Modeling of hardening caused by spinodal decomposition in Fe-Cr systems

Suzudo, Tomoaki   ; Nagai, Yasuyoshi*

In the ferrite phase of stainless steel weld-overlay cladding of reactor pressure vessels, the hardening caused by a phase separation of Fe-Cr systems is reported, and the experiments suggests that the hardening takes place even in the early stage of phase separation. In the current study, we reproduced and thoroughly analyzed this hardening phenomena by exploiting molecular dynamics. We observed that the Cr-rich phase caused by the phase separation is a week obstacle for dislocation motions. In addition, the deviation of Cr-concentration distribution function from the binomial distribution (i.e. V-parameter) and hardness roughly had a linear relationship as observed in experiments.