Nanophase separated nickel powder and method for identifying same

Abstract

The alloys can be designed to function as structural metals in both cryogenic and high temperature applications.

Description

[Technical field]

[0001] Priority claim This application claims priority to U.S. Provisional Patent Application No. 63 / 310,432, filed February 15, 2022, which is incorporated by reference in its entirety.

[0002] Government Sponsorship Statement This invention was made with Government support under Grant No. 80MSFC19C0050 awarded by the NASA Goddard Space Flight Center. The Government has certain rights in this invention.

[0003] The present invention relates to phase-separated powders and methods for identifying same. [Background technology]

[0004] Sintered nanocrystalline materials are often subjected to pressure or other post-sintering processing techniques to achieve a denser material. Summary of the Invention

[0005] In one embodiment, a method for designing a metal alloy powder having a miscibility gap at low temperatures may include identifying a first metal element and a second metal and forming a metal alloy, selecting a third metal having a solubility gap with the metal alloy, and mechanically alloying the third metal with the metal alloy to form a metal alloy powder having a nanoscale grain size.

[0006] In certain circumstances, the metal alloy powder can be engineered to have a phase separation temperature at which diffusion of a third metal occurs to phase separate as a nanoscale phase.

[0007] In certain circumstances, the nanoscale phase may re-melt at a transition temperature higher than the phase separation temperature.

[0008] In certain circumstances, the metal alloy may be a nano-phase separated powder.

[0009] In certain circumstances, the first metal can include nickel.

[0010] In certain circumstances, the second metal may include chromium, cobalt, vanadium, silver, molybdenum, tungsten, or iron.

[0011] In certain circumstances, the third metal may include copper.

[0012] In certain circumstances, the metal alloy powder may include manganese.

[0013] In certain circumstances, the metal alloy powder may include vanadium.

[0014] In certain circumstances, the metal alloy powder may include molybdenum.

[0015] In certain circumstances, the metal alloy powder may include tungsten.

[0016] In certain circumstances, the metal alloy powder may include silver.

[0017] In certain circumstances, the metal alloy powder may include zirconium.

[0018] In certain circumstances, the metal alloy powder may include iron.

[0019] In certain circumstances, the metal alloy may include ternary nano-phase separated powders.

[0020] In certain circumstances, the metal alloy may include quaternary nano-phase separated powders.

[0021] In certain circumstances, the first metal may have a concentration of about 25 atomic % to about 95 atomic % of the alloy.

[0022] In certain circumstances, the second metal may have a concentration of from about 25 atomic % to about 95 atomic % of the alloy.

[0023] In certain circumstances, the third metal may have a concentration of from about 5 atomic % to about 50 atomic % of the alloy.

[0024] In certain circumstances, the metal alloy powder may include a deoxidizing metal.

[0025] In another aspect, a method of powder nano-phase separation sintering can include providing a fine grained powder including a first metallic element and a second metal that form a metal alloy and a third metal that has a solubility gap with the metal alloy, and sintering the fine grained powder to form a sintered body.

[0026] In another embodiment, the metal alloy powder for sintering may include a mechanically alloyed powder including a first metal element and a second metal that form a metal alloy, and a third metal that has a solubility gap with the metal alloy.

[0027] In certain circumstances, the fine powder may be a mechanically alloyed powder.

[0028] In certain circumstances, the sintered body achieves a density of at least 80% at low temperatures without the need for the application of pressure during sintering.

[0029] In certain circumstances, the sintered body achieves a density of at least 90% at low temperatures without the need for the application of pressure during sintering.

[0030] In certain circumstances, the mechanically alloyed powder is a nano-phase separated powder.

[0031] In certain circumstances, the mechanically alloyed powder may include nickel, chromium, iron, copper, vanadium, molybdenum, tungsten, silver, zirconium, or combinations thereof.

[0032] In certain circumstances, the sintering may include nano-phase separation sintering.

[0033] In certain circumstances, the grain size of the metal alloy powder and the grain size of the sintered powder may be substantially the same.

[0034] In certain circumstances, the metal alloy powder may include: NiCu having 5 atomic % to 20 atomic % Cr; NiCu having 5 atomic % to 45 atomic % Fe; NiCu having 5 atomic % to 45 atomic % Co; NiFeCu having 5 atomic % or 8 atomic % Mn; NiCu having 5 atomic % to 15 atomic % V; or NiCu having 5 atomic % to 45 atomic % Co.

[0035] In certain circumstances, the mechanically powder is a quaternary nano-phase separated powder.

[0036] In certain circumstances, the metal alloy powder may include NiCu with 5 atomic % to 45 atomic % Co and up to 5 atomic % Mn.

[0037] In another embodiment, the sintered body may comprise the powder described above.

[0038] Other aspects, embodiments, and features will become apparent from the following description, drawings, and claims. [Brief description of the drawings]

