Neutron activation analysis with PE moderated252Cf neutron source

Mechanical properties and dynamic strain aging behavior of Zr–1.5Nb–0.4Sn–0.2Fe alloy

“…The DSA intensity of specimens with the final heat treatment at 470 • C could be higher than that with the final heat treatment at 510 • C because the former was only stress-relieved to have its initial dislocation density which could capture more solute atoms but the latter has a lesser dislocation density to capture as much due to a partial re-crystallization. Since the velocity of the moving dislocation in a Zr alloy is almost equal to the diffusivity of a solute atom such as oxygen at 340 • C [8], it seems that the specimen with the final heat treat- ment at 470 • C shows a serration on the stress-strain curve but that with the final heat treatment at 510 • C does not. The yield drops in the specimens with the final heat treatment at 510 • C might be from the release of the dislocations which were fixed to the solute atoms with a higher stress or with the help of a ther- mal fluctuation at a higher temperature.…”

Microstructure and dynamic strain aging phenomena in two structural steels

“…In structural steels, many studies have reported that DSA manifests in an embrittling manner. [7][8][9][10][11][12][13] The effects can be suppressed by controlling the availability of responsible solutes, which are contingent on alloying, heat treatment and microstructure of the material. Previous studies on plain carbon and alloy steels suitably heat treated to give dual phase ferrite-pearlite, ferritemartensitic microstructure as well as tempered martensite microstructure have revealed that manifestations of DSA are contingent on the solute content [26][27][28] rather than on changes in the microstructure.…”

“…Thus, the trends seen in AISI 403 are consistent with earlier investigations where the role of Cr has been unequivocally established. In the case of low alloy steels, many studies have shown that they are susceptible to DSA due to interaction of dislocations with C and N. [8][9][10][11][12] It is well known from the investigation of the chemical nature of carbides in the tempered bainitic structure that they are Cr rich carbides. 37 As a result, the elements, such as Mn and Ni, are free to form X-N or X-C complexes (X5Mn/Ni), thereby curtailing their migration to the dislocations.…”

“…These studies have shown that there is also a reduced resistance to crack initiation and growth as a result of the operation of DSA phenomena. [8][9][10][11][12][13] In conventional structural steels for component applications in power plants, conditions during sevice (i.e. temperature and strain rate) can be favourable for DSA to manifest in an embrittling fashion due to jerky dislocation motions, collective motion of dislocations and strong obstacles such as precipitates.…”

A Comprehensive Review of Selected Major Categories of Lithium Isotope Separation Techniques

“…The effect of chelating agents in eluents on the separation factor was studied by Kim et al [45] and it was observed that the separation factor improved with increasing coordination site (α ¼ 1.0022-1.0038) at the same distribution coefficient and the distribution coefficient (α ¼ 1.0017-1.0026) at the same chelating agent concentration. [45][46][47] The Li concentration and isotopic ratios for effluent fractions from a biphasic zeolite column were measured by Ishikawa et al [48] The biphasic condition was due to a mixture of [ 7 Li isotopes pass into the aqueous process as tetrahydrate [Li(OH 2 ) 4 ] þ , whereas 6 Li isotopes were left with two hydrated water molecules of [Li 0.08 (NH 4 ) 0.92 ]A and [Li 0.33 (NH 4 ) 0.67 ]A hydrates in the sixmembered oxygen rings of the biphasic zeolite. [48]…”