Method for producing an object containing beryllium

Abstract

A method for producing an object comprising beryllium by depositing a layer of beryllium and a metal inoculant is disclosed. Grain refinement allows the beryllium article to have beneficial properties in terms of strength and durability.

Description

[Technical Field]

[0001] Priority claims

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 409,102, filed September 22, 2022, which is incorporated herein by reference in its entirety.

[0002]

[0002] This disclosure relates to methods for manufacturing objects comprising beryllium. In particular, the methods involve depositing successive layers that solidify to form a continuous beryllium matrix having an equiaxed grain crystalline structure. [Background technology]

[0003] Beryllium is a metal with highly desirable properties. These include high stiffness (Young's modulus 287 GPa), low density (1.85 g / cc), high modulus of elasticity (130 GPa), high specific heat (1925 J / kg·K), high thermal conductivity (216 W / m·K), and a low coefficient of linear thermal expansion (11.4×10 6 / K). As a result, beryllium and its composites are useful in aerospace structures, high performance engines and brakes, and electronic components for thermal performance and vibration damping. Beryllium and its composites are also useful in several different applications, including combustion applications, hypersonic vehicles, computer components, optics for space and ground-based systems, satellite structures, solar energy collectors, and nuclear energy amplification applications.

[0004] One limitation is that casting methods are not suitable for producing beryllium products, resulting in columnar solidification. Beryllium is a highly reactive metal with a high melting point and susceptible to reaction with mold wall materials, forming beryllium compounds (BeO and others) that become trapped in the solidified metal. In addition, grain sizes exceed 500 microns, typically significantly larger, up to 50,000 microns. This is too large to meet strength requirements, making the material brittle. Further attempts to refine the grain size through mechanical work have not met commercial success. To overcome the problems of beryllium production, beryllium powder has been used. Beryllium powder may be formed by ball milling, disk grinding, or gas atomization processes. The powder is consolidated into ingots, which may be further processed into beryllium molding components. This process requires careful handling of the beryllium powder. Additionally, powder processes have low material utilization, leading to inefficiencies and increased costs. Powder processes are also limited in their ability to form complex shapes.

[0005]

[0005] Objects built by depositing layers can have complex shapes, but they still suffer from poor crystalline structure due to the lack of plastic deformation from mechanical forming. Because the layers are built unidirectionally, solidification tends to result in a poor microstructure, with columnar grains predominating. This undesirable reduction in mechanical properties results in a loss of strength and durability. Summary of the Invention [Problem to be solved by the invention]

[0006]

[0006] There remains a need to eliminate columnar solidification in order to produce beryllium articles having reduced grain size in an efficient manner. [Means for solving the problem]

[0007]

[0007] The present disclosure relates to a method for producing beryllium articles by reducing, or more preferably eliminating, columnar structure. The microstructure of the beryllium article is improved by adding an inoculant, thereby improving mechanical properties. In one embodiment, the method disclosed herein provides for forming molten beryllium into a layer comprising a continuous beryllium matrix having an equiaxed grain crystal structure. Increased equiaxed grain size is preferred for achieving a more consistent microstructure. The grain refinement achieved by the disclosed embodiment also enables the fabrication of complex objects made from beryllium having an average grain size of 1 to 80 microns, preferably 5 to 40 microns.

[0008] In one aspect, a method for manufacturing an object comprising beryllium is provided, comprising the steps of preparing a mixture of beryllium powder and at least one metal inoculant; depositing a layer comprising the mixture on a surface; applying energy to at least a portion of the layer in a reducing atmosphere to form molten beryllium; solidifying the molten beryllium into a layer comprising a continuous beryllium matrix having a crystalline structure of equiaxed grains; and repeating the deposition / application / solidification steps for successive layers until the object having the geometric shape is obtained. In one embodiment, at least a portion of the metal inoculant is bonded to the surface of the beryllium powder. The metal inoculant may be selected from the group consisting of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, Be7Cu, and the like. 13The layer may include at least one particle containing BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, or W. Preferred metal inoculants may include Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, or Be5Zr. The mixture may be prepared by blending, atomization, mechanical alloying, or resonance mixing and includes 90 to 99.99 wt. % beryllium and 0.01 to 10 wt. % at least one metal inoculant. The beryllium powder may have a D50 average particle size of 10 to 50 microns. The metal inoculant may have a D50 average particle size of 0.001 to 5 microns. In one embodiment, an electron beam or laser is used to apply energy to at least a portion of the layer.

[0009]

[0009] In one aspect, there is provided a method for grain refinement of an object containing beryllium, the method comprising: 13 The method includes combining a beryllium alloy with at least one metal inoculant selected from the group consisting of BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W to form a prealloy composition; depositing a layer containing the prealloy composition on a surface; thermally cycling at least a portion of the layer by applying energy to form molten beryllium; solidifying the molten beryllium; and repeating the deposition / thermal cycling / precipitation steps for successive layers, each of which contains the prealloy composition and has an average grain size of 1 to 80 microns. Preferred metal inoculants may include Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, or Be5Zr. The prealloy composition contains 90 to 99.99 wt. % beryllium and 0.01 to 10 wt. % at least one metal inoculant.

