Grain boundary nucleation

[mtoloui]

Hi,
I have a problem with the nucleation subroutine of MICRESS. I try to put nuclei at the austenite/austenite interfaces with a parent relation with the orientation of the austenite grains. The problem is that along a the boundary of two austenite grains, say 1 and 2 with corresponding orientations of teta_1 and teta_2, nuclei form with either teta_1 or teta_2 and we never can get nuclei with both orientations. This problem leads to uneven nucleation i.e. in some grains we see excessive nucleation while in the other no nucleation occurs.

# Type of 'position' of the seeds?
# Options: bulk region interface triple quadruple [restrictive]
interface
# Phase of new grains?
3
# Reference phase?
1
# Substrat phase [2nd phase in interface]?
# (for taking into account curvature undercooling, set to 1 to disable)
1
...
# Choice of growth mode:
# Options: stabilisation analytical_curvature
analytical_curvature
# Critical radius? [micrometers]
5
...
# Determination of nuclei orientations?
# Options: random randomZ fix range parent_relation
parent_relation
# Minimal value of rotation angle? [Degree]
-3.000
# Maximal value of rotation angle? [Degree]
+3.000

[Bernd]

Hi,

MICRESS should set 50% of the grains with each parent, and it looks like it is just taking the grain with lower number as parent
Janin is currently working on the parent relation stuff, and I will check tomorrow whether your findings are correct and whether she already fixed that! You will need a new version in this case, I do not see any workaround...

Bernd

[janin]

Yes, this is indeed a problem: in the current version Micress always selects the first possible grain, i.e. the grain with lowest grain number. In my new improved version, the grain with the highest local fraction is determined, which should solve your problem. Could you send me your input-file, so that I can use it as testcase?

Best regards,
Janin

[mtoloui]

Hi Janin,
I just emailed it to you
Thank you