Theory and Practice of γ + α2 Ti Aluminide: A Review

Gupta, Rohit; Pant, Bhanu; Sinha, P. P.

doi:10.1007/s12666-013-0334-y

Cited by 40 publications

(13 citation statements)

References 216 publications

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“…%) alloy, which is currently used by General Electric for low-pressure turbine blades [3,4]. While TiAl alloys possess high strength, their poor ductility and brittleness at room temperatures severely complicate their processability by conventional manufacturing techniques and limit their application [5]. Casting followed by hot isostatic pressing (HIP) has been used to conventionally fabricate TiAl alloy parts [6]; however, this approach has its limitations in terms of high cost and design flexibility.…”

Section: Introductionmentioning

confidence: 99%

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

et al. 2020

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In this paper, laser powder-bed fusion (L-PBF) additive manufacturing (AM) with a high-temperature inductive platform preheating was used to fabricate intermetallic TiAl-alloy samples. The gas atomized (GA) and mechanically alloyed plasma spheroidized (MAPS) powders of the Ti-48Al-2Cr-2Nb (at. %) alloy were used as the feedstock material. The effects of L-PBF process parameters—platform preheating temperature—on the relative density, microstructure, phase composition, and mechanical properties of printed material were evaluated. Crack-free intermetallic samples with a high relative density of 99.9% were fabricated using 900 °C preheating temperature. Scanning electron microscopy and X-Ray diffraction analyses revealed a very fine microstructure consisting of lamellar α2/γ colonies, equiaxed γ grains, and retained β phase. Compressive tests showed superior properties of AM material as compared to the conventional TiAl-alloy. However, increased oxygen content was detected in MAPS powder compared to GA powder (~1.1 wt. % and ~0.1 wt. %, respectively), which resulted in lower compressive strength and strain, but higher microhardness compared to the samples produced from GA powder.

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Section: Introductionmentioning

confidence: 99%

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

et al. 2020

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“…Fe [25] substitutes for both sites, Co [15][16][17]19,20] and Cu [24] mostly for the Ni-site, and Hf [15][16][17], Ta [15][16][17], Ti [15][16][17]26,27], V [28], and W [29,30] mostly for the Nb-site. The ternary systems with Al [15][16][17], with Cr [21][22][23], and with Si [15][16][17] did not provide clear indications of the substitution behavior in Ni 3 Nb because of very small solid solubilities.…”

Section: Reported Workmentioning

confidence: 99%

“…Al [31][32][33][34][35] and Cr [37] substitute for both sites, Co [36], Cu [24,32,39], Fe [40], Ir [41], Mn [42], and Re [46,47] mostly for the Ni-site and Mo [32,42,43], and Nb [44,45] mostly for the Ta-site.…”

Section: Reported Workmentioning

confidence: 99%

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Substitution Behavior of Ni₃X-type Compounds with D0a Structure

2011

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The site preference of ternary additions in GCP (geometrically close-packed) Ni 3 X-type compounds with D0a structure was determined from the direction of the single-phase region of the D0a phase in the reported ternary phase diagrams. The thermodynamic model based on the Bragg-Williams approximation, which is based on the change in heat of formation of the host compound by a small addition of ternary solute, was applied to predict the site preference of ternary additions. The heat of formation used in the thermodynamic calculation was derived from Miedema's formula. Good agreement was obtained between the thermodynamic model and the result of the literature search.

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“…These properties meet the demands of next-generation aircraft and automotive engines. The main obstacles that limit commercial applications of TiAl alloys are their inherently brittle nature, low fluidity and high processing cost6. Nevertheless, the casting process provides a method with advantages for the manufacture of TiAl alloys when compared to forging and rolling7.…”

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confidence: 99%

Microstructure formation and interface characteristics of directionally solidified TiAl-Si alloys in alumina crucibles with a new Y2O3 skull-aided technology

Fan

Liu

et al. 2017

Sci Rep

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The microstructure evolution and interface characteristics of a directionally solidified Ti-43Al-3Si (at.%) alloy in an alumina (Al2O3) crucible with new Y2O3 skull-aided technology were investigated. The Y2O3-skull that is in contact with the TiAl-melt is relatively stable, which results in a more controlled reaction between the skull and the melt than in the case of an Al2O3 crucible is used. A thin reaction layer was formed between the mould and the melt through mutual diffusion. The layer thickness increased with increasing reaction time. The thickness of this layer was less than 80 μm for reaction times up to 5800 s. Y2O3 particles were not found in the specimen because the mould coating was prepared with fine Y2O3 powder without a binder, which prevented the Y2O3 particles splitting from the coating as a consequence of thermal physical erosion. The oxygen content of the TiAl-alloy increased with increasing reaction time. The total oxygen content of the solidified specimen was less than that of the specimen solidified in the Al2O3 crucibles. This new Y2O3 skull-aided technology is expected to improve the surface quality of TiAl-alloys and reduce the reaction between the crucible/mould and molten TiAl alloys during directional solidification processing with longer contact times.

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Theory and Practice of γ + α2 Ti Aluminide: A Review

Cited by 40 publications

References 216 publications

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

Substitution Behavior of Ni₃X-type Compounds with D0a Structure

Microstructure formation and interface characteristics of directionally solidified TiAl-Si alloys in alumina crucibles with a new Y2O3 skull-aided technology

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Theory and Practice of γ + α2 Ti Aluminide: A Review

Cited by 40 publications

References 216 publications

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

Additive Manufacturing of Ti-48Al-2Cr-2Nb Alloy Using Gas Atomized and Mechanically Alloyed Plasma Spheroidized Powders

Substitution Behavior of Ni3X-type Compounds with D0a Structure

Microstructure formation and interface characteristics of directionally solidified TiAl-Si alloys in alumina crucibles with a new Y2O3 skull-aided technology

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Product

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Substitution Behavior of Ni₃X-type Compounds with D0a Structure