[0010] In another embodiment, a composition is provided for forming a composite of beryllium and any of the following: a beryllium alloy having a crystalline structure including equiaxed grains of beryllium; and a beryllium alloy having any of the following: Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, and Be7Cu. 13 The present invention provides an object comprising a beryllium alloy containing at least one metal inoculant selected from the group consisting of BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W, forming grains that are lattice matched 1:1 or 2:1 to the beryllium grains, with the equiaxed beryllium grains having an average grain size of 1 to 80 microns. The crystal structure may contain 50 vol.% to 100 vol.% equiaxed grains. Preferred metal inoculants may include Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, or Be5Zr.

[0011]

[0011] These and other non-limiting features are more particularly described below. DETAILED DESCRIPTION OF THE INVENTION

[0012]

[0012] The present disclosure may be more readily understood by reference to the following detailed description of the preferred embodiment and examples contained therein. In the following specification and in the claims that follow, reference will be made to a number of terms which shall be defined to have the following meanings:

[0013]

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. In the case of conflict, the present document, including definitions, will control. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. The materials, methods, and examples disclosed herein are illustrative only and are not intended to be limiting.

[0014]

[0014] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0015] As used in this specification and claims, the term "comprising" can include the embodiments "consisting of" and "consisting essentially of." The terms "comprise," "include," "having," "has," "can," "contain," and variations thereof, as used herein, are intended to be open-ended transitional phrases that require the presence of the named ingredients / steps and allow for the presence of other materials / steps. However, such statements should also be construed as describing a composition or method as "consisting of" and "consisting essentially of" the recited ingredients / steps, which allows for the presence of only the recited ingredients / steps, along with any impurities that may result from them, and excludes other ingredients / steps.

[0015]

[0016] Numerical values ​​in this specification and in the claims of this application, when they refer to mixtures, pre-alloy compositions, or objects, reflect average values ​​of compositions that may contain individual polymers with different characteristics. Numerical values ​​disclosed herein include numerical values ​​that are identical when rounded to the same number of significant figures, and that do not differ from the stated value by more than experimental error using conventional measurement techniques of the type described in this application to determine the value.

[0016]

[0017] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "1 micron to 80 microns" includes the endpoints 1 micron and 80 microns, and all intermediate values). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values, as they are sufficiently imprecise to include values ​​that approximate those ranges and / or values.

[0017]

[0018] As used herein, approximating words can be used to modify any quantitative expression, which can vary without resulting in a change in the basic function to which it pertains. Thus, values ​​modified by terms such as "about" and "substantially" may in some cases not be limited to the exact value specified. The modifier "about" should also be considered to disclose a range defined by the absolute values ​​of the two endpoints. For example, the expression "about 2 to about 4" also discloses the range "2 to 4." The term "about" can refer to plus or minus 10% of the indicated number. For example, "about 10%" can indicate a range of 9% to 11%, and "about 1" can mean 0.9 to 1.1.

[0018]

[0019] For the recitation of ranges of numbers herein, each intervening number is expressly contemplated with the same precision. For example, for the range 6 to 9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0 to 7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 are expressly contemplated.

[0019]

[0020] As described herein, there is a method for manufacturing a beryllium article. Beryllium powder and a metal inoculant are used to form a continuous beryllium matrix having an equiaxed grain crystal structure. First, a mixture of beryllium, preferably beryllium powder, and the metal inoculant is prepared. In some embodiments, the mixture may be referred to as a prealloy composition. The mixture may evenly distribute the metal inoculant throughout the beryllium powder. The beryllium powder and metal inoculant mixture is exposed to an energy source and solidified by thermal cycling through heating and cooling to produce a continuous beryllium matrix having an equiaxed grain crystal structure. It has been found that the added metal inoculant acts as a nucleation site for forming a fine grain structure during solidification. These steps may be repeated until an object having a geometric or three-dimensional shape is obtained. In one embodiment, the mixture of beryllium, preferably beryllium powder, and the metal inoculant may be thermally cycled through heating and cooling to allow each layer to have a continuous beryllium matrix having an equiaxed grain crystal structure. In one embodiment, the grain structure of the beryllium article may have equiaxed grains after the heating / cooling cycle.

