Grain refinement method of beryllium product

Abstract

The invention discloses a grain refinement method for beryllium products. The grain refinement enables the beryllium article to have beneficial properties in terms of strength and durability. A method stabilizes the beta phase of precipitated beryllium after cycling at a temperature above a beta transition temperature greater than or equal to the beta transition temperature.

Description

Priority declaration

[0001] This application claims priority to U.S. Provisional Application No. 63 / 404,362, filed on September 7, 2022, which is incorporated herein by reference in its entirety. Technical Field

[0002] The present disclosure relates to a method of producing a beryllium article. In particular, the method produces a beryllium article having a β-phase grain structure and a reduced columnar grain structure. The increased β-phase grain structure results in improved strength and processing. background

[0003] Beryllium is a metal with very desirable properties. These include high stiffness (Young's modulus = 287 GPa), low density (1.85 g / cc), high elastic modulus (130 GPa), high specific heat (1925 J / kg·K), high thermal conductivity (216 W / m·K), and low linear thermal expansion coefficient (11.4×10 6 / °K). Therefore, beryllium and its composites can be used in aviation and aerospace structures, high-performance engines and brakes, and electronic components to provide thermal performance and vibration damping. Beryllium and its composites can also be used in a variety of different applications, including combustion applications, hypersonic vehicles, computer components, optical devices for space-based and land-based systems, satellite structures, solar collectors, and nuclear energy growth applications.

[0004] One limitation is that casting methods are not suitable for making beryllium products and result in columnar solidification. Beryllium is a highly reactive metal with a high melting point, making it easy to react with the mold wall material to form beryllium compounds (BeO, etc.) trapped in the solidified metal. In addition, the grain size is greater than 500 microns, and is often much higher, up to 50,000 microns. This is too large to meet strength requirements and results in brittle materials. Further attempts to refine the grains by mechanical processing have not yet achieved commercial success. In order to overcome the beryllium production problem, beryllium powder has been used. Beryllium powder can be formed by ball milling, disc milling or gas atomization processes. The powder is consolidated into an ingot, which can be further processed into a molded component of beryllium. This method requires careful handling of beryllium powder. In addition, the powder process has a low material utilization rate, which leads to low efficiency and increased costs. The powder process is also limited in forming complex shapes.

[0005] Objects built by depositing layers can allow for complex shapes, but still suffer from poor crystal structure due to the lack of plastic deformation from mechanical forming. Since the layers are built in one direction, solidification tends to result in poor microstructure, and columnar grains are prevalent. The undesirable reduction in mechanical properties results in a loss of strength and durability.

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

[0007] The present disclosure relates to methods of making beryllium articles. In one embodiment, a method of grain refinement of beryllium in an efficient manner is provided, which achieves improvements in strength and durability. In one embodiment, the method disclosed herein provides efficient grain refinement by including a stabilizer to precipitate beta phase grains of beryllium.

[0008] In one embodiment, a method of grain refining a beryllium-based article is provided, the method comprising combining beryllium and at least one stabilizer, the stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron to form a pre-alloy composition, depositing a layer comprising the pre-alloy composition on a surface, cycling at least a portion of the layer at a temperature above or equal to the beta transus temperature of the pre-alloy composition, preferably 1050° C. to 1250° C., precipitating a beryllium beta phase in the layer, and repeating the deposition / cycling / precipitation for one or more subsequent layers, wherein each subsequent layer comprises the pre-alloy composition. In one embodiment, the beryllium-based article has an average grain size of 1 to 80 microns. In one embodiment, the beryllium-based article may comprise 1 atomic % to 99 atomic % of beta phase species, more preferably 10 atomic % to 60 atomic %, based on the total beryllium in the beryllium-based article. In one embodiment, the pre-alloy composition comprises 40 to 95 weight percent beryllium and 5 to 60 weight percent of the at least one stabilizer. The pre-alloy composition may be in the form of particles, and the particles may have a D50 average particle size of 10 to 50 microns. The cycle may involve exposing each deposited layer to an energy source and then cooling.

