Average lattice parameters in SQS and melting temperature

Alloy Theoretic Automated Toolkit (ATAT)
1

Dear all,

I want to reproduce the phase diagram of a bcc binary system, especially for the miscibility gap where there is no experimental data available. I know that this gap could be determine by the mixing enthalpy, which I can obtain by the SQS method. And there are only the lattice parameter of the bcc solid solution and the melting curve available in the experimetal studies. So I want to compare the equilibrium lattice paramters of my SQS to the experiment data for the validation of the structure. But my SQS structure is not in bcc lattice, how can I average the lattice parameter? I also want to know whether the melting temperature of the binary system can be obtain in the ATAT code.

Thanks,

Regards,

wzchen

2

A simple suggestion:
lattice parameter = (2*relaxed volume of SQS cell/nb of atoms in cell)^(1/3)

ATAT does not currently predict melting points (it’s rather difficult to do ab initio).
However, my group has developed a method that makes this feasible, see:

https://dx.doi.org/10.1063/1.4819792

3

Perfect! Thanks.