[0020]

[0021] Without being bound by theory, the presence of equiaxed grains has been shown to contribute to grain refinement in beryllium articles. Grain refinement in beryllium articles can lead to improved strength and processability when forming articles with a series of layers. In one embodiment, the beryllium article can have an average grain size of 1 to 80 microns, e.g., 1 to 75 microns, 1 to 60 microns, 1 to 50 microns, 1 to 40 microns, 5 to 40 microns, 5 to 25 microns, 5 to 15 microns, or 10 to 15 microns. In one embodiment, a portion of the grains in the beryllium article can have an aspect ratio of less than 3:1. In particular, 75% of the grains in the beryllium article can have an aspect ratio of less than 3:1, e.g., less than 2.5:1 or less than 2:1. The average grain size and aspect ratio can be determined using optical imaging, such as SEM imaging, and by comparison, area measurement, or the intercept parameter of ASTM E 112-12.

[0021]

[0022] The resulting grain structure of the beryllium-containing object has an average grain size that is significantly reduced in average grain size compared to the disclosed process that does not include a metal inoculant.

[0022]

[0023] The beryllium matrix contains beryllium crystals that form grains, each with its own characteristic orientation. The grains are connected to one another through grain boundaries formed during the thermal cycle process and solidification that applies energy. The grain boundaries can affect mechanical properties. The crystal structure contains equiaxed grains due to the metal inoculation, which creates multiple sites for grain refinement. In one embodiment, the beryllium-containing object has a continuous beryllium matrix with a crystal structure of equiaxed grains. The equiaxed grains are roughly similar in length, width, and height. In one embodiment, the crystal structure contains 50 vol.% or more equiaxed grains, e.g., 75 vol.% or more equiaxed grains, or 90 vol.% or more equiaxed grains. In terms of ranges, the crystal structure can contain 50 vol.% to 100 vol.% equiaxed grains, e.g., 75 vol.% to 100 vol.% or 90 vol.% to 100 vol.% equiaxed grains. Increasing the amount of equiaxed grains results in a decrease in the amount of columnar grains. Quantification of the grain size can be performed using microscopic techniques, such as X-ray diffraction analysis.

[0023]

[0024] In one embodiment, the metal inoculant or inoculant combined with beryllium comprises a metal that forms a 1:1 or 2:1 interface with the edges of the beryllium grains. In one embodiment, at least a portion of the metal inoculant is bonded to the surface of the beryllium powder, allowing for distribution of the metal inoculant throughout the beryllium matrix. The metal inoculant can exist as a loose powder, paste, or suspension that can be combined with the beryllium. In one embodiment, the metal inoculant remains unreacted when bonded to the surface of the beryllium powder. There are several techniques for combining the metal inoculant and beryllium, including mixing, blending, atomization, mechanical alloying, resonance mixing, or a combination thereof. Resonance mixing is useful for achieving thorough mixing when the beryllium powder and metal inoculant have different sizes. In one embodiment, resonance mixing induces non-contact acoustic mixing with sound waves at frequencies between 20 and 80 Hz, achieving good mixing in a short time without inducing fragmentation or stress on the beryllium and metal inoculant. Thus, while one type of metal inoculant can be combined with beryllium, in some embodiments, a mixture of metal inoculants may be used.

[0024]

[0025] In one embodiment, the metal inoculant is selected from the group consisting of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, and Be7Cu. 13 , BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, or W. Combinations of metal inoculants may be used in some embodiments. More preferably, the metal inoculant may include Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, or Be5Zr. In particular, the metal inoculants introduce grain refinement and result in an equiaxed grain crystal structure. These metal inoculants can efficiently match beryllium in terms of interatomic and interplanar spacing mismatch. Crystal orientation can be measured by polarized optical microscopy and / or EBSD (electron backscatter diffraction).

[0025]

[0026] In one embodiment, the mixture preparation step may be optional, and the beryllium and metal inoculant may be deposited as a layer without forming a mixture. Accordingly, a method for manufacturing a beryllium article is provided, comprising the steps of depositing a layer comprising beryllium and a metal inoculant on a surface, heating at least a portion of the layer by applying energy to form molten beryllium, solidifying the molten beryllium, and repeating the deposition / thermal cycle / precipitation steps for successive layers. After the desired layers have been built, an object may be formed, the beryllium-based article having an average grain size of 1 to 80 microns.

[0026]

[0027] In one embodiment, the metal inoculant can be a metal powder. The metal powder can have an aspect ratio (average length to average width) of 1:1 to 100:1, for example, 1:1 to 50:1, 1:1 to 20:1, 1:1 to 10:1, or 1:1 to 5:1. The metal powder can be smaller than the beryllium powder. The metal powder can have an average diameter (D) of less than 10 microns, for example, less than 8 microns, less than 5 microns, less than 2.5 microns, less than 2 microns, or less than 1 micron. 50 In some embodiments, the metal powder can be nanoparticles, e.g., have an average (D 50 In some embodiments, the nanoparticles may have an average diameter (D) of 10 to 1000 nanometers, e.g., 25 to 950 nanometers, 50 to 900 nanometers, 100 to 800 nanometers, or 300 to 700 nanometers. 50 Thus, the metal powder may have an average (D 50 ) particle size. 50 , i.e. the diameter at which a cumulative percentage of 50% of the particle's volume is reached.

