Cementite instability during fast heating

solid-solid phase transformations, influence of stresses and strains
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vmattosferreir
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Cementite instability during fast heating

Post by vmattosferreir » Tue Feb 09, 2021 5:09 pm

Hello,

I am trying to simulate the austenite formation during fast heating (200C/s) in pearlitic steels.
In our simulation, several nuclei have been placed at the colony boundaries close to a cementite lamella. Nucleation is not allowed, only growth.
During fast heating, the austenite starts growing but at some point, the cementite lamellae become thinner and disappear ahead of the austenite front. The same doesn't happen for simulations with slow heating (1C/s). I am not sure of why this is happening, it seems that some lamellae are unstable during fast heating... Attached you can find the input file and the results for the phase obtained for different time steps.


Thank you in advance,

Vitoria.
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cb-200Cs-p1-red1-mult-nuc-06.in
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simulation_phase.png
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admin
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Re: Cementite instability during fast heating

Post by admin » Tue Feb 09, 2021 5:31 pm

Dear Vitoria,

Why are you sure that the cementite lamellae should not dissolve? Does it happen below the normal thermal dissolution?
I have seen in your input file that you use infinite diffusion for C in bcc, thus the distance of the cementite from the austenite front does not play any role. I guess you do that in order to avoid performance loss, but you perhaps should not...

Bernd

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