Molecular dynamics simulation of the amorphization and alloying of a mechanically milled Fe-Cu system

The amorphization and alloying behavior of an Fe-Cu system were investigated by a three-dimensional molecular dynamics simulation. A repetitive process of attachment and compression of Fe and Cu boxes was applied for modeling the mechanical milling. Metallic glass and amorphous structures formed upon compression and relaxation, respectively. Short- and medium-range orders were found by normalizing all the radial distribution function peak positions to the first peak position. The values of the compressed box agreed well with those of undercooled melts, while the relaxed box values aligned with the glassy iron value. Voronoi polyhedron analysis revealed that the fraction of crystalline structure decreased and the icosahedra-like short-range order increased upon the processes. Fe and Cu atoms became uniformly distributed, and the fraction of Fe-Cu pairs increased upon the attachment processes. The molecular dynamics simulation with the repetitive processes can reveal the processes of amorphization and mixing in the Fe-Cu system.