US3677331A - Casting process for nickel base alloys - Google Patents

Casting process for nickel base alloys Download PDF

Info

Publication number
US3677331A
US3677331A US841408A US3677331DA US3677331A US 3677331 A US3677331 A US 3677331A US 841408 A US841408 A US 841408A US 3677331D A US3677331D A US 3677331DA US 3677331 A US3677331 A US 3677331A
Authority
US
United States
Prior art keywords
percent
alloy
cast
hafnium
castings
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US841408A
Other languages
English (en)
Inventor
Carl H Lund
John Hockin
Michael J Woulds
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Martin Marietta Corp
Original Assignee
Martin Marietta Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Martin Marietta Corp filed Critical Martin Marietta Corp
Application granted granted Critical
Publication of US3677331A publication Critical patent/US3677331A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C19/00—Alloys based on nickel or cobalt
    • C22C19/03—Alloys based on nickel or cobalt based on nickel
    • C22C19/05—Alloys based on nickel or cobalt based on nickel with chromium
    • C22C19/051—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W
    • C22C19/056—Alloys based on nickel or cobalt based on nickel with chromium and Mo or W with the maximum Cr content being at least 10% but less than 20%
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
    • B22D27/04—Influencing the temperature of the metal, e.g. by heating or cooling the mould
    • B22D27/045—Directionally solidified castings

