scholarly journals Investigation of Particles and Gas Bubbles in Zr–0.8Sn–1Nb–0.3Fe Zr Alloys Irradiated by Krypton Ions

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2056
Author(s):  
Wenzhu Shen ◽  
Chenwei Liu ◽  
Penghui Lei ◽  
Guang Ran
Keyword(s):  
Cold Rolling ◽  
Bubble Size ◽  
Bubble Growth ◽  
Bubble Formation ◽  
Gas Bubbles ◽  
Irradiation Temperature ◽  
Face Centered Cubic ◽  
Face Centered ◽  
Fcc Structure ◽  
Zr Alloys

Two types of Zr–0.8Sn–1Nb–0.3Fe Zr alloys were irradiated by krypton ions in the temperature range from 320 to 400 °C. The microstructure of the as-received alloys showed that the sizes of Zr crystals and (Zr, Nb)2Fe particles with face-centered cubic (FCC) structure increased from 3.9 μm to 6.0 μm and from 74.6 nm to 89.6 nm, respectively, after cold rolling and subsequent annealing. Kr+ irradiation-induced bubble formation in the Zr matrix was observed. The size of the gas bubbles increased with increasing ion fluence and irradiation temperature. An equation that related the bubble size, ion fluence, and temperature were established. Irradiation-induced amorphization of particles was observed and found to be related to the fabrication process and irradiation parameters. The particles in alloy #1 showed a higher irradiation tolerance than those in alloy #2. The threshold damage dose for the amorphization of particles in alloy #2 was 3.5 dpa at 320 °C and 4.9 dpa at 360 °C. The mechanisms for bubble growth and particle amorphization are also discussed.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

scholarly journals Potential high-Tc superconducting lanthanum and yttrium hydrides at high pressure

2017 ◽  
Vol 114 (27) ◽  
pp. 6990-6995 ◽  
Author(s):  
Hanyu Liu ◽  
Ivan I. Naumov ◽  
Roald Hoffmann ◽  
N. W. Ashcroft ◽  
Russell J. Hemley
Keyword(s):  
Group Structure ◽  
High Temperature Superconductors ◽  
Face Centered Cubic ◽  
Superconducting Transition ◽  
High Tc ◽  
Structure Search ◽  
Systematic Structure ◽  
Face Centered ◽  
Fcc Structure ◽  
Very High

A systematic structure search in the La–H and Y–H systems under pressure reveals some hydrogen-rich structures with intriguing electronic properties. For example, LaH10 is found to adopt a sodalite-like face-centered cubic (fcc) structure, stable above 200 GPa, and LaH8 a C2/m space group structure. Phonon calculations indicate both are dynamically stable; electron phonon calculations coupled to Bardeen–Cooper–Schrieffer (BCS) arguments indicate they might be high-Tc superconductors. In particular, the superconducting transition temperature Tc calculated for LaH10 is 274–286 K at 210 GPa. Similar calculations for the Y–H system predict stability of the sodalite-like fcc YH10 and a Tc above room temperature, reaching 305–326 K at 250 GPa. The study suggests that dense hydrides consisting of these and related hydrogen polyhedral networks may represent new classes of potential very high-temperature superconductors.

scholarly journals Ti-V-C-Based Alloy with a FCC Lattice Structure for Hydrogen Storage

Molecules ◽  
2019 ◽  
Vol 24 (3) ◽  
pp. 552
Author(s):  
Bo Li ◽  
Liqing He ◽  
Jianding Li ◽  
Hai-Wen Li ◽  
Zhouguang Lu ◽  
...  
Keyword(s):  
Hydrogen Storage ◽  
Room Temperature ◽  
Lattice Structure ◽  
Activation Process ◽  
Face Centered Cubic ◽  
Hydrogen Storage Materials ◽  
Fcc Lattice ◽  
Bcc Structure ◽  
Face Centered ◽  
Fcc Structure

Here we report a Ti50V50-10 wt.% C alloy with a unique lattice and microstructure for hydrogen storage development. Different from a traditionally synthesized Ti50V50 alloy prepared by a melting method and having a body-centered cubic (BCC) structure, this Ti50V50-C alloy synthesized by a mechanical alloying method is with a face-centered cubic (FCC) structure (space group: Fm-3m No. 225). The crystalline size is 60 nm. This alloy may directly absorb hydrogen near room temperature without any activation process. Mechanisms of the good kinetics from lattice and microstructure aspects were discussed. Findings reported here may indicate a new possibility in the development of future hydrogen storage materials.

