Greetings everyone,
I would like to change the
min and
max values for the lattice parameter of certain phases according to the lattice parameter of a reference phase.
Because I am evaluating a data set that is submitted to big temperature variations, a big peak shift is observed. Therefore, I would like to shift the
min/max limits of the lattices based on a particular phase in which I know the relationship between temperature and lattice parameters.
The easier answer would be just to increase the limits to account for the temperature shift. However, when I do this, many phase peak positions jump to peaks from a different phase. So I would like to shift the
min/max range without changing the actual difference between them.
To do this, first, I set a prm with the lattice value from the phase which I want to use as the shift:
str
...
phase_name "Austenite"
...
prm aAkorr = Get(a)
Then, I set the lattice limits in all remaining phases like this example:
str
...
phase_name "Fe3C"
...
a @ 5.15000`_0.01907 min =5.05+(aAkorr-3.619); max =5.25+(aAkorr-3.619);
b @ 6.88744`_0.01633 min =6.78+(aAkorr-3.619); max =6.98+(aAkorr-3.619);
c @ 4.54005`_0.00833 min =4.44+(aAkorr-3.619); max =4.64+(aAkorr-3.619);
...
OBS: Here, 3.619 is the lattice parameter of the Austenite from which, above this value, I start to see a more significant peak shift.
My questions are:
- Will Topas automatically update the prm
aAkorr during the refinement? Or will the
aAkorr not be updated?
- Even if this works, does anyone thinks it's a good idea or has a better solution for these temperature shifts?
As always, thanks in advance for any comment, hint, or suggestion,
Antonio