[0027]

[0028] In one embodiment, each of the deposited layers may contain beryllium in an amount of 90 to 99.99 wt %, based on the total weight of each layer. More preferably, each layer may contain beryllium in an amount of 95 to 99.9 wt %, such as 97 to 99.5 wt % or 98 to 99 wt %.

[0028]

[0029] In one embodiment, the beryllium comprises beryllium powder. Exemplary beryllium powders include S-65 grade (minimum Be content 99.2%, maximum BeO 0.9%), S-200 (minimum Be content 98.5%), 0-30 (isostatically pressed beryllium, minimum Be content 99%, maximum BeO 0.5%), and all available from Materion Corporation. The beryllium powder may have an aspect ratio (average length to average width) of 1:1 to 100:1, e.g., 1:1 to 50:1, 1:1 to 20:1, 1:1 to 10:1, or 1:1 to 5:1. In one embodiment, the beryllium powder may be spherical in shape. The beryllium powder may have an average diameter (D) of 1 micron to 200 microns, e.g., 5 microns to 175 microns, 10 microns to 150 microns, 15 microns to 100 microns, 25 microns to 70 microns, or 25 microns to 50 microns. 50 ) particle size. 50 , i.e., the diameter at which a cumulative percentage of 50% of the particles reach by volume. Powders smaller than 200 microns may be constructively used to form beryllium articles with reduced grain refinement. If required, the beryllium powder may be sieved to achieve the desired particle size.

[0029]

[0030] In one embodiment, the beryllium powder can be in the form of particles having a core-shell structure, with the beryllium constituting the core and a continuous or semi-continuous coating constituting the shell. In some embodiments, the continuous or semi-continuous coating can include a metal inoculant. The beryllium coating can be achieved by ball milling, resonance mixing, spray bonding, spray drying, laser ablation, electrical discharge machining, and atomic layer deposition. In some embodiments, the coating includes nickel, either in the form of pure nickel or a nickel alloy. The core can be 0.1 wt% to 99.9 wt%, or 50 wt% to 99.9 wt%, or about 92 wt% to less than 100 wt% of the particle. In some embodiments, the coating can be 0.1 wt% to 99.9 wt%, or 0.1 wt% to 50 wt%, or greater than zero wt% to about 8 wt% nickel. In certain embodiments, the beryllium powder comprises about 92 wt% to less than 100 wt% beryllium and greater than zero wt% to about 8 wt% nickel. It is generally contemplated that the coating forms particles for grain refinement.

[0030]

[0031] The metal inoculant can be combined with the beryllium in an effective amount to increase the number of grains during solidification. In one embodiment, the metal inoculant can be present in an amount of 0.01 to 10 wt %, based on the total weight of each layer. More preferably, the metal inoculant can be present in an amount of 0.1 to 5 wt %, e.g., 0.5 to 3 wt %, or 1 to 2 wt %.

[0031]

[0032] By thermally cycling several deposited layers, an object including a beryllium article can be formed. In particular, the method can achieve a three-dimensional beryllium article. In the method, the thermal cycling can include applying energy to at least a portion of the layer to form molten beryllium and solidifying the molten beryllium into a layer through cooling. After thermal cycling above the temperature at which the molten beryllium is formed, the molten beryllium solidifies. This results in the formation of an equiaxed grain crystal structure, achieving the desired grain refinement. The equiaxed grain crystal structure can also reduce or eliminate columnar grain growth. In one embodiment, a complex shape can be formed from an article having multiple layers. In one embodiment, the resulting shape can be a geometric or three-dimensional shape formed from multiple layers. In one embodiment, the method preferably deposits the first layer at a relatively high rate. In one embodiment, the first layer can be uniformly deposited by depositing the mixture on the surface of a substrate. In some embodiments, the first layer can be deposited on a surface such as a substrate, base, or substrate.

[0032]

[0033] The method can begin by depositing a first layer in a build box. Preferably, a mixture containing beryllium powder and a metal inoculant is transferred to the build box with minimal loss or contamination of the surrounding area. The build box includes a surface, e.g., a build base, and sidewalls. The build base is a generally flat surface upon which successive layers are deposited. The build base can move along a vertical z-axis based on signals from a computerized controller. The sidewalls cooperate with the build base to form a "box" that contains the deposited mixture. Generally, the sidewalls remain in a fixed position, allowing the build base to move downward to deposit the next layer of mixture.

[0033]

[0034] Each layer can be deposited on a surface in a predetermined pattern. In some embodiments, the preset pattern is determined based on a computer-aided design (CAD) layer. Any suitable technique for depositing the first layer is suitable for the method, including spreading, painting, brushing, rolling, spraying, or dispensing. In one embodiment, one or more deposition heads are used to move in a horizontal xy plane. A controller can be used to move the one or more deposition heads as specified by the design. The horizontal xy plane is the plane defined by the x-axis and y-axis, where the x-axis, y-axis, and z-axis are orthogonal to each other.

