Microstructure and phase stability of single crystal NiAl alloyed with Hf and Zr

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National Aeronautics and Space Administration, National Technical Information Service, distributor , [Washington, D.C, Springfield, Va
Microstructure., Single crystals., Nickel alloys., Aluminum alloys., Hafnium alloys., Phase stability (Materials), Directional solidification (Crys
StatementI.E. Locci ... [et al.].
SeriesNASA-TM -- 112766., NASA technical memorandum -- 112766.
ContributionsLocci, I. E., United States. National Aeronautics and Space Administration.
The Physical Object
FormatMicroform
Pagination1 v.
ID Numbers
Open LibraryOL15543055M

Microstructure and phase stability of single crystal NiAI mold that also contained Si as one of the mold additives. The resultant Si content in the system III alloy (Table I) turned out to be similar to that measured in alloys processed by the Bridgman melt processing technique.

Moreover, the starting Hf stock material used in the. Six near stoichiometric, NiAl single-crystal alloys, with at.% of Hf and Zr additions plus Si impurities, were microstructurally analyzed in the as-cast, homogenized, and aged conditions.

In other alloys, long-term aging resulted in the formation of the NiXSi phase. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging.

If the ratio is low, then the NiHfSi phase appears to be the stable phase. Get this from a library. Microstructure and phase stability of single crystal NiAl alloyed with Hf and Zr. [Ivan E Locci; United States. National Aeronautics and Space Administration.;].

In other alloys, long-term aging resulted in the formation of the NiXSi phase. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging.

A systematic study of microstructure evolution, phase stability, and mechanical properties in NiAl alloys containing Zr and Si was conducted. The study was based on the premise that fine, stable second phase precipitates in NiAl should increase its otherwise very poor creep : Yongjin Lim. Two experimental single crystal superalloys, the Ru-free alloy and the Ru-containing alloy with [] orientation, were cast in a directionally solidified furnace, while other alloying element contents were kept unchanged.

The effects of Ru on the microstructure and phase stability of the single crystal superalloy were investigated. γ′ directional coarsening and rafting were observed in the Cited by: The morphology, crystal structure and orientation relationship (O.R.) of the silicide phase in a NiAl ( at.

%Hf) single-crystal alloy have been determined using transmission electron microscopy, electron microdiffraction and energy dispersive X-ray by: An NiAl–Cr(Mo) alloy modified with Hf was fabricated by vacuum induction, melted and drop cast and then was hot isostatically pressed (HIPed) at K, MPa for h.

The alloy was mainly composed of NiAl matrix, Cr(Mo) and Hf-rich phase distributed on the NiAl and Cr(Mo) phase by: The microstructure, fracture toughness and tensile properties at °C as well as tensile creep in the temperature range – °C were studied.

The alloy is composed of NiAl, Cr(Mo) and Hf-rich phase and the NiAl and Cr(Mo) interface is not smooth and by: Minor Hf additions in NiAI single crystals result in the precipitation of one or more of the three phases, a Gphase (Nil6Hf6SiT), a Heusler phase (Ni2AIHf) and a NiHfSi phase [6, 8, 9,10].

Two of. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging. The previous research indicates that the Al x -Hf-Nb-Ta-Ti-Zr HEA system exhibits a single BCC crystal structure with the x value in the range of 0 to 1 [50].

As shown in Fig. 5a, the yield stress. The γ -phase is the principal strengthening phase [27] in turbine single-crystal materials and also of FCC structure. The γ/γ -phase composition is shown in the Scanning Electron Microscope.

The microstructure of as-cast NiAlCrZr alloy is the eutectic colonies of NiAl and Cr phase with non-continuous Heusler (Ni2AlZr) phase segregating at the cell boundaries. After hot isostatic press (HIP) processing at K, MPa for 2h, the Ni2AlZr phase changes into Zr-rich phase. The elevated temperature tensile strength and elongation of the HIP-ed alloy are much higher than Author: Yi Hui Qi, Jian Ting Guo.

However, state-of-the-art single-crystal NiAl alloys lack the balance of properties available in conventional superalloys. In particular, no single alloy has both high-temperature creep resistance, and adequate ductility and toughness.

Additionally, due to the higher melting temperature of the NiAl alloys. Compression properties of a refractory multi-component alloy, Ta 20 Nb 20 Hf 20 Zr 20 Ti 20, were determined in the temperature range of – K and strain rate range of 10 −1 –10 −5 s − properties were correlated with the microstructure developed during compression by: The literature contains detailed descriptions of the microstructures of the NiAl–Cr–Mo eutectic alloys with a high content of Cr and Mo (up to 28 and 6 at.%, respectively).

Thus, according to Ref. the as-cast NiAl–28Cr–5Mo–Hf alloy contains the NiAl, Cr(Mo) phases, and the Heusler phase (Ni 2 AlHf). The authors also reported that the Author: M. Khomutov, P. Potapkin, V.

