Effects of carbon impurity on microstructural evolution in irradiated -iron

Abe, Yosuke  ; Suzudo, Tomoaki   ; Jitsukawa, Shiro; Tsuru, Tomohito   ; Tsukada, Takashi 

Static and dynamic interactions between SIA loops and carbon impurities as a major impurity in -iron was studied using atomic-scale computer simulations to clarify possible mechanisms of trapping of SIA loops by carbon impurities. It was found that bindings of carbon-vacancy complexes with SIA loops are so strong when they locate inside the loop habit plane. This situation would be realized below 450 K at which carbon-vacancy complexes become to dissociate. At higher temperatures, it can be expected that the dissociated interstitial carbon atoms tend to migrate towards the loop periphery due to the internal stress field associated with SIA loops, and this could attribute to the continuous 1D motion of SIA loops with dragging impurities as observed by experiments. A long-term microstructural evolution induced by radiation damage was also simulated by taking into account the trapping and detrapping rates of SIA loops deduced from the knowledge obtained in this study.