[0034]

[0035] In some embodiments, deposition occurs under an inert gas atmosphere. In one embodiment, deposition can occur in a reducing atmosphere to reduce oxide formation. After the beryllium and metal inoculant layers are deposited, energy can be applied in a reducing atmosphere. In one embodiment, the reducing atmosphere contains less than 20 vol.% oxygen or other oxidizing agents, such as less than 15 vol.%, less than 10 vol.%, or less than 5 vol.%.

[0035]

[0036] In one embodiment, each layer can be deposited in a uniform manner. The initial layer can have a thickness of 20 to 200 microns, e.g., 25 to 150 microns, 25 to 110 microns, 30 to 100 microns, 35 to 75 microns, or 40 to 60 microns. In some embodiments, the layers can be formed by compressing the deposited material using an optional compacting method. Compressing the powder may be desired to provide a thin layer, using a mechanical compactor such as a doctor blade, double rolling, or electrostatic force. In some embodiments, the layers can be deposited.

[0036]

[0037] Following deposition of the initial layer, the method uses a thermal cycling process to apply energy, preferably from an electron beam or laser, to at least a portion of the layer to form molten beryllium, which then solidifies into a layer. In one embodiment, the method includes solidifying the molten beryllium into a layer comprising a continuous beryllium matrix having an equiaxed grain crystal structure. The thermal cycle transitions through a thermal gradient at a high rate to form the molten beryllium. In one embodiment, an energy source can be directed at at least a portion of the initial layer. The energy source can generate localized or focused energy to heat at least a portion of the initial layer, preferably to heat at least a portion of the initial layer. In one embodiment, the energy source can be sufficient to form the molten beryllium. The energy source can be an electron beam or a laser beam, and can be 10 3 W / mm 2 ~10 7 W / mm 2 , e.g. 10 4 W / mm 2 ~10 7 W / mm 2 , or 10 5 W / mm 2 ~10 6 W / mm 2 It has a power density of 10 7 W / mm 2 Operating the energy source at a power less than 1000 W is sufficient to form molten beryllium. In one embodiment, the effective diameter of the energy source can be 10 to 200 microns, e.g., 25 to 150 microns, or 35 to 100 microns. The scanning speed of the energy source can be 10 mm / s to 2000 mm / s, e.g., 50 to 1500 mm / s or 100 to 1000 mm / s. The raster width of the energy source can be 50 to 500 microns, e.g., 75 to 450 microns, 75 to 400 microns, or 100 to 350 microns. In one embodiment, the layer thickness can be 20 microns to 200 microns, e.g., 25 microns to 175 microns or 50 microns to 150 microns.

[0037]

[0038] In one embodiment, the energy source and / or another source heats the first layer to a temperature between 1000° C. and 1600° C., e.g., between 1100° C. and 1450° C., between 1200° C. and 1400° C., or between 1290° C. and 1325° C. In one embodiment, the applied energy is applied for less than 300 seconds, e.g., less than 240 seconds, less than 180 seconds, less than 120 seconds, less than 90 seconds, less than 60 seconds, less than 50 seconds, less than 45 seconds, less than 30 seconds, less than 25 seconds, less than 20 seconds, less than 10 seconds, less than 5 seconds, less than 1 second, or less than 0.5 seconds. In terms of ranges, in one embodiment, the energy is applied for 0.01 to 300 seconds, e.g., 0.01 to 240 seconds, 0.1 to 180 seconds, 0.2 to 120 seconds, 0.2 to 90 seconds, 0.25 to 60 seconds, 0.5 to 60 seconds, 0.5 to 30 seconds, 0.5 to 15 seconds, or 0.5 to 10 seconds.

[0038]

[0039] Unless preheat is used, the first layer can be deposited at room temperature (20-25°C). In some embodiments, the deposited first layer can be preheated in the build box to a temperature of at least 100°C, e.g., at least 120°C, or 150°C, at least 200°C, at least 400°C, at least 450°C, or at least 500°C.

[0039]

[0040] The thermal condition of the article can be monitored using an infrared temperature sensor, a thermocouple, a resistance temperature detector, a thermistor, or other suitable temperature sensor. The sensor can monitor the temperature in the area where the energy and / or coolant is applied. In response to the temperature, the method can adjust the cooling rate by adjusting the flow rate, duration, or temperature of the coolant.

[0040]

[0041] Carrying out the method under reduced pressure or vacuum may allow for quality control of the layer and beryllium article material. Nevertheless, in some embodiments, the method may be carried out at atmospheric pressure.