Details Microstructure and phase stability of single crystal NiAl alloyed with Hf and Zr PDF

Cheverikin, P. Petrovskiy, A. Travyanov, I. Logachev, A. Sova, I. Smuro. The morphology and crystallography of phases in the Cu % Zr alloy were investigated by scanning electron microscope (SEM), transmission electron microscope (TEM), and high-resolution transmission electron microscope (HRTEM).

The results show that the as-cast microstructure of Cu–Zr alloy is mainly Cu matrix and eutectic structure which consist of Cu and Cu5Zr phases with Cited by: 7.

The microstructure of alloy F as shown in Fig. 3 a and b, consists of primary B2 dendrites as it is depicted by the EDS analysis shown in Table 2, Cr is dissolved in about at.% into the primary B2 phase. A white Cr, Mo rich phase around the primary NiAl phase and finally a eutectic microstructure are : C.

Mathiou, K. Giorspyros, E. Georgatis, A. Karantzalis. Significant progress has been made in the understanding of solidification conditions, microstructure evolution, and defect formation during investment casting of NiAl single crystals.

The high liquidus temperatures of NiAl alloys result in a larger dendrite arm spacing than is found in superalloy René by: Although the compositions of strong NiAl single crystals are relatively simple, the microstructures are complex and vary with the heat treatment and with small ingot-to- ingot variations in the alloy chemistry (ref.

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In addition, initial testing (ref. The microstructure and mechanical property of directionally solidified NiAl-Cr(Mo)-Hf/Ho alloy were studied. The results indicate that the alloy is composed of NiAl matrix and Cr(Mo) phase, the dispersion of Hf is identical with the NiAl matrix, and at the cell boundary, the dispersion of Ho is disperse.

As the pull speed increase from 8mm/min to 15mm/min, the size of eutectic cell decreases Author: Ping Han, Yi Hui Qi, Juan Meng, Jian Ting Guo. Classification and microstructural stability of high generation single crystal nickel-based superalloys the alloy microstructure starts to evolve and raft.

Description Microstructure and phase stability of single crystal NiAl alloyed with Hf and Zr EPUB

It was reported that rafting Chemical composition of single crystal nickel-based superalloys classified from the first to sixth generation [1, 35]File Size: KB. Nowadays, for the advanced cast single crystal superalloys in the turbine blades, the alloy capability exceeds 1,ºC. In this chapter, the polycrystalline Ni superalloys, which have slightly less temperature capability up to °C, applied in the turbine discs and the adjoined shafts, will be introduced focusing on their microstructures Cited by: 8.

A NiAl intermetallic alloy and article is provided with improved high temperature strength, particularly stress rupture strength, through the generation of a multiphase microstructure comprising a beta matrix and at least one precipitate phase.

The strength properties and microstructure are the result of alloying with at least two elements selected from Ga, Hf, and optionally Ti, Zr, Ta, Nb Cited by: mechanik 2/ microstructure and corrosion resistance of hf-modified nial layers on nickel based superalloy ni-cr-co-mo-2tial mikrostruktura i odpornoŚĆ korozyjna warstw nial modyfikowanych hf naniesionych na nadstopach ni-cr-co-mo-2ti-1,5al małgorzata zagÓrska 1, ryszard sitek1, janusz kamiŃski1, hubert matysiak2, krzysztof jan kurzydŁowski1.

The NiAl/Cr (Mo,Dy) hypoeutectic alloy was fabricated by rapid solidification. The microstructure and mechanical properties as well as tribological properties for the alloy at different temperatures were investigated. The results revealed that the rapidly solidified NiAl/Cr (Mo,Dy) hypoeutectic alloy was composed of primary NiAl, fine NiAl/Cr (Mo) eutectic lamella, Ni5Dy phase and Cr7Ni3 Cited by: 3.

3](Al,Ti) single crystals using magnetic technique p. 79 Microstructures in cold-rolled Ni[subscript 3]Al single crystals p. 85 Crystal structure, phase stability and plastic deformation behavior of Ti-rich Ni[subscript 3](Ti,Nb) single crystals with various long-period ordered structures p.

microstructure of a Nb-Zr-C alloy containing wt % Zr and wt % C were studied. Chemical analysis, metallographic examination, energy dispersive x-ray spectra of the bulk material, and chemical and x-ray analyses of the phase-extracted residue were used to characterize the microstructure.

The. Zr-containing superalloys, a Ni-lOCo-8Cr-4WZr (wt.%) alloy was selected as an interlayer alloy for brazing and transient-liquid-phase (TLP) bonding of single crystal superalloys.

All the elements in the interlayer alloy are beneficial to the single crystal suneralloys. Using the above.Abstract: Ni54Mn25Ga21 alloy was prepared to investigate the microstructure, martensitic transformation and high-temperature shape-memory effect. Ni54Mn25Ga21 alloy exhibits single phase of non-modulated martensite with tetragonal structure at room temperature.Influence of Ru addition on microstructure and stress-rupture property of Ni-based single crystal superalloys Jing-yang CHEN1, Qiang FENG1, 2, La-mei CAO3, Zu-qing SUN1 1.

State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing.