edge dislocation

Question 1: [ET.1] [10pts]

Consulting the tutorial on edge dislocation, set up simulations to examine dislocation core splitting in different FCC metals, i.e., Al, Ni, Cu, Ag, Au.

For these FCC metals, their potential files are provided, being:

The lattice constant a₀ and stacking fault energy () values are also provided in the table above.

A sample script (in.dislocation_Ni.lmp) is provided for Ni for the dislocation model construction and subsequent energy minimization for dislocation core splitting (i.e., a full dislocation  split into two Shockley partials). The simulation will output a dump file “dump_FCC_Disl.atom”, which you may visualize the core splitting process and measure the split core size (denoted as ), as illustrated in the figure below:

In the figure, atoms are colored using the CNA parameter (i.e., parameter c2 in Lammps script line 37).

Based on the sample script for Ni, please create the corresponding Lammps scripts for other FCC metals. Specifically, you will need to modify the script at:

· Line 5: Use the correct lattice constant;

· Line 16: Use the correct interatomic potential and element type;

· Line 37: Use the correct cutoff value for CNA computation (see https://docs.lammps.org/compute_cna_atom.html)

With the lammps scripts created, please do the following:

(a) [5 pts] Run the simulations for all the FCC systems above, and measure the split core size values, normalized by their corresponding lattice constant (i.e., /a₀). Please put the values into a table (e.g., something like the one below).

(b) [2 pts] Plot /a₀ versus the stacking fault energy .

(c) [3 pts] Based on the plot you get from (b), consider a hypothetical FCC metal with a lattice constant a₀ = 3.9 Å and stacking fault energy  = 50 mJ/m². Please estimate its split core size .