Vapor phase dealloying-driven synthesis of bulk nanoporous cobalt with a face-centered cubic structure

CrystEngComm ◽  
2021 ◽  
Author(s):  
Yujun Shi ◽  
Yu Wang ◽  
Wanfeng Yang ◽  
Jingyu Qin ◽  
Qingguo Bai ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Vapor Phase ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Cubic Structure ◽  
Hcp Structure ◽  
Face Centered ◽  
Fcc Structure

Cobalt (Co) mainly exists in two allotropic forms: a low temperature hexagonal close-packed (HCP) structure and a high temperature face centered cubic (FCC) structure. However, annealing at high temperature only...

Formation of Face Centered Cubic Titanium Thin Films on MgO(111) Single Crystal Substrate

2018 ◽  
Vol 913 ◽  
pp. 264-269
Author(s):  
Lei Li ◽  
Yan Liu ◽  
Xiao Nan Mao ◽  
Vincent Ji
Keyword(s):  
Single Crystal ◽  
Single Crystal Substrate ◽  
Temperature Phase ◽  
Face Centered Cubic ◽  
Hexagonal Close Packed ◽  
Crystal Substrate ◽  
Cubic Structure ◽  
Hcp Structure ◽  
Face Centered ◽  
Ti Films

High strength, low density, and excellent corrosion resistance are the main properties that make titanium attractive for a variety of applications. The phase structures and phase transitions of titanium, which are of tremendous scientific and technological interest, have attracted a great deal of attention for many years. In addition to hexagonal close packed α-Ti, high temperature phase β-Ti with body-centered cubic structure and ω-Ti with the hexagonal structure of high-pressure phase, the face-centered cubic structure, which is not in the P-T diagram of titanium, is observed in ultrathin films. In the present paper, the Ti films prepared by magnetron sputtering on MgO(111) single crystal substrate were investigated by means of X-Ray Diffraction (XRD) and High-Resolution Transmission Electron Microscope (HRTEM). The results showed that the Ti films grow epitaxial with a face centered cubic (fcc) structure even the thickness is up to about 50nm. With the thickness increases, the Ti films transformed to hexagonal close packed (hcp) structure and showed an epitaxial growth along (002)hcp-Ti direction. The results show that the onset thickness of fcc-hcp structure transformation is 50-100nm. The temperature and power of sputter affect the formation of fcc-Ti.

NICROFER 5923 HMo-ALLOY 59

Alloy Digest ◽  
1993 ◽  
Vol 42 (5) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
Face Centered Cubic ◽  
Low Carbon ◽  
High Alloy ◽  
Temperature Performance ◽  
Cubic Structure ◽  
Face Centered

Abstract NICROFER 5923 hMo, often called Alloy 59, was developed with extra low carbon and silicon contents and with a high alloy level of molybdenum to optimize its corrosion resistance. Nicrofer 5923hMo has a face-centered cubic structure. This datasheet provides information on composition, physical properties, elasticity, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and joining. Filing Code: Ni-430. Producer or source: VDM Technologies Corporation.

scholarly journals Microstructure Refinement by Low-Temperature Ausforming in an Fe-Based Metastable High-Entropy Alloy

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 742
Author(s):  
Motomichi Koyama ◽  
Takeaki Gondo ◽  
Kaneaki Tsuzaki
Keyword(s):  
Low Temperature ◽  
Plastic Anisotropy ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Microstructure Refinement ◽  
Hexagonal Close Packed ◽  
Solution Treated Condition ◽  
Solution Treated ◽  
Face Centered

The effects of ausforming in an Fe30Mn10Cr10Co high-entropy alloy on the microstructure, hardness, and plastic anisotropy were investigated. The alloy showed a dual-phase microstructure consisting of face-centered cubic (FCC) austenite and hexagonal close-packed (HCP) martensite in the as-solution-treated condition, and the finish temperature for the reverse transformation was below 200 °C. Therefore, low-temperature ausforming at 200 °C was achieved, which resulted in microstructure refinement and significantly increased the hardness. Furthermore, plasticity anisotropy, a common problem in HCP structures, was suppressed by the ausforming treatment. This, in turn, reduced the scatter of the hardness.

