Regensburg 2022 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 4: Structural Materials
MM 4.10: Vortrag
Montag, 5. September 2022, 12:45–13:00, H46
Effect of Sn on generalized stacking fault energy surfaces in zirconium and its hydrides — •P. Chakraborty1, I. Mouton2, B. Gault1,3, A. Tehranchi1, J. Neugebauer1, and T. Hickel1,4 — 1Max-Planck-Institut für Eisenforschung GmbH, D-40237 Düsseldorf, Germany — 2Université Paris-Saclay, CEA, Service de Recherches Métallurgiques Appliquées, 91191, Gif-sur-Yvette, France — 3Department of Materials, Imperial College, South Kensington, London SW7 2AZ, UK — 4BAM Federal Institute for Materials Research and Testing, 12489 Berlin, Germany
Hydrogen embrittlement in Zr alloy fuel cladding is a primary safety concern for water based nuclear reactors. In order to explain formation of hydrides and planar defects observed in our experiments in Zircaloy-4 primarily used in cladding, we performed ab initio calculations focusing on the solute interactions with generalized stacking faults in hcp α-Zr and fcc zirconium hydrides. Our calculations showed that an increase in Sn concentration leads to a stabilisation of stacking faults in both α-Zr and hydride phases. However, the solution enthalpy of Sn is lower in the α-Zr as compared to the other hydride phases indicative of two competing processes of Sn depletion/enrichment at the Zr hydride/matrix interface. This is corroborated by experimental findings, where Sn is repelled by hydrides and is mostly found trapped at interfaces and planar defects indicative of stacking faults inside the hydride phases. Our systematic investigation enables us to understand the presence and distribution of solutes in the hydride phases, which provides a deeper insight into the microstructural evolution of such alloy's properties during its service lifetime.