[0041]

[0042] As part of the thermal cycling process, the method also cools the deposited layer. In one embodiment, the minimum cooling rate can be greater than 10°C / min, e.g., greater than 15°C / min or greater than 20°C / min. In some embodiments, to achieve solidification, the cooling rate can be greater than 1000°C / min, e.g., greater than 10,000°C / min. Cooling or undercooling can be achieved at a cooling rate between 10°C / min and 10,000°C / min, e.g., between 20°C / min and 5,000°C / min, between 50°C / min and 3,000°C / min, or between 100°C / min and 1000°C / min. In one embodiment, the cooling can be in the build direction of the layer. During solidification, the molten beryllium forms a continuous beryllium matrix having an equiaxed grain crystal structure. In one embodiment, the crystal structure is not oriented exclusively in the build direction.

[0042]

[0043] In one embodiment, the cooling or undercooling for solidification can be reduced due to the lattice match of the metal inoculant and the continuous beryllium matrix and low interfacial energy. Stress reduction can be improved during the solidification of each layer to produce an object comprising beryllium.

[0043]

[0044] A coolant can be used to achieve the desired cooling. The coolant can further reduce temperature gradients within the layer that tend to result in the formation of columnar grains, thereby improving grain refinement. In one embodiment, the coolant can be an inert gas such as nitrogen or a noble gas, particularly argon. The coolant can be a mixture of gases. The coolant can be delivered to the layer as a focused gas stream at temperatures below 100°C, e.g., below 75°C, below 50°C, below 25°C, below 0°C, below -10°C, below -25°C, or below -50°C. In terms of ranges, the coolant can be applied at temperatures between -200°C and 100°C, e.g., between -150°C and 50°C, or between -100°C and 25°C, including subranges thereof. The coolant flow can be adjusted as the layer is deposited, and the flow rate can be less than 500 L / min, e.g., less than 250 L / min or less than 100 L / min.

[0044]

[0045] The method continues in a similar manner for successive layers, with each layer of the deposited mixture being thermally cycled in this manner to form a continuous layer of beryllium matrix having an equiaxed grain crystal structure. After a sufficient time for precipitation has elapsed, one or more successive layers can be deposited in a predetermined pattern on at least a portion of the first layer opposite the surface. Each successive layer thereby builds upon at least a portion of the previously deposited layer, continuing to build the beryllium article. In one embodiment, the successive layers are deposited to acquire a complex shape, such as a three-dimensional shape. The successive layers can be deposited at room temperature or can be preheated similarly to the first layer. In a similar manner, an energy source is directed at at least a portion of the successive layers to thermally cycle them above a temperature that forms molten beryllium. In one embodiment, the energy source is controlled within similar operating parameters as for the first layer. Depending on the article, the pattern for each successive layer can be different. In some embodiments, the successive layers can be deposited on at least a portion of the previous or first layer.

[0045]

[0046] In some embodiments, the surface or build plate can be lowered by the thickness of the next successive layer. The thickness of successive layers can vary; in one embodiment, successive layers can have thicknesses of 20 to 200 microns, e.g., 25 to 150 microns, 25 to 110 microns, 30 to 100 microns, 35 to 75 microns, or 40 to 60 microns. In some embodiments, each successive layer can have a similar thickness, or the thickness can accommodate the beryllium article. The method can continue by repeated deposition, thermal cycling, and precipitation until the desired beryllium article is formed. In one embodiment, a three-dimensional object is formed. In one embodiment, the beryllium article can be formed from one or more successive layers, e.g., at least five successive layers, at least 10 successive layers, or at least 20 successive layers. For some articles, hundreds of layers can be used, and thus the number of layers is unlimited.

[0046]

[0047] Each successive layer may include a metal inoculant, and the method may repeat the depositing / applying / solidifying steps for each layer.

[0048] The direction of the microstructure is not limited to the build direction of successive layers. The microstructure of the beryllium-containing object can contain multiple dendritic layers with different primary growth direction angles relative to each other. This results in a beryllium-containing object that is crack-free, has complex shapes, and can be manufactured in a cost-, material-, and time-efficient manner. The presence of a metal inoculant further improves the crack-free characteristics of the object.

[0047]

[0049] In some embodiments, the method further includes curing the multiple layers prior to sintering the preform. In one embodiment, the beryllium article may be solidified and subsequently quenched. The beryllium article may be tempered for 6 to 12 hours, e.g., 8 to 10 hours. The quenching rate may be greater than 25°C / min, e.g., greater than 50°C / min or greater than 100°C / min. The quenching may be performed gradually at room temperature. The tempered article may be finished, e.g., by polishing or plating. The surface roughness of the article may be reduced, e.g., through bead blasting or barrel finishing. In some embodiments, the fabricated beryllium article may have loose or unfused particles in one or more layers. The unfused particles may be removed by blowing or suction, if necessary.

[0048]

[0050] The present disclosure has been described with reference to exemplary embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the present disclosure be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

[0049]

[0051] As used hereinafter, any reference to a series of embodiments will be understood as a disjunctive reference to each of those embodiments (e.g., "Embodiments 1-4" will be understood as "Embodiments 1, 2, 3 or 4").

