Simulation of Cu Precipitation in the Fe-Cu Binary System

2014 ◽  
Vol 922 ◽  
pp. 728-733 ◽  
Author(s):  
Georg Stechauner ◽  
Ernst Kozeschnik
Keyword(s):  
Minimum Energy ◽  
Large Temperature ◽  
Density Radius ◽  
Diffusion Enhancement ◽  
Dislocation Pipe ◽  
Physical Interactions ◽  
Coarsening Kinetics ◽  
Experimental Values ◽  
Comprehensive Modeling ◽  
Kinetics Of

Cu precipitation in steel has been investigated numerous times. Still, a consistent simulation of the nucleation, growth and coarsening kinetics of Cu precipitates is lacking. Major reason for this is the fact that Cu precipitation involves complex physical interactions and mechanisms, which go beyond the classical precipitation models based on evaporation and absorption of precipitate-forming monomers (atoms). In the present work, we attempt a comprehensive modeling approach, incorporating coalescence results from Monte Carlo simulation, prediction of the nucleus composition based on the minimum energy barrier concept, diffusion enhancement from quenched-in vacancies, dislocation pipe diffusion, as well as the transformation sequence of Cu-precipitates from bcc-9R-fcc. Our simulations of number density, radius and phase fraction coincide well with experimental values. The results are consistent over a large temperature range, which is demonstrated in a TTP-plot.

Diffusion Enhancement in Glassy Metals Under Non-Equilibrium Conditions

1995 ◽  
Vol 400 ◽  
Author(s):  
S. Bellini ◽  
G. Mazzone ◽  
A. Montone ◽  
M. Vittori-antisari Enea ◽  
C.R. Casaccia
Keyword(s):  
Free Volume ◽  
Growth Kinetics ◽  
Bulk Diffusion ◽  
High Energy ◽  
First Case ◽  
Diffusion Enhancement ◽  
Glass Crystal ◽  
Kinetics Of ◽  
Crystal Interface ◽  
Diffusion Properties

AbstractThe diffusion properties of a Ni-Zr metallic glass formed at the interface of a bulk diffusion couple have been studied in conditions far from a fully relaxed state. The growth kinetics of the interface film have been enhanced by both plastic deformation and high energy electron irradiation. Different results have been obtained in the two cases, since in the first case the film grows exponentially with time, while in the second case the usual square root dependence on time is observed. This behaviour has been interpreted as a consequence of the annihilation kinetics of the excess free volume introduced in the glass by the above methods. Two different mechanisms of free volume annihilation , namely exchange with a crystal vacancy at the glass-crystal interface and structural relaxation in the bulk glassy phase have been considered to be operative so that the nature of the growth kinetics has been found to depend on the mechanism predominant in each experimental condition.

scholarly journals On the high temperature coarsening kinetics of γ′ precipitates in a high strength Co37.6Ni35.4Al9.9Mo4.9Cr5.9Ta2.8Ti3.5 fcc-based high entropy alloy

2019 ◽  
Vol 177 ◽  
pp. 82-95 ◽  
Author(s):  
Prafull Pandey ◽  
Sanjay Kashyap ◽  
Dhanalakshmi Palanisamy ◽  
Amit Sharma ◽  
Kamanio Chattopadhyay
Keyword(s):  
High Temperature ◽  
High Strength ◽  
High Entropy Alloy ◽  
High Entropy ◽  
Coarsening Kinetics ◽  
Kinetics Of

scholarly journals Coarsening kinetics of the bimodal γ’ distribution in DS GTD111™ superalloy

2011 ◽  
Author(s):  
V. S. K. G. Kelekanjeri ◽  
S. K. Sondhi ◽  
T. Vishwanath ◽  
F. Mastromatteo ◽  
B. Dasan
Keyword(s):  
Coarsening Kinetics ◽  
Kinetics Of

scholarly journals Study of the regularity of the process of decomposition of apatite with sulfuricacid at the boilingpoint of the solution

2019 ◽  
Vol 58 (4) ◽  
pp. 119-122
Author(s):  
Rauf F. Sabirov ◽  
◽  
Alexey F. Makhotkin ◽  
Yury N. Sakharov ◽  
Igor A. Makhotkin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Boiling Point ◽  
Batch Reactor ◽  
Material Balance ◽  
Mercury Thermometer ◽  
Experimental Values ◽  
Kinetics Of ◽  
Liquid And Solid Phases ◽  
Phosphoric Acids

