HRTEM study of oxide nanoparticles in K3-ODS ferritic steel developed for radiation tolerance

• Published in: Journal of nuclear materials Vol. 409; no. 2; pp. 72 - 79
• Main Authors: Hsiung, L., Fluss, M., Tumey, S., Kuntz, J., El-Dasher, B., Wall, M., Choi, B., Kimura, A., Willaime, F., Serruys, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 15.02.2011; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fission nuclear power plants; Fuels; Installations for energy generation and conversion: thermal and electrical energy; Nuclear fuels; Particle size; High resolution; Oxides; Ferritic steel; Formation mechanism; Radiation damage; Reactor core; Nuclear reactor; Crystalline structure
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/j.jnucmat.2010.09.014

Crystal and interfacial structures of oxide nanoparticles and radiation damage in 16Cr–4.5Al–0.3Ti–2W–0.37 Y 2O 3 ODS ferritic steel have been examined using high-resolution transmission electron microscopy (HRTEM) techniques. Oxide nanoparticles with a complex-oxide core and an amorphous shell were frequently observed. The crystal structure of complex-oxide core is identified to be mainly monoclinic Y 4Al 2O 9 (YAM) oxide compound. Orientation relationships between the oxide and the matrix are found to be dependent on the particle size. Large particles (>20 nm) tend to be incoherent and have a spherical shape, whereas small particles (<10 nm) tend to be coherent or semi-coherent and have a faceted interface. The observations of partially amorphous nanoparticles and multiple crystalline domains formed within a nanoparticle lead us to propose a three-stage mechanism to rationalize the formation of oxide nanoparticles containing core/shell structures in as-fabricated ODS steels. Effects of nanoparticle size and density on cavity formation induced by (Fe 8+ + He +) dual-beam irradiation are briefly addressed.