Synthesis of niobium aluminides using mechanically activated self-propagating high-temperature synthesis and mechanically activated annealing process

Gauthier, V.; Josse, Claudie; Bernard, Frédéric; Gaffet, Éric; Larpin, J.P.

doi:10.1016/s0921-5093(98)01141-1

Cited by 81 publications

(37 citation statements)

References 15 publications

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“…[1][2][3] Three intermetallic compounds are present in the Nb-Al binary system including Nb 3 Al (A15 structure), Nb 2 Al (D8b structure) and NbAl 3 (DO22 structure, TiAl 3 type). [4][5][6][7] Among the various compounds in the Nb-Al system (Figure 1), NbAl 3 with its high melting point (1680°C), low density (4.54 g/cm 3 ), is attractive as a potential material for high-temperature applications. 6,8 The applications of NbAl 3 include its use in turbine blades in aircraft engines or in stationary gas turbines.…”

Section: Introductionmentioning

confidence: 99%

Effect of holding time on the production of Nb-NbAl3 intermetallic composites via electric-current-activated sintering

Aybey¹,

Yener²,

İpek³

et al. 2017

Mater. Tehnol.

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A recently developed powder metallurgy processing technique -Electric Current Activated (Assisted) Sintering (ECAS) was employed to produce intermetallic Nb-NbAl3 composites. In this study, to produce Nb-NbAl3 in-situ intermetallic composites, Nb (99.8 % purity, less than 44 μm) and Al (99.5 % purity, less than 44 μm) elemental powders were mixed in the stoichiometric ratio corresponding to the Nb-Al phase diagram. The effect of different processing times, for (10, 30, 60) s, under maximum of 2000 A and 1.5-2.0 V, was investigated. Scanning electron microscopy and X-ray diffraction analysis were used to characterize the produced samples. X-ray diffraction studies revealed that the dominant phases are NbAl3 and Nb. Scanning electron microscopy examinations showed a dense microstructure with a very low amount of porosity and also a trace amount of residual aluminium. The microhardness of the test materials sintered for 60 s via electric-current-activated sintering was about 405 HV±46 HV0,05. Keywords: in situ composites, NbAl 3 aluminides, electric current activated sintering (ECAS) Pred kratkim razvita tehnika v metalurgiji prahov: sintranje, aktivirano z elektri~nim tokom (ECAS), je bilo uporabljeno za in situ izdelavo intermetalnega kompozita Nb-NbAl3. V {tudiji sta bila za in situ proizvodnjo Nb-NbAl3 intermetalnega kompozita zme{ana elementna prahova Nb (99.8 %~istost, delci manj{i od 44 μm) in Al (99.5 %~istost, delci manj{i od 44 μm), zme{ana v stehiometri~nem razmerju, skladno s faznim diagramom Nb-Al. Preiskovan je bil vpliv razli~nih~asov izdelave: (10, 30, 60) s pri toku maksimalno 2000 A in napetosti 1,5-2,0 V. Izdelani vzorci so bili karakterizirani z vrsti~no elektronsko mikroskopijo in rentgensko difrakcijo. Rentgenska difrakcija je odkrila, da sta prevladujo~i fazi NbAl3 in Nb. Vrsti~na elektronska mikroskopija je pokazala gosto mikrostrukturo z majhnim dele`em poroznosti in sledovi preostalega aluminija. Mikrotrdota preizkusnega materiala, sintranega 60 s, s sintranjem aktiviranim z elektri~nim tokom, je bila okrog 405 HV±46 HV0,05. Klju~ne besede: in situ kompoziti, NbAl3 aluminidi, sintranje aktivirano z elektri~nim tokom (ECAS)

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Section: Introductionmentioning

confidence: 99%

Effect of holding time on the production of Nb-NbAl3 intermetallic composites via electric-current-activated sintering

Aybey¹,

Yener²,

İpek³

et al. 2017

Mater. Tehnol.