Experimental research of the kinetics of the decomposition process of Kovdorsky apatite with a size = 0.16 mm with sulfuric acid in a 1 dm3 batch reactor. Phosphoric acid with the concentration of 68.6 % wt and the sulfuric acid with the concentration of 12.3% wt in stoichiometric amount was introduces at the beginning of the process. The process was carried out at a ratio of liquid and solid phases 2.5:1 respectively at the boiling point of the mixture equal to 136 °C. The observing the progress was carried out according to the method of joint designation of sulfuric and phosphoric acids by titrimetric analysis. With methyl orange and then phenolphthalein 2 titration jumps were recorded, the first of which corresponded to the neutralization of sulfuric acid to Na2SO4 and phosphoric acid to NaH2PO4, the second to the neutralization of NaH2PO4 to Na2HPO4. The change in temperature of the reaction mixture was fixed during the process using a mercury thermometer. In the analysis of the derived experimental values of specified parameters that the boiling point decreases from 136 to 133.1 оС within 50 minutes during the process. A comparison of the reported values with the concentration values of sulfuric and phosphoric acids measured during the process shows that the change in boiling point of the reaction mixture is proportional to the change in the concentrations of sulfuric and phosphoric acids. This model is a closed system that provides thermal insulation and no loss of material balance. Thus, the kinetics of the decomposition of apatite with sulfuric acid at the boiling point can be monitored by the temperature change under specified conditions.

scholarly journals Trimeric heptad repeat synthetic peptides HR1 and HR2 efficiently inhibit HIV-1 entry

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
Olfa Mzoughi ◽  
Meritxell Teixido ◽  
Rémi Planès ◽  
Manutea Serrero ◽  
Ibtissem Hamimed ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Heptad Repeat ◽  
Fusion Activity ◽  
Helical Structures ◽  
Fusion Inhibitors ◽  
Immunodeficiency Virus ◽  
Antiviral Activities ◽  
Physical Interactions ◽  
Kinetics Of ◽  
Hiv 1

Abstract The trimeric heptad repeat domains HR1 and HR2 of the human immunodeficiency virus 1 (HIV-1) gp41 play a key role in HIV-1-entry by membrane fusion. To develop efficient inhibitors against this step, the corresponding trimeric-N36 and C34 peptides were designed and synthesized. Analysis by circular dichroism of monomeric and trimeric N36 and C34 peptides showed their capacities to adopt α-helical structures and to establish physical interactions. At the virological level, while trimeric-C34 conserves the same high anti-fusion activity as monomeric-C34, trimerization of N36-peptide induced a significant increase, reaching 500-times higher in anti-fusion activity, against R5-tropic virus-mediated fusion. This result was associated with increased stability of the N36 trimer peptide with respect to the monomeric form, as demonstrated by the comparative kinetics of their antiviral activities during 6-day incubation in a physiological medium. Collectively, our findings demonstrate that while the trimerization of C34 peptide had no beneficial effect on its stability and antiviral activity, the trimerization of N36 peptide strengthened both stability and antiviral activity. This approach, promotes trimers as new promising HIV-1 inhibitors and point to future development aimed toward innovative peptide fusion inhibitors, microbicides or as immunogens.

scholarly journals Effect of Thermophysical Properties on Coupled Heat and Mass Transfer in Porous Material during Forced Convective Drying

2014 ◽  
Vol 6 ◽  
pp. 830387 ◽  
Author(s):  
Wei Cai ◽  
Lexian Zhu ◽  
Shilin Dong ◽  
Guozhen Xie ◽  
Junming Li
Keyword(s):  
Porous Medium ◽  
Diffusion Coefficient ◽  
Temperature Distribution ◽  
Moisture Content ◽  
Initial Conditions ◽  
Positive Impact ◽  
Soret Effect ◽  
Convective Drying ◽  
Large Temperature ◽  
Kinetics Of

The convective drying kinetics of porous medium was investigated numerically. A mathematical model for forced convective drying was established to estimate the evolution of moisture content and temperature inside multilayered porous medium. The set of coupled partial differential equations with the specified boundary and initial conditions were solved numerically using a MATLAB code. An experimental setup of convective drying had been constructed and validated the theoretical model. The temperature and moisture content of the potato samples were dynamically measured and recorded during the drying process. Results indicate that thermal diffusion coefficient has significant positive impact on temperature distribution and mass diffusion coefficient might directly affect the moisture content distribution. Soret effect has a significant impact on heat flux and temperature distribution in the presence of large temperature gradient.

Sign in / Sign up

Export Citation Format

Share Document