Improving the Quantification of Deuterium in Zirconium Alloy Atom Probe Tomography Data Using Existing Analysis Methods

Zirconium alloys are common fuel claddings in nuclear fission reactors and are susceptible to the effects of hydrogen embrittlement. There is a need to be able to detect and image hydrogen at the atomic scale to gain the experimental evidence necessary to fully understand hydrogen embrittlement. Through the use of deuterium tracers, atom probe tomography (APT) is able to detect and spatially locate hydrogen at the atomic scale. Previous works have highlighted issues with quantifying deuterium concentrations using APT due to complex peak overlaps in the mass-to-charge-state ratio spectrum between molecular hydrogen and deuterium (H2 and D). In this work, we use new methods to analyze historic and simulated atom probe data, by applying currently available data analysis tools, to optimize solving peak overlaps to improve the quantification of deuterium. This method has been applied to literature data to quantify the deuterium concentrations in a concentration line profile across an α-Zr/deuteride interface.

Phonon dynamics of Zr67Ni33 AND Fe80B20 binary glassy alloys

Binary amorphous alloys are the primary bulk metallic glasses (BMGs). Two binary BMGs Zr67Ni33 and Fe80B20 have been studied in the present work using the pseudo- alloy-atom (PAA) model based on the pseudopotential theory. Some important thermodynamic properties like Debye temperature and elastic properties like elasticity moduli and Poisson’s ratio at room temperature are theoretically computed with the help of pseudopotential theory from the elastic limit of the phonon dispersion curves (PDCs). The collective dynamics of longitudinal and transverse phonon modes are investigated in terms of eigenfrequencies of the localized collective modes. The presently computed results are compared with the other such data including theoretically generated results from the molecular dynamics at different temperatures as available in the literature and an acceptable agreement is found. BIBECHANA 18 (2021) 33-47

Investigation on the Freeze Casting Porous Al2O3 Ceramic Bodies Infiltrated with Nb-Ti-Al-Cr Alloy by Pressureless Infiltration

This paper adopted freeze casting method to prepare porous Al2O3 ceramic bodies with different volume percentage and interconnected pore channels as the preform. The porous Al2O3 ceramic bodies were pressureless infiltrated with Nb-35Ti-20Al-10Cr alloy (atom percentage, at%) by using electromagnetic induction furnace. The results indicated that there is a well wettability between Nb-35Ti-20Al-10Cr melt and porous Al2O3 ceramic body. And it would be possible to infiltrate Nb-35Ti-20Al-10Cr melt into porous Al2O3 ceramic body through pressureless infiltration. The microstructure observation for the Nb-35Ti-20Al-10Cr/Al2O3 composites demonstrated that it was still retained the layer structure characteristics of the preform. The Nb-35Ti-20Al-10Cr melt was filled into the interconnected pore channels existed in the porous Al2O3 ceramic bodies and the Nb, Ti, Al, Cr alloy elements diffused into the reinforced Al2O3 particles during pressureless infiltration.

SUPERCONDUCTING STATE PARAMETERS OF 4d-TRANSITION METALS BASED BINARY ALLOYS

The theoretical study of the superconducting state parameters (SSP) viz. electron–phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature TC, isotope effect exponent α and effective interaction strength NoV of 4d-transition metals based binary alloys have been made extensively in the present work using a model potential formalism for the first time. In the present computation, the use of pseudo-alloy-atom model (PAA) is proposed and found successful. A considerable influence of various exchange and correlation functions on λ and μ* is found from the present study. The present results of the SSP are found in qualitative agreement with the available experimental data wherever they exist.

PSEUDOPOTENTIAL IN THE STUDY OF SUPERCONDUCTING STATE PARAMETERS OF METALLIC GLASSES

A recently proposed model potential is used to study the superconducting state parameters viz. electron-phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature TC, isotope effect exponent α and effective interaction strength NOV of 40 metallic glasses of simple, non-simple as well as transition metals. The advanced screening function due to Sarkar et al. has been employed to include the exchange and correlation effects. Instead of Vegard's law, the use of pseudo-alloy-atom model in the investigation of superconducting state properties of metallic glasses is proposed and found successfully.

THE STUDY OF SUPERCONDUCTING STATE PARAMETERS OF in-BASED BINARY ALLOYS BY PSEUDOPOTENTIAL

The study of the superconducting state parameters (SSP) viz. electron–phonon coupling strength λ, Coulomb pseudopotential μ*, transition temperature T C , isotope effect exponent α and effective interaction strength N0V of In-based binary alloys In 1-x Na x, In 1-x Mg x, In 1-x Zn x, In 1-x Tl x, In 1-x Sn x, In 1-x Pb x and In 1-x Bi x have been made extensively in the present work using a model potential. To explain electron–ion interaction pseudo-alloy-atom (PAA) model is applied for the first time instead of Vegard's Law. A considerable influence of various exchange and correlation functions on λ and μ* is found from the present study. It is also concluded that T C strongly depends on the value of the effective valence Z* of binary alloys.