The Influence of Stacking Fault Energy on the Cold-Rolling Cu and Cu-Al Alloy: Structure and Mechanics Properties

2011 ◽  
Vol 683 ◽  
pp. 95-102 ◽  
Author(s):  
Hao Yang ◽  
Peng Yang ◽  
Jing Mei Tao ◽  
Cai Ju Li ◽  
Xin Kun Zhu
Keyword(s):  
Cold Rolling ◽  
Deformation Twin ◽  
High Strength ◽  
Liquid Nitrogen Temperature ◽  
Al Alloy ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face Centered ◽  
Strength And Ductility

Sacking fault energy (SFE) is the key role in solving this problem of getting high strength and expected ductility simultaneously. This work adds Al as the procedure of decreasing SFE in Cu face-centered cubic. It is an economic and effective method to counterpart Cold-rolling at liquid nitrogen temperature to get high density deformation twin and ultrafine-grains size. After undergoing tensile and X-ray diffraction tests, Cu-4.5 wt.% Al plays the best performance on both strength and ductility. Thus there exist the optimal SFE of Cu-Al alloys which get both high strength and expected ductility simultaneously.

Ozone-Based Atomic Layer Deposition of HfO2 and HfxSi1-xO2 and Film Characterization

2004 ◽  
Vol 811 ◽  
Author(s):  
Yoshihide Senzaki ◽  
Seung Park ◽  
Douglas Tweet ◽  
John F. Conley ◽  
Yoshi Ono
Keyword(s):  
Atomic Layer ◽  
Optical Measurements ◽  
Face Centered Cubic ◽  
Hafnium Silicate ◽  
X Ray ◽  
Layer Deposition ◽  
Face Centered ◽  
Fcc Phase ◽  
20 Nm ◽  
Fcc Structure

Abstract:New ALD processes for hafnium silicate films have been developed at Aviza Technology by co-injection of tetrakis(ethylmethylamino)hafnium and tetrakis(ethylmethylamino)silicon precursors. Alternating pulses of the Hf/Si precursor vapor mixture and ozone allow process temperatures below 400°C to grow HfxSi1-xO2 films. Film characterization, including film density, crystallinity, and thermal anneal effect, was performed on five 20 nm thick HfxSi1-xO2 films where x = 0.2, 0.4, 0.6, 0.8, 1.0. X-ray measurements revealed the film densities and thicknesses for the as-deposited and 1000°C annealed samples. The densification with anneals seen in the optical measurements were confirmed. The as-deposited amorphous HfO2 and Hf0.8Si0.2O2 were crystallized after a 600°C anneal. The HfO2 formed the well known monoclinic phase while the silicate formed a face-centered-cubic (fcc) structure. This fcc phase has only recently been mentioned in the literature [1].

scholarly journals Simple Metal and Binary Alloy Phases Based on the fcc Structure: Electronic Origin of Distortions, Superlattices and Vacancies

2017 ◽  
Author(s):  
Valentina F. Degtyareva ◽  
Nataliya S. Afonikova
Keyword(s):  
Binary Alloy ◽  
Complex Structures ◽  
Face Centered Cubic ◽  
Energy Contribution ◽  
Simple Metal ◽  
Fermi Sphere ◽  
The Face ◽  
Face Centered ◽  
The Stability ◽  
Fcc Structure

Crystal structures of simple metals and binary alloy phases based on the face-centered cubic (fcc) structure are analyzed within the model of Fermi sphere – Brillouin zone interactions to understand the stability of original cubic structure and derivative structures with distortions, superlattices and vacancies. Examination of the Brillouin-Jones configuration in relation to the nearly-free electron Fermi sphere for several representative phases reveals significance of the electron energy contribution to the phase stability. Representation of complex structures in the reciprocal space clarifies their relationship to the basic cubic cell.

scholarly journals Influence of Si Atoms Insertion on the Formation of the Ti-Si-N Composite by DFT Simulation