[0009] In one embodiment, a method of grain refining a beryllium-based article is provided, the method comprising depositing a layer on a surface, the layer comprising a prealloy composition, the prealloy composition comprising beryllium and at least one stabilizer, the stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron, cycling at least a portion of the layer at a temperature above a beta transus temperature greater than or equal to the beta transus temperature of the prealloy composition, precipitating a beta phase of beryllium in the layer, and repeating the deposition / cycling / precipitation for one or more subsequent layers, wherein each subsequent layer comprises the prealloy composition, and the beryllium-based article has an average grain size of 1 to 80 microns. In one embodiment, the beryllium-based article may comprise 1 atomic % to 99 atomic % of beta phase species based on the total beryllium in the beryllium-based article.

[0010] In one embodiment, a beryllium-based article is provided, comprising beryllium and at least one stabilizer comprising at least one metal selected from cobalt, copper, nickel, and iron, wherein the beryllium-based article has an average grain size of 1 to 80 microns, and wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of beta phase species based on the total beryllium in the beryllium-based article.

[0011] In one embodiment, a beryllium-based article is provided, comprising beryllium and at least one stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron, wherein the beryllium-based article has an average grain size of 1 to 80 microns, and wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of beta phase species, based on the total beryllium in the beryllium-based article, produced by: combining beryllium and at least one stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron to form a pre-alloyed composition; depositing a layer comprising the pre-alloyed composition on a surface; cycling at least a portion of the layer at a temperature above a beta transus temperature greater than or equal to the pre-alloyed composition; precipitating a beta phase of beryllium in the layer; and repeating the deposition / cycling / precipitation for one or more subsequent layers.

[0012] These and other non-limiting features are more particularly described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] A further understanding of the nature and advantages of the disclosed technology may be realized by reference to the remaining portions of the specification and the accompanying drawings.

[0014] Figure 1 is a phase diagram of a beryllium-based article having a metal stabilizer according to embodiments disclosed herein; and

[0015] Figure 2 is a flow chart of an exemplary method of forming a beryllium article wherein each layer comprises a pre-alloyed composition. Details

[0016] The present disclosure may be understood more readily by reference to the following detailed description of contemplated embodiments and the examples included 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.

[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as are generally understood by those of ordinary skill in the art. In the event of a conflict, this document (including definitions) shall prevail. Preferred methods and materials are described below, although methods and materials similar or equivalent to those described herein may be used in the practice or testing of the present disclosure. All publications, patent applications, patents, and other references mentioned herein are incorporated herein by reference in their entirety. The materials, methods, and examples disclosed herein are exemplary only and are not intended to be limiting.

[0018] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0019] The term "comprising" as used in the specification and claims may include the embodiments of "consisting of" and "consisting essentially of." As used herein, the terms "comprising," "including," "having," "having," "may," "containing," and variations thereof are intended to be open transition phrases that require the presence of specified ingredients / steps and allow for the presence of other ingredients / steps. However, such descriptions should be interpreted as also describing compositions or methods as "consisting of" and "consisting essentially of" the listed ingredients / steps, which only allow for the presence of the specified ingredients / steps, and any impurities that may result therefrom, and exclude other ingredients / steps.

[0020] The numerical values ​​in the specification and claims of this application, when they refer to polymers or polymer compositions, reflect the average values ​​of the composition that may contain individual polymers with different characteristics. The numerical values ​​disclosed herein should be understood to include the same value when reduced to the same number of significant figures and the value that differs from the specified value by less than the experimental error of the conventional measurement techniques type described in this application for determining the value.

[0021] All ranges disclosed herein are inclusive of the recited endpoints and are independently combinable (e.g., the range "1 micron to 40 microns" includes the endpoints 1 micron and 40 microns, and all intermediate values). The endpoints of the ranges and any values ​​disclosed herein are not limited to the exact ranges or values; they are imprecise enough to include values ​​approximating these ranges and / or values.

[0022] As used herein, approximations can be used to modify any quantitative representation that may vary without causing a change in the basic function to which it relates. Therefore, values ​​modified by terms such as "approximately" and "substantially" may not be limited to the specified exact value in some cases. The modifier "approximately" 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 a range of "2 to 4". The term "approximately" can refer to plus or minus 10% of the numerical value shown. For example, "about 10%" can refer to a range of 9% to 11%, and "about 1" can refer to 0.9-1.1.

[0023] For the enumeration of numerical ranges herein, each intermediate number with the same precision is explicitly considered. For example, for the range of 6-9, in addition to 6 and 9, the numbers 7 and 8 are also considered, and for the range of 6.0-7.0, 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 explicitly considered.

