Site-occupation tendencies for ternary additions (Fe, Co, Ni) in β-phase transition-metal aluminides

1995 ◽  
Vol 51 (13) ◽  
pp. 8102-8106 ◽  
Author(s):  
Mahalingam Balasubramanian ◽  
Douglas M. Pease ◽  
Joseph I. Budnick ◽  
Tariq Manzur ◽  
Dale L. Brewe
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Site Occupation ◽  
Β Phase ◽  
Ternary Additions ◽  
Metal Aluminides

Local environment of transition metal ternary dopants in β phase transition metal aluminides

1995 ◽  
Vol 208-209 ◽  
pp. 493-494
Author(s):  
M. Balasubramanian ◽  
D.M. Pease ◽  
J.I. Budnick ◽  
T. Manzur ◽  
D.L. Brewe
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Local Environment ◽  
Β Phase ◽  
Metal Aluminides

Novel modification of anhydrous transition metal oxalates from powder diffraction

2017 ◽  
Vol 73 (11) ◽  
pp. 911-916 ◽  
Author(s):  
Anna N. Puzan ◽  
Vyacheslav N. Baumer ◽  
Pavel V. Mateychenko
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Crystal Structures ◽  
Powder Diffraction ◽  
Crystal Packing ◽  
Space Group ◽  
One Dimensional ◽  
Β Phase ◽  
Metal Oxalate ◽  
Diffraction Patterns

The known metal–C2O4 structures may be divided into two modifications, α and β. The α-modification has an order–disorder struxture, revealing one-dimensional disordering of the metal–oxalate chains, and the β-modification is ordered. The crystal structures of orthorhombic γ-MnC2O4 {poly[μ-oxalato-manganese(II)]; space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) Å, V = 378.19 (1) Å3, Z = 4 and Dx = 2.511 Mg m−3} and γ-CdC2O4 {poly[μ-oxalato-cadmium(II)]; space group Pmna, a = 7.3218 (1), b = 6.0231 (1), c = 9.2546 (2) Å, V = 408.13 (1) Å3, Z = 4 and Dx = 3.262 Mg m−3} have been obtained from powder diffraction patterns. The structures are isostructural. Each metal atom in each structure is coordinated by seven O atoms which belong to five oxalate ions. The crystal packing, which contains noticeable cavities in the [101] and [001] directions, is not close packed and essentially differs from the known disordered α- and ordered β-modifications of transition metal oxalates. This modification seems to be metastable. It was found that a spontaneous γ→β phase transition takes place for γ-CdC2O4.

Electron energy loss near edge structures of intermetallic alloys and grain boundaries in NiAl

1996 ◽  
Vol 54 ◽  
pp. 522-523
Author(s):  
G.A. Botton ◽  
C.J. Humphreys
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Energy Loss ◽  
Grain Boundaries ◽  
Industrial Applications ◽  
Edge Structure ◽  
Structural Applications ◽  
Yield Behaviour ◽  
Late Transition ◽  
Metal Aluminides

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.

scholarly journals Strain Induced Phase Transition of WS2 by Local Dewetting of Au/Mica Film upon Annealing

Surfaces ◽  
2020 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Tomasz Kosmala ◽  
Pawel Palczynski ◽  
Matteo Amati ◽  
Luca Gregoratti ◽  
Hikmet Sezen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Thermal Annealing ◽  
Tensile Strain ◽  
Structural Phase ◽  
Transition Metal Dichalcogenides ◽  
Proof Of Concept ◽  
Threshold Strain ◽  
Metal Dichalcogenides ◽  
Phase Engineering

Here, we present a proof-of-concept experiment where phase engineering at the nanoscale of 2D transition metal dichalcogenides (TMDC) flakes (from semiconducting 2H phase to metallic 1T phase) can be achieved by thermal annealing of a TMDC/Au/mica system. The local dewetting of Au particles and resulting tensile strain produced on the TMDC flakes, strongly bound to the Au surface through effective S-Au bonds, can induce a local structural phase transition. An important role is also played by the defects induced by the thermal annealing: when vacancies are present, the threshold strain needed to trigger the phase transition is significantly reduced. Scanning photoelectron microscopy (SPEM) was revealed to be the perfect tool to monitor the described phenomena.

scholarly journals First-principle investigations of structural and electronic properties of TMAl (TM = Fe, Co, and Ni) transition metal aluminides

2015 ◽  
Vol 33 (2) ◽  
pp. 251-258
Author(s):  
Bendouma Doumi ◽  
Allel Mokaddem ◽  
Mustapha Ishak-Boushaki ◽  
Miloud Boutaleb ◽  
Abdelkader Tadjer
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Density Functional ◽  
First Principle ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Plane Wave Method ◽  
Structural And Electronic Properties ◽  
The Difference ◽  
Metal Aluminides

AbstractIn the present work, we have investigated the structural and electronic properties of TMAl (TM = Fe, Co, and Ni) transition metal aluminides in the B2 structure, using first-principle calculations of the density functional theory (DFT) based on the linearized augmented plane wave method (FP-LAPW) as implemented in the WIEN2k code, in which the energy of exchange and correlation are treated by the generalized gradient approximation (GGA), proposed in 1996 by Perdew, Burke and Ernzerhof (PBE). The ground state properties have been calculated and compared with other calculations, and the electronic structures of all FeAl, CoAl, and NiAl compounds exhibited a metallic behavior. It was depicted that the density of states is characterized by the large hybridization between the s-p (Al) and 3d (Fe, Co, and Ni) states, which creates the pseudogap in the region of anti-bonding states. Moreover, the band structures of FeAl, CoAl, and NiAl are similar to each other and the difference between them is in the energy level of each band relative to the Fermi level.

First principles site occupation and migration of hydrogen, helium, and oxygen in β-phase erbium hydride

2008 ◽  
Vol 103 (12) ◽  
pp. 123708 ◽  
Author(s):  
R. R. Wixom ◽  
J. F. Browning ◽  
C. S. Snow ◽  
P. A. Schultz ◽  
D. R. Jennison
Keyword(s):  
First Principles ◽  
Site Occupation ◽  
Β Phase ◽  
And Migration

Heat Capacity in α-β Phase Transition of Quartz

1985 ◽  
Vol 54 (2) ◽  
pp. 625-629 ◽  
Author(s):  
Masahide Matsuura ◽  
Haruhiko Yao ◽  
Kazutoshi Gouhara ◽  
Ichiro Hatta ◽  
Norio Kato
Keyword(s):  
Phase Transition ◽  
Heat Capacity ◽  
Β Phase

Photodecomposition of gas-phase transition metal carbonyl anions

1974 ◽  
Vol 96 (12) ◽  
pp. 3816-3820 ◽  
Author(s):  
Robert C. Dunbar ◽  
Bennett B. Hutchinson
Keyword(s):  
Phase Transition ◽  
Transition Metal ◽  
Gas Phase ◽  
Metal Carbonyl
Sign in / Sign up

Export Citation Format

Share Document