PanPrecipitation for Kinetic Simulations
PanPrecipitation is designed for simulating precipitation kinetics during
heat treatment processes. It is built as a shared library and integrated
into Pandat as a specific module that extends the capability of Pandat for
kinetic simulations, while taking full advantage of the automatic
thermodynamic calculation engine (PanEngine) and the user-friendly Pandat
Graphical User Interface (PanGUI). For this reason, precipitation
simulations for highly complex alloys under arbitrary heat treatment
conditions can be accomplished with only a few operations. More detailed
information about PanOptimizer can be found in reference [2008Cao
].
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Data Structure
PanPrecipitation is a purely object-oriented module written in C++ with
generic data structures like PanEngine, balancing performance,
maintainability and scalability. The basic data structure for storing
precipitation information in the system of interest is schematically shown
in Figure 1.
Figure 1. Date structure of system information in
PanPrecipitation (from 2008Cao
).
Based on the above data structure, input parameters for the matrix and
its precipitate phases are organized in ¡°Extensible Markup Language¡± (XML)
format, which is a standard markup language and well-known for its
extendibility. In accordance with the XML syntax, a set of well-formed tags
are specially designed to define the kinetic model for each precipitate
phase and its corresponding model parameters such as interfacial energy,
molar volume, nucleation type, and morphology type. In PanPrecipitation,
three kinetic models at different levels known as the KWN, Fast-Acting and
JMAK were implemented and available for user¡¯s choice. All models can be
used to simulate the co-precipitation of phases with various morphologies
with concurrent processes of nucleation, growth and coarsening. With the
selection of the KWN model, the particle size distributions (PSD) of various
precipitate phases can be obtained in addition to the temporal evolution of
the average size and volume fraction as obtained from the Fast-Acting model.
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Graphical User Interface of
PanPrecipitation
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Figure 2. Dialog box for setting precipitation simulation
conditions.
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Figure 3. Dialog box for setting simulation units.
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Figure 4. Dialog box for selection of matrix and
precipitate phases.
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Applications
I. Ni-14Al at%
(diagrams from
2008Cao
)
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Figure 5. Predicted evolution of average
g¡¯ particle size with time compared with the
experimental data.
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Figure 6. KWN-predicted particle size distributions for
the g¡¯ particles at t = 21, 217 and 3720 min.
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Figure 7. KWN-predicted evolution of g¡¯
number density & supersaturation compared with the experimental data.
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II. Alloy Rene88DT
Figure 8. Predicted evolution of average size at different
temperatures for Alloy Rene88DT.
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