Vacancy type defects in oxide dispersion strengthened steels

This study was focused on commercial oxide-dispersion strengthened (ODS) steels - MA 956 (20%Cr), PM 2000 (19%Cr), ODM 751 (16%Cr) and MA 957 (14%Cr) developed for fuel cladding of Generation IV reactors. The ODS steels are investigated in order to compare their microstructure features. Vacancy defects were observed by Doppler broadening spectroscopy and positron annihilation lifetime spectroscopy. Residual stress proportional to all kinds of defects was investigated by magnetic Barkhausen noise measurement. The highest presence of vacancy defects was found in MA 956 and the lowest defect concentration in MA 957, although this steel contains the largest defects (six-vacancies together with dislocations or mono-vacancies). Other investigated steels contained probably three- or four-vacancy clusters. Further, the results from the positron techniques indicated a relation between the chromium content and the defect concentration. The magnetic Barkhausen noise results also showed that a peak position (describing a grain size) increased with the chromium content. However residual stress was independent of a chromium level.

SLUGEN Vladimir;  VETERNIKOVA Jana;  DEGMOVA Jarmila;  KILPELÄINEN Simo;  TUOMISTO Filip;  KRSJAK Vladimir; 

2012-12-19

Trans Tech Publications

JRC77829

0255-5476,   

http://www.scientific.net/MSF.733.264,    https://publications.jrc.ec.europa.eu/repository/handle/JRC77829,   

10.4028/www.scientific.net/MSF.733.264,