MICRESS Forum

Dear all,

I want to explore the effect of inert particles (diameter as 50 nm) on the dendrite morphology (primary dendrite arm spacing as 500 nm) during L-PBF of alloys. In Micress we can use Zener pinning and the nucleation model to implicitly explore the effect of particles.

Can we explicitly put the particles? I guess this is difficult because we have to use much finer grid size to resolve the particles.

Best Regards,
Shailendra

Dear Shailendra,

That is true. If you want to explicitly set particles for interacting with the dendrites they need to be big enough to be properly resolved. Otherwise (i.e. if the fraction in the central grid cell of the particle doesn't come close to a fraction of 1) it is questionable whether the simulated interaction with the dendrites is properly displayed. However, if your primary dendrite arm spacing is only 10 times bigger than the particle, this should not be a problem at all. I guess that the effect of the particles will be overestimated in 2D-simulations, so you should also think about doing some 3D-simulations if possible.

MICRESS automatically treats phases as inert if no phase interaction is defined with any other phase. Using "INERT" as phase name will further suppress unnecessary warnings.

Bernd

Dear Bernd,

Thank you for the guidance. I will perform 3D simulations.

I have used no phase interaction for liquid and inert particles. Can we define the interface energy and mobility for the inert particle - dendrite system so that Micress model Zener pinning force on dendrites due to inert particles? I am thinking of calibrating the mobility using the method given in ISIJ Intl. v 49 (2009) No. 7, 1024-1029.

Best Regards,
Shailendra

Dear Shailendra,

You can use an interface energy for the phase interaction with the inert particles even without defining a "phase-Interaction":

no_phase_interaction junction force

Then, you are asked for an interfacial energy. However, an interface mobility is not required (because the interface with an inert particle is not allowed to move).

For the interface between the dendrite and liquid, you may use the calibration method which I recommended in 2009. However, meanwhile, using our mobility correction ("mob_corr" is more simple and straightforward. It has been explained e.g. here:

viewtopic.php?f=9&t=874&p=4139&hilit=mob_corr#p4139

There is a publication where besides the antitrapping current (atc) the mobility correction (mob_corr) has been derived:

A.Carré, B.Böttger, M.Apel
Implementation of an antitrapping current for a multicomponent multiphase-field ansatz
Journal of Crystal Growth 380(2013)5–13

Bernd