Cluster dynamics simulation on microstructure evolution of austenitic stainless steel and -iron under cascade damage condition

Abe, Yosuke  ; Jitsukawa, Shiro; Okubo, Nariaki   ; Matsui, Hideki*; Tsukada, Takashi 

It is known that the mechanical properties degradation of reactor pressure vessel steels caused by neutron irradiation is partly due to the formation of nanometer-size solute and point-defect (PD) clusters. Therefore, the rationalization of radiation induced effects on the microstructure and their consequences on the material properties by developing predictive models is thus of great importance. Cluster dynamics (CD) simulation with rate equations has been used to estimate the long-term evolution of point defect clusters. We have extended the CD simulation code to allow hopping motion for all the self-interstitial atom (SIA) clusters to be mobile. Results of calculation on 316 stainless steel and -iron have been compared. The difference and underlying mechanism of microstructural evolution between austenitic stainless steel and -iron is discussed with regard to the dose dependence.