scholarly journals The Effects of Mo and Nb on the Microstructures and Properties of CrFeCoNi(Nb,Mo) Alloys

Entropy ◽  
2018 ◽  
Vol 20 (9) ◽  
pp. 648 ◽  
Author(s):  
Chun-Huei Tsau ◽  
Meng-Chi Tsai
Keyword(s):  
Volume Fraction ◽  
Eutectic Structure ◽  
Close Packing ◽  
304 Stainless Steel ◽  
Hexagonal Close Packing ◽  
Face Centered Cubic ◽  
Simple Cubic ◽  
Corrosion Behaviors ◽  
Dendritic Microstructures ◽  
Face Centered

The effects of niobium and molybdenum additions on the microstructures, hardness and corrosion behaviors of CrFeCoNi(Nb,Mo) alloys were investigated. All of the CrFeCoNi(Nb,Mo) alloys displayed dendritic microstructures. The dendrites of CrFeCoNiNb and CrFeCoNiNb0.5Mo0.5 alloys were a hexagonal close packing (HCP) phase and the interdendrites were a eutectic structure of HCP and face-centered cubic (FCC) phases. Additionally, the dendrites of CrFeCoNiMo alloys were a simple cubic (SC) phase and the interdendrites were a eutectic structure of SC and FCC phases. The volume fraction of dendrites and interdendrites in these alloys were calculated. The influences of the volume fraction of dendrite in the alloys on the overall hardness were also discussed. The CrFeCoNiNb alloy had the larger volume fraction of dendrite and thus had the highest hardness among these alloys. The CrFeCoNi(Nb,Mo) alloys also showed better corrosion resistances in 1 M H2SO4 and 1 M NaCl solutions by comparing with commercial 304 stainless steel. The CrFeCoNiNb0.5Mo0.5 alloy possessed the best corrosion resistances in these solutions among the CrFeCoNi(Nb,Mo) alloys.

Electromagnetic Thermal Energy Transfer in Nanoparticle Assemblies Below Diffraction Limit

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Anil Yuksel ◽  
Edward T. Yu ◽  
Michael Cullinan ◽  
Jayathi Murthy
Keyword(s):  
Three Dimensional ◽  
Close Packing ◽  
Face Centered Cubic ◽  
Copper Nanoparticle ◽  
Colloidal Solutions ◽  
Plasmonic Coupling ◽  
Nanoparticle Assemblies ◽  
Enhanced Absorption ◽  
Face Centered ◽  
Insight Into

Abstract Fabrication of micro- and nanoscale electronic components has become increasingly demanding due to device and interconnect scaling combined with advanced packaging and assembly for electronic, aerospace, and medical applications. Recent advances in additive manufacturing have made it possible to fabricate microscale, 3D interconnect structures but heat transfer during the fabrication process is one of the most important phenomena influencing the reliable manufacturing of these interconnect structures. In this study, optical absorption and scattering by three-dimensional (3D) nanoparticle packings are investigated to gain insight into micro/nano heat transport within the nanoparticles. Because drying of colloidal solutions creates different configurations of nanoparticles, the plasmonic coupling in three different copper nanoparticle packing configurations was investigated: simple cubic (SC), face-centered cubic (FCC), and hexagonal close packing (HCP). Single-scatter albedo (ω) was analyzed as a function of nanoparticle size, packing density, and configuration to assess effect for thermo-optical properties and plasmonic coupling of the Cu nanoparticles within the nanoparticle packings. This analysis provides insight into plasmonically enhanced absorption in copper nanoparticle particles and its consequences for laser heating of nanoparticle assemblies.

scholarly journals Pressure-Induced Dimerization of C60 at Room Temperature as Revealed by an In Situ Spectroscopy Study Using an Infrared Laser

Crystals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 182 ◽  
Author(s):  
Bing Li ◽  
Jinbo Zhang ◽  
Zhipeng Yan ◽  
Meina Feng ◽  
Zhenhai Yu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Infrared Laser ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Simple Cubic ◽  
Excitation Laser ◽  
Face Centered ◽  
830 Nm Laser ◽  
Structure Evaluation

Using in situ high-pressure Raman spectroscopy and X-ray diffraction, the polymerization and structure evaluation of C60 were studied up to 16 GPa at room temperature. The use of an 830 nm laser successfully eliminated the photo-polymerization of C60, which has interfered with the pressure effect in previous studies when a laser with a shorter wavelength was used as excitation. It was found that face-centered cubic (fcc) structured C60 transformed into simple cubic (sc) C60 due to the hint of free rotation for the C60 at 0.3 GPa. The pressure-induced dimerization of C60 was found to occur at about 3.2 GPa at room temperature. Our results suggest the benefit and importance of the choice of the infrared laser as the excitation laser.