[0024] As described herein, there is a method for producing a beryllium article. The beryllium article may contain a stabilizer for promoting precipitation of β-phase grains. The mixture of beryllium and the stabilizer is cycled through heating and cooling to produce a grain structure with an increased amount of β-phase grains. In one embodiment, the mixture of beryllium and the stabilizer can be rapidly cycled through heating and cooling to produce a grain structure with an increased amount of β-phase grains. In one embodiment, the grain structure of the beryllium article after cycling may have equiaxed-grains. Without being bound by theory, the presence of β-phase grains has been shown to contribute to grain refinement of the beryllium article. When forming an article having a series of layers, grain refinement of the beryllium-based article can result in improved strength and processing. In one embodiment, the beryllium article may have an average grain size of 1 to 80 microns, such as 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 of the beryllium article may have an aspect ratio of less than 3:1. In particular, 75% of the grains of the beryllium article may have an aspect ratio of less than 3:1, such as 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 using the comparative, planimetric, or intercept parameters of ASTM E112-12. Grain refinement improves the mechanical properties of beryllium-based articles.

[0025] In one embodiment, the beryllium product is enriched with β-phase species. Stable β-phase species can improve strength and reduce the cost of producing beryllium products. Having a certain volume of β-phase species enables the production of beryllium products with controlled grain refinement. In one embodiment, based on the total beryllium in the beryllium-based product, the beryllium product contains 1 atomic % to 99 atomic % of β-phase species, such as 5 atomic % to 90 atomic %, 10 atomic % to 90 atomic %, 10 atomic % to 75 atomic %, 10 atomic % to 60 atomic %, 20 atomic % to 60 atomic %, or 25 atomic % to 50 atomic %. Quantification of β-phase species can be performed using microscopy techniques such as x-ray diffraction analysis. In addition, the physical properties of the beryllium product may show a strong correlation with the presence of β-phase species.

[0026] In one embodiment, the stabilizer combined with beryllium includes a metal of a β-phase species that stabilizes beryllium. The stabilizer forms a pre-alloyed composition when combined with beryllium. In one embodiment, the stabilizer is a eutectoid type β-stabilizing element. The stabilizer can exist as a loose powder, paste, or suspension that can be combined with beryllium. In one embodiment, the metal remains unreacted when combined with beryllium. There are several methods to combine stabilizers and beryllium, such as mixing, blending, atomization, mechanical alloying, resonant mixing, or a combination thereof. When the blend of beryllium and stabilizer has different sizes, resonant mixing is useful in order to achieve adequate mixing. In one embodiment, resonant mixing uses a sound wave with a frequency of 20 to 80 Hz to induce non-contact acoustic mixing to achieve good mixing in a short time without causing rupture or stress of beryllium and stabilizer. Accordingly, a single stabilizer may be combined with beryllium to achieve beta phase grains, while in some embodiments, a mixture of stabilizers may be present. In one embodiment, the stabilizer comprises cobalt, copper, nickel, iron, and combinations thereof. A preferred embodiment may combine cobalt and / or copper with beryllium to form a pre-alloyed composition.

[0027] In one embodiment, the combining step may be optional, and the pre-alloyed composition comprising beryllium and the at least one stabilizer is deposited as a layer. Accordingly, a method of producing a beryllium article is provided, comprising depositing a layer of a pre-alloyed composition comprising beryllium and at least one stabilizer on a surface, the stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron, cycling at least a portion of the layer at a temperature above a beta transus temperature greater than or equal to the beta transus temperature of the pre-alloyed composition, precipitating a beta phase of beryllium in the layer, and repeating the deposition / cycling / precipitation for one or more subsequent layers, wherein each subsequent layer comprises the pre-alloyed composition, and the beryllium-based article has an average grain size of 1 to 80 microns.

[0028] Figure 1 is a phase diagram showing an exemplary beta phase region 102 of beryllium caused by temperature and addition of metal stabilizers, such as cobalt, copper, nickel, iron, and combinations thereof. A beta transformation temperature line 104 is shown, and the beta phase of beryllium is formed in cycles above this temperature during the process. An alpha phase region 106, in the absence of metal stabilizers, beryllium approaches an alpha phase with a low beta phase, which cannot achieve grain refinement.

