Search found 25 matches

by billyzhangubc
Mon Jul 06, 2020 7:55 pm
Forum: solid-solid phase transformations
Topic: Nucleation on selected grain boundaries
Replies: 6
Views: 4137

Re: Nucleation on selected grain boundaries

Hi Bernd, Thanks for your explanation and I'm sorry for the confusion. I meant to say >15 degrees. I am trying to do some proof of concept studies to introduce a bainitic initial structure and put austenite nuclei on high angle grain boundaries. I'm glad to know that's possible and the rest is for m...
by billyzhangubc
Sun Jul 05, 2020 11:58 pm
Forum: solid-solid phase transformations
Topic: Nucleation on selected grain boundaries
Replies: 6
Views: 4137

Re: Nucleation on selected grain boundaries

Hi Bernd,
Sorry to bring this up again. With "add_to_grain", it possible to place nuclei on selected boundaries based on boundary misorientation angle (for example, only boundaries with <15 degrees misorientation angle)?

Thanks,
Billy
by billyzhangubc
Mon Jun 15, 2020 9:50 pm
Forum: thermodynamics
Topic: Driving force calculation for NPLE with TQ
Replies: 4
Views: 5921

Re: Driving force calculation for NPLE with TQ

Thanks Bernd! Apparently I was confused by the notations of these terms. Billy
by billyzhangubc
Wed Jun 10, 2020 8:41 am
Forum: thermodynamics
Topic: Driving force calculation for NPLE with TQ
Replies: 4
Views: 5921

Re: Driving force calculation for NPLE with TQ

Hi Bernd, Thanks for your reply. Just a few follow-up questions: (1) Just to confirm, the total "local" driving force is the sum of quasi-equilibrium driving force \Delta G_0 and \chi(T) (c^C_\gamma - c^C_{\gamma*}) (or generalized to a system with n components, \sum_{i=1}^{n}\chi_i(T) (c^i_\gamma -...
by billyzhangubc
Tue Jun 09, 2020 3:50 am
Forum: thermodynamics
Topic: Driving force calculation for NPLE with TQ
Replies: 4
Views: 5921

Driving force calculation for NPLE with TQ

Hi all, I have a few questions regarding the determination of ΔG for the α-to-γ transformation with the NPLE model. Here are the questions. Say I have Fe, C and Mn: (1) I assume that ΔG is calculated by χ(C_γ-C*_γ) in MICRESS with TQ where C_γ is the local composition, C*_γ is the "equilibrium C con...
by billyzhangubc
Wed Apr 01, 2020 3:51 pm
Forum: recrystallisation/grain growth
Topic: Place randomly distributed nuclei
Replies: 8
Views: 8687

Re: Place randomly distributed nuclei

Hi Billy, You should not restrict the number of nuclei, neither per seed type ("maximum number of new nuclei") nor per time step ("Max. number of simultaneous nucleations?"). This often leads to erratic grain distributions (if you do not use it for the exact purpose), because it just stops nucleati...
by billyzhangubc
Wed Apr 01, 2020 1:14 am
Forum: recrystallisation/grain growth
Topic: Place randomly distributed nuclei
Replies: 8
Views: 8687

Re: Place randomly distributed nuclei

Hi Bernd, Sorry for a late follow-up. Hope you are doing well. I am now simulating intercritical austenite formation from ferrite that involves nucleation. A major problem I have at the moment is that austenite nuclei are not quite randomly distributed (esp. comparing to a micrograph; see images att...
by billyzhangubc
Fri Mar 06, 2020 3:28 am
Forum: recrystallisation/grain growth
Topic: "Grain radius" in grain input (v 6.402)
Replies: 1
Views: 4220

"Grain radius" in grain input (v 6.402)

Hi all, The "(minumum/maximum) grain radius" in the random option of grain input seems a bit misleading. For example, I would like to generate a structure of 5 round grains with a mean diamater of 80 μm (with periodic boundary conditions). I did a quick calculation and a box of 160x160 μm will be ab...
by billyzhangubc
Thu Mar 05, 2020 7:30 am
Forum: solid-solid phase transformations
Topic: Benchmark 2D single grain growth with square law
Replies: 2
Views: 3684

Re: Benchmark 2D single grain growth with square law

Hello Janin,
Thanks for your answer and sorry for the late reply. My colleague tried your method just now and got the correct result.

Billy
by billyzhangubc
Wed Feb 26, 2020 7:27 pm
Forum: solid-solid phase transformations
Topic: Benchmark 2D single grain growth with square law
Replies: 2
Views: 3684

Benchmark 2D single grain growth with square law

Hi all, Asking on behalf of a colleague: My colleague is doing some benchmark work on grain growth. Basically he started by modelling the shrinkage of a single round grain inside an infinitely big grain (using periodical boundary conditions). He adapted the model from a recrystallization simulation ...