Crystal structure influence on ion-irradiation tolerance of Ln2TiO5 compounds

No Thumbnail Available
Journal Title
Journal ISSN
Volume Title
Engineers Australia
As a controllable and reproducible technique ion beam irradiation is routinely used as a method for simulating recoil damage caused by alpha-decay in actinide containing materials and neutron damage within fission and fusion reactor systems [1]. The transition from a crystalline to amorphous structure may lead to larger scale effects in the material properties such as an increase in volume (swelling) linked to the generation and agglomeration of defects and decreased thermodynamic and structural stability. Compounds in this study consist of the nominal stoichiometry Ln2TiO5 (where Ln represents the lanthanide series plus yttrium). There are 4 crystal structure symmetries in this series; orthorhombic Pnma, hexagonal P63/mmc, cubic (pyrochlore-like) Fd-3m and cubic (fluorite-like) Fm-3m. The final structure is dependent upon the lanthanide size and processing conditions used (pressure and temperature regime) [2]. Ln2TiO5 compounds have been proposed for potential nuclear based applications [3]. For example, Dy2TiO5 has been incorporated into inert matrix fuel as a neutron absorber [4] and Gd2TiO5 has also been proposed for similar use [5] and it’s radiation tolerance has been tested for this purpose [6]. In this study a systematic series of samples of the nominal stoichiometry Sm(x)Yb(2-x)TiO5 (where x = 2, 1.4, 1, 0.6, and 0) are used to test and compare the ion-irradiation tolerance of the major structures within the Ln2TiO5 system of compounds. An improved radiation tolerance with the higher symmetry cubic structures was found, which is consistent with previous studies of similar compounds.
Crystal structure, Irradiation, Ion beams, Alpha decay, Rare earths, Pyrochlore
Aughterson, R. D., Lumpkin, G. R., Gault, B., Whittle, K. R., de los Reyes, M., Smith, K.L.,& Cairney, J. (2014). Crystal structure influence on ion-irradiation tolerance of Ln2TiO5 compounds. Paper presented at CAMS 2014, 3rd biennial conference of the Combined Australian Materials Society Meeting, 26-28 November 2014, Charles Perkins Centre, University of Sydney.