paraequilibrium/nple

new developments, future functionalities, hints for further applications of MICRESS
Post Reply
Bernd
Posts: 1074
Joined: Mon Jun 23, 2008 9:29 pm

paraequilibrium/nple

Post by Bernd » Thu Jul 02, 2009 11:46 am

Hi all,

since the end of 2008, a new paraequilibrium and nple mode is available. It can be used for the redistribution of elements which a diffusion length which is much smaller than the interface thickness. Using standard interactions, MICRESS would predict a growth mode which lies between paraequilibrium and nple. Now, the two extreme cases of redistribution behaviour can be specifically requested. Input has to be changed in two places:


# Data for phase interaction 1 / 2:
# ---------------------------------
# Simulation of interaction between phase 1 and 2?
# Options: phase_interaction no_phase_interaction identical phases nb.
# [standard|particle_pinning[_temperature]|solute_drag]
phase_interaction redistribution_control
# 'DeltaG' options: default
# avg ... [] max ... [J/cm**3] smooth ... [degrees]

...

#
# Input of the phase diagram of phase 1 and phase 2:
# --------------------------------------------------
# Which phase diagram is to be used?
# Options: database [local|global] linear linearTQ
linear
# Temperature of reference point? [K]
1149.9000
# Entropy of fusion between phase 1 and 2 ? (real) [J/(cm**3 K)]
0.14900
# Input of the concentrations at reference point
# Concentration of component 1 in phase 1 ? [wt%]
3.20000E-03
# dissolved concentration in phase 2 ? [wt%]
1.58110E-04
# Concentration of component 2 in phase 1 ? [wt%]
0.17399
# dissolved concentration in phase 2 ? [wt%]
9.62880E-02
# Input of the slopes at reference point
# Slope m_iPh = dT/dC_iPh relative to component 1 ? [K/wt%]
-386.5673523
# Slope m_jPh = dT/dC_jPh relative to component 1 ? [K/wt%]
-8036.549805
# Slope m_iPh = dT/dC_iPh relative to component 2 ? [K/wt%]
-39.82677078
# Slope m_jPh = dT/dC_jPh relative to component 2 ? [K/wt%]
-73.34864807
# Please specify the redistribution behaviour of each component:
# Format: forward [backward] [dGMin]
# Options: para nple normal
# Component 1
normal normal 1.
# Component 2
nple nple 1.

The keywords "normal", "nple" or "para" have to be specified for each element and growth direction which is evaluated form the average driving force of the grain interface. A third optional parameter gives the driving force range for a smooth transition between the regimes if the same is used for both directions.

Bernd

Bernd
Posts: 1074
Joined: Mon Jun 23, 2008 9:29 pm

Re: paraequilibrium/nple

Post by Bernd » Mon Nov 23, 2009 10:04 am

Hi all,

the model for NPLE mentioned above has been considerably improved. The third parameter for a smooth transition between different regimes is no longer necessary.
The "pseudo"-para-equilibrium model (which was only relying on the redistribution behaviour) is now replaced by a new approach which is based on the model implemented in Thermo-Calc. Unforunately, it works only with TQ version S which is currently not running properly with MICRESS...

Bernd

Bernd
Posts: 1074
Joined: Mon Jun 23, 2008 9:29 pm

Re: paraequilibrium/nple

Post by Bernd » Thu Feb 10, 2011 8:48 pm

Hi all,

With the next MICRESS release which is expected for March/April 2011, the following models will be available:

1.) nple: This is the redistribution-based NPLE model which has been mentioned above and which has been further improved/corrected.

2.) para: The also above mentioned "pseudo para-equilibrium" model which is redistribution-based like the nple model is recovered and can be used also with linearized phase diagrams.

3.) paraTQ: This thermodynamically based para-equilibrium model (using the para-equilibrium model of Thermo-Calc) works only with the newest version of TQ which will finally be available with this MICRESS release!

Examples for all three cases will be included in the release.

Bernd

Post Reply