[0039] [Figure 1A] FIG. 1A is a schematic diagram illustrating nano-phase separation sintering, including phase separation, necking, sintering, and densification. [Figure 1B] FIG. 1B shows the phase diagram. [Figure 1C] FIG. 1C is a schematic diagram illustrating one example of the general process described herein. [Figure 2A] FIG. 2A shows the Ni-Cu phase diagram. [Figure 2B] FIG. 2B is a graph showing the behavior of the system. [Diagram 3] FIG. 3 shows the phase diagram. [Figure 4A] FIG. 4A is a graph showing densification rate. [Figure 4B] FIG. 4B is a graph showing the change in relative density. [Figure 5A] FIG. 5A shows the Ni—Cr phase diagram. [Figure 5B] FIG. 5B shows the Cu—Cr phase diagram. [Figure 6A] FIG. 6A shows the Ni-Cu phase diagram at 5 at. % Cr. [Figure 6B] FIG. 6B shows the Ni-Cu phase diagram at 10 at. % Cr. [Figure 6C] FIG. 6C shows the Ni-Cu phase diagram at 15 at. % Cr. [Figure 6D] FIG. 6D shows the phase diagram for 60 atomic % Ni and 15% Cr. [Figure 6E] FIG. 6E is a table showing the composition of the stable phase at 550° C. [Figure 6F] FIG. 6F is a graph showing the temperature dependence of densification at 5° C. / min to 1200° C. and cooling at 40° C. / min. [Figure 7A] FIG. 7A shows the Ni-Fe phase diagram. [Figure 7B] FIG. 7B shows the Cu—Fe phase diagram. [Figure 8A] FIG. 8A shows the Ni—Cu phase diagram at 5 at. % Fe. [Figure 8B] FIG. 8B shows the Ni—Cu phase diagram at 20 at. % Fe. [Figure 8C] FIG. 8C shows the Ni—Cu phase diagram at 42 at. % Fe. [Figure 8D] FIG. 8D shows the Ni—Cu phase diagram at 42 at. % Fe. [Figure 8E] FIG. 8E is a table showing the composition of the stable phase at 550° C. [Figure 8F] FIG. 8F is a graph showing the temperature dependence of densification at 5° C. / min to 945° C. and cooling at 40° C. / min. [Figure 8G] FIG. 8G is a graph showing the change in relative density over time when heated at 5° C. / min. [Figure 8H]FIG. 8H is a graph showing the temperature dependence of densification when heated at 10° C. / min to 1000° C. and cooled at 40° C. / min. [Figure 8I] FIG. 8I is a graph showing the change in relative density over time when heated at 5° C. / min to a final relative density of 0.5864%. [Figure 8J] FIG. 8J is a graph showing the temperature dependence of densification when heated at 15° C. / min to 1000° C. and cooled at 40° C. / min. [Figure 8K] FIG. 8K is a graph showing the change in relative density over time when heated at 15° C. / min to a final relative density of 0.5477%. [Figure 8L] FIG. 8L is a graph showing the temperature dependence of densification when heated to 1000° C. at 20° C. / min and cooled at 40° C. / min. [Figure 8M] FIG. 8M is a graph showing the change in relative density over time when heated at 20 degrees / minute to a final relative density of 0.4276%. [Figure 8N] FIG. 8N is a graph showing the temperature dependence of densification at 5° C. / min to 1100° C. and cooling at 40° C. / min. [Figure 8O] FIG. 8O is a graph showing the change in relative density versus temperature when heated at 5° C. / min. [Figure 8P] FIG. 8P is a graph showing the change in relative density over time when heated at 5° C. / min. [Figure 8Q] FIG. 8Q is a graph showing the temperature dependence of densification at 10° C. / min to 1100° C. and cooling at 40° C. / min. [Figure 8R] FIG. 8R is a graph showing the change in relative density versus temperature when heated at 10° C. / min. [Figure 8S] FIG. 8S is a graph showing the change in relative density over time at 15° C. / min. [Figure 8T] FIG. 8T is a graph showing the temperature dependence of densification at 20° C. / min to 1100° C. and cooling at 40° C. / min. [Figure 8U]FIG. 8U is a graph showing the temperature dependence of densification at 20° C. / min to 1100° C. and cooling at 40° C. / min. [Figure 8V] FIG. 8V is a graph showing the change in relative density over time at 20° C. / min. [Figure 9A] FIG. 9A shows the Ni—Co phase diagram. [Figure 9B] FIG. 9B shows the Cu—Co phase diagram. [Figure 10A] FIG. 10A shows the Ni—Cu phase diagram at 5 at. % Co. [Figure 10B] FIG. 10B shows the Ni—Cu phase diagram at 20 at. % Co. [Figure 10C] FIG. 10C shows the Ni—Cu phase diagram at 44 at. % Co. [Figure 11A] FIG. 11A shows the Ni-V phase diagram. [Figure 11B] FIG. 11B shows the Cu-V phase diagram. [Figure 12A] FIG. 12A shows the Ni—Cu phase diagram at 6 atomic % V. [Figure 12B] FIG. 12B shows the Ni—Cu phase diagram at 10 at. % V. [Figure 12C] FIG. 12C shows the Ni—Cu phase diagram at 13 at. % V. [Figure 12D] FIG. 12D shows the Ni—Cu phase diagram at 13 at. % V and 15 at. % Cu. [Figure 12E] FIG. 12E is a table showing the stable phases at 1150° C. [Figure 12F] FIG. 12F is a graph showing the temperature dependence of densification rate at 5° C. / min to 1200° C. and cooling at 40° C. / min. [Figure 12G] FIG. 12G is a graph showing the temperature dependence of the change in relative density. [Figure 13] FIG. 13 is a chart showing the diffusion rates and temperature ranges of the metals described herein. [Figure 14A] FIG. 14A shows the phase diagram of Fe-Cu with 40 at. % Ni, taken from the Fe database. [Figure 14B] FIG. 14B shows the phase diagram of Fe—Cu containing 40 at. % Ni, obtained from the Ni database. [Figure 14C] FIG. 14C shows the phase diagram of Fe—Cu with 40 at. % Ni, obtained from the Cu database. [Figure 14D] FIG. 14D shows the phase diagram of Fe—Cu with 40 at. % Ni, taken from the High Entropy Alloy Database. [Figure 15] FIG. 15 shows the Cr-Cu phase diagram at 60 atomic % Ni. [Figure 16] FIG. 16 shows the Co-Cu phase diagram at 40 atomic % Ni. [Figure 17] FIG. 17 shows the Cu-V phase diagram at 75 atomic % Ni. [Figure 18A] FIG. 18A is a graph showing densification after hydrogen pretreatment at different heating rates. [Figure 18B] FIG. 18B is a graph showing densification after hydrogen pretreatment at different heating rates. [Figure 18C] FIG. 18C is a graph showing densification after hydrogen pretreatment at different heating rates. [Figure 19] FIG. 19 is a graph showing the effect on density of 5 at. % Mn and 8 at. % Mn in a Ni-Fe-Cu composition. [Figure 20] FIG. 20 is a graph showing the densification behavior when a composition of 37.5 at % Ni-37.5 at % Co-20 at % Cu-5 at % Mn is heated to 1200° C. and Mn is added. [Figure 21] FIG. 21 is a photomicrograph of the composition of FIG. [Figure 22] FIG. 22 is a photomicrograph of the composition of FIG. [Figure 23] FIG. 23 is a photomicrograph of the composition of FIG. [Figure 24] FIG. 24 is a photomicrograph of the composition of FIG. [Diagram 25]FIG. 25 is a graph showing the mechanical properties of sintered bodies containing 37.5 atomic % Ni, 37.5 atomic % Fe, 20 atomic % Cu, and 5 atomic % Mn. [Figure 26] FIG. 26 is a graph showing the mechanical properties of sintered bodies containing 37.5 atomic % Ni, 37.5 atomic % Fe, 20 atomic % Cu, and 5 atomic % Mn. [Figure 27] FIG. 27 is a graph showing the mechanical properties of sintered bodies containing 37.5 atomic % Ni, 37.5 atomic % Fe, 20 atomic % Cu, and 5 atomic % Mn. [Figure 28] FIG. 28 is a graph showing the mechanical properties of sintered bodies containing 37.5 atomic % Ni, 37.5 atomic % Fe, 20 atomic % Cu, and 5 atomic % Mn. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Ternary and higher order metallic alloys are designed to function as structural metals in both cryogenic and high temperature applications. More specific properties of these alloys may include the ability to be rapidly sintered from powder and achieve full density at low temperatures without the need for pressure during the sintering process. This allows for the processing of these alloys in additive manufacturing operations in bulk form.