Definitions

  • ABSTRACT m s Application n A casting process and castings produced thereby wherein a nickel-base, chrominum containing alloy which also contains comlnuailon-ln-pan of 725,074, P" 29, sufficient amounts of aluminum and titanium to produce eu- 1968 abafldonedtectic gamma-prime phase in the alloy as cast is caused to contain about 0.5 percent to about 5 percent hafnium, is cast into [52] U.S. Cl. 164/122, 75/171 final configuration and is cooled from the molten state rapidly [51] Int. Cl ..B22d 27/04 through the range of 2,200 to 1,850 F.
  • FIG.6 FIG.7
  • the present invention is concerned with a process of casting and, more particularly, with a process of casting and the cast products produced thereby.
  • ln alloys of the kind employed to produce castings useful in hot-stage, gas turbine engine service, freezing-induced segregation is a severe problem.
  • such alloys contain a major amount of nickel, much smaller amounts of chromium, cobalt, aluminum and titanium, small amounts of one or more of molybdenum, tungsten, columbium, vanadium, tantalum, till much smaller amounts of carbon and zirconium and usually a very small amount of boron.
  • the frozen alloy comprises a matrix phase, one or more carbide phases dispersed in said matrix phase a precipitate of gamma-prime and an intermetallic eutectic (Ni Al Ti) phase called eutectic gamma-prime phase also dispersed throughout the matrix in sufficient amount such that it forms directly on solidification of the alloy or in the temperature range immediately below freezing and is not readily fully solutionable in the solid matrix.
  • eutectic gamma-prime phase intermetallic eutectic (Ni Al Ti) phase
  • the particles of gamma-prime phase can differ in composition one from another and at one location is a given particle from another location in the same particle. Accordingly, although the alloys of the kind in question are inherently ofa segregated nature by virtue of their contained phases, additional segregation at freezing or in the temperature interval therebelow down to about l,850 F. can and does often occur. This segregation can be highly deleterious in that it can provide metallurgically unstable areas in the castings and further can cause or contribute to the occurrence of overly weak and overly brittle areas in the castings.
  • lt is a discovery of the present invention that, by means of a new casting process, novel cast objects can be produced having excellent mechanical characteristics both at l,800 F. and 1 ,400 F.
  • Another object of the present invention is to provide novel, highly useful cast objects by means of said novel casting process.
  • FIG. 1 is a series of graphs interrelating mechanical characteristics and relative cooling rates of castings through selected temperature ranges
  • FIGS. 2 to 13 comprise a series of reproductions of photomicrographs from various loci in sections of turbine blade castings.
  • the present invention contemplates a process wherein an alloy, having a nickel base and containing chromium and having in the solidified state a gamma matrix phase, a carbide phase dispersed in said matrix a gamma prime precipitate and an essentially non-solutionable, eutectic gamma-prime phase dispersed in said matrix, is caused to contain about 0.5 to about 5 percent by weight of hafnium; is cast from the molten state into a mold having essentially the final configuration of use of the object thus cast; and is caused to solidify in said mold at a rate tending to maximize mechanical characteristics as measured at l,800 F.
  • the melting, casting and solidification operations are carried out under high vacuum.
  • cast-to-size specimens represent the mechanical characteristics of only that portion of the cast item which is subject to the same cooling treatment as the specimen.
  • An actual cast item would exhibit a range of characteristics dependent upon the location from which a test specimen might be taken.
  • the relative sizeof the ranges of cooling rates which can be employed to give acceptable mechanical characteristics in castings. It is a major advantage of the process of the present invention that relatively wide ranges of cooling rates will produce acceptable mechanical characteristics at both l,800 F. and l,400 F.
  • castings produced by the process of the present invention will contain much greater amounts of alloy thermally conditioned to give good mechanical characteristics at both l,800 and l,400 F. than are present in castings produced by prior art processes.
  • FIG. 1 of the drawing A comparison of the process of the present invention and the processes of the prior art is shown in FIG. 1 of the drawing.
  • FIG. 1 A comparison of the process of the present invention and the processes of the prior art is shown in FIG. 1 of the drawing.
  • the data on which these graphs is based was obtained from a series of cast-to-size test bars made at various cooling rates spanning the range of cooling rates normally encountered in casting airfoil-shaped hot stage, gas turbine blades. Test bars representing relative cooling rates were tested for lift-to-rupture at 1,800" F. under a load of 29 k.s.i. and for percent prior creep(percentage of creep more than one hour prior to rupture) at 1,400" F. under a load of 94 lt.s.i.
  • the alloys employed to give data for both pairs of graphs were identical nickel-base alloys containing eutectic gamma-prime phase as cast except that, in accordance with the requirements of the present invention, the alloy employed to obtain the data for the lower graph was caused to contain about 1.5 percent hafnium.
  • Graphs B and D of FIG. 1 show that the stress-rupture lives at 1,800 F. of metal in castings is essentially unaffected by use of the precess of the present invention.
  • the cooling rate is slow through the range of 2,200 to l,850 F. the lift-to-rupture of cast metal at 1,800 F. under high stress is relatively poor.
  • the cooling rate is fast through this range, the lifeto-rupture is relatively good.
  • the minimum of an acceptable range of cooling rates is fixed by engineering judgment as to the minimum acceptable life-to-rupture at l,800 F. and is the same in both graphs.
  • thecurve is the same in both of graphs B and D except that the curve of graph D (derived from alloy specimens containing hafnium) is drawn more diffuse to indicate the possibility that the process of the present invention may narrow slightly the range of cooling rates which give good stress-rupture characteristics at l,800 F. This slight narrowing is of no real practical significance since practically obtainable cooling rates indicated by the cross hatched boxes in FIG. 1 are safely within the acceptable range of cooling rates.