Structure of Self-Assembled Fe and FePt Nanoparticle Arrays

2000 ◽  
Vol 636 ◽  
Author(s):  
S. Yamamuro ◽  
D. Farrell ◽  
K. D. Humfeld ◽  
S. A. Majetich
Keyword(s):  
Phase Contrast ◽  
Face Centered Cubic ◽  
Nanoparticle Arrays ◽  
Hexagonal Close Packed ◽  
Transmission Electron ◽  
Self Assembled ◽  
Hcp Structure ◽  
Face Centered ◽  
Contrast Image ◽  
Image Simulations

AbstractArrays were self-assembled by evaporating suspensions of 4 nm FePt or 8 nm Fe nanoparticles. The monolayers had a hexagonal close packed (hcp) structure, but the multilayer structure varied. To identify the multilayer structures, transmission electron microscopy (TEM) images were compared with phase contrast image simulations. The results showed that Fe could be grown as both hcp and face-centered cubic (fcc), or fcc-like, structures. The results of image analysis of the FePt arrays were consistent with fcc structures.

The Bismuth-Barium Oxides

1998 ◽  
Vol 547 ◽  
Author(s):  
K. Müller ◽  
J.K. Meen ◽  
D. Elthon
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Low Temperature ◽  
Phase Relations ◽  
The Other ◽  
Face Centered Cubic ◽  
Polymorphic Transformations ◽  
Face Centered ◽  
T Phase

AbstractPhase relations have been determined for the Bi-Ba oxide pseudobinary up to 50 cat % Ba in 1 atm of oxygen at 640°-1000°C. The low-temperature α-Bi2O3 polymorph does not dissolve appreciable BaO. All other phases in the system have significant ranges of solution. The δ-Bi2O3 polymorph, stable from 730°C to 825°C is an end-member of a face-centered cubic solid solution (FCCss) that dissolves up to 2.7 % Ba. Ba-saturated FCCss and Bi-saturated rhombohedral (ß) solid solution (6.3 % Ba) melt at a eutectic at 753 °C. Less Bi is needed to saturate the ß phase at lower temperatures so α-Bi2O3 coexists with a ß phase containing 11.5 % Ba at 646°C.The amount of Ba required to saturate the ß phase depends less strongly on temperature. Ba-saturated ß phase contains 19 % Ba at 700°C. These ß materials are in equilibrium with an oxide near Bi3BaO5.5 that undergoes two polymorphic transformations: low-temperature cubic (<700°C); orthorhombic (700-730°C); high-temperature cubic (Cht). There is a eutectic between the ß and Cht, at 775±6°C. At T<700°C, 26.5 % Ba saturates the latter but it can take in up to 29.5 % Ba (at 812°C). At T<815°C the coexisting phase is BiBaO3. A tetragonal (T) phase forms by reaction of Ch, and BiBaO3 and has ~35% BaO at 815°C. The composition span of T widens as temperature increases. Cht, melts incongruently at 820°C to a liquid and T with 29.8 % Ba. Above that temperature the Bi-saturated and Ba-saturated T phases both become more Ba-rich as temperature is elevated. T melts incongruently to liquid and BiBaO3.The δ-Bi2O3 and ß, both anion conductors, have structures based on that of fluorite. The other oxides have perovskite-like structures. Half of the Bi in BiBaO3 is pentavalent and half is trivalent. The other oxides appear to have all their Bi in the 3+ state.

