Dr. Eberhard Altstadt

Structural Material­s
Phone: +49 351 260 2276

Porträt Dr. Kaden, Cornelia; FWOM

Dr. Cornelia Kaden,
Phone: +49 351 260 3431

Structural Materials

We investigate the behavior of materials exposed to energetic particle irradiation. The work contributes to the program NUSAFE (Nuclear Waste Management, Safety and Radiation Research) of the Helmholtz Association.

Neutron irradiation provokes the formation and long-term evolution of nm-scale defects such as dislocation loops and solute atom clusters. These defects give rise to hardening accompanied by a reduced fracture resistance of reactor pressure vessel steels of running nuclear power plants. Materials for advanced reactor concepts will be exposed to higher operation temperatures and higher neutron doses. The overall objectives of our research are to identify the mechanisms of irradiation-induced damage in structural materials and to assess the resulting changes of the mechanical properties.

We work on two main directions:

  • In the case of running nuclear power plants, the work is focused on long-term irradiation effects in reactor pressure vessel steels.
  • Our work in the field of advanced reactor concepts is dedicated to ferritic/martensitic Cr-steels, oxide dispersion strengthened (ODS) steels and the emerging class of high-entropy alloys.

The new insight substantially contributes to the scientific background for the safety assessment of nuclear reactors. The work is embedded in the Euratom projects SOTERIA, MATISSE and M4F. A close cooperation with the Fundamentals and Simulation Group provides additional insight via atomistic simulation.

Our expertise:

Latest Publication

Microstructure-informed prediction of hardening in ion-irradiated reactor pressure vessel steels

Lai, L.; Brandenburg, J.-E.; Chekhonin, P.; Duplessi, A.; Cuvilly, F.; Etienne, A.; Radiguet, B.; Rafaja, D.; Bergner, F.

Ion irradiation combined with nanoindentation is a promising tool to study irradiation-induced hardening of nuclear materials including reactor pressure vessel (RPV) steels. For RPV steels, the major sources of hardening are nm-sized irradiation-induced dislocation loops and solute atom clusters, both representing barriers for dislocation glide. The dispersed barrier hardening (DBH) model provides a link between the irradiation-induced nanofeatures and hardening. However, a number of details of the DBH model still require consideration. These include the role of the unirradiated microstructure, the proper treatment of the indentation size effect (ISE), and the appropriate superposition rule of individual hardening contributions. In the present study, two well characterized RPV steels, each ion-irradiated up to two different levels of displacement damage, were investigated. Dislocation loops and solute atom clusters were characterized by transmission electron microscopy and atom probe tomography, respectively. Nanoindentation with a Berkovich indenter was used to measure indentation hardness as a function of the contact depth. In the present paper, the measured hardening profiles are compared with predictions based on different DBH models. Conclusions about the appropriate superposition rule and the consideration of the ISE (in terms of geometrically necessary dislocations) are drawn.

Keywords: reactor pressure vessel steels; ion irradiation; microstructure characterization; transmission electron microscopy; atom probe tomography; nanoindentation; hardening

Related publications


Foto: Gruppenbild der Abteilung "Konstruktionswerkstoffe" am Institut für Ressourcenökologie ©Copyright: Dr. Eberhard Altstadt


NameBld./Office+49 351 260Email
Dr. Eberhard Altstadt801/P1512276
Dr. Cornelia Kaden801/P1023431,


NameBld./Office+49 351 260Email
Dr. Frank Bergner801/P1503186
Dr. Jann-Erik Brandenburg801/P1522301
Dr. Paul Chekhonin801/P1462149
Vanessa Dykas801/P1053363
Mario Houska801/P1482242
Libang Lai801/P1533032
Jens Pietzsch801/P0322814
Dr. Andreas Ulbricht801/P1463155
Tilo Welz801/P0322814