  • the curve representing percent prior creep is another matter. In the instance of graph A (based on alloys devoid of hafnium), the curve representing percent prior creep shows a high percent priorcreep at a slow cooling rate through the range of 2,200 to 1,850 F. At very fast cooling rates the percent prior creep is very low and is unacceptable.
  • the maximum of the acceptable range of cooling rates is fixed by engineering judgement as to the minimum acceptable percent prior creep.
  • graph C derived from alloy specimens containing hafnium
  • the curve representing percent prior creep shows not only a higher value at very, slow cooling rates but also a difference in slope such that at very fast cooling rates the percent prior creep is still above an acceptable level.
  • the cross hatched boxes on graphs A and C show the range of cooling rates normally encountered in the cooling of gas turbine blade castings from 2,400 to 2,200 F. In the process of the invention this range of practical cooling rates is entirely within the acceptable range of cooling rates whereas, in prior art processes, the acceptable range of cooling rates barely abuts on the range of cooling rates encountered in practice.
  • the relative cooling rates have been expressed in dimensionless units which have been obtained from theoretically calculated, numerically identical, rates of cooling in degrees Fahrenheit per second. It is the intent of graphs A to D of FIG. 1 to show trends based on relative cooling rates rather than a prediction of specific results to be obtained for specific mechanical characteristics with specific cooling rates. For thisreason specific values of mechanical characteristics have not been used, but rather only linear scales have been indicated. Another factor which tends to prohibit use of FIG. I as a precise tool is the probability that, at any increment of time during the cooling of a casting, every point within the casting will be cooling at a different rate from almost any other point.
  • econd 7 25F .lsecond l2F./second 2200-l 850F. 5. 8F./
  • the castings of the present invention are characterized by substantial uniformity of basic metallographic structure across sections thereof even such sections as those cut transversely across an airfoil shape.
  • basic metallographic characteristics are intended to include the relationship of carbides and gamma-prime phase to the grain structure.
  • the particular form in which the gamma-prime phase occurs within the grain structure is not particularly uniform across a transverse blade section but this species of non-uniformity does not appear to be detrimental.
  • FIGS. 2 to 13 are photomicrographs in sets as tabulated in Table II.
  • the present invention comprises cast high temperature turbine engine hardware, such as turbine blades, vanes, integrally cast turbine wheels and nozzle guide vanes and, in general, castings having a plurality of loci adapted to cool after solidification at different rates through both of the temperature ranges of 2,400 to 2,200 F. and 2,200 to 1,850 F. made from a nickel-base, chromium-containing alloy having, in its original form, commercially acceptable strength and ductility characteristics, which alloy is modified by the inclusion of at least 0.5 percent to about 5 percent (by weight) of hafnium in the cast alloy composition.
  • cast high temperature turbine engine hardware such as turbine blades, vanes, integrally cast turbine wheels and nozzle guide vanes and, in general, castings having a plurality of loci adapted to cool after solidification at different rates through both of the temperature ranges of 2,400 to 2,200 F. and 2,200 to 1,850 F.
  • a nickel-base, chromium-containing alloy having, in its original form, commercially acceptable strength and ductility characteristics, which alloy is
  • hafnium can be included in the cast alloy as a substitute for an equal percent by weight of nickel, tantalum and, at times, other refractory elements.
  • hafnium in amounts of about 0.6 percent to about 1.8 percent, is substituted for equal percents by weight of tantalum when tantalum is present in the basic alloy being improved in accordance with the present invention.
  • hafnium when hafnium is substituted for elements such as tantalum in an alloy, it is likely that the strength characteristics of the basic alloy will not be significantly changed while, at the same time, the ductility of the alloy will be significantly enhanced.
  • hafnium When hafnium is substituted for alloying elements such as nickel, the ductility characteristics of the alloy will be significantly improved while, at the same time, it is possible that the strength characteristics of the base alloy will be improved. It is to be observed, however, that the inclusion of hafnium in a nickel-base alloy already extremely loaded with hardening elements and designed specifically for the highest strength levels at the highest temperatures without due regard for ductility will not necessarily raise the ductility to levels of generally acceptable commercial standards at trough temperatures.
  • the present invention is not a substitute for the exercise of reasonable metallurgical judgement in the balancing of alloy compositions to obtain a commercially viable compromise between strength and ductilit Iii the present invention, ductility deficiencies appear to be much more pronounced in castings made using revert, that is, previously remelted and cast alloy. lf test specimens, machined from turbine blades made from revert-containing heats are tested under creep inducing conditions at l,400 F it is possible that such tests will indicate the existence of practically no ductility if the casting is devoid of hafnium.
  • revert heats are modified to contain about 0.5 percent to about 2 percent hafnium, in accordance with the present invention, applicants have found that the revert-containing heats will provide hardware of a quality at least fully equivalent to the quality of hardware made from virgin heats.
  • hafnium has the ability to either combine with and effectively scavenge such impurities or to modify the metallurgical balance of the alloys in such a fashion so as to make the alloy less sensitive to the impurities.
  • applicants invention is, in part, the discovery that by treating revert heats to include small quantities of hafnium therein, the characteristics of castings made from such revert heats can be made to substantially equal, if not better, the characteristics of castings made from virgin heats of substantially the same alloy.