Optical Properties of Three-Dimensional Photonic Crystal with Face-Centered-Cubic Structure

2013 ◽  
Vol 821-822 ◽  
pp. 622-625 ◽  
Author(s):  
Hong Bo Zhang ◽  
Xiao Yan Liu ◽  
Wei Dong Yu
Keyword(s):  
Optical Properties ◽  
Photonic Crystal ◽  
Incident Angle ◽  
Three Dimensional ◽  
Structural Color ◽  
Face Centered Cubic ◽  
Microsphere Size ◽  
Cubic Structure ◽  
Face Centered ◽  
Fcc Structure

Based on transfer matrix method (TMM), the model and calculation of 3-D Photonic Crystal with Face-Centered-Cubic (FCC) Structure are presented. The microsphere size, the crystal stack thickness and the incident angle have an influence on optical properties of 3-D Photonic Crystal. With the microsphere size increasing, the wavelength corresponding to the positions of PBG becomes larger causing structural color changing from blue to red. The reflectivity becomes higher and PBG is narrower when the crystal stack thickness increases. With the incident angle becoming larger, the reflectivity does not change significantly, while the wavelength corresponding to the positions of PBG becomes shorter causing structural color changing from red to blue.

Microstructure of Liquid Co50Ni50 During Rapid Solidification

2020 ◽  
Vol 20 (12) ◽  
pp. 7593-7600 ◽  
Author(s):  
Min Li ◽  
Quan Xie ◽  
Shan Li
Keyword(s):  
Rapid Solidification ◽  
Cluster Structure ◽  
Solidification Process ◽  
Face Centered Cubic ◽  
Index Method ◽  
Bond Type ◽  
Bcc Structure ◽  
Hcp Structure ◽  
Face Centered ◽  
Fcc Structure

The rapid solidification process of Co50Ni50 alloy was simulated by molecular dynamics method, and the formation and evolution characteristics of cluster structure in the solidification process were analyzed by the pair distribution function, Honeycutt–Andersen bond type index method and the largest standard cluster. The results show that during the solidification process with a cooling rate of 1×1012 K·‐1, the probability of mutual bond formation between Co–Co atoms is always greater than that of Ni–Ni, and the formation of the 1421 bond type is dominant in the crystalline structure. The inflection point of the characteristic bond type 1421 varies with the crystalline transition temperature Tg of the system. The Co–Ni alloy is mainly composed of a face-centered cubic atomic group composed of the 1421 bond type. Meanwhile, there will also be a small amount of hcp structure and a smaller amount of bcc structure. Further analysis revealed that the formation of the fcc structure requires the fast decomposition of TCP structures (at 1450 K). That is to say, the TCP structure must be disassembled before the fcc structure is formed. These findings are useful to provide important guidance for the crystallization of Co50Ni50 alloy under rapid cooling in the experiment.

Deformation Mechanisms of Nanocrystalline Hexagonal Close-Packed Metals

2006 ◽  
Vol 924 ◽  
Author(s):  
Guangping Zheng
Keyword(s):  
Deformation Twinning ◽  
Dynamics Simulation ◽  
Deformation Mechanisms ◽  
Face Centered Cubic ◽  
Transformation Mechanism ◽  
Shockley Partial Dislocation ◽  
Hexagonal Close Packed ◽  
Simulation Results ◽  
Face Centered ◽  
Fcc Structure

ABSTRACTUsing molecular dynamics simulation of nanocrystalline (nc) samples with grain size of 10 nm, a reverse martensitic transformation from hexagonal close-packed (hcp) to face-centered cubic (fcc) structure is observed in nc-cobalt and nc-zirconium undergoing plastic deformation. In nc-cobalt hcp-to-fcc transformation is prevalent and deformation twinning is rarely observed. The transformation mechanism involves the motion of Shockley partial dislocation 1/3<1100> in every other (0001)hcp /(111)fcc plane. In nc-zirconium the hcp-to-fcc transformation competes with the deformation twinning. From the simulation results, it is suggested that the interaction among partials should be considered to understand the deformation mechanisms of hcp nc metals.

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