September 4, 2019: PhD public defense - Niels Cautaers - Nanoscale study of ageing and irradiation induced precipitates in the DIN 1.4970 alloy - UAntwerpen

Name: Niels Cautaers

Date: September 4, 2019 16:00 h

Venue:

Universiteit Antwerpen
Campus Groenenborger
Room U0.24, Building U
Groenenborgerlaan 171
2020 Antwerpen

Nanoscale study of ageing and irradiation induced precipitates in the DIN 1.4970 alloy

The MYRRHA fuel cladding material will be the DIN 1.4970 alloy, an austenitic stainless steel part of the 15-15Ti family. This material has been qualified for use as cladding at elevated temperatures in sodium fast reactors. MYRRHA will operate at lower temperatures and this may pose novel challenges to the material. A characteristic microstructural feature in this material is the precipitation of small titanium carbide (TiC) precipitates under irradiation. These are believed to contribute to the good swelling resistance of the alloy. At lower irradiation temperatures, these precipitates may be unstable, with unknown consequences to the material behavior. Ageing heat treatments were considered to temporarily remediate this phenomenon.

This work is about understanding the microstructural evolution that takes place during ageing heat treatment and separately ion irradiation of the DIN 1.4970 alloy. Of particular interest to this thesis are the nano-scale titanium carbide (TiC) particles; detailing their structure, mode of formation, stability under irradiation, and interaction with other precipitating phases (mainly M23C6 and G-phase) are the main themes of this work and were studied primarily with transmission electron microscopy (TEM) and atom probe tomography (APT). Relationships between the microstructures and mechanical properties were established via tensile testing, hardness testing and nanoindentation.

 

 

Promotor:
  • (UAntwerpen) Dominique Schryvers
SCK•CEN mentor:
  • Rémi Delville
  • Erich Stergar

Click here for a list of obtained PhD degrees.