Study of structural inhomogeneity of commercial oxide-dispersion-strengthened steels

• Published in: Journal of physics. Conference series 2014-01, Vol.505 (1), p.12017-5
• Main Authors: Veternikova, J, Degmova, J, Skraba, M, Petriska, M, Sojak, S, Slugen, V
• Format: Article
• Language: English
• Subjects: Defects; Dispersion hardening alloys; Dispersion hardening steels; Doppler; Doppler effect; Ferritic stainless steels; Ferrous alloys; Inhomogeneity; Materials selection; Mechanical alloying; Mechanical properties; Nuclear reactors; Orientation; Physics; Positron annihilation; Positrons; Steel construction; Structural steels; Superalloys
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/505/1/012017

Oxide-dispersion-strengthened steels, candidate materials for construction of new generation of nuclear reactors, can have inhomogeneous structure and anisotropic mechanical properties due to their fabrication, especially by process of mechanical alloying. This paper examines two similar commercial oxide-dispersion-strengthened steels MA 956 and PM 2000 in two different orientations of samples in order to study inhomogeneity of defect presence using positron annihilation techniques. Positron data showed small or negligible differences between samples of individual steels (up to 4 % for average lifetime). Moreover, structural divergence between two orientations (transversal cut and longitudinal cut) of the same steel was also not apparent. However, higher presence of defects and also bigger defects were found for both orientations of MA 956 samples. The structure of PM 2000 probably contains fewer defects with smaller size, though their occurrence in surface and subsurface layers up to 1.6 μm (from Doppler broadening spectroscopy) seem to be less homogeneous than in MA 956.