[0041] As described herein, Ni-based alloys suitable for use in space applications can be manufactured primarily with Ni, replacing Inconel / superalloys. This material can lead to improved processing. For example, accelerated (low temperature) sintering from powder allows for 3D printing by bound metal deposition without sagging of structures. Mechanical properties can also be improved. Nanocrystallization can provide strength and lighter weight structures over Inconel. This material shows improved thermal stability and scalability of sintered parts / components.

[0042] Nanophase sintering shows the need for the secondary phase to be transitional. It can be important to avoid contiguous secondary phases, which could cause the material to fail without taking advantage of the hard-won gains in Ni. Importantly, the Ni-Cu system meets that criterion thermodynamically. However, in pure Ni-Cu, diffusion is too slow, which causes a neck to form in the two-phase region due to the low transus temperature.

[0043] Rapid densification can be achieved by nanophase separation and designing ternary Ni, quaternary Ni, or higher Ni systems. The Ni-Cu phase diagram shows a solubility gap with Ni-rich and Cu-rich phases at low temperatures, and a single phase over the entire composition range above 400 °C. The phase separation element is Cu, which forms interparticle necks between the powders. Cu was chosen because i) it precipitates into a second phase at low temperatures, ii) it has a relatively small activation energy for Ni diffusion and a low melting point, which favors the formation of new precipitates at the interparticle necks, and iii) it promotes rapid diffusion of Ni into the interparticle necks after the single solid solution phase region is reached. Thus, it meets all the thermodynamic criteria for nanophase separation.

[0044] To effect the diffusional nature of the phase separation kinetics, a third element can be selected to increase the transus temperature and widen the two-phase region (solubility gap) of the binary Ni-Cu system. Illustratively, pseudo-binary phase diagrams are calculated herein for systems containing various alloying amounts of Fe, Cr, Mn, V, W, Ag, Mo, or Co. Any of these ternary or higher order Ni phase diagrams may exhibit two-phase and single-phase regions at high temperatures in a range of compositions, as does the binary Ni-Cu system. Any of these ternary or higher systems exhibit a transition from binary to single-phase regions in a range of compositions that occurs at a higher temperature than any possible composition of the binary Ni-Cu system.

[0045] To prepare these alloys, powders of Ni, Cu, and one of the elements described herein are mechanically alloyed to produce supersaturated powders with uniform distribution of the alloying components and fine grain size on the order of a few nanometers. All alloy powders are then cold isostatically pressed into the shape of pellets (green bodies). After sintering, the supersaturated powders decompose into a two-phase microstructure with a Ni-containing main phase and a Cu-rich phase that forms intergranular necks. The Cu-rich phase makes contacts between adjacent grains. These necks act as rapid diffusion paths and remelt at temperatures higher than the transus, which is the main densification mechanism for ternary and higher Ni alloys. Phase decomposition at low temperatures and interdiffusion between the two phases promotes rapid densification, with relative densities reaching over 98%.

[0046] Thermo-Calc software can be used to evaluate the equilibrium bulk phase diagrams of all ternary or higher order nanophase-segregated Ni alloys having the characteristics or properties described below, such as the volume fractions and chemical compositions of the layers involved. For example, calculations such as Thermo-Calc can be used as a design tool to identify and predict potential alloy candidates for nanophase-segregated ternary or higher order Ni systems.

[0047] The criteria for identifying alloying elements to design ternary or higher order nanophase-segregated Ni alloys may include one or more of the following features. The third alloying element should extend the thermodynamic stability of the low-temperature solubility gap phase region of the binary Ni-Cu system while maintaining a single-phase solid solution at the high homologous temperatures of the alloy. Another factor to consider is that the low-temperature solubility gap is composed of Ni- and Cu-rich containing phases. Furthermore, ternary or higher order alloying elements may be selected to increase the two-phase to single-phase transition temperature to such an extent that thermodynamic equilibrium is reached. For example, phase decomposition to a two-phase structure may occur kinetically. Another consideration is that in addition to two phases at low temperatures and single phase at high temperatures, no other phases (i.e., intermetallic phases) are formed that would thermodynamically or kinetically inhibit nanophase separation of ternary or higher order Ni powders. It can be important to identify the compositional range of the appropriate volume fraction of the second phase that forms in the low temperature solubility gap, or the appropriate compositional range of the phases involved, the thermodynamic and kinetic implications of nanophase separation sintering, or both.

