Radiation-induced material redistribution in concentrated binary alloys
Abstract
We studied irradiation-induced material redistribution in concentrated binary alloys, AB. When a material is irradiated, Frenkel pairs (vacancies and interstitials) are produced in concentrations much more above their thermal concentrations. Depending upon the crystal structure and size of the alloying elements, various defect configurations are formed. It has been seen that, if the solute size is such that they can fit in the interstices (C, H, Boron, etc), the mobile defect configurations are vacancies and interstitials. But, if the size of the solute is equal to bigger than the solvent atoms, formation of dumb-bell interstitial configurations is observed (FCC, BCC). In present study, we have considered a FCC binary alloy, AB, in which the size of B is almost equal to A. Therefore, we may have vacancies, AA, BB, AB (dumb-bells) as mobile defect configurations. In the presence of defect sinks, the defect move towards them resulting in depletion of faster diffusing alloying species and enrichment of slower diffusing species: Inverse Kirkendall Effect. This causes segregation of alloying elements near defect sinks, which may deteriorate various material properties. In the absence of defect sinks, we can see redistribution of alloying elements as a result of irradiation. Present study is done to create a conceptual framework for the actual problem: Radiation- induced microstructural and microchemical changes in concentrated binary alloys.