[0029] In one embodiment, the stabilizer can be a metal powder. The metal powder can have an aspect ratio (average length to average width) of 1:1 to 100:1, such as 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 beryllium powder. The metal powder can have an average (D) of less than 10 microns, such as less than 8 microns, less than 5 microns, less than 2.5 microns, less than 2 microns, or less than 1 micron. 50 ) particle size. In some embodiments, the metal powder may have an average (D 50 ), such as less than 1 micron. In some embodiments, the nanoparticles may have an average (D) of 10 to 1000 nanometers, such as 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) of 0.0001 to 10 microns, such as 0.0005 to 7.5 microns, 0.001 to 5 microns, 0.01 to 2.5 microns, or 0.1 to 1.5 microns. 50 ) particle size. Metal powders having the appropriate size are effective in stabilizing the beta phase of beryllium.

[0030] In one embodiment, the pre-alloy composition may include beryllium in an amount of 40 to 95 weight percent based on the total weight of the pre-alloy composition. More preferably, the pre-alloy composition may include beryllium in an amount of 50 to 85 weight percent, such as 55 to 80 weight percent or 60 to 75 weight percent.

[0031] In one embodiment, the beryllium comprises beryllium powder. Exemplary beryllium metals include S-65 grade (99.2% minimum Be content, 0.9% maximum BeO), S-200 grade (98.5% minimum Be content), 0-30 (Hot Isostatically Pressed beryllium, minimum 99% Be content, 0.5% maximum BeO), and are 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. The beryllium powder may have an average (D) of 1 micron to 200 microns, such as 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. The particle size is D 50 , or the diameter at which a cumulative percentage of particles of 50% by volume is reached. Powders less than 200 microns can be constructively used to form beryllium products with reduced grain refinement. When necessary, the beryllium powder can be screened to achieve the desired size.

[0032] In one embodiment, beryllium powder can be in the form of particles with a core-shell structure, wherein beryllium constitutes the core and a continuous or semi-continuous coating constitutes the shell. In some embodiments, the continuous or semi-continuous coating may include a stabilizer. The coating of beryllium may be achieved by ball milling, resonance mixing, spray binding, spray drying, laser ablation, electrical-discharge machining, and atomic layer deposition. In some embodiments, the coating includes nickel in the form of pure nickel or a nickel alloy. The core may be 0.1% to 99.9% by weight of the particle, or 50% to 99.9% by weight, or about 92% to less than 100% by weight of the particle. In some embodiments, the coating may be 0.1% to 99.9% by weight of the particle, or 0.1% to 50% by weight, or greater than 0% to about 8% by weight of nickel. In a particular embodiment, the beryllium powder includes from about 92 wt% to less than 100 wt% beryllium and from greater than 0 wt% to about 8 wt% nickel. Generally, the coating is considered to constitute particles for grain refinement.

[0033] In one embodiment, the beryllium powder can have at least a portion of the stabilizer bound to the surface of the beryllium powder.

[0034] The stabilizer may be combined with beryllium in an effective amount to stabilize the beta phase of beryllium that precipitates after cycling through heating and cooling. In one embodiment, the amount of stabilizer combined with beryllium may be 5 to 60 weight percent based on the total weight of the pre-alloy composition. More preferably, the stabilizer may be present in an amount of 5 to 40 weight percent, such as 10 to 35 weight percent, 10 to 25 weight percent, or 15 to 20 weight percent.

[0035] In one embodiment, the stabilizer is cobalt, which can be combined with beryllium in an effective amount to precipitate the beta phase of beryllium. Cobalt can effectively stabilize the precipitated beryllium beta phase and can be effective for grain refinement to produce an article with improved strength and performance. In one embodiment, cobalt can be present in the pre-alloy composition as a stabilizer in an amount of 15 to 25 weight percent based on the total weight of the pre-alloy composition. More preferably, cobalt can be present in an amount of 15 to 23 weight percent, such as 17 to 22 weight percent or 18 to 20 weight percent.

