scholarly journals Обнаружение новой фазы типа B1 в монокристаллах магнитомягких сплавов Fe-Al и Fe-Ga

2019 ◽  
Vol 61 (11) ◽  
pp. 2000 ◽  
Author(s):  
Ю.П. Черненков ◽  
Н.В. Ершов ◽  
В.А. Лукшина
Keyword(s):  
Volume Fraction ◽  
Ferromagnetic State ◽  
Aluminum Concentration ◽  
Al Alloy ◽  
Alloy Sample ◽  
Face Centered Cubic ◽  
Bcc Lattice ◽  
Fcc Lattice ◽  
Face Centered ◽  
Fcc Phase

AbstractThe atomic structure of Fe–Al (7 and 9 at % Al) and Fe–Ga (18 at % Ga) alloys is studied by X‑ray diffraction using a laboratory four-circle diffractometer. After refining annealing, single-crystal alloy samples were annealed in the ferromagnetic state ( T < T _C). One sample of the Fe–18 at % Ga alloy, after short holding in the paramagnetic state ( T > T _C), was quenched in room temperature water. Earlier, the authors reported on the peculiarities of the ordering of alloying atoms in B 2 and D 0_3 phase structures in quenched and annealed samples of these alloys. Here, we present and discuss the results of our observations in these alloys of a new phase with a face-centered cubic (fcc) lattice ( B 1-type structure with NaCl prototype and unit cell parameter ~5.2 nm). The fcc phase appears in the Fe–Al alloy as the aluminum concentration increases from 7 to 9 at %; it is observed in the Fe–18 at % Ga alloy, and its volume fraction increases after annealing in the ferromagnetic state in comparison with a quenched alloy sample. In these alloys (9 at % Al) and (18 at % Ga), different ways of embedding fcc crystals in the bcc phase of single crystals are realized; i.e., the axes of the fcc lattice are directed in four different ways relative to the axes of the bcc lattice.

scholarly journals Magnetic Properties of Nickel-Titanium Alloy during Martensitic Transformations under Plastic and Elastic Deformation

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 665
Author(s):  
Ludmila I. Kveglis ◽  
Fedor M. Noskov ◽  
Mikhail N. Volochaev ◽  
Alexander V. Nyavro ◽  
Aleksander Filarowski
Keyword(s):  
Titanium Nickelide ◽  
Tensile Deformation ◽  
Intermediate Phase ◽  
Martensitic Transformations ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Bcc Lattice ◽  
Fcc Lattice ◽  
Face Centered ◽  
B2 Structure

This paper focuses on the processes of the occurrence of magnetization during structure formation in samples of Ni51Ti49 alloy under deformation conditions. The possibility of the existence of a phase with an FCC (face-centered cubic) lattice in titanium nickelide has been demonstrated by electron microscopy and electron diffraction. It has been discovered that the interplanar distances of BCC110 (body-centered cubic), FCC111, and HCP002 (hexagonal close packed) in the alloy under study have similar values, which indicates the possibility of their mutual polymorphic transformation. Based on the modular self-organization, a scheme of martensitic transformations in titanium nickelide from the B2 structure (BCC lattice) to the B19’ structure (HCP lattice) through an intermediate phase with an FCC lattice is proposed. It is shown that lenticular crystals appear in the Ni51Ti49 alloy under tensile deformation until rupture, which is accompanied by the onset of ferromagnetism. The effect of magnetization in Ni51Ti49 samples when immersed in liquid nitrogen has been also discovered. In this case, the reason for the appearance and disappearance of magnetization can be associated with microdeformation processes caused by direct and reverse martensitic transitions that occur during cooling and heating of the samples.

scholarly journals Stability and equation of state of face-centered cubic and hexagonal close packed phases of argon under pressure

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Agnès Dewaele ◽  
Angelika D. Rosa ◽  
Nicolas Guignot ◽  
Denis Andrault ◽  
João Elias F. S. Rodrigues ◽  
...  
Keyword(s):  
Equation Of State ◽  
Single Crystal ◽  
Single Crystal Sample ◽  
Moderate Pressure ◽  
Face Centered Cubic ◽  
Experimental Conditions ◽  
Crystal Sample ◽  
Hexagonal Close Packed ◽  
Face Centered ◽  
Fcc Phase

