Effects of grain boundaries on the radiation-induced defects evolution in BCC Fe–Cr alloy: A molecular dynamics study

Molecular dynamics (MD) method was conducted on four types of symmetric tilt grain boundaries (GBs) in body-centered cubic (BCC) Fe–9Cr alloy. The formation energy and segregation energy of different types of defects (interstitial and vacancy) was firstly calculated in each system, and the GB energy and width were also calculated. It is found that the Fe interstitials have higher segregation energy than Cr interstitials for all GB systems, which can explain energetic drive of the defect behavior in GB systems. By analyzing the defect production in GB systems and comparing them with those in single crystal, it was found that more interstitials than vacancies disappeared due to the existence of GB. But the influence of GB varies between GB types. The migration of GB was only found in ∑25(430) possibly because of the temperature gradient during the cascade evolution.