  • compositions set forth in Table 111 are nominal compositions and the percentage of each element present may be varied plus or minus about 10 percent of the amount specified.
  • the alloys can also contain up to about 2 percent (by weight) total of incidental elements such as manganese, silicon, iron, etc.
  • Non-metallics such as sulfur, oxygen and nitrogen and deleterious metallics such as lead, bismuth, arsenic, etc. are kept at as low a level possible consistent with good commercial practice.
  • all of the alloys in Table 111 and the alloys of the present invention are prepared by vacuum melting and casting, while under vacuum, into investment-casting molds having gas turbine engine hardware form.
  • hafnium or, advantageously, substitution of hafnium in amounts of about 0.5 percent to about 1.5 percent or even 5 percent by weight in balanced alloy compositions within the range set forth in Table IV enhances ductility of the castings particularly in the trough region about 1,400 F. without detrimentally affecting other important engineering characteristics of the alloys.
  • the hafnium addition is made to the alloy after deoxidation with no difficulty and, thereafter, the modified alloy is treated exactly as it would be if no modification has been made.
  • revert heats which are made with revert already containing hafnium, itis sometimes not necessary to add additional hafnium unless the aggregate composition of the heat or the processing technique lowers thehafnium content to below about 0.5 percent.
  • Alloys within the range set forth in Table IV can be balanced especially with regard to the elements tantalum and tungsten (when tungsten is present) by maintaining the tungsten content in excess of about 8 percent by weight and maintaining the total of tantalum plus tungsten below about 13 percent or even percent by weight. Also, advantageously, the alloys within the range set forth in Table IV are balanced such thatv the carbon content is, at most, approximately equal to the hafnium content in an atom-for-atom basis.
  • the present invention is more particularly concerned with castings having compositions as set forth (in weight percent) in Table V.
  • Alloys 1 and 2 set forth in Table V were melted and cast under vacuum to provide cast-to-size hardware and incidental specimens for chemical analysis. Comparative specimens were prepared from alloy series A and B which, except for hafnium, are essentially similar to Alloys 1 and 2, respectively.
  • Tables V1 and VII The ductility characteristics of castings made of revert-containing heats of Alloy B and similar alloys of the present invention containing hafnium are shown in Tables V1 and VII.
  • the data in Tables VI and VII were obtained ontest samples machined from cast turbine blades. The cast turbine blades were produced by casting alloy under vacuum into investment molds and causing said alloy to solidify in said molds under conditions tending to maximize mechanical characteristics at 1,800 F.
  • Table VI contains room temperature tensile data.
  • Table VII contains creep rupture data obtained at 1,400 F. under a load of 85k.s.i.
  • Table VI shows that constituin of hafnium in the composition of Alloy B clearly improves room temperature tensile elongation exhibited by specimens machined from blades made from revert-containing heats.
  • Table VIII sets forth the chemical compositions of some a1- loys from which castings of the present invention are made.
  • hafnium, hafnium master alloy or possibly by means of intermetallic hafnium compounds Unless already contained in metal being melted, the hafnium should be included in molten alloy at a time after the melt has been refined, as by a carbon boil, and essentially killed to avoid formation of excessive amounts of the very stable hafnium oxide.
  • compositions of other alloys from which advantageous castings of the invention are made are set forth in terms of percent by weight of Table IX.
  • Tables X and X1 contains creep data with respect to castings of heats of Alloy B which have been modified by inclusion of the various indicated amounts of hafnium therein and tested at l,400 F. The data in Table X was obtained on specimens machined from investment cast turbine blades cooled under conditions tending to maximize mechanical characteristics at TABLE X 1400F./94,000 psi Heat No. Wt.
  • Heat treatment comprises holding at 1800F. for 4 hours
  • Table X11 shows that for castings of Alloy F, the present invention is effective not only to increase tensile elongation but also to provide a casting which is less sensitive to the deleterious effects of a heat treatment, which heat treatment is often necessary as a portion of process for providing on the casting a protective coating against corrosion. Additional data indicates that castings of the present invention exhibit highly advantageous fracture toughness characteristics.
  • a casting process comprising casting an alloy having a nickel base and containing chromium at least about 6.5 percent total aluminum plus titanium, less than about 6 percent tantalum and about 0.5 percent to about 5 percent by weight of hafnium and having in the solidified state a gamma matrix phase. a precipitate of gamma-prime and a eutectic gammaprime phase and a carbide phase dispersed in said matrix from the molten state into a mold having essentially the final con-- figuration of use of the object thus cast, and causing said alloy to solidify and cool in said mold at a rapid rate through the range of about 2,200 to 1,850 F. to thereby induce in said casting a high proportion of metal thermally conditioned to exhibit good mechanical characteristics at both high temperatures about l,800 F. and at intermediate temperatures about 1,400 F.
  • a process as in claim 1 wherein thealloy in addition to hafnium contains in percent by weight about 0.2 percent to about 0.5 percent carbon, about 7 percent to about 15 percent chromium, up to about 35 percent cobalt, up to about 14 tungsten, up to about 8 percent molybdenum, about 0.5 percent to about 6 percent titanium, about 4 percent to about 7 percent aluminum, about 6.5 percent to about 10.5 percent aluminum plus titanium, up to about 0.3 percent boron, up to about 0.5 percent zirconium, up to about 3 percent columbium, up to about 1.5 percent vanadium, with the balance being essentially nickel in an amount of at least about 36 percent.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)
  • Forging (AREA)
US841408A 1969-07-14 1969-07-14 Casting process for nickel base alloys Expired - Lifetime US3677331A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US84140869A 1969-07-14 1969-07-14

