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AssigneeMarko Materials, Inc.
InventorsRanjan Ray, Donald E. Polk, Bill C. Giessen
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Nickel and iron-nickel base alloys are described together with a rapid solidification process used in the preparation thereof to provide materials useful in the fabrication of parts subject to high temperature operating conditions. The alloys include commercial nickel base superalloys to which a specified amount of boron is added.
A nickel base alloy obtained by adding 0.4 to 1.7 wt% boron to an alloy having a composition represented by Ni.sub.Balance M.sub.a M'.sub.b T.sub.c, where M is at least one element selected from the group consisting of titanium, aluminum, columbium, and tantalum and mixtures thereof, M' is at least one element selected from the group consisting of chromium, cobalt, iron, tungsten and molybdenum and mixtures thereof, and T is at least one element selected from the group consisting of carbon, hafnium, zirconium, vanadium, manganese, silicon and magnesium and mixtures thereof, and where a, b and c are atomic percentages ranging from 7 to 20, 8 to 43 and 0.1 to 4, respectively, where the sum of a, b and c is less than 50, where the molybdenum and tungsten content combined is in the range of 0 to 15 at %, said alloy being prepared from the melt thereof by a rapid solidification process characterized by cooling rates in the range of about 10.sup.5 and 10 .sup.7 .degree.C./sec. said alloy consisting of an ultra fine grain structure having an average grain size of less than about 2 microns comprised predominately of a nickel rich solid solution phase having a face-centered cubic crystalline structure, said alloy having very low bend ductility.
A nickel base alloy having the composition represented by the formula [Ni.sub.Balance Cr.sub.6-20 Ti.sub.0-6 Al.sub.1-8 Cb.sub.0-4 Ta.sub.0-10 Mo.sub.0-13 W.sub.0-13 Co.sub.0-25 Fe.sub.0-20 C.sub.0.04-0.35 (Hf, Zr, V, Mn, Si, Mg).sub.0-4 ].sub.98.3-99.6 B.sub.0.4-1.7, where the subscripts define weight percent and where the nickel is present at a level of more than 50 wt%, said alloy being prepared from the melt thereof by a rapid solidification process characterized by cooling rates on the order of about 10.sup.5 to 10.sup.7 .degree.C./sec, said alloy consisting of an ultrafine grain structure having an average grain size of less than about 2 microns comprised predominately of a nickel rich solid solution phase having a face-centered cubic crystalline structure, said alloy having very low bend ductility.
An iron-nickel base alloy obtained by adding 0.4-1.7 wt% boron to an alloy having a composition represented by Fe.sub.x Ni.sub.y M.sub.a M".sub.b T.sub.c where M is at least one element selected from the group consisting of titanium, aluminum, columbium, and tantalum and mixtures thereof, M" is at least one element selected from the group consisting of chromium, cobalt, tungsten and molybdenum and mixtures thereof, and T is at least one element selected from the group consisting of carbon, hafnium, zirconium, vanadium, manganese, silicon and magnesium and mixtures thereof, where x, y, a, b and c are atomic percentages ranging from 20 to 65, 5 to 50, 7 to 20, 8 to 43 and 0.1 to 4, respectively, and where the sum of a, b and c is less than 50 and the molybdenum and tungsten content combined is in the range of 0 to 15 at%, said alloy being prepared from the melt thereof by a rapid solidification process characterized by cooling rates in the range of about 10.sup.5 to 10.sup.7 .degree.C/sec. said alloy consisting of an ultrafine grain structure having an average grain size of less than about 2 microns comprised predominately of a solid solution phase having very low bend ductility.
An iron-nickel base alloy having the composition represented by the formula 98.3-99.6 B.sub.0.4-1.7 where the subscripts define weight percent and where the iron and nickel taken together comprise more than 50 wt% and where said alloy is characterized by a structure comprised of an iron-nickel rich matrix containing ultrafine borides having an average particle size of less than about 0.3 micron.
A nickel base alloy having the composition represented by the formula 98.3-99.6.sup.B 0.4-1.7, where the subscripts define weight percent and where the nickel is present at a level of more than 50 wt%, said alloy being characterized by a structure comprised of a nickel rich matrix containing ultrafine borides having an average particle size of less than about 0.3 micron and a fine dispersion of an intermetallic Ni.sub.3 (Ti, Al) base compound.
