Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10674975 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2005 | 11 Pages |
Abstract
Atomistic simulations of collision cascades in a Fe-0.04at.%P matrix and a pure Fe matrix are compared to investigate the interaction of the phosphorus atoms with the radiation. The simulations were performed for a primary knock-on atom having an energy in the range 1-16Â keV. It is observed that the P atom in the Fe matrix does not increase significantly the damage induced to the lattice post irradiation. The density of vacancies and the morphology of the clusters formed in the Fe-0.04at.%P system are indistinguishable from residual defects produced in a pure irradiated Fe matrix. There are two mechanisms by which the Fe interstitials interact with the P atoms. The first occurs when a P atom is dislodged from its substitutional position by a recoil atom and combines with an Fe interstitial to form a ã1Â 1Â 0ã mixed dumbbell. The second is one in which the Fe interstitial is attracted to a substitutional P atom due to the lattice strain region in the vicinity of the P atom. In this case the P atom acts as an attractive centre for interstitial Fe atoms and stabilises them into Fe-P nano-clusters. Nearly 35% of the atoms which are ejected from the core region of the cascade during the ballistic phase form such solute-defect clusters which remain pinned over the period of several hundred picoseconds. Finally, the radiation induced mobility of the P atom is reported. Substitutional P atoms whether isolated or as part of the larger defect clusters have a high energy barrier for diffusion but the P atoms displaced from substitutional sites can diffuse through the lattice by hopping between ã1Â 1Â 0ã dumbbell and tetrahedral sites.
Related Topics
Physical Sciences and Engineering
Materials Science
Surfaces, Coatings and Films
Authors
H. Hurchand, S.D. Kenny, C.F. Sanz-Navarro, R. Smith, P.E.J. Flewitt,