Zero-Point Effects in Heisenberg Antiferromagnets with Arbitrary Range of Interaction

1972 ◽  
Vol 50 (23) ◽  
pp. 2991-2996 ◽  
Author(s):  
M. F. Collins ◽  
V. K. Tondon
Keyword(s):  
Ground State ◽  
State Energy ◽  
Correction Term ◽  
Zero Point ◽  
Face Centered Cubic ◽  
Heisenberg Antiferromagnet ◽  
Body Centered Cubic ◽  
Cubic Lattices ◽  
Simple Cubic ◽  
Face Centered

The ground state energy, spin-wave energy, and sublattice magnetization have been calculated for a Heisenberg antiferromagnet at the absolute zero of temperature. The treatment extends the earlier work of Anderson, Kubo, and Oguchi to apply for any two-sublattice antiferromagnet with arbitrary range of interaction. It is shown that for each exchange interaction there is a different characteristic correction term to the energies. Explicit calculations are made of these terms for the simple cubic, body-centered cubic, and face-centered cubic lattices, with both first- and second-neighbor interactions. Applications are also made to NiO and MnO. An extra term in the magnetization series beyond that given by earlier workers is derived.

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.

Enhancement Of Power Factor In A Thermoelectric Composite With A Periodic Microstructure

2000 ◽  
Vol 626 ◽  
Author(s):  
Leonid G. Fel ◽  
Yakov M. Strelniker ◽  
David J. Bergman
Keyword(s):  
Thermoelectric Power ◽  
Power Factor ◽  
The Other ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
High Quality ◽  
Thermoelectric Power Factor ◽  
Simple Cubic ◽  
Periodic Microstructures ◽  
Face Centered

ABSTRACTThe thermoelectric power factor has been calculated for a two-constituent composite medium, where one constituent is a “high quality thermoelectric” while the other constituent is a “benign metal”, with large electrical and thermal conductivities but poor thermoelectric properties. It was recently discovered that, in such a mixture, the power factor could be greatly enhanced by an appropriate choice of microstructure. Here we report on a study of three periodic microstructures with cubic point symmetry under rotations: simple cubic (SC), body centered cubic (BCC), and face centered cubic (FCC) arrays of identical spheres of the benign metal embedded in the high quality thermoelectric host. We show detailed results for these microstructures in the case where the benign metal constituent is Copper, while the high quality thermoelectric constituent is the thermoelectric alloy (Bi2Te3)0.2 (Sb2Te3)0.8.

Comparison of Deformation Microtwins in Planar and Cylindrical Explosive Loaded Type 304 Stainless Steel

1969 ◽  
Vol 27 ◽  
pp. 196-197 ◽  
Author(s):  
J. V. Foltz ◽  
L. E. Murr
Keyword(s):  
Shock Wave ◽  
Considerable Change ◽  
Impulsive Loading ◽  
304 Stainless Steel ◽  
Face Centered Cubic ◽  
Planar Shock ◽  
The Face ◽  
Geometrical Constraints ◽  
Planar Shock Wave ◽  
Face Centered

It is well known that the passage of a planar shock wave through a metallic solid causes in general a considerable change in the microstructure of the crystalline matrix and a corresponding change in the residual mechanical properties of the material. For example, a number of investigators have confirmed the presence of deformation faults with a pronounced twin character in the face centered cubic metals deformed under planar shock wave loading conditions. For the purpose of studies of shock induced defects, experiments are usually designed so that geometrical constraints prevent lateral flow of the specimen during shock loading. Such a deformation is termed one-dimensional strain. It is of interest to investigate the nature of the defects generated in a metal under impulsive loading for a geometry other than uniaxial strain.