Publications (1)

Publication Number Publication Date
US3677331A true US3677331A (en) 1972-07-18

Family

ID=25284811

Family Applications (1)

Application Number Title Priority Date Filing Date
US841408A Expired - Lifetime US3677331A (en) 1969-07-14 1969-07-14 Casting process for nickel base alloys

Country Status (8)

Country Link
US (1) US3677331A (ja)
BE (1) BE753418A (ja)
CA (1) CA924129A (ja)
CH (1) CH563821A5 (ja)
FR (1) FR2051733B1 (ja)
GB (1) GB1320005A (ja)
IL (1) IL34952A (ja)
SE (1) SE370343B (ja)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3807993A (en) * 1971-10-15 1974-04-30 Avco Corp Nickel base alloy containing hafnium
US5470371A (en) * 1992-03-12 1995-11-28 General Electric Company Dispersion strengthened alloy containing in-situ-formed dispersoids and articles and methods of manufacture
US20040177901A1 (en) * 2002-12-17 2004-09-16 Hitachi, Ltd. High-strength ni-base superalloy and gas turbine blades
US20040229072A1 (en) * 2002-12-16 2004-11-18 Murphy Kenneth S. Nickel base superalloy
US20060285974A1 (en) * 2005-06-16 2006-12-21 General Electric Company Turbine bucket tip cap
US20100028197A1 (en) * 2006-09-21 2010-02-04 Mark Heazle Nickel-based alloys and articles made therefrom

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2329755A1 (fr) * 1975-10-31 1977-05-27 Armines Alliage nickel-chrome-cobalt a l'aluminium et au titane pour pieces de forge
GB1562082A (en) * 1977-10-17 1980-03-05 Gen Electric Nickel-base olloys

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3005705A (en) * 1959-07-30 1961-10-24 Westinghouse Electric Corp High temperature alloys
US3129069A (en) * 1956-10-11 1964-04-14 Gen Motors Corp Oxidation-resistant turbine blades
US3260505A (en) * 1963-10-21 1966-07-12 United Aircraft Corp Gas turbine element
US3312449A (en) * 1964-06-29 1967-04-04 Trw Inc Turbine wheel
US3494709A (en) * 1965-05-27 1970-02-10 United Aircraft Corp Single crystal metallic part
US3526499A (en) * 1967-08-22 1970-09-01 Trw Inc Nickel base alloy having improved stress rupture properties
US3552479A (en) * 1967-11-22 1971-01-05 Martin Metals Co Casting process involving cooling of a shell mold prior to casting metal therein

