A multiscale approach to study the effect of chromium and nickel concentration in the hardening of iron alloys

A multiscale approach is presented to study the effect of chromium and nickel concentration on the deformation behavior of iron systems. A combination of molecular dynamics (MD) and dislocation dynamics (DD) simulations are employed. In this framework, the critical information is passed from the atomistic (MD) to the microscopic scale (DD) in order to study the degradation of the material under examination. In particular, information pertaining to the dislocation mobility is obtained from MD simulations. Since accurate measurements of dislocation velocity are difficult to obtain through experiment, atomistic simulations constitute an adequate alternative tool. Then this information is used by DD to simulate large systems with high dislocation and defect densities. In particular, we study the effect of nickel and chromium concentration on the strength, as well as the effect of dislocation loops concentration on the yield stress of the aforementioned systems. The results reveal, among other, defect free zones, in accordance to experimental observations, and an evolution law for the defect density.