MICRESS Forum

Hi Taka, impressive results! From size and resolution it seem reasonable that it takes one week to get there - but this does not necessarily mean that it cannot be improved! And that it hangs afterwards must have a reason... First of all just one remark on your simulation setup: Why did you set the ...

Dear swh, It seems that the simulation starts to get instable when rest liquid is enclosed between the two dendrites. This can be e.g. due to the fact that the size of stable phase-field time-steps depend on local compositions and local thermodynamics ( see here ). Using a smaller time-step or autom...

Dear swh, (1) The phase minimum should be small enough in order not to cause too much trapping of solute (as the step from phMin to 0 is not involving redistribution anymore). From this point of view, a value of 1E-4 is typically small enough. In cases when the factor between the composition of an e...

Dear swh, The difference in the two outputs is that - by default - the .korn output (grain number output) does not show interface regions while the .phas output (phase number output) does. That means that the .korn output always displays the grain number of the grain with the highest fraction, while...

Hi Martin,

The four-fold symmetry of the dendrite is due to the anisotropy functions and is specified in the phase data for fcc with the keyword "cubic". More on anisotropy you can find e.g. here!

Bernd

Hi swh, There are many types of intermetallics you can see in figure 5b! I guess you mean the eutectic Si which forms the black/white structures (black is when they are not well-resolved). If I remember right, I assumed them to grow plate-like, and thus defined the phase in the following way (sorry ...

Hi Martin, MICRESS does not have a direct output for constitutional undercooling, because a reference state is needed for its calculation, like the liquidus temperature at the initial composition. But if the kinetic undercooling is small - and this is what we assume in case of diffusion-limited grow...

Hi Martin, but if you assume a constant cooling rate (as you do in MICRESS, I suppose), there cannot be any temperature drop in front of the dendrites - instead, the higher constitutional undercooling results in a slower growth of the interface in the concave regions where diffusion of solute away f...

Hi Martin, I an a bit confused with the term "solute drag model". For my understanding (and how it is used in MICRESS see here ), a solute drag model is a sort of meso-model which takes into account the effect of impurities or solute during e.g. grain growth, without explicitly modeling the redistri...

Hi swh, needle-like growth is very complicated in MICRESS, because growth of a needle (plate) means that growth is only possible in exactly one direction (plane). Due to the effect of the numerical grid on the evaluation of the gradient direction, this is difficult to achieve. In principle, needle g...