[0050]

[0052] Embodiment 1 is a method for manufacturing an object comprising beryllium, the method comprising the steps of preparing a mixture of beryllium powder and at least one metal inoculant; depositing a layer comprising the mixture on a surface; applying energy to at least a portion of the layer in a reducing atmosphere to form molten beryllium; solidifying the molten beryllium into a layer comprising a continuous beryllium matrix having an equiaxed grain crystal structure; and repeating the depositing / applying / solidifying steps for successive layers until an object having the geometric shape is obtained.

[0051]

[0053] Embodiment 2 is an embodiment of embodiment 1, wherein at least a portion of the metal inoculant is bound to the surface of the beryllium powder.

[0054] In a third embodiment, the at least one metal inoculant is selected from the group consisting of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, and Be7Cu. 13 , BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W.

[0052]

[0055] Embodiment 4 is any one of Embodiments 1 or 2, wherein the at least one metal inoculant comprises at least one particle selected from the group consisting of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, and Be5Zr.

[0053]

[0056] Embodiment 5 is any one of Embodiments 1-4, wherein the continuous beryllium matrix has an average grain size of 1-80 microns.

[0057] Embodiment 6 is any one of Embodiments 1-5, wherein the continuous beryllium matrix has an average grain size of 5-40 microns.

[0054]

[0058] Embodiment 7 is any one of Embodiments 1-6, wherein the continuous beryllium matrix has an average grain size of 5-25 microns.

[0059] Embodiment 8 is any one of embodiments 1-7, wherein the mixture is prepared by blending, micronizing, mechanical alloying, or resonance mixing.

[0055]

[0060] Embodiment 9 is any one of embodiments 1-8, wherein the mixture comprises 90-99.99 wt% beryllium.

[0061] Embodiment 10 is any one of embodiments 1-9, wherein the mixture comprises 0.01-10 wt. % of at least one metal inoculant.

[0056]

[0062] Embodiment 11 is any one of embodiments 1-10, wherein an electron beam or a laser is used to apply energy to at least a portion of the layer.

[0063] Embodiment 12 is any one of embodiments 1-11, wherein the reducing atmosphere has a volume concentration of oxygen or other oxidizing agent of 10% or less by volume.

[0057]

[0064] Embodiment 13 is any one of embodiments 1 to 12, wherein the beryllium powder has a D50 average particle size of 10 to 50 microns.

[0065] Embodiment 14 is any one of embodiments 1 to 13, wherein the at least one metal inoculant has a D50 average particle size of 0.001 to 5 microns.

[0058]

[0066] In a fifteenth embodiment, the object produced by the method is a crystalline structure of beryllium containing equiaxed grains of beryllium, and one of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, and Be7Cu. 13, and at least one metal inoculant selected from the group consisting of BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W, forming grains that are 1:1 or 2:1 lattice matched to the beryllium grains.

[0059]

[0067] Embodiment 16 is a method for grain refinement of an object containing beryllium, comprising the step of: forming a beryllium alloy containing one or more of: Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, Be7Cu 13 , BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W to form a pre-alloy composition; depositing a layer including the pre-alloy composition on a surface; thermally cycling at least a portion of the layer by applying energy to form molten beryllium; solidifying the molten beryllium; and repeating the deposition / thermal cycling / precipitation steps for successive layers, each successive layer including the pre-alloy composition and having an average grain size of 1 to 80 microns.

[0060]

[0068] Embodiment 17 is an embodiment of embodiment 16, wherein the pre-alloy composition includes beryllium powder.

[0069] Embodiment 18 is any one of embodiments 16 or 17, wherein the at least one metal inoculant comprises at least one particle selected from the group consisting of Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, and Be5Zr.

[0061]

[0070] Embodiment 19 is any one of Embodiments 16 to 18, wherein the average grain size is 5 to 40 microns.

[0071] Embodiment 20 is any one of Embodiments 16 to 18, wherein the average grain size is 5 to 25 microns.

[0062]

[0072] Embodiment 21 is any one of embodiments 16-20, wherein the pre-alloy composition is prepared by compounding, atomization, mechanical alloying, or resonance mixing.

[0073] Embodiment 22 is any one of embodiments 16-21, wherein the pre-alloy composition includes 90-99.99 wt. % beryllium.

[0063]

[0074] Embodiment 23 is any one of embodiments 16-22, wherein the pre-alloy composition includes 0.01-10 wt. % metal inoculant.

[0075] Embodiment 24 is any one of embodiments 16-23, wherein an electron beam or a laser is used to apply energy to at least a portion of the layer.

[0064]

[0076] Embodiment 25 is any one of embodiments 16-24, wherein the reducing atmosphere has a volume concentration of oxygen or other oxidizing agent of 10% or less by volume.

[0077] Embodiment 26 is any one of embodiments 16 to 25, wherein the beryllium powder has a D50 average particle size of 10 to 50 microns.

[0065]

[0078] Embodiment 27 is any one of embodiments 16 to 26, wherein the at least one metal inoculant has a D50 average particle size of 0.001 to 5 microns.

