Refinement of Size Distributions for Primary Crystallizations

1997 ◽  
Vol 481 ◽  
Author(s):  
E. Pineda ◽  
T. Pradell ◽  
D. Crespo ◽  
N. Clavaguera ◽  
J. ZHU ◽  
...  
Keyword(s):  
Grain Size ◽  
Metastable Phase ◽  
Primary Crystallization ◽  
Controlled Growth ◽  
Diffusion Controlled ◽  
Average Grain Size ◽  
Soft Impingement ◽  
Single Grain ◽  
Kinetics Of ◽  
And Diffusion

ABSTRACTThe microstructure developed in primary crystallizations is studied under realistic conditions. The primary crystallization of an amorphous alloy is modeled by considering the thermodynamics of a metastable phase transition and the kinetics of nucleation and crystal growth under isothermal annealing. A realistic growth rate, including an interface controlled growth at the beginning of the growth of each single grain and diffusion controlled growth process with soft impingement afterwards is considered. The reduction in the nucleation rate due to the compositional change in the remaining amorphous matrix is also taken into account. The microstructures developed during the transformation are obtained by using the Populational KJMA method, from the above thermodynamic and kinetic factors. Experimental data of transformed fraction, grain density, average grain size, grain size distribution and other related parameters obtained from annealed metallic glasses are modeled.

Current transient study of the kinetics of nucleation and diffusion-controlled growth of bimetallic phases

2012 ◽  
Vol 17 (2) ◽  
pp. 345-351 ◽  
Author(s):  
Oscar Díaz-Morales ◽  
Jorge Mostany ◽  
Carlos Borrás ◽  
Benjamin R. Scharifker
Keyword(s):  
Current Transient ◽  
Controlled Growth ◽  
Diffusion Controlled ◽  
Transient Study ◽  
Kinetics Of ◽  
And Diffusion

Vacancy-Mediated Diffusion and Diffusion-Controlled Processes in Ordered Binary Intermetallics by Kinetic Monte Carlo Simulations

2021 ◽  
Vol 29 ◽  
pp. 95-115
Author(s):  
Rafal Kozubski ◽  
Graeme E. Murch ◽  
Irina V. Belova
Keyword(s):  
Monte Carlo ◽  
Kinetic Monte Carlo ◽  
Simulation Studies ◽  
Self Diffusion ◽  
Monte Carlo Techniques ◽  
Diffusion Controlled ◽  
Kinetic Monte Carlo Simulations ◽  
Kinetic Effects ◽  
Kinetics Of ◽  
And Diffusion

We review the results of our Monte Carlo simulation studies carried out within the past two decades in the area of atomic-migration-controlled phenomena in intermetallic compounds. The review aims at showing the high potential of Monte Carlo methods in modelling both the equilibrium states of the systems and the kinetics of the running processes. We focus on three particular problems: (i) the atomistic origin of the complexity of the ‘order-order’ relaxations in γ’-Ni3Al; (ii) surface-induced ordering phenomena in γ-FePt and (iii) ‘order—order’ kinetics and self-diffusion in the ‘triple-defect’ β-NiAl. The latter investigation demonstrated how diverse Monte Carlo techniques may be used to model the phenomena where equilibrium thermodynamics interplays and competes with kinetic effects.

Thermal and Mechanical Stability of Polycrystalline Nanowires

2007 ◽  
Vol 264 ◽  
pp. 133-140
Author(s):  
Leonid Klinger ◽  
Eugen Rabkin
Keyword(s):  
Plastic Deformation ◽  
Applied Load ◽  
Mechanical Stability ◽  
Deformation Behaviour ◽  
High Yield ◽  
Morphological Stability ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
And Diffusion ◽  
Shape Changes

We considered a polycrystalline cylindrical nanowire with bamboo microstructure strained uniaxially by an external load. Our molecular dynamic computer simulations demonstrated that grain boundary grooving plays an important role in determining the morphological stability of nanowires. Also, an exceptionally high yield stress of nanowires emphasizes the importance of diffusion in their plastic deformation under applied load. We formulated a phenomenological diffusion-based model describing morphological stability and diffusion-controlled deformation behaviour of polycrystalline nanowires. The kinetics of the shape changes was calculated numerically.

The current transient for nucleation and diffusion-controlled growth of spherical caps

2008 ◽  
Vol 13 (4) ◽  
pp. 565-571 ◽  
Author(s):  
Daniel Branco P. ◽  
Jorge Mostany ◽  
Carlos Borrás ◽  
Benjamin R. Scharifker
Keyword(s):  
Current Transient ◽  
Controlled Growth ◽  
Diffusion Controlled ◽  
Spherical Caps ◽  
And Diffusion

Kinetics of Phase Separation in Lithium Bearing HLW Alkaliborosilicate Glasses

1995 ◽  
Vol 412 ◽  
Author(s):  
J. GÖttlicher ◽  
H. J. Pentinghaus
Keyword(s):  
Phase Separation ◽  
Transformation Temperature ◽  
Ostwald Ripening ◽  
Metastable Phase ◽  
Particle Growth ◽  
Glass Frit ◽  
Diffusion Controlled ◽  
Metastable Phase Separation ◽  
Scale Particle ◽  
Kinetics Of

AbstractA TEM study on the kinetics of metastable phase separation in a lithium bearing HLW glass frit is presented. As nothing was known about the kinetics of metastable phase separation below the glass transformation temperature we had to carry out annealing experiments just above and below the transformation temperature, in order to achieve phase separation on a laboratory time scale- Particle growth in the WAKID5 HLW glass frit at 550 °C occurs by a diffusion controlled Ostwald ripening process (about 40 °C above Tg). Metastable phase separation in the lithium bearing glasses even at lower temperatures cannot be excluded from the present study. In NaBSi3O8 glass (Tg ≈ 580 °C) phase separation could be detected at 500 °C well below Tg after about 160 days.

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