[0048] The processing steps for producing and testing these alloys are described herein. Mechanical alloying of elemental nickel, copper, and iron (with vanadium, cobalt, molybdenum, tungsten, silver, zirconium, manganese, or chromium) powders can be achieved by high energy ball milling techniques and the formation of (forced) supersaturated solid solutions. The powders can then be cold isostatically pressed to produce compacts (powder pellets) of the desired shape. Sintering of the powder pellets can then be performed in a controlled atmosphere (argon and some forming gas). In general, the heating cycle to the desired temperature includes initial (phase separation) and secondary (interdiffusion, remelting) densification occurring at 500-700°C and above 850°C, respectively, with full density being reached at a temperature of 1100°C. The details of the temperatures and heating rates can vary, as discussed herein and understood in practice.

[0049] The methods and materials described herein may be useful for commercial applications. Ternary or higher order nanophase-segregated Ni alloys can be designed to promote rapid consolidation of bulk powders without the application of pressure during sintering, a property that is suitable for application in additive manufacturing processes. Sintered ternary or higher order Ni alloys may be used as structural alloys in many applications requiring high thermal, mechanical and corrosion stability, such as turbine, engine and nuclear reactor parts. The simplified processability of ternary or higher order Ni alloys may reduce the complexities of 3D printing typically associated with Ni-based superalloys, which require additional isothermal precipitation treatments to tailor the appropriate phase fraction of the two-phase structure. This technology is of particular interest for high-tech and space applications, as it is planned to introduce parts printed from powders of these ternary or higher order Ni alloys. The preferred printing technique is bound metal deposition, which allows for large-scale production of parts with relatively complex geometries and shapes.

[0050] A method for designing a metal alloy powder having a solubility gap at low temperatures can include identifying a first metallic element and a second metal to form a metal alloy, selecting a third metal that has a solubility gap with the metal alloy, and mechanically alloying the third metal and the metal alloy to form a metal alloy powder having a nanoscale particle size.

[0051] For example, the Ni-Cu alloy may include one or more third metals, which may include chromium, cobalt, vanadium, silver, molybdenum, tungsten, or iron. The third metal is selected based on ternary phase diagram characteristics that allow nanophase separation to occur, as described herein. In certain embodiments, iron may be the preferred metal in the alloy. In other embodiments, the preferred metal in the alloy may be chromium. In other embodiments, the preferred metal in the alloy may be cobalt. In other embodiments, the preferred metal in the alloy may be vanadium. In other embodiments, the preferred metal in the alloy may be silver. In other embodiments, the preferred metal in the alloy may be molybdenum. In other embodiments, the preferred metal in the alloy may be tungsten. The composition of the metal alloy may be selected for nanophase separated powders, such as ternary nanophase separated powders or quaternary nanophase separated powders.

[0052] In certain circumstances, the alloy may include a deoxidizing metal. The deoxidizing metal may be present in the alloy at a low concentration, such as 5 atomic %, 4 atomic %, 3 atomic %, 2 atomic %, 1 atomic %, or less. The deoxidizing metal may be manganese or zirconium. The deoxidizing metal may be added to a ternary alloy to make a quaternary alloy.

[0053] In certain circumstances, the metal alloy powder can be designed to have a phase separation temperature at which diffusion of a third metal occurs to phase separate into a nanoscale phase, and preferably the nanoscale phase can re-melt at a transition temperature higher than the phase separation temperature.

[0054] According to certain embodiments, the mechanical alloying (e.g., ball milling) is performed at a relatively low temperature. For example, in some embodiments, the mechanical alloying (e.g., ball milling) is performed while the particles are at a temperature of 150° C. or less, 100° C. or less, 75° C. or less, 50° C. or less, 40° C. or less, 35° C. or less, 30° C. or less, 25° C. or less, or 20° C. or less. In some embodiments, the mechanical processing (e.g., ball milling) is performed while the particles are at a temperature of at least 0° C. In some embodiments, the mechanical alloying (e.g., ball milling) may be performed at the temperature of the ambient environment.

[0055] In certain embodiments, the mechanical alloying (e.g., ball milling) may be carried out for a period of 6 hours or more (e.g., 8 hours or more, 10 hours or more, 12 hours or more, or 15 hours or more). In certain embodiments, the mechanical alloying (e.g., ball milling) may be carried out for a period of 18 hours or less. In some embodiments, the mechanical alloying (e.g., ball milling) may be carried out for a period of between 6 hours and 18 hours.

[0056] In some embodiments, the mechanical alloying (eg, ball milling) may be carried out in an inert atmosphere, such as an argon atmosphere.

[0057] In certain circumstances, a nanoscale feature or nanophase can be 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, 5 nm, or less. A nanophase, nanoscale feature, or nanocrystal can refer to a crystal (or "particle") having a size of about 1000 nm or less, e.g., 500 nm, 200 nm, 100 nm, 50 nm, 20 nm, 10 nm, 5 nm, 2 nm, etc. For example, the particle size can be between 1000 nm and about 2 nm, e.g., about 500 nm to about 2 nm, about 200 nm to about 2 nm, about 100 nm to about 2 nm, about 50 nm to about 2 nm, about 30 nm to about 2 nm, about 20 nm to about 2 nm, about 10 nm to about 2 nm. In some embodiments, size can refer to the largest dimension of the particle. Particle sizes referred to herein may be determined as "average" and may be measured by any suitable technique. Dimensions may refer to diameter, length, width, height, depending on the shape of the particle. In some instances (and as shown below), stable nanocrystalline materials may also refer to materials that include an amorphous phase.

[0058] An alloy may be composed of three, four, or more metals. Each metal may have a concentration of about 25 atomic % to about 95 atomic % of the alloy. When two metal components of a ternary alloy each have a concentration of about 25 atomic % to about 95 atomic % of the alloy, the third metal component may have a concentration of about 5 atomic % to about 50 atomic % of the alloy. For example, each metal concentration may be at least 5 atomic %, at least 10 atomic %, at least 15 atomic %, at least 20 atomic %, at least 25 atomic %, at least 30 atomic %, at least 35 atomic %, at least 40 atomic %, at least 45 atomic %, at least 50 atomic %, at least 55 atomic %, at least 60 atomic %, at least 65 atomic %, at least 70 atomic %, at least 75 atomic %, at least 80 atomic %, at least 85 atomic %, at least 90 atomic %, or at least 95 atomic %.