2016 ◽  
Vol 12 (23) ◽  
pp. 11-23
Author(s):  
Juan Manuel Gonzalez ◽  
Johans Steeven Restrepo ◽  
Carolina Ortega Portilla ◽  
Alexander Ruden Muñoz ◽  
Federico Sequeda Osorio
Keyword(s):  
Density Functional ◽  
Amorphous Matrix ◽  
Bond Formation ◽  
Crystalline Lattice ◽  
Face Centered Cubic ◽  
Functional Theory ◽  
Dft Simulation ◽  
Face Centered ◽  
Nano Grains ◽  
Fcc Structure

Using Density Functional Theory (DFT) SiN and TiN structures were simulated, in order to study the influence of the silicon atoms insertion in the TiN lattice placed on interstitial and substitutional positions in a face centered cubic (FCC) crystalline lattice. Results showed that the SiN - FCC structure is pseudo-stable; meanwhile the tetragonal structure is stable with ceramic behavior. The TiN - FCC structure is stable with ceramic behavior similar to SiN - Tetragonal. 21% silicon atoms insertion in interstitial positions showed high induced deformation, high polarization and Si - N bond formation, indication an amorphous transition that could lead to the production of a material composed from TiN grains or nano-grains embedded in a Si - N amorphous matrix. When including 21% of silicon atoms, substituting titanium atoms, the distribution showed higher stability that could lead to the formation of different phases of the stoichiometric Ti1 -x SixNy compound.

scholarly journals Pt–Ti Alloy Coatings Deposited by DC Magnetron Sputtering: A Potential Current Collector at High Temperature

Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 224 ◽  
Author(s):  
Pascal Briois ◽  
Mohammad Arab-Pour-Yazdi ◽  
Nicolas Martin ◽  
Alain Billard
Keyword(s):  
Ostwald Ripening ◽  
Substrate Surface ◽  
Annealing Treatment ◽  
Current Collector ◽  
Titanium Content ◽  
Face Centered Cubic ◽  
Reducing Atmosphere ◽  
The Face ◽  
Face Centered ◽  
Fcc Structure

Metallic platinum–titanium coatings were deposited by co-sputtering of two metallic Pt and Ti targets in pure argon atmosphere. The titanium concentrations varied from 0 to 47 atomic percent and were adjusted as a function of the current applied to the titanium target. The structural and chemical features of these films were assessed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). All as-deposited coatings exhibit a perfect covering of the alumina pellets’ substrate surface. The coatings containing more than 4 at.% Ti are amorphous, whereas the others crystallize in the face-centered cubic (fcc) structure of platinum. After an annealing treatment under air for 2 h, all of the coatings adopt the fcc structure with a crystallization temperature depending on the titanium content. For titanium concentrations higher than 32 at.%, the TiO2 phase appears during the annealing treatment. For the smaller film thickness of Pt–Ti alloys (15 nm), the Ostwald ripening mechanism is observed by SEM increasing the annealing temperature regardless of the content of Ti. The film resistivity measured at room temperature is lower than 7 × 10−4 Ω·cm and increases with the temperature to achieve an insulating behavior (in air and reducing atmosphere Ar-H2 (90-10) at 1123 K the resistivity is ρ ≈ 10+36 Ω·cm). When the thickness of intermetallic Pt3Ti layer is higher than 50 nm, the coating is continuous and the resistivity is below 5 × 10−4 Ω·cm in air and in reducing atmosphere (Ar with 10% of H2) up to 1273 K.

Atomic structures of twin boundaries in CoO

2021 ◽  
Author(s):  
Wandong Xing ◽  
Yang Zhang ◽  
Jizhe Cui ◽  
Shiyou Liang ◽  
Fanyan Meng ◽  
...  
Keyword(s):  
Rock Salt ◽  
Face Centered Cubic ◽  
Twin Boundaries ◽  
Fcc Metals ◽  
Atomic Structures ◽  
Twinning Plane ◽  
Face Centered ◽  
Fcc Structure

The twinning plane of crystals with face-centered-cubic (FCC) structure is usually the (111) plane, as found in FCC metals and oxides with FCC sublattice of oxygen, like rock-salt-type NiO and...

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