 1 mol %. The formation of Zn3B2O6 phase gave rise to an increase of the grain growth kinetic exponent and the grain growth activation energy. The kinetic grain growth exponent value (n) and the activation energy for the grain growth of the 2 mol % B2O3-doped ZnO ceramics were found to be 3 and 307 kJ/mol, respectively. This can be attributed to the second particle drag (pinning) mechanism in the liquid phase sintering.

scholarly journals Discussion on the Rate Controlling Process of Coarsening of Niobium Carbonitrides in a Niobium Microalloyed Steel

2005 ◽  
Vol 500-501 ◽  
pp. 703-710 ◽  
Author(s):  
David San Martín ◽  
Francisca García Caballero ◽  
Carlos Capdevila ◽  
Carlos García de Andrés
Keyword(s):  
Grain Growth ◽  
Volume Diffusion ◽  
Microalloyed Steels ◽  
Second Phase ◽  
Austenite Grain Size ◽  
Austenite Grain ◽  
The Matrix ◽  
Niobium Microalloyed Steel ◽  
Grain Growth Kinetics ◽  
Austenite Grain Growth

Austenite grain growth in microalloyed steels is governed by the coarsening of fine precipitates present at grain boundaries below the grain coarsening temperature. Zener model is widely used in metals to describe the pinning effect of second phase particles precipitated in the matrix. In this work it has been discussed whether grain boundary or volume diffusion is the rate controlling process for the coarsening of the niobium carbonitrides. Calculations on austenite grain growth kinetics, obtained coupling Zener theory and both rate controlling processes of precipitate coarsening, have been compared against experimental austenite grain size results under nonisothermal heating conditions. In this sense, it has been concluded that the coarsening of niobium carbonitrides is mainly controlled by volume diffusion of Nb in austenite.

THERMAL STABILITY OF NANOCRYSTALLINE COPPER FILMS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 3830-3835 ◽  
Author(s):  
PENG CAO ◽  
DELIANG ZHANG
Keyword(s):  
Activation Energy ◽  
Grain Size ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Phase Particle ◽  
Second Phase ◽  
Pinning Force ◽  
Nanocrystalline Copper ◽  
Grain Growth Kinetics ◽  
Kinetics Of

The grain growth kinetics of nanocrystalline copper thin film samples was investigated. The grain size of nanocrystalline copper samples was determined from the broadening of X-ray spectra. It was found that the grain size increased linearly with isothermal annealing time within the first 10 minutes, beyond which power-law growth kinetics is applied. The activation energy for grain growth was determined by constructing an Arrhenius plot, which shows an activation energy of about 21 – 30 kJ/mol. The low activation energy is attributed to the second phase particle drag and the porosity drag, which act as the pinning force for grain growth in nanocrystalline copper.

scholarly journals The landfill from nickel production in Danubian Lowland and its environmental implications

GeoScape ◽  
2021 ◽  
Vol 15 (2) ◽  
pp. 173-182
Author(s):  
Martin Boltižiar ◽  
Eva Michaeli ◽  
Vladimír Solár
Keyword(s):  
Chemical Properties ◽  
Field Research ◽  
Environmental Damage ◽  
Second Phase ◽  
Physical And Chemical Properties ◽  
Industrial Zone ◽  
Environmental Implications ◽  
Private Company ◽  
Physical And Chemical ◽  
And Chemical Properties

Abstract The main objective of the paper is to point out to the origin of the waste from the production of nickel at the landfill in Sereď and its physical and chemical properties that affect the environmental conditions of the site. The landfill of metallurgical technological waste in Sereď is the second largest landfill for non-ferrous metallurgy in Slovakia (Central Europe). It is located in the northern part of the Danubian Lowland, southwest of the industrial zone of town Sereď. We divided the research into two phases. The preparatory phase consisted in obtaining all available archival materials for the years 1956−1993, so from of the construction of the plant to the end of production. The production was lasting from 1963 to 1993. The second phase concerned field research and was associated with sludge sampling for laboratory analysis. The results of the analysis identified the physical and chemical properties of the sludge as well as the possibilities of its use in some sectors of the economy. The production process in the nickel smelter was stopped in 1993 due to economic (annual state production subsidy was CZK 250 million) and ecological reasons. The landfill at the city’s industrial zone has remained to this day, but it was sold to a private company in 1994, thus relieving of the state’s liability for environmental damage.

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