Sruthi Mohan; S. Balaji; S. Amirthapandian; C. David; B.K. Panigrahi
Abstract
Fe-14Cr-0.2Ti-0.3Y2O3, ODS alloy samples are irradiated with 880 keV Fe + ions at 230 K and 300 K upto a damage of 40 dpa at the surface. Transmission electron microscopy studies reveal a reduction in sizes of oxide dispersions in the ion irradiated alloys as compared to the as-prepared specimens; with ...
Read More
Fe-14Cr-0.2Ti-0.3Y2O3, ODS alloy samples are irradiated with 880 keV Fe + ions at 230 K and 300 K upto a damage of 40 dpa at the surface. Transmission electron microscopy studies reveal a reduction in sizes of oxide dispersions in the ion irradiated alloys as compared to the as-prepared specimens; with greater diminution for samples irradiated at 230 K. Although the ion irradiation conditions (stage III) are favorable for vacancies to couple with solute atoms to cause precipitate growth, it is shown that such effects are less pronounced here and the ballistic effects dominate to cause oxide particle dissolution.
P. Jegadeesan; S. Amirthapandian; Kitheri Joseph; C. David; B.K. Panigrahi; K.V. G Kutty
Abstract
Iron phosphate glass (IPG) is considered as a suitable matrix for the immobilization of nuclear waste containing higher concentration of Cs, rare earth, Mo and Cr. The central issue, while disposing nuclear waste in glass matrices, is the damage in glass matrices due to the ballistic processes caused ...
Read More
Iron phosphate glass (IPG) is considered as a suitable matrix for the immobilization of nuclear waste containing higher concentration of Cs, rare earth, Mo and Cr. The central issue, while disposing nuclear waste in glass matrices, is the damage in glass matrices due to the ballistic processes caused by atomic displacements due to α-particles and the recoiling of heavy nuclei resulting from actinide decay. Ion irradiation produces similar kind of damage, and hence the samples are irradiated with 4 MeV O + (self) ion. The microstructural studies were carried out using transmission electron microscopy (TEM) for as-prepared, annealed and ion irradiated samples. It is observed that ion irradiation in IPG leads to the formation of nanocrystals with different phases containing Fe, P and O. Thermally activated crystallization process is ruled out based on the non-equilibrium experimental conditions. In the present experiments, stress driven crystallization mechanism was invoked. The stress, around the ion track formed during ion irradiation, is larger than the yield strength of the glass and hence, the surrounding matrix undergoes substantial deformation resulting in the formation of shear bands. Nucleation of nanocrystals is driven by the stress in the vicinity of the shear bands.