[0059] In another aspect, a method for nano-phase separation sintering of a powder can include providing a mechanically alloyed powder including a first metallic element and a second metal that form a metal alloy, and a third metal having a solubility gap with the metal alloy, and sintering the mechanically alloyed powder to form a sintered body.

[0060] In another aspect, the metal alloy powder for sintering can include a mechanically alloyed powder including a first metal element and a second metal that form a metal alloy, and a third metal that has a solubility gap with the metal alloy.

[0061] In certain circumstances, the sintered body achieves a density of at least 80%, at least 85%, at least 90%, at least 95%, at least 97%, or at least 98%. These densities can be achieved at low temperatures without the need for application of pressure during sintering. In certain circumstances, the sintering can include nanophase separation sintering.

[0062] According to certain embodiments, sintering the plurality of particles includes heating the particles to a sintering temperature of 2200° C. or less, 2000° C. or less, 1900° C. or less, 1800° C. or less, 1700° C. or less, 1600° C. or less, 1500° C. or less, 1400° C. or less, 1300° C. or less, 1200° C. or less, 1100° C. or less. 1000° C. or less, 900° C. or less, 850° C. or less, 800° C. or less, or 750° C. or less. According to certain embodiments, sintering the plurality of particles includes heating the particles to a sintering temperature of 750° C. or more, 850° C. or more, 1000° C. or more, 1200° C. or more, 1450° C. or more, or 1600° C. or more. Combinations of these ranges are also possible. For example, in some embodiments, sintering the plurality of particles includes heating the particles to a sintering temperature of 750° C. or more and 2200° C. or less. In some embodiments, the temperature of the sintered material is within these ranges for at least 10%, at least 25%, at least 50%, at least 75%, at least 90%, or at least 99% of the sintering time.

[0063] According to certain embodiments, sintering the plurality of particles includes maintaining the particles within a sintering temperature range for 72 hours or less, 48 ​​hours or less, 24 hours or less, 12 hours or less, 6 hours or less, 4 hours or less, 3 hours or less, 2 hours or less, or 1 hour or less (and / or, in some embodiments, at least 10 minutes, at least 20 minutes, at least 30 minutes, at least 50 minutes, at least 3 hours, or at least 6 hours). Combinations of these ranges are also possible. For example, in some embodiments, sintering the plurality of particles includes heating the particles to a first sintering temperature of 600° C. or more and 1100° C. or less for a sintering time of 6 hours or more and 24 hours or less.

[0064] In certain circumstances, the heating rate may be 2° C. / min, 3° C. / min, 4° C. / min, 5° C. / min, 10° C. / min, 15° C. / min, or 20° C. / min.

[0065] In certain circumstances, the grain size of the metal alloy powder and the grain size of the sintered powder may be substantially the same. The grain size may be on the nanoscale. The powder may be a fine powder.

[0066] The alloys described herein include Ni-Cu-Fe, Ni-Cu-Co, Ni-Cu-Cr, Ni-Cu-V, Ni-Cu-Ag, Ni-Cu-Mo, Ni-Cu-W, Ni-Cu-Mn, Ni-Cu-Zr, Ni-Cu - Can be at least one of Fe-Mn, Ni-Cu-Co-Mn, Ni-Cu-Cr-Mn, Ni-Cu-V-Mn, Ni-Cu-Ag-Mn, Ni-Cu-Mo-Mn, or Ni-Cu-W-Mn.

[0067] In the alloy, the Ni content can be 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0068] In the alloy, the Cu content can be 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0069] In the alloy, the Fe content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0070] In the alloy, the Co content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0071] In the alloy, the Cr content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0072] In the alloy, the V content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0073] In the alloy, the Mo content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0074] In the alloy, the W content can be 1 atomic%, 2 atomic%, 3 atomic%, 4 atomic%, 5 atomic%, 6 atomic%, 7 atomic%, 8 atomic%, 9 atomic%, 10 atomic%, 11 atomic%, 13 atomic%, 14 atomic%, 15 atomic%, 20 atomic%, 30 atomic%, 35 atomic%, 40 atomic%, 45 atomic%, 50 atomic%, 55 atomic%, 60 atomic%, 65 atomic%, 70 atomic%, 75 atomic%, 80 atomic%, 85 atomic%, 90 atomic%, or 95 atomic% of the composition.

[0075] In certain circumstances, NiCu can have 5 atomic % to 20 atomic % Cr; NiCu can have 5 atomic % to 45 atomic % Fe; NiCu can have 5 atomic % to 45 atomic % Co; NiFeCu can have 5 atomic % or 8 atomic % Mn; NiCu can have 5 atomic % to 15 atomic % V; or NiCu can have 5 atomic % to 45 atomic % Co. For example, the metal alloy powder may include: NiCu having 5 atomic %, 10 atomic %, 11 atomic %, 12 atomic %, 13 atomic %, 14 atomic %, 15 atomic %, 16 atomic %, 17 atomic %, 18 atomic %, or 19 atomic % Cr; NiCu having 5 atomic %, 10 atomic %, 12 atomic %, 14 atomic %, 16 atomic %, 18 atomic %, 20 atomic %, 22 atomic %, 24 atomic %, 26 atomic %, 28 atomic %, 30 atomic %, 32 atomic %, 34 atomic %, 36 atomic %, 38 atomic %, 40 atomic %, or 42 atomic % Fe; NiCu having 30 atomic %, 32 atomic %, 34 atomic %, 36 atomic %, 38 atomic %, 40 atomic %, 42 atomic %, or 44 atomic % Co; NiFeCu having 5 atomic % or 8 atomic % Mn; NiCu having 6 atomic %, 7 atomic %, 8 atomic %, 9 atomic %, 10 atomic %, 11 atomic %, 12 atomic %, or 13 atomic % V; or NiCu having 5 atomic %, 10 atomic %, 12 atomic %, 14 atomic %, 16 atomic %, 18 atomic %, 20 atomic %, 22 atomic %, 24 atomic %, 26 atomic %, 28 atomic %, 30 atomic %, 32 atomic %, 34 atomic %, 36 atomic %, 38 atomic %, 40 atomic %, 42 atomic %, or 44 atomic % Co.