AbstractThe compression of argon is measured between 10 K and 296 K up to 20 GPa and and up to 114 GPa at 296 K in diamond anvil cells. Three samples conditioning are used: (1) single crystal sample directly compressed between the anvils, (2) powder sample directly compressed between the anvils, (3) single crystal sample compressed in a pressure medium. A partial transformation of the face-centered cubic (fcc) phase to a hexagonal close-packed (hcp) structure is observed above 4.2–13 GPa. Hcp phase forms through stacking faults in fcc-Ar and its amount depends on pressurizing conditions and starting fcc-Ar microstructure. The quasi-hydrostatic equation of state of the fcc phase is well described by a quasi-harmonic Mie–Grüneisen–Debye formalism, with the following 0 K parameters for Rydberg-Vinet equation: $$V_0$$ V 0 = 38.0 Å$$^3$$ 3 /at, $$K_0$$ K 0 = 2.65 GPa, $$K'_0$$ K 0 ′ = 7.423. Under the current experimental conditions, non-hydrostaticity affects measured P–V points mostly at moderate pressure ($$\le$$ ≤ 20 GPa).

scholarly journals Свойства движущихся дискретных бризеров в бериллии

2018 ◽  
Vol 60 (5) ◽  
pp. 978
Author(s):  
O.B. Бачурина ◽  
P.T. Мурзаев ◽  
A.C. Семенов ◽  
E.A. Корзникова ◽  
C.B. Дмитриев
Keyword(s):  
Energy Transport ◽  
Interatomic Potential ◽  
Maximum Velocity ◽  
Face Centered Cubic ◽  
Sound Waves ◽  
Many Body ◽  
Hexagonal Close Packed ◽  
Bcc Lattice ◽  
Face Centered ◽  
The Many

AbstractDiscrete breathers (DBs) have been described among pure metals with face-centered cubic (FCC) and body-centered cubic (BCC) lattice, but for hexagonal close-packed (HCP) metals, their properties are little studied. In this paper, the properties of standing and moving DBs in beryllium HCP metal are analyzed by the molecular dynamics method using the many-body interatomic potential. It is shown that the DB is localized in a close-packed atomic row in the basal plane, while oscillations with a large amplitude along the close-packed row are made by two or three atoms, moving in antiphase with the nearest neighbors. Dependences of the DB frequency on the amplitude, as well as the velocity of the DB on its amplitude and on parameter δ, which determines the phase difference of the oscillations of neighboring atoms, are obtained. The maximum velocity of the DB movement in beryllium reaches 4.35 km/s, which is 33.7% of the velocity of longitudinal sound waves. The obtained results supplement our concepts about the mechanisms of localization and energy transport in HCP metals.

scholarly journals Development of Novel Lightweight Dual-Phase Al-Ti-Cr-Mn-V Medium-Entropy Alloys with High Strength and Ductility

Entropy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 74
Author(s):  
Yu-Chin Liao ◽  
Po-Sung Chen ◽  
Chao-Hsiu Li ◽  
Pei-Hua Tsai ◽  
Jason Jang ◽  
...  
Keyword(s):  
Compression Strength ◽  
High Strength ◽  
Alloy System ◽  
Dual Phase ◽  
Face Centered Cubic ◽  
Compression Tests ◽  
Arc Melting ◽  
Face Centered ◽  
Fcc Phase ◽  
Strength And Ductility

A novel lightweight Al-Ti-Cr-Mn-V medium-entropy alloy (MEA) system was developed using a nonequiatiomic approach and alloys were produced through arc melting and drop casting. These alloys comprised a body-centered cubic (BCC) and face-centered cubic (FCC) dual phase with a density of approximately 4.5 g/cm3. However, the fraction of the BCC phase and morphology of the FCC phase can be controlled by incorporating other elements. The results of compression tests indicated that these Al-Ti-Cr-Mn-V alloys exhibited a prominent compression strength (~1940 MPa) and ductility (~30%). Moreover, homogenized samples maintained a high compression strength of 1900 MPa and similar ductility (30%). Due to the high specific compressive strength (0.433 GPa·g/cm3) and excellent combination of strength and ductility, the cast lightweight Al-Ti-Cr-Mn-V MEAs are a promising alloy system for application in transportation and energy industries.

