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sundmanbo / opencalphad

Open Calphad, thermodynamic calculation code
http://www.opencalphad.org
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Error 4244 at peritectic reaction #43

Closed nitride84 closed 4 years ago

nitride84 commented 4 years ago

I have been having error 4244 at peritectic reactions when using cost507R.tdb to calculate aluminum alloys. The error is not limited to Al-Zr alloys and the following script will reproduce my error message:

r t cost507R Al Zr

set c w%(Zr)=0.3 t=800 p=1e5 n=1 c e l,,, set axis 1 t 500 1000 5 step normal

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I get error after the stepping. The message is below:

Line 1 from 8.000000E+02 with: AL3ZR1 FCC_A1 SMP2 Successful calculation of a node point 1 Creating node where a new phase LIQUID becomes stable Finishing line with 33 equilibria at T= 933.83

Line 2 from 8.000000E+02 with: AL3ZR1 FCC_A1 Terminating line with 46 equilibria at axis limit 6.0000E+02

Line 3 from 9.338849E+02 with: LIQUID AL3ZR1 FCC_A1 MM Phase change not allowed: -FCC_A1 MM Phase change not allowed: -FCC_A1 MM Phase change not allowed: -FCC_A1 Terminating line with 0 equilibria at 6.0000E+02 due to error 4244 Finished step/map 9.4000E-02 s and 105 clockcycles

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sundmanbo commented 4 years ago

Hi

As is written when you STEP or MAP this is fragile and I appreciate to have feedback of problems. You have hit on a problem I know but I have not had time to fix. What happens at 933.83 K is that the STEP finds an invariant with 3 phase in equilibrium and I have not implemented how STEP should handle that. Basically it is trivial but I have just 24 hours/day and 7 dats/week to fix everything. The simplest remedy for you is to set a new startpoint maybe at 1000 K and give a new STEP command (and not reinitiate). After that you can plot the whole T range.

OC works normally better when you have more components, in binaries there are a lot of invariant equilibria, less so when you have 6 or more components.

Best wishes

Bo Sundman

sundmanbo commented 4 years ago

Hi again

Thanks to your question I have fixed the problem passing an invariant equilibria during STEP. The version I uploaded here yesterday (or the Windows version at opencalphad.org) should now manage invariant equilibria (but may still need several startpoint for other reasons).

Best wishes

Bosse