Author : Chenwei He
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (922 download)
Book Synopsis Experimental Study of the Interaction of Vacancy Defects with Y, O and Ti Solutes to Better Understand Their Roles in the Nanoparticles Formation in ODS Steels by : Chenwei He
Download or read book Experimental Study of the Interaction of Vacancy Defects with Y, O and Ti Solutes to Better Understand Their Roles in the Nanoparticles Formation in ODS Steels written by Chenwei He and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The severe operating conditions of the future nuclear reactor, Generation-IV, -high temperature and high irradiation damage-, require the adapted materials development. Oxide-dispersion strengthened (ODS) alloy is one of the most potential candidates expected to be used for fuel cladding material because of their outstanding swelling and creep properties. Their excellent properties are induced by the fine dispersion of oxide nanoparticles (Y, O, Ti), obtained by mechanical alloying of steel and oxide powders and which has to be better mastered. But the atomic scale clustering mechanism of these nanoparticles is not yet cleared. In this context, the present thesis using positron annihilation spectroscopy (PAS) and secondary ion mass spectrometry (SIMS) sheds light on the interaction of vacancy defects with Y, O and Ti solutes to better understand their roles in the nanoparticles formation. The He irradiations have been performed to reveal the vacancy defects properties and Y, Ti, O implantations realized to study the Y, Ti, O-vacancy interactions in bcc Fe matrix. In all cases, the defects depth distribution shows a lower size of vacancy defects in the region where the concentration of the incident ions Y, Ti and O is the highest. This effect of the ions on the damage formation is more pronounced for respectively O, Y and Ti. It is explained by the formation of V-X (X=O, Y, Ti) complexes which reduce the mobility and agglomeration probability of the vacancy defects. The annealing of the Y and O implanted samples reveals that some O-vacancy complexes are mobile at room temperature and Y doesn't diffuse up to 550°C whilst Y-vacancy complexes remain as it is expected from theory. A model of the first steps of the ODS nanoparticles nucleation is proposed by using the results obtained in this thesis.