On the new structural phases in Al65Cu20Cr15 quasicrystalline alloy

1995 ◽  
Vol 10 (8) ◽  
pp. 1905-1912 ◽  
Author(s):  
Varsha Khare ◽  
N.P. Lalla ◽  
R.S. Tiwari ◽  
O.N. Srivastava
Keyword(s):  
Metastable Phase ◽  
Structural Characteristics ◽  
Icosahedral Phase ◽  
Cubic Phase ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Structural Variants ◽  
Simple Cubic ◽  
Face Centered ◽  
Specific Orientation

The quasicrystalline (qc) alloy Al65Cu20Cr15, unlike its Ru- and Fe-bearing counterparts like Al65Cu20Ru15 and Al65Cu20Fe15, is a metastable phase. This qc alloy has been shown to possess several structural variants and curious structural characteristics. We have investigated the qc alloy Al65Cu20Cr15 with special reference to the possible occurrence of new structural variants. TEM exploration of the as-quenched qc alloy has indeed revealed the existence of several new phases. These are (i) body-centered cubic (bcc) (a = 12.60 Å, disordered) and simple cubic (s.c.) (a = 12.60 Å, ordered), which are the 1/1 approximants of the primitive icosahedral phase (i phase); (ii) a twice order-induced modulated cubic phase (bcc, a = 25.20 Å) which has been shown to correspond to 1/1 approximant of the ordered i phase [i.e., face-centered icosahedral (FCI)]; and (iii) real crystalline bcc (a = 8.90 Å) and face-centered cubic (fcc) (a = 17.98 Å) phases possessing a specific orientation relationship with the icosahedral matrix phase. Tentative structural models showing the interrelationships between the bcc/fcc phases have been outlined.

A TEM study of the microstructures formed during the crystallization of Ni–Zr metallic glasses

1991 ◽  
Vol 6 (4) ◽  
pp. 755-759 ◽  
Author(s):  
R. Allem ◽  
G. L'Espérance ◽  
Z. Altounian ◽  
J.O. Ström-Olsen
Keyword(s):  
Metallic Glasses ◽  
Crystallization Process ◽  
Early Stage ◽  
Face Centered Cubic ◽  
Simple Cubic ◽  
Transmission Electron ◽  
The Face ◽  
Face Centered ◽  
Two Phases ◽  
Average Size

The microstructure of two metastable crystalline phases, which are formed during the first step of the crystallization process in Ni–Zr metallic glasses, was investigated by transmission electron microscopy. For the composition Ni33Zr67, crystallites with average size of 150 nm having the face-centered cubic E93 structure are formed. For the Ni42Zr58 composition, 100 nm size crystallites with a simple cubic unit cell, space group Pa3 are formed. The microstructure of the crystallites in the early stage of crystallization of the two phases is similar to globular morphology and internal striations.

Thermal Energy Transport Below the Diffraction Limit in Close-Packed Metal Nanoparticles

2017 ◽  
Author(s):  
Anil Yuksel ◽  
Michael Cullinan ◽  
Jayathi Murthy
Keyword(s):  
Energy Transport ◽  
Three Dimensional ◽  
Close Packing ◽  
Face Centered Cubic ◽  
Copper Nanoparticle ◽  
Colloidal Solutions ◽  
Plasmonic Coupling ◽  
Enhanced Absorption ◽  
Face Centered ◽  
Insight Into

Fabrication of micro and nanoscale electronic components has become increasingly demanding due to device and interconnect scaling combined with advanced packaging and assembly for electronic, aerospace and medical applications. Recent advances in additive manufacturing have made it possible to fabricate microscale, 3D interconnect structures but heat transfer during the fabrication process is one of the most important phenomena influencing the reliable manufacturing of these interconnect structures. In this study, optical absorption and scattering by three-dimensional (3D) nanoparticle packings are investigated to gain insight into micro/nano heat transport within the nanoparticles. Because drying of colloidal solutions creates different configurations of nanoparticles, the plasmonic coupling in three different copper nanoparticle packing configurations were investigated: simple cubic (SC), face-centered cubic (FCC) and hexagonal close packing (HCP). Single-scatter albedo (ω) was analyzed as a function of nanoparticle size, packing density, and configuration to assess effect for thermo-optical properties and plasmonic coupling of the Cu nanoparticles within the nanoparticle packings. This analysis provides insight into plasmonically enhanced absorption in copper nanoparticle particles and its consequences for laser heating of nanoparticle assemblies.

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