[0076] In some circumstances, the mechanical powder is a quaternary nano-phase separated powder. For example, the metal alloy powder can include NiCu with 5 atomic %, 10 atomic %, 12 atomic %, 14 atomic %, 16 atomic %, 18 atomic %, 20 atomic %, 22 atomic %, 24 atomic %, 26 atomic %, 28 atomic %, 30 atomic %, 32 atomic %, 34 atomic %, 36 atomic %, 38 atomic %, 40 atomic %, 42 atomic %, or 44 atomic % Co and up to 5 atomic % Mn.

[0077] Referring to FIG. 1A, the generalized requirements for nano-phase separation sintering are illustrated, including phase separation, necking, sintering, and densification. To perform these steps, the properties of the alloy are important. For example, nanocrystallinity can ensure rapid diffusion to the particle surface. Furthermore, supersaturation can form the desired second phase at the necks. Mechanical alloying can facilitate both of these key elements.

[0078] Referring to FIG. 1B, the phase diagram suggests an interplay between concentration, temperature, phase separation, reduced surface energy, and high solubility that leads to the phase-separation enhanced sintering described herein.

[0079] FIG. 1C shows an example of a typical process using Fe.

[0080] Ternary and higher Ni-Cu alloy systems are of particular interest. Requirements for the selection of the ternary element include: The ternary element should have a high positive heat of mixing with copper, which can raise the transition temperature from the solubility gap to the solid-solution phase field. The ternary element should also ideally form a solid solution with Ni, which can promote the interdiffusion required for nanophase separation sintering.

[0081] Figure 2A shows the Ni-Cu phase diagram. Figure 2B shows the behavior of the system. For example, increased mobility leads to decreased supercooling, and increased supercooling leads to decreased mobility.

[0082] For example, a 70 at.% Ni, 15 at.% Cu, 15 at.% Co alloy was investigated. The phase diagram for the system is shown in Figure 3. The alloy was heated at different rates (5, 10, 15 °C / min) to 1000 °C and then cooled at 40 °C / min. Figure 4A shows the densification rate at 10 K / min to 1000 °C and then cooled at 40 K / min. Figure 4B shows the evolution of the relative density.

[0083] Cr alloys were also investigated. Figure 5A shows the Ni-Cr phase diagram. Figure 5B shows the Cu-Cr phase diagram. Other phase diagrams at other Cr concentrations can be seen in Figures 6A-6C. Figure 6A shows the Ni-Cu phase diagram at 5 at. % Cr. Figure 6B shows the Ni-Cu phase diagram at 10 at. % Cr. Figure 6C shows the Ni-Cu phase diagram at 15 at. % Cr.

[0084] Alloys with 60 at.% Ni, 25 at.% Cu and 15 at.% Cr were investigated. The phase diagram for 60 at.% Ni and 15% Cr is shown in Figure 6D. Figure 6E is a table showing the composition of the stable phases at 550°C. Figure 6F shows the temperature dependence of densification at 5°C / min to 1200°C and then cooled at 40°C / min.

[0085] Fe alloys were investigated. Figure 7A shows the Ni-Fe phase diagram. Figure 7B shows the Cu-Fe phase diagram. Other phase diagrams at other Fe concentrations can be seen in Figures 8A-8C. Figure 8A shows the Ni-Cu phase diagram at 5 at. % Fe. Figure 8B shows the Ni-Cu phase diagram at 20 at. % Fe. Figure 8C shows the Ni-Cu phase diagram at 42 at. % Fe.

[0086] FIG. 8D shows the Ni-Cu phase diagram at 42 at.% Fe. FIG. 8E is a table showing the composition of the stable phases at 550° C. One set of experiments was performed with 15 at.% Cu. FIG. 8F shows the temperature dependence of densification at 5° C. / min to 945° C. and then cooling at 40° C. / min. FIG. 8G shows the time course of relative density for heating at 5° C. / min. FIG. 8H shows the temperature dependence of densification at 10° C. / min to 1000° C. and then cooling at 40° C. / min. FIG. 8I shows the time course of relative density for heating at 5° C. / min to a final relative density of 0.5864%. FIG. 8J shows the temperature dependence of densification at 15° C. / min to 1000° C. and then cooling at 40° C. / min. FIG. 8K shows the time course of relative density for heating at 15° C. / min to a final relative density of 0.5477%. Figure 8L shows the temperature dependence of densification at 20°C / min to 1000°C and then cooling at 40°C / min. Figure 8M shows the change in relative density over time at 20°C / min heating to a final relative density of 0.4276%.

[0087] Another set of experiments was performed with 15 at. % Cu. Figure 8N shows the temperature dependence of densification at 5°C / min to 1100°C and then cooling at 40°C / min. Figure 8O shows the relative density versus temperature for heating at 5°C / min. Figure 8P shows the relative density versus time for heating at 5°C / min. Figure 8Q shows the temperature dependence of densification at 10°C / min to 1100°C and then cooling at 40°C / min. Figure 8R shows the relative density versus temperature for heating at 10°C / min. Figure 8S shows the relative density versus time at 15°C / min. Figure 8T shows the temperature dependence of densification at 20°C / min to 1100°C and then cooling at 40°C / min. Figure 8U shows the temperature dependence of densification at 20°C / min to 1100°C and then cooling at 40°C / min. Figure 8V shows the relative density versus time at 20°C / min.

[0088] Co alloys were investigated. Figure 9A shows the Ni-Co phase diagram. Figure 9B shows the Cu-Co phase diagram. Other phase diagrams at other Co concentrations can be seen in Figures 10A-10C. Figure 10A shows the Ni-Cu phase diagram at 5 at. % Co. Figure 10B shows the Ni-Cu phase diagram at 20 at. % Co. Figure 10C shows the Ni-Cu phase diagram at 44 at. % Co.