[0079] Embodiment 28 is a crystalline structure containing equiaxed grains of beryllium, and Be2Co, Be2Nb, Be2Ta, Be2Ti, Be2W, Be5Hf, Be5Sc, Be5Zr, Be7Cu 13 and at least one metal inoculant selected from the group consisting of BeFe3, Cu3Mo, Cu9W, Mo, Nb, RbO2, ReRh, Ta, TiV, and W, forming crystal grains that are lattice matched to the beryllium crystal grains at a 1:1 or 2:1 ratio, and the equiaxed beryllium crystal grains have an average crystal grain size of 1 to 80 microns.

[0066]

[0080] Embodiment 29 is an embodiment of embodiment 28, wherein the crystalline structure comprises 50 vol.% to 100 vol.% equiaxed grains.

[0067]

[0081] While the present invention has been described in detail, modifications within the spirit and scope of the present invention will be readily apparent to those skilled in the art. In view of the foregoing discussion, relevant knowledge in the art, and the references discussed above in connection with the Background Art and Detailed Description, the disclosures of which are incorporated herein by reference in their entirety. In addition, aspects of the present invention and portions of the various embodiments and features referred to below and / or in the appended claims may be combined or interchanged, either in whole or in part. In the foregoing description of various embodiments, embodiments referring to other embodiments may be appropriately combined with other embodiments, as will be recognized by those skilled in the art. Furthermore, those skilled in the art will recognize that the foregoing description is illustrative only and is not intended to be limiting.

Claims

1. 1. A method for producing an object comprising beryllium, comprising: preparing a mixture of beryllium powder and at least one metal inoculant; depositing a layer comprising said mixture on a surface; applying energy to at least a portion of the layer in a reducing atmosphere to form molten beryllium; solidifying the molten beryllium into a layer comprising a continuous beryllium matrix having an equiaxed grain crystalline structure; and repeating the depositing / applying / solidifying steps for successive layers until the object having the geometric shape is obtained. A method comprising:

2. The method of claim 1 , wherein at least a portion of the metal inoculant is bound to a surface of the beryllium powder.

3. The at least one metal inoculant is Be ２ Co, Be ２ Nb, Be ２ Ta, Be ２ Ti, Be ２ W, Be ５ Hf, Be ５ Sc, Be ５ Zr, Be ７ Cu １３ , BeFe ３ , Cu ３ Mo, Cu ９ W, Mo, Nb, RbO ２ 3. The method of claim 1, wherein the SiO 2 particles comprise at least one particle selected from the group consisting of ReRh, Ta, TiV and W.

4. The at least one metal inoculant is Be ２ Co, Be ２ Nb, Be ２ Ta, Be ２ Ti, Be ２ W, Be ５ Hf, Be ５ Sc and Be ５ 3. The method of claim 1, further comprising at least one particle selected from the group consisting of Zr.

5. The method of any one of claims 1 to 4, wherein the continuous beryllium matrix has an average grain size of 1 to 80 microns.

6. The method of any one of claims 1 to 4, wherein the continuous beryllium matrix has an average grain size of 5 to 40 microns.

7. The method of any one of claims 1 to 4, wherein the continuous beryllium matrix has an average grain size of 5 to 25 microns.

8. The method of any one of claims 1 to 7, wherein the mixture is prepared by blending, atomization, mechanical alloying or resonance mixing.

9. 8. The method of claim 1, wherein the mixture comprises 90 to 99.99% by weight of beryllium.

10. The method according to any one of claims 1 to 7, wherein the mixture comprises 0.01 to 10% by weight of the at least one metal inoculant.

11. The method according to any one of claims 1 to 10, wherein an electron beam or a laser is used to apply energy to at least a portion of the layer.

12. The method of any one of claims 1 to 11, wherein the reducing atmosphere has a volume concentration of oxygen or other oxidizing agent of 10% by volume or less.

13. 13. The method of any one of claims 1 to 12, wherein the beryllium powder has a D50 average particle size of 10 to 50 microns.

14. 14. The method of any one of claims 1 to 13, wherein the at least one metal inoculant has a D50 average particle size of 0.001 to 5 microns.

15. 10. An object prepared by the method of claim 1, Beryllium, a crystalline structure containing equiaxed grains of beryllium; Be ２ Co, Be ２ Nb, Be ２ Ta, Be ２ Ti, Be ２ W, Be ５ Hf, Be ５ Sc, Be ５ Zr, Be ７ Cu １３ , BeFe ３ , Cu ３ Mo, Cu ９ W, Mo, Nb, RbO ２ , at least one metal inoculant selected from the group consisting of ReRh, Ta, TiV and W; Including, forming grains that are lattice matched 1:1 or 2:1 to the beryllium grains; The object, wherein the equiaxed grains of the beryllium have an average grain size of 1 to 80 microns.

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