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“…In particular, Nb 3 Al is recognized as excellent source for future superconducting multifilamentary conductors at magnetic fields of much higher than 25 T, under extreme mechanical and irradiation conditions, because of low upper critical field (H C2 ) values of 21 T at 4.2 K, low critical temperatures (T c ), and high critical current density (J c ) in low fields of \14 T [3,4]. Therefore, Nb 3 Al intermetallics are possibly applied for turbine blades in aircraft engines and stationary gas turbines, perhaps for nuclear magnetic resonance and nuclear magnetic imaging magnets [5][6][7][8][9]. However, it has the lack of deformability and brittle, which leads to fracture and low ductility at room temperature and makes it machine difficultly [10].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Nb3Al powder by chemical reaction in molten salts

Wang

Huang²,

Zhang

et al. 2015

Rare Met.

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Nb 3 Al nanoparticles were directly synthesized by metallothermic reduction process in the molten salts with mNbCl 5 -nAlCl 3 powders as raw materials and sodium as reducing reagent. The effects of different feeding material orders, soaking time, Nb content in raw materials, and 3NbCl 5 -AlCl 3 content in molten salts on the obtained Nb 3 Al powder were discussed. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It is found that the only phase Nb 3 Al nanoparticles are obtained by controlling the variation of the feeding material orders, soaking time, and Nb content in raw materials. And the morphologies of as-prepared nanoparticles change owning to different 3NbCl 5 -AlCl 3 contents in molten salts.

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“…14,15) The sintering temperature of high-energy mechanically milled powder is lower than that of unmilled powder due to the increased reactivity, internal and surface energies, and surface area of the milled powder, which contribute to its so-called mechanical activation. [16][17][18] The grain size in sintered materials becomes much larger than that in pre-sintered powders due to rapid grain growth during a conventional sintering process. Therefore, controlling grain growth during sintering is one of the keys to the commercial success of nanostructured materials.…”

Section: Introdutionmentioning

confidence: 99%

Simultaneous Synthesis and Consolidation of Nanostructured MoSi2-NbSi2 Composite by High-Frequency Induction Heated Sintering and Its Mechanical Properties

Kang¹,

Shon²

2014

Korean. J. Mater. Res.

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The current concern about these materials (MoSi 2 and NbSi 2 ) focuses on their low fracture toughness below the ductile-brittle transition temperature. To improve the mechanical properties of these materials, the fabrication of nanostructured and composite materials has been found to be effective. Nanomaterials frequently possess high strength, high hardness, excellent ductility and toughness, and more attention is being paid to their potential application. In this study, nanopowders of Mo, Nb, and Si were fabricated by high-energy ball milling. A dense nanostructured MoSi 2 -NbSi 2 composite was simultaneously synthesized and sintered within two minutes by high-frequency induction heating method using mechanically activated powders of Mo, Nb, and Si. The high-density MoSi 2 -NbSi 2 composite was produced under simultaneous application of 80MPa pressure and an induced current. The sintering behavior, mechanical properties, and microstructure of the composite were investigated. The average hardness and fracture toughness values obtained were 1180 kg/mm 2 and 3 MPa·m 1/2 , respectively. These fracture toughness and hardness values of the nanostructured MoSi 2 -NbSi 2 composite are higher than those of monolithic MoSi 2 or NbSi 2 .

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Synthesis of niobium aluminides using mechanically activated self-propagating high-temperature synthesis and mechanically activated annealing process

Cited by 81 publications

References 15 publications

Effect of holding time on the production of Nb-NbAl3 intermetallic composites via electric-current-activated sintering

Effect of holding time on the production of Nb-NbAl3 intermetallic composites via electric-current-activated sintering

Preparation of Nb3Al powder by chemical reaction in molten salts

Simultaneous Synthesis and Consolidation of Nanostructured MoSi2-NbSi2 Composite by High-Frequency Induction Heated Sintering and Its Mechanical Properties

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