[0089] 12C shows the Ni-Cu phase diagram at 10 at. % V. FIG. 12C shows the Ni-Cu phase diagram at 13 at. % V. FIG. 12D shows the Ni-Cu phase diagram at 13 at. % V. FIG. 12E shows the stable phase at 1150° C. FIG. 12F shows the temperature dependence of the densification rate at 5° C. / min to 1200° C. and then cooled at 40° C. / min. FIG. 12G shows the temperature dependence of the change in relative density.

[0090] Based on the experiments described herein, Ni self-diffusion influences the limit of densification enhancement.

[0091] FIG. 13 is a chart showing the diffusion rates and temperature ranges of the metals described herein.

[0092] Phase diagram information may vary depending on the data source. Figure 14A is a phase diagram of Fe-Cu with 40 at. % Ni obtained from the Fe database. Figure 14B is a phase diagram of Fe-Cu with 40 at. % Ni obtained from the Ni database. Figure 14C is a phase diagram of Fe-Cu with 40 at. % Ni obtained from the Cu database. Figure 14D is a phase diagram of Fe-Cu with 40 at. % Ni obtained from the High Entropy Alloys Database.

[0093] Other phase diagrams can also be constructed: Figure 15 is the Cr-Cu phase diagram at 60 at.% Ni; Figure 16 is the Co-Cu phase diagram at 40 at.% Ni; and Figure 17 is the Cu-V phase diagram at 75 at.% Ni.

[0094] Pretreatment of the alloy in a reducing atmosphere can improve the sintering performance of the alloy. For example, pretreatment in hydrogen gas at 300°C for 24 hours can suppress the swelling. Figures 18A, 18B, and 18C show the densification after hydrogen pretreatment at different heating rates.

[0095] As mentioned above, deoxidizers can be included in the alloy. Figure 19 shows the effect on density of adding 5 at. % and 8 at. % Mn to a Ni-Fe-Cu composition.

[0096] As another example, Figure 20 shows the densification behavior of a 37.5at%Ni-37.5at%Co-20at%Cu-5at%Mn composition heated to 1200°C and with the addition of Mn. The microstructure is shown in the images of Figures 21, 22, 23 and 24.

[0097] The mechanical properties of the sintered bodies described herein were tested. The mechanical test results for 37.5 at. % Ni-37.5 at. % Fe-20 at. % Cu-5 at. % Mn are shown in Figures 25-28.

[0098] Experimental Method

[0099] In this experiment, we focus on the sintering of a model nanocrystalline material, produced by a relatively standard route, with standard inputs, in order to highlight the physics of the kinetic competition outlined above. Ni was chosen for its technological relevance and because it occupies a unique position: in microcrystalline materials debinding readily precedes sintering, whereas in nanocrystalline materials the onset of sintering is at the low end of the debinding range, so that conflation of organic burnout and sintering is expected to be almost inevitable.

[0100] Nanocrystalline Ni-Fe alloy powders were produced by high-energy ball milling. Nickel powder (Alfa Aesar, 99.9% purity, 3–7 μm particle size) was milled in a SPEX 8000D mixer / mill with a ball-to-powder ratio of 10:1 (5 g powder batches) using hardened steel vials and media. High-energy ball milling was performed in a glove box maintained under an ultra-high purity Ar atmosphere to reduce atmospheric oxygen contamination. Approximately 5 weight percent (wt%) of ethanol (C2H6O) was added as a process control agent (PCA) to balance the fracturing and cold-welding of powder particles during high-energy ball milling. Note that this was the only organic species used in this study and therefore the main carbon source in the system.

[0101] After milling for 20 hours, the powder was imaged in secondary electron (SE) mode with a Merlin Zeiss high-resolution scanning electron microscope (HR-SEM) and the milled powder size was estimated to be 51 (±23) μm. The milled grain size was determined to be about 23 nm using a Panalytical X'Pert PRO with Cu-Kα radiation at 45 kV and 40 mA with a wavelength of λ = 1.5418 Å and step size of 0.0167°. The average grain size was determined from peak broadening corrected for lattice distortion using classical Williamson-Hall analysis and instrumental contributions referenced to NIST LaB6. Although pure Ni is input in this process, wear of the steel media / vials under these milling conditions leads to the formation of Ni-Fe solid solution alloy powder. The final composition of the powder was measured using the energy dispersive X-ray (EDX) spectroscopy detector of the SEM under the same conditions as above. The accumulation of Fe contamination as a function of ball milling time. All powders described herein were produced under the same 20-hour milling conditions and had an iron content of 9.75 atomic percent (at%) (±0.41), which was generally confirmed by wavelength dispersive spectroscopy measurements. Wavelength dispersive spectroscopy (WDS) analysis was based on four separate measurements, all of which were comparable. The analysis was performed on a JEOL JSM7900F scanning electron microscope equipped with an Oxford Wave WDS spectrometer (voltage 20 kV, probe current 1.25 nA). For each element analyzed, Kα radiation was used as the standard references for all elements that were expected to become part of the alloy due to wear of the initial Ni powder with the milling media. The pressed compacts experiments reported below include powders from three independent but otherwise identical ball milling batches. X-ray diffraction confirmed that the milled powders were FCC solid solutions.

[0102] The ball-milled powder was pressed into cylindrical specimens with a diameter and height of about 6 mm and 1.5 mm, respectively, using a uniaxial hydraulic press (Model YLJ-15L, MTI) with a pressure of -400 to 450 MPa acting on the pellets, so that the initial relative density was in the range of -55.8 to 58.9%, and without the addition of any additional binder phase. The initial relative density of the pressed specimens was calculated based on the mass and dimensional measurements, and was calculated as the initial density plus the theoretical density (8.80 g / cm3, taking into account the Fe content). 3 ) The TMA data were expressed as raw change in length converted to relative density, assuming isotropic shape change, which was typically confirmed by caliper measurements after each experiment.

[0103] The details of one or more embodiments are set forth in the accompanying drawings and specification. Other features, objects, and advantages will become apparent from the specification, drawings, and claims. Although a number of embodiments of the invention have been described, it will be understood that various modifications can be made without departing from the spirit and scope of the invention. It will also be understood that the accompanying drawings are not necessarily to scale and that they depict various features and underlying principles of the invention in a somewhat simplified manner.

