First principles calculations of beryllium stability in zirconium surfaces

Abstract

High-temperature oxidation of zircaloys poses a serious safety risk for nuclear fuel cladding applications, thus driving the search for oxidation resistant alloys. Ellingham diagrams suggest preferential oxidation of beryllium over zirconium, but the atomicscale behavior of Be near Zr surfaces is unknown. We perform first principle calculations using density functional theory to investigate the stability of Be at possible sites in the Zr surfaces and bulk. Our calculations predict that Be favors substitutional sites and prefers to segregate to the surface layers. Charge density analysis shows charge redistribution around the solute atom in substitutional sites which leads to increased bonding and explains the high stability of these sites. The calculated surface segregation energy suggests that Be migrates towards the surface at high temperatures, which could enhance oxidation resistance.

<i>Ab Initio</i> Study of Tin Segregation in Zirconium at the Σ17(0̅337) Tilt Grain Boundary

“…With the assumption of an infinitely diluted solution, the segregation energy of a solute atom located at site i, ∆E seg i , is calculated by the following formula [6,11]:…”

“…For all polycrystalline materials, the consequences of intergranular segregation on structural and functional properties are considerable: embrittlement or consolidation, intergranular corrosion and modification of electrical properties [2]. * corresponding author; e-mail: selm2002nor@yahoo.fr Several studies have been carried out on crystal defects of metals having the hexagonal close-packed structure such as Mg, Ti, and Zr [3], particularly on the atomic scale, by ab initio calculations [4][5][6][7][8][9][10] or by molecular dynamics [11,12].…”

Surface Segregation of NbAl3 Alloys by Boron Doping

“…The oxidation behavior is a difficult challenge to the use of hightemperature structural materials, [1][2][3] where the oxidation process depends on the compositions, microstructures and diffusivity of high-temperature structural materials at a given temperature. [4][5][6] The usual way of improving the oxidation resistance is the use of oxidation-resistant coatings, [7][8][9] but this way has its limits hindering the applications of high-temperature structural materials.…”

“…[4][5][6] The usual way of improving the oxidation resistance is the use of oxidation-resistant coatings, [7][8][9] but this way has its limits hindering the applications of high-temperature structural materials. [1] Recently, the selective oxidation to improve oxidation resistance on the surfaces has been quickly developed, [10][11][12][13] which can be used to protect any material, for example high-temperature alloys. NbAl 3 is a potential alloy for high-temperature applications due to its high melting point, low density, high strength and stability at high temperature.…”

“…The oxidation behavior is a difficult challenge to the use of high‐temperature structural materials, where the oxidation process depends on the compositions, microstructures and diffusivity of high‐temperature structural materials at a given temperature . The usual way of improving the oxidation resistance is the use of oxidation‐resistant coatings, but this way has its limits hindering the applications of high‐temperature structural materials . Recently, the selective oxidation to improve oxidation resistance on the surfaces has been quickly developed, which can be used to protect any material, for example high‐temperature alloys.…”