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3129069A (en) * 1956-10-11 1964-04-14 Gen Motors Corp Oxidation-resistant turbine blades
US3005705A (en) * 1959-07-30 1961-10-24 Westinghouse Electric Corp High temperature alloys
US3260505A (en) * 1963-10-21 1966-07-12 United Aircraft Corp Gas turbine element
US3312449A (en) * 1964-06-29 1967-04-04 Trw Inc Turbine wheel
US3494709A (en) * 1965-05-27 1970-02-10 United Aircraft Corp Single crystal metallic part
US3526499A (en) * 1967-08-22 1970-09-01 Trw Inc Nickel base alloy having improved stress rupture properties
US3552479A (en) * 1967-11-22 1971-01-05 Martin Metals Co Casting process involving cooling of a shell mold prior to casting metal therein

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3807993A (en) * 1971-10-15 1974-04-30 Avco Corp Nickel base alloy containing hafnium
US5470371A (en) * 1992-03-12 1995-11-28 General Electric Company Dispersion strengthened alloy containing in-situ-formed dispersoids and articles and methods of manufacture
US20040229072A1 (en) * 2002-12-16 2004-11-18 Murphy Kenneth S. Nickel base superalloy
US20040177901A1 (en) * 2002-12-17 2004-09-16 Hitachi, Ltd. High-strength ni-base superalloy and gas turbine blades
US6818077B2 (en) * 2002-12-17 2004-11-16 Hitachi, Ltd. High-strength Ni-base superalloy and gas turbine blades
US20060285974A1 (en) * 2005-06-16 2006-12-21 General Electric Company Turbine bucket tip cap
US7837440B2 (en) * 2005-06-16 2010-11-23 General Electric Company Turbine bucket tip cap
US20100028197A1 (en) * 2006-09-21 2010-02-04 Mark Heazle Nickel-based alloys and articles made therefrom
US7824606B2 (en) * 2006-09-21 2010-11-02 Honeywell International Inc. Nickel-based alloys and articles made therefrom

Also Published As

Publication number Publication date
DE2034607B2 (de) 1977-01-13
DE2034607A1 (de) 1971-11-18
GB1320005A (en) 1973-06-13
IL34952A0 (en) 1971-02-25
FR2051733B1 (ja) 1974-09-20
CA924129A (en) 1973-04-10
IL34952A (en) 1974-05-16
FR2051733A1 (ja) 1971-04-09
BE753418A (fr) 1971-01-13
CH563821A5 (ja) 1975-07-15
SE370343B (ja) 1974-10-14

Similar Documents

Publication Publication Date Title
EP0246082B1 (en) Single crystal super alloy materials
US11118247B2 (en) Highly processable single crystal nickel alloys
US4371404A (en) Single crystal nickel superalloy
CA1098425A (en) Heat treated superalloy single crystal article and process
CA1206398A (en) Superalloy single crystal articles
US5173255A (en) Cast columnar grain hollow nickel base alloy articles and alloy and heat treatment for making
GB2056488A (en) Ni-based superalloy
US4853044A (en) Alloy suitable for making single crystal castings
JP6356800B2 (ja) 超合金及びそれからなる部品
JPH0323613B2 (ja)
US4288247A (en) Nickel-base superalloys
US4476091A (en) Oxidation-resistant nickel alloy
US20020104594A1 (en) Niobium-silicide based composites resistant to high temperature oxidation
US3677331A (en) Casting process for nickel base alloys
JP3402603B2 (ja) 単結晶製品を製造するための改善された低角粒界耐性を有するニッケル基―超合金
US20040042927A1 (en) Reduced-tantalum superalloy composition of matter and article made therefrom, and method for selecting a reduced-tantalum superalloy
AU630623B2 (en) An improved article and alloy therefor
EP2730670A1 (en) Ni-based casting alloy and steam turbine casting part using the same
US4127410A (en) Nickel based alloy
JPS6125773B2 (ja)
US4092183A (en) Directionally solidified castings
JP2002235135A (ja) 産業用タービンの単結晶ブレードのための非常に高い耐高温腐食性をもつニッケル系超合金
US3677746A (en) Heat treatable alloy
US8241560B2 (en) Nickel base superalloy and single crystal castings
US3902899A (en) Austenitic castable high temperature alloy