Claims

1. 1. A method for designing a metal alloy powder having a solubility gap at low temperature, comprising: identifying a first metallic element and a second metal to form a metallic alloy; selecting a third metal that has a solubility gap with the metal alloy; and mechanically alloying the third metal with the metal alloy to form a metal alloy powder having nanoscale particle size; A method comprising:

2. The method of claim 1 , wherein the metal alloy powder is engineered to have a phase separation temperature at which diffusion of the third metal occurs and the metal separates as a nanoscale phase.

3. The method of claim 2 , wherein the nanoscale phase remelts at a transition temperature above the phase separation temperature.

4. The method of claim 1 , wherein the metal alloy is a nanophase separated powder.

5. The method of claim 1 , wherein the first metal comprises nickel.

6. The method of claim 1 , wherein the second metal comprises chromium, cobalt, vanadium, silver, molybdenum, tungsten, or iron.

7. The method of claim 1 , wherein the third metal comprises copper.

8. The method of claim 1 , wherein the metal alloy powder comprises manganese.

9. The method of claim 1 , wherein the metal alloy powder comprises vanadium.

10. The method of claim 1 , wherein the metal alloy powder comprises molybdenum.

11. The method of claim 1 , wherein the metal alloy powder comprises tungsten.

12. The method of claim 1 , wherein the metal alloy powder comprises silver.

13. The method of claim 1 , wherein the metal alloy powder comprises zirconium.

14. The method of claim 1 , wherein the metal alloy powder comprises iron.

15. The method of claim 1 , wherein the metal alloy comprises a ternary nanophase separated powder.

16. The method of claim 1 , wherein the metal alloy comprises a quaternary nanophase separated powder.

17. The method of claim 1 , wherein the first metal has a concentration of about 25 atomic % to about 95 atomic % of the alloy.

18. The method of claim 1 , wherein the second metal has a concentration of about 25 atomic % to about 95 atomic % of the alloy.

19. The method of claim 1 , wherein the third metal has a concentration of about 5 atomic % to about 50 atomic % of the alloy.

20. The method of claim 1 , wherein the metal alloy powder comprises a deoxidized metal.

21. 1. A method for nanophase separation sintering of a powder, comprising: providing a fine powder comprising a first metal element and a second metal that form a metal alloy, and a third metal that has a solubility gap with the metal alloy; and sintering the fine powder to form a sintered body; A method comprising:

22. 22. The method of claim 21, wherein the fine powder is a mechanically alloyed powder.

23. 22. The method of claim 21, wherein the sintered body achieves at least 80% density at low temperatures without the need for applied pressure during sintering.

24. 22. The method of claim 21, wherein the sintered body achieves at least 90% density at low temperatures without the need for applied pressure during sintering.

25. 22. The method of claim 21, wherein the fine powder is a nanophase separated powder.

26. 22. The method of claim 21, wherein the fine powder comprises nickel, chromium, iron, copper, vanadium, molybdenum, tungsten, silver, zirconium, manganese, or a combination thereof.

27. The method of claim 21 , wherein the sintering comprises nanophase separation sintering.

28. 22. The method of claim 21, wherein the particle size of the metal alloy powder and the particle size of the sintered powder are substantially the same.

29. 1. A metal alloy powder for sintering, comprising a mechanically alloyed powder comprising a first metal element and a second metal that form a metal alloy, and a third metal that has a solubility gap with the metal alloy.

30. 30. The powder of claim 29, wherein the mechanically alloyed powder is a nanophase separated powder.

31. 30. The powder of claim 29, wherein the mechanically alloyed powder comprises nickel, chromium, iron, copper, vanadium, molybdenum, tungsten, silver, zirconium, manganese, or a combination thereof.

32. 30. The powder of claim 29, wherein the mechanical powder is a ternary nanophase separated powder.

33. 30. The powder of claim 29, wherein the metal alloy powder comprises: NiCu with 5 at.%, 10 at.%, 11 at.%, 12 at.%, 13 at.%, 14 at.%, 15 at.%, 16 at.%, 17 at.%, 18 at.%, or 19 at.% Cr; NiCu with 5 at.%, 10 at.%, 12 at.%, 14 at.%, 16 at.%, 18 at.%, 20 at.%, 22 at.%, 24 at.%, 26 at.%, 28 at.%, 30 at.%, 32 at.%, 34 at.%, 36 at.%, 38 at.%, 40 at.%, or 42 at.% Fe; NiCu with 5 at.%, 10 at.%, 12 at.%, 14 at.%, 16 at.%, 18 at.%, 20 at.%, 22 at.%, 24 at.%, 26 at.%, 28 at.%, 30 at.%, 32 at.%, 34 at.%, 36 at.%, 38 at.%, 40 at.%, 42 at.%, or 44 at.% Co; NiFeCu with 5 or 8 atomic % Mn; NiCu with 6 at.%, 7 at.%, 8 at.%, 9 at.%, 10 at.%, 11 at.%, 12 at.%, or 13 at.% V; or NiCu having 5 atomic %, 10 atomic %, 12 atomic %, 14 atomic %, 16 atomic %, 18 atomic %, 20 atomic %, 22 atomic %, 24 atomic %, 26 atomic %, 28 atomic %, 30 atomic %, 32 atomic %, 34 atomic %, 36 atomic %, 38 atomic %, 40 atomic %, 42 atomic %, or 44 atomic % Co.

34. 30. The powder of claim 29, wherein the mechanically alloyed powder is a quaternary nanophase separated powder.

35. 30. The powder of claim 29, wherein the metal alloy powder comprises: NiCu with 5 at.%, 10 at.%, 12 at.%, 14 at.%, 16 at.%, 18 at.%, 20 at.%, 22 at.%, 24 at.%, 26 at.%, 28 at.%, 30 at.%, 32 at.%, 34 at.%, 36 at.%, 38 at.%, 40 at.%, 42 at.%, or 44 at.% Co and up to 5 at.% Mn.

36. A sintered body comprising the powder described in claim 29.

Images