about precipitation

[Passion28-y]

I can use the precipitation file in the bin folder to generate a precipitation file, but I cannot call this file in the ctrl file. I did not find any parameters to specify this file. In addition, when generating precipitation, can't I specify the size and position of the precipitation? I have been thinking about this question for a long time. I hope you can answer my confusion. Thank you very much.

[nrbertin]

In ParaDiS precipitates are represented as Eshelby inclusions. To activate this feature, first make sure the code is compiled with option -DESHELBY (line 336 of makefile.setup). Then you can take a look at example tests/onescrew.ctrl. In this control file you can see that the precipitate/inclusion file is specified with option inclusionFile, e.g. inclusionFile = "tests/onescrew.dat". In this example, the precipitates configuration is defined in file tests/onescrew.dat, where each line specifies a precipitate using the following format:

#
# Data for an precipitate consists of the following items separated with white space
#
# Precipitate ID     : 1 integer identifying the precipitate regardless of its position in the simulation or the domain encompassing it. (Should be sequential values)
# Position           : 3 values specifying the XYZ coordinates of the center of the precipitate
# Semi-principal axes: 3 values defining the three semi-principal axis of the ellipsoidal precipitate in units of b
# Rotation matrix    : 2 vectors defining the rotation of the ellipsoidal precipitates
# Strain field       : 6 components of the strain field for the particleStrain field is a symmetric matrix so only six components are specified
#

• If you want to place precipitates at very specific locations then you can generate the precipitate file manually following the format above.
• For randomly positioned spherical inclusions you can use tool bin/inclusiongen
• For randomly positioned more specific types of inclusions (e.g. ellispoid T or ThetaPrime precipitates) you can use tool bin/precipitates

[Passion28-y]

@nrbertin I understand. Words are powerless to express my gratitude.Thank you!

[Passion28-y]

@nrbertin Hello, in ParaDiS, I added the precipitation phase simulation. However, I cannot observe the precipitation phase using the visualization software visit. I wonder if there is a problem with my operation. Can you help me solve it? Thank you

[nrbertin]

@Passion28-y Unfortunately the precipitates configuration is not written out in the output files, so it won't display when visualizing the dislocation configuration.

[Passion28-y]

@nrbertin I see, thank you for your answer.

[Passion28-y]

@nrbertin Hello, developer. I found that the initial model generated by the paradisgen tool is too random. Is there any way to generate a model that meets my needs according to my own ideas? For example, I want to create a dislocation line that only moves along a certain direction of a certain surface, and there is no dislocation line in other places. I read the OpenDiS document, but I don’t understand the method described in the document. Is there any other way to generate the initial dislocation configuration? Looking forward to your reply.

[nrbertin]

@Passion28-y There is no tool provided with ParaDiS to create dislocation configurations besides paradisgen. However, it should be easy to create arbitrary configurations using OpenDiS. I have added a new initial configuration tutorial section to provide more details about the different ways to do so. For setting a dislocation that only moves along a given direction on a given plane, the Rotated crystal frames subsection may be useful. I hope this helps.

[Passion28-y]

@nrbertin Ok, thank you very much.

[Passion28-y]

@nrbertin Dear developer
Can precipitated phases define strength?

[nrbertin]

@Passion28-y Not sure if this is what you are asking about, but the presence of precipitates will certainly have an effect on the predicted strength.

[Passion28-y]

@nrbertin I am now simulating the interaction between dislocations and precipitates. I found that dislocations can always cut precipitates, but there is also a way to bypass precipitates, which is the orowan bypass mechanism. So I want to know if it is possible to define the strength of precipitates? For example, harder precipitates or softer precipitates.

[nrbertin]

@Passion28-y You can use control parameters shearModulus2 and pois2 to define the elastic parameters associated with the inclusions. To precisely account for elastic interactions (forces) between dislocations and precipitates, one needs to compile the code with option -DESHELBYFORCE (line 342 of makefile.setup).

[Passion28-y]

@nrbertin Thank you very much.I'll try it.