[lammps-users] tensile of binary system

Dear Steve and users
I am working on tensile simulation of binary system (Al-Si). I have a
problem with relaxation of this system before tensile simulation . I couldn't
use “fix deform” , because box in this direction must be periodic ( it means

that several layers of Al-Si-Al-Si-.. atoms). By fixing boundary atoms, the
stress is very negative.

Do you have any idea to fix this problem ?
It's your favour to help me.
hamed amini

If you have a free surface (non-periodic) and you just
run dynamics, won't the system relax to where it wants
to be - e.g. 0 stress?