Interatomic bonding, elastic properties, and ideal strength of transition metal aluminides: A case study forAl3(V,Ti)

2005 ◽  
Vol 71 (2) ◽  
Author(s):  
M. Jahnátek ◽  
M. Krajčí ◽  
J. Hafner
Keyword(s):  
Transition Metal ◽  
Elastic Properties ◽  
Ideal Strength ◽  
Metal Aluminides ◽  
Interatomic Bonding

Ab-Initio Study of Mechanical Properties of Transition-Metal Aluminides: A Case Study for Al3(V,Ti)

2005 ◽  
Vol 482 ◽  
pp. 139-142
Author(s):  
M. Jahnátek ◽  
M. Krajčí ◽  
J. Hafner
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Tensile Deformation ◽  
Uniaxial Tensile ◽  
Ideal Strength ◽  
Maximal Stress ◽  
Metal Aluminides ◽  
Interatomic Bonding ◽  
The Ideal

On the basis of ab-initio density-functional calculations we have analyzed the character of interatomic bonding in the intermetallic compounds Al3(V,Ti) with the D022 and L12 structures. In all structures we found an enhanced charge density along the Al-(V,Ti) bonds, a characteristic feature of covalent bonding. The bond strength is quantitatively examined by tensile deformations. The ideal strength of Al3V and Al3Ti under uniaxial tensile deformation was found to be significantly higher than that of both fcc Al and bcc V. We investigated also the changes of the interatomic bonding in Al3V during tensile deformations. We found that the covalent interplanar Al- V bonds disappear before reaching the maximal stress. The weakening of the bonding between the atomic planes during the deformation is accompanied by a strengthening of in-plane bonding and an enhanced covalent character of the intraplanar bonds. Interplanar bonding becomes more metallic under tensile deformation.

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.

Tuning Transition Metal Carbides Activity by Surface Metal Alloying: Case Study on CO2 Capture and Activation

2018 ◽  
Author(s):  
Marti Lopez ◽  
Luke Broderick ◽  
John J Carey ◽  
Francesc Vines ◽  
Michael Nolan ◽  
...  
Keyword(s):  
Transition Metal ◽  
Co2 Capture ◽  
Density Functional ◽  
Deep Understanding ◽  
Metal Carbides ◽  
Transition Metal Carbides ◽  
Adsorption Sites ◽  
Surface Metal ◽  
A Minor

<div>CO2 is one of the main actors in the greenhouse effect and its removal from the atmosphere is becoming an urgent need. Thus, CO2 capture and storage (CCS) and CO2 capture and usage (CCU) technologies are intensively investigated as technologies to decrease the concentration</div><div>of atmospheric CO2. Both CCS and CCU require appropriate materials to adsorb/release and adsorb/activate CO2, respectively. Recently, it has been theoretically and experimentally shown that transition metal carbides (TMC) are able to capture, store, and activate CO2. To further improve the adsorption capacity of these materials, a deep understanding of the atomic level processes involved is essential. In the present work, we theoretically investigate the possible effects of surface metal doping of these TMCs by taking TiC as a textbook case and Cr, Hf, Mo, Nb, Ta, V, W, and Zr as dopants. Using periodic slab models with large</div><div>supercells and state-of-the-art density functional theory based calculations we show that CO2 adsorption is enhanced by doping with metals down a group but worsened along the d series. Adsorption sites, dispersion and coverage appear to play a minor, secondary constant effect. The dopant-induced adsorption enhancement is highly biased by the charge rearrangement at the surface. In all cases, CO2 activation is found but doping can shift the desorption temperature by up to 135 K.</div>

scholarly journals Predicting the Effect of Dopants on CO2 Adsorption in Transition Metal Carbides: Case Study on TiC (001)

2020 ◽  
Vol 124 (29) ◽  
pp. 15969-15976 ◽  
Author(s):  
Martí López ◽  
Francesc Viñes ◽  
Michael Nolan ◽  
Francesc Illas
Keyword(s):  
Transition Metal ◽  
Co2 Adsorption ◽  
Metal Carbides ◽  
Transition Metal Carbides

scholarly journals Conspicuous interatomic bonding in chalcogenide crystals and implications on electronic, optical, and elastic properties

AIP Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 075216 ◽  
Author(s):  
Sahib Hasan ◽  
Puja Adhikari ◽  
Khagendra Baral ◽  
Wai-Yim Ching
Keyword(s):  
Elastic Properties ◽  
Interatomic Bonding

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.

Do Transition Metal Carbonates Have Greater Lithium Storage Capability Than Oxides? A Case Study of Monodisperse CoCO3 and CoO Microspindles

2014 ◽  
Vol 6 (15) ◽  
pp. 12346-12352 ◽  
Author(s):  
Lianbang Wang ◽  
Weijie Tang ◽  
Yu Jing ◽  
Liwei Su ◽  
Zhen Zhou
Keyword(s):  
Transition Metal ◽  
Lithium Storage ◽  
Metal Carbonates
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