1D austenite-ferrite transformation

solid-solid phase transformations, influence of stresses and strains
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ayushsuhane
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Joined: Fri Jul 08, 2022 2:43 am
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1D austenite-ferrite transformation

Post by ayushsuhane » Fri Jul 08, 2022 2:59 am

Hi,

I am using the example file for austenite-ferrite transformation to simulate 1D phase transformation (see attached sample input file).

I am running two cases (1) with the grid size 1e-7 m (2) with grid size 1e-10 and both the cases have 500 points in the simulation domain and 10 points resolving the interface and all other parameters such as diffusivity/mobility are constant. In the latter case, the concentration profile (according to diffusion control transformation) does not develop as expected. However, if I turn on the fd_correction, it returns the composition profile and interface kinetics correctly. Can anyone explain what is the cause of incorrect dynamics for smaller grid spacing in the absence of fd_correction?

The input file corresponding to Case-II is attached and the parameters that were modified for Case-I can be seen below.

# Cell dimension (grid spacing in micrometers):
0.100000
# Time input data
linear_step 1e-3 10.0
# Grain input
# Type of grain positioning?
deterministic
# Number of grains at the beginning?
2
# Input data for grain number 1:
rectangular
# Center x,z coordinates [micrometers], grain number 1?
0.0000
0.0000
# Length along x-axis [micrometers]
1.000
# Length along z-axis [micrometers]
20.00
# Should the Voronoi criterion be applied?
no_voronoi
# Phase number? (integer)
1
# Input data for grain number 2:
rectangular
# Center x,z coordinates [micrometers], grain number 2?
0.000
30.00
# Length along x-axis [micrometers]
1.000
# Length along z-axis [micrometers]
40.0000


Thanks.

Best Regards,
Ayush
Attachments
PT_gamma_alpha.in
(12.96 KiB) Downloaded 95 times

Bernd
Posts: 1504
Joined: Mon Jun 23, 2008 9:29 pm

Re: 1D austenite-ferrite transformation

Post by Bernd » Fri Jul 08, 2022 12:32 pm

Dear Ayush,

Welcome to the MICRESS forum.

I have run Case II (the attached file) on my computer with MICRESS Version 6.4, and (as expected) I don't find any difference in the concentrations profile if I change from "normal" to "atc" redistribution behaviour, i.e. I cannot reproduce your findings. Can you show how the concentration profiles look like in your results? Please note that due to limiting the time step to 1.E-10s or bigger, the interface mobility was reduced to about 0.008 cm**4/(Js) what is probably not intended by you.

Given the fact that the diffusion length under the chosen conditions is only few nanometers, you should not expect any reasonable result from Case I, because the diffusion profile cannot be resolved with a grid size of 100 nm.

Best wishes
Bernd

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