Dear all,
I was trying to reproduce a work on simulating the temperature-induced phase transformation of NiTi by Byeongchan Lee, et al.
(2015), "Phase transformations, detwinning and superelasticity of shape-memory NiTi from MEAM with practical capability." Journal of Computational Materials Science The thermal cycle simulation is：
The isothermal, isobaric (NPT) ensemble is applied to a 40×40×40 B2 cell with 128,000 atoms using the Nosé-Hoover thermostat and barostat. The bulk cell is periodic in all three dimensions, and allowed to change triclinically, i.e. lattice constants and lattice angles simultaneously. The system is initially equilibrated at 600 K; a complete thermal cycle consists of cooling down to 10 K and heating back to 600 K with a cooling/heating rate of 0.5 K/ps. However, in my simulation result ，there were no sudden change of volume or pe. I guess there were something wrong with my script，i dont konw whether the command“fix npt”is correct here is part of my input script#minimize
dump 1 all custom 100 dump.min id type x y z
velocity all create 10 12345 dist gaussian
fix 1 all box/relax aniso 0.0
min_style cg
minimize 1e-12 1e-12 10000 100000
#equlibriation
timestep 0.001
thermo 200
thermo_style custom step temp pe ke etotal press vol
undump 1
fix 2 all npt temp 600 600 1 aniso 0.0 0.0 1 drag 1
fix 3 all ave/atom 1 20 2000 x y z
dump 1 all custom 2000 dump.equ id type x y z f_3[1] f_3[2] f_3[3]
restart 20000 restart.equ
run 100000
#thermoloading undump 1
unfix 1
unfix 2
unfix 3
fix 2 all ave/atom 1 20 1000 x y z
fix 3 all npt temp 600 10 1.0 aniso 0.0 0.0 1 drag 1.0
#output
dump 1 all custom 1000 dump.cooling id type x y z f_2[1] f_2[2] f_2[3]
restart 10000 restart.cooling
run 100000
Hope someone give
me some advice. Thank you in advance.
Best regards,