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.

scholarly journals Effect of Mn Addition on the Microstructures and Mechanical Properties of CoCrFeNiPd High Entropy Alloy

Entropy ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 288
Author(s):  
Yiming Tan ◽  
Jinshan Li ◽  
Jun Wang ◽  
Hongchao Kou
Keyword(s):  
Intermetallic Compound ◽  
Interface Energy ◽  
High Entropy Alloy ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
Liquid Interfaces ◽  
High Entropy ◽  
Single Face ◽  
Face Centered ◽  
Fcc Phase

CoCrFeNiPdMnx (x = 0, 0.2, 0.4, 0.6, 0.8) high entropy alloys (HEAs) were prepared and characterized. With an increase in Mn addition, the microstructures changed from dendrites (CoCrFeNiPd with a single face-centered-cubic (FCC) phase) to divorced eutectics (CoCrFeNiPdMn0.2 and CoCrFeNiPdMn0.4), to hypoeutectic microstructures (CoCrFeNiPdMn0.6), and finally to seaweed eutectic dendrites (CoCrFeNiPdMn0.8). The addition of Mn might change the interface energy anisotropy of both the FCC/liquid and MnPd-rich intermetallic compound/liquid interfaces, thus forming the seaweed eutectic dendrites. The hardness of the FCC phase was found to be highly related to the solute strengthening effect, the formation of nanotwins and the transition from CoCrFeNiPd-rich to CoCrFeNi-rich FCC phase. Hierarchical nanotwins were found in the MnPd-rich intermetallic compound and a decrease in either the spacing of primary twins or secondary twins led to an increase in hardness. The designing rules of EHEAs were discussed and the pseudo binary method was revised accordingly.

Finite-size scaling and power law relations for dipole-quadrupole interaction on Blume-Emery-Griffiths model

Open Physics ◽  
2011 ◽  
Vol 9 (3) ◽  
Author(s):  
Aycan Özkan ◽  
Bülent Kutlu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Critical Exponent ◽  
Quadrupole Interaction ◽  
Order Parameter ◽  
Finite Size ◽  
Face Centered Cubic ◽  
Finite Size Scaling ◽  
Fcc Lattice ◽  
Face Centered

AbstractThe Blume-Emery-Griffiths model with the dipole-quadrupole interaction ($$ \ell = \frac{I} {J} $$) has been simulated using a cellular automaton algorithm improved from the Creutz cellular automaton (CCA) on the face centered cubic (fcc) lattice. The finite-size scaling relations and the power laws of the order parameter (M) and the susceptibility (χ) are proposed for the dipole-quadrupole interaction (ℓ). The dipole-quadrupole critical exponent δχ has been estimated from the data of the order parameter (M) and the susceptibility (χ). The simulations have been done in the interval $$ 0 \leqslant \ell = \frac{I} {J}0 \leqslant 0.01 $$ for $$ d = \frac{D} {J} = 0,k = \frac{K} {J} = 0 $$ and $$ h = \frac{H} {J} = 0 $$ parameter values on a face centered cubic (fcc) lattice with periodic boundary conditions. The results indicate that the effect of the ℓ parameter is similar to the external magnetic field (h). The critical exponent δℓ are in good agreement with the universal value (δh = 5) of the external magnetic field.

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.

Nearly Dislocation-Free APB Termination at Pure Grain Boundary Step Defects in L10 Alloys

1993 ◽  
Vol 319 ◽  
Author(s):  
Abha Singh ◽  
A.H. King
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Tetragonal Phase ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Antiphase Boundaries ◽  
New Type ◽  
Face Centered ◽  
Fcc Phase ◽  
Step Defect

AbstractL10 alloys typically derive from a high-temperature, disordered fcc phase. For example, CuAu has a face centered tetragonal structure below 380°C and is derived from its high temperature, disordered face centered cubic phase. As the material transforms from the disordered fcc phase to the ordered tetragonal phase, the four distinct Σ3 fcc twin misorientations generate twelve distinct tetragonal twin misorientations, four being characterized as Σ3 and eight as Σ6. Of particular interest is the Σ6 structure because it is possible to terminate lattice antiphase boundaries without dislocations at this interface. A pure step defect at the interface can accommodate the APB termination due to anti-site coincidence (coincidence between copper and gold sites). We term these defects “antiphase steps”. The antiphase step is a new type of interfacial defect that has not been described by other workers. The possibility of forming antiphase steps in ordered L10 alloys is related to even-Σ interfaces. Since the Σ6 boundary is common in the ordered phase, the formation of dislocation-free APB terminations may be important in L10 alloys.

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].

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