Ultimate Theoretical Strength of Fcc Fe-Ni Alloy Polycrystals

摘要

An atomistic analysis of the fracture in fcc iron and the Fe-30 at. % Ni alloy (for an ideal lattice and near the special grain boundary) has been performed with the application of the molecular dynamics method. To characterize the fracture energy, the decohesion energy and Griffith surface energy for the crack planes have been calculated. A slight difference has been obtained in the tendency of Fe to fracture along the body and along the grain boundary. The Fe-30 at. % Ni alloy is more prone to fracture along the grain boundary. The energy of interaction between Ni and the grain boundary has been calculated, and it is shown that Ni atoms in the Fe-30 at. % Ni alloy do not have their own thermodynamic impetuses for segregation on the special boundary.