An overview of monolithic titanium aluminides based on Ti3Al and TiAl

Djanarthany, S.; Viala, J.C.; Bouix, J.

doi:10.1016/s0254-0584(01)00328-5

Cited by 254 publications

(103 citation statements)

References 70 publications

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“…[5][6][7] The mechanism of oxidation of Ti-Al is a fundamental and important issue for this kind of practical application. [8][9][10][11] It is reported that there is a large difference between the formation energies of two metals with oxygen in some binary intermetallics, [12,13] and the metal with larger formation energy will be oxidized first and segregate to the surface even at low oxygen pressures and low temperatures. The other one with smaller formation energy will only be oxidized when the temperature is high enough in the oxygen atmosphere.…”

Section: Introductionmentioning

confidence: 99%

First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface

Wei

Guo

Dai

et al. 2016

Surface & Interface Analysis

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a Adsorption energies and density of states for O atoms adsorption on the Ti 3 Al (0001) surface have been calculated using first-principles calculations based on density functional theory. It is found that the order of O atom adsorption on the Ti 3 Al (0001) surface is associated with the adsorption energy as well as the distance of O atoms because of the interaction. The adsorption energy mainly depends on the bond number and bond strength between O and Ti atoms, and the adsorption site with rich-Ti surface (H I and HCP Al ) is first priority. The adsorption energy decreases with the increase of the oxygen coverage because of the characteristics of the valence d-orbitals of transition metals surface. Furthermore, the density of states indicates that the hybridization peak of O and Ti atoms is mainly from the contribution of Ti 3d-and O 2p-orbitals, and the hybridization peak of O and Al atoms from the contribution of Al 2p-and O 2p-orbitals.

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Section: Introductionmentioning

confidence: 99%

First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface

Wei

Guo

Dai

et al. 2016

Surface & Interface Analysis

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“…[1] The TiAl-based alloys have several advantages over the conventional titanium alloys, such as higher elasticity modulus, lower density, better mechanical properties at elevated temperatures, and higher oxidation resistance due to the formation of a surface-passivated alumina layer. [2] The intermetallic-matrix composites (IMCs) reinforced with ceramic particles generally possess an even higher specific strength and specific stiffness, increased creep strength, improved toughness, and hightemperature strength retention. [3,4] Discontinuously reinforced intermetallic-matrix composites have been produced by a variety of techniques, most of which rely on a powder processing route, including mechanical alloying and a combustionreaction synthesis or reactive sintering technique, cryomilling, reactive hot isostatic pressing, and exothermic dispersion (XD) synthesis.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of carbide-particle-reinforced titanium aluminide-matrix composites by laser-engineered net shaping

Liu

DuPont

2004

Metall Mater Trans A

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TiAl-based titanium aluminide alloys and their composites reinforced with ceramic particles are considered to be important candidate materials for high-temperature structural applications. Laser-engineered net shaping (LENS) is a layered manufacturing process, which involves laser processing fine powders into three-dimensional components directly from a computer-aided design (CAD) model. In this work, the LENS process was employed to fabricate carbide-particle-reinforced titanium aluminide-matrix composites using TiC and gas-atomized Ti-48Al-2Cr-2Nb powders as the feedstock materials. The composites deposited by the LENS process were susceptible to solid-state cracking due to high thermal stresses. The microstructures of the laser-deposited monolithic and composite titanium aluminide materials were characterized using light optical microscopy (LOM), scanning electron microscopy (SEM), X-ray energy-dispersive spectroscopy (EDS) analysis, electron-probe microanalysis (EPMA), and X-ray diffraction (XRD) techniques. Effects of the LENS processing parameters on the cracking susceptibility and microstructure were studied. Crack-free deposits were fabricated by preheating the substrate to 450°C to 500°C during LENS processing. The fabricated composite deposits exhibit a hardness of more than twice the value of the Ti-6Al-4V alloy.

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“…Figure 2b shows, at higher magnification, such an area that appears to be only lamellar. This figure also shows that different grains could be identified by the orientation of their lamellae (areas [3][4][5].…”

Section: Microstructural Characterisation Of Alloys and Hardnessmentioning

confidence: 99%

Effect of platinum group metal addition on microstructure and corrosion behaviour of Ti–47·5 at-%Al

Mwamba¹,

Cornish²,

Lingen³

2013

Corrosion Engineering, Science and Technology

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Plain and alloyed titanium aluminides of composition Ti-47?5 at-%Al were prepared with the addition of 1?0 at-% platinum group metals (PGMs). The as cast alloys were subjected to potentiodynamic scans in 5, 15 and 25 wt-%HCl solutions at room temperature, and the PGM containing alloys were assessed for their abilities to spontaneously passivate by cathodic modification. Plain titanium aluminide had a duplex microstructure consisting of lamellar (a 2 and c alternating lamellae) and c-TiAl phase grains. The introduction of 1?0 at-%PGMs (platinum, palladium and iridium) led to the formation of a new phase, developing more in the c-TiAl phase grains and a general improvement of corrosion resistance by increasing the corrosion potential to nobler values. Platinum group metal additions to plain TiAl resulted in the corrosion potentials falling in the passive region of plain TiAl, indicating spontaneous passivation of PGM alloyed TiAl in 5 and 15 wt-%HCl solutions. In 25 wt-%HCl solution, the addition of PGMs shifted the cathodic process in the transpassive or active region of plain TiAl, resulting in either case in the dissolution of the alloy due to the absence of an extended passivation region. The cathodic modification of PGM alloyed TiAl occurred as a result of PGM accumulation on the surface of the TiAl alloys, which simultaneously improved the hydrogen evolution efficiency and inhibited anodic dissolution.

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An overview of monolithic titanium aluminides based on Ti3Al and TiAl

Cited by 254 publications

References 70 publications

First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface

First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface

Fabrication of carbide-particle-reinforced titanium aluminide-matrix composites by laser-engineered net shaping

Effect of platinum group metal addition on microstructure and corrosion behaviour of Ti–47·5 at-%Al

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An overview of monolithic titanium aluminides based on Ti3Al and TiAl

Cited by 254 publications

References 70 publications

First‐principles calculations of oxygen adsorption on the Ti3Al (0001) surface

First‐principles calculations of oxygen adsorption on the Ti3Al (0001) surface

Fabrication of carbide-particle-reinforced titanium aluminide-matrix composites by laser-engineered net shaping

Effect of platinum group metal addition on microstructure and corrosion behaviour of Ti–47·5 at-%Al

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First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface

First‐principles calculations of oxygen adsorption on the Ti₃Al (0001) surface