A nickel base alloy obtained by adding 0.4 to 1.7 wt% boron to an alloy having a composition represented by Ni.sub.Balance M.sub.a M'.sub.b T.sub.c, where M is at least one element selected from the group consisting of titanium, aluminum, columbium, and tantalum and mixtures thereof, M' is at least one element selected from the group consisting of chromium, cobalt, iron, tungsten and molybdenum and mixtures thereof, and T is at least one element selected from the group consisting of carbon, hafnium, zirconium vanadium, manganese, silicon and magnesium and mixtures thereof, and where a, b and c are atomic percentages ranging from 7 to 20, 8 to 43 and 0.1 to 4, respectively, where the sum of a, b and c is less than 50, where the molybdenum and tungsten content combined is in the range of 0 to 15 at %, said alloy being characterized by a structure comprised of a nickel rich matrix containing ultrafine borides having an average particle size of less than about 0.3 micron and a fine dispersion of an intermetallic Ni.sub.3 (Ti, Al) base compound.
Dependencies are inferred from the claim text.
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Based on nickel: with chromium
Specialized metallurgical processes, compositions for use therein, consolidated metal powder compositions, and loose metal particulate mixtures:…
Alloys
Technical subjects covered by former uspc cross-reference art collections [xracs] and digests
Term ended 19 Nov 1999 (estimated)
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1. Field of the Invention
This invention is concerned with (a) metal alloys which are useful, e.g., to construct the high temperature components of gas turbines for aerospace and industrial needs and which have compositions obtained by adding boron to alloys similar to commercial nickel base superalloys, and, (b) the preparation of these materials using a rapid solidification process and the consolidation of the rapidly solidified ribbons, powders, etc. into bulk parts which are then heat treated to uniform microstructure and desirable high temperature properties.
2. Description of the Prior Art
A number of commercial nickel base superalloys such as Udimet 700, Waspaloy, Astroloy, B-1900, IN-100, MAR-M200 and Rene 80 were alloyed with 0.4 to 1.7 wt% boron in accordance with the present invention (see Table 1-an alloy designaed as Waspaloy +0.4B means commercial Waspaloy modified by the addition of 0.4 wt% boron and so forth). The alloys were fabricated as ribbons having thicknesses of .about.0.0015-0.0020 inches by the RSP method of melt spinning using a rotating Cu-Be cylinder having a quench surface speed of .about.5000 ft/min. The ribbons were found by x-ray diffraction analysis to consist predominantly of a single solid solution phase with a f.c.c. crystal structure. Ductility of a ribbon was measured by the bend test. The ribbon was bent to form a loop and the diameter of the loop was gradually reduced until the loop is fractured. The breaking diameter of the loop is a measure of ductility. The larger the breaking diameter for a given ribbon thickness, the more brittle the ribbon is considered to be, i.e., the less ductile. The as-quenched ribbons were all found to have breaking diameters of .about.0.1 inch and thus are quite brittle. The ribbons were heat treated at 1900.degree. F. for 3 hours and then air cooled to room temperature. The ribbons were found to be fully ductile, i.e., to bend back onto themselves so as to plastically deform into a U shape without breaking, and have high hardness as measured by a Microhardness tester. The results are given in Table 1. The heat treatment (1900.degree. F., 3 hours) corresponds approximately to a time temperature cycle which might be used for a hot consolidation operation. At 1900.degree. F., the alloys contain primarily a fine dispersion of boride particles (less than 0.5 microns) in the .gamma. matrix. During cooling .gamma.' precipitates as fine particles in the matrix.
Two commercial iron-nickel base superalloys A-286 and Unitemp-212 (see Table 2 below for compositions) are alloyed with 0.9 wt% boron in accordance with the present invention and fabricated as ribbons having thicknesses of .about.0.0015 inches by the RSP method of melt spinning on a rotating chill Cu-Be substrate. The ribbons are found by X-ray diffraction analysis to consist predominantly of a single solid solution phase with a f.c.c. crystal structure. The as-quenched ribbons are found to be brittle by the bend test. The ribbons upon heat treatment at 1900.degree. F. for 3 hours followed by air cooling to room temperature are found to be fully ductile to 180.degree. bending.
TABLE 2 __________________________________________________________________________ Alloy Fe Ni Cr Mo Cb Ti Al B Zr C Mn Si __________________________________________________________________________ A-286 Bal 26 15 1.25 -- 2.15 0.2 .003 -- .05 1.4 .4 Unitemp Bal 25 16 -- 0.5 4.0 0.15 .06 .05 .08 .05 .15 212 __________________________________________________________________________