[0036] In one embodiment, the stabilizer is copper, which can be combined with beryllium in an effective amount to precipitate the beta phase of beryllium. Copper can effectively stabilize the beta phase of precipitated beryllium and can be effective for grain refinement to produce an article with improved strength and performance. In one embodiment, copper can be present in the pre-alloy composition as a stabilizer in an amount of 40 to 60 weight percent based on the total weight of the pre-alloy composition. More preferably, copper can be present in an amount of 45 to 60 weight percent, such as 45 to 55 weight percent or 45 to 50 weight percent.

[0037] In one embodiment, the stabilizer is nickel, which can be combined with beryllium in an effective amount to precipitate the beta phase of beryllium. Nickel can effectively stabilize the beta phase of precipitated beryllium and can be effective for grain refinement to produce an article with improved strength and performance. In one embodiment, nickel can be present in the pre-alloy composition as a stabilizer in an amount of 25 to 35 weight % based on the total weight of the pre-alloy composition. More preferably, nickel can be present in an amount of 27 to 35 weight %, such as 27 to 33 weight % or 27 to 30 weight %.

[0038] In one embodiment, the stabilizer is iron, which can be combined with beryllium in an effective amount to precipitate the beryllium beta phase. Iron can effectively stabilize the precipitated beryllium beta phase and can be effective for grain refinement to produce an article with improved strength and performance. In one embodiment, iron can be present in the pre-alloy composition as a stabilizer in an amount of 5 to 15 weight percent based on the total weight of the pre-alloy composition. More preferably, iron can be present in an amount of 7 to 15 weight percent, such as 7 to 12 weight percent or 7 to 10 weight percent.

[0039] The stabilization of the beta phase may also be combined with a nucleating agent for grain refinement. In one embodiment, the pre-alloy composition may include an intermetallic compound of beryllium that acts as a nucleant. In one embodiment, the intermetallic compound of beryllium is a beryllium compound, such as beryllium titanium (BeTi). 12 Ti, Be2Ti), beryllium chromium (Be2Cr or Be 12 Cr), iron beryllium (FeBe5), beryllium zirconium (Be 13 Zr, Be5Zr, Zr2Be 17 ), Tantalum Beryllium (TaBe2, Ta2Be 17 、TaBe 12 or TaBe 17 ), beryllium molybdenum (Be2Mo, Be 12 Mo, Be 22 Mo), niobium beryllium (NbBe2, NbBe3, Nb2Be 17 、NbBe 12 ), beryllium tungsten (Be 22 W), beryllium strontium (Be 13 The nucleating agent may be present in an amount of 0 to 40 wt %, such as 0 to 35 wt %, 0 to 30 wt %, 0.5 to 35 wt %, 1 to 30 wt %, or 1 to 20 wt %, based on the total weight of the pre-alloy composition.

[0040] In one embodiment, the pre-alloy composition can be in the form of particles, such as a powder. The particles have a D50 average particle size of 10 to 50 microns, such as 15 to 50 microns, 20 to 45 microns, or 25 to 40 microns. At least a portion of the stabilizer can be bonded to the surface of the beryllium powder.

[0041] By cycling several deposited pre-alloy composition layers, a beryllium product can be formed. After a temperature cycle above the β-transformation temperature greater than or equal to the pre-alloy composition, the β-phase of beryllium can be precipitated. Beryllium is transformed from its α-form to the β-form at a temperature known as the β-transformation, such as 1050°C to 1250°C. Stabilization of the β-phase of beryllium is provided to achieve the desired grain refinement. In one embodiment, a complex shape can be formed by a product having multiple layers. In one embodiment, the resulting shape can be a geometric shape or a three-dimensional shape formed by multiple layers. In one embodiment, the method deposits an initial layer, preferably at a relatively high rate. In one embodiment, the initial layer can be uniformly deposited by depositing the pre-alloy composition on the surface of the substrate. In some embodiments, the initial layer can be deposited on a surface such as a substrate, a platform or a substrate.

[0042] Figure 2 2 is a flow chart of an exemplary method 200 for grain refining a beryllium-based article. In step 210, a pre-alloy composition is formed by combining beryllium 212 and at least one stabilizer 214. In one embodiment, the stabilizer 214 is a metal stabilizer, which can be at least one metal selected from cobalt, copper, nickel, and iron. Step 210 can involve mixing, blending, atomizing, mechanical alloying, resonance mixing, or a combination thereof to combine the beryllium 212 and the at least one stabilizer 214.

[0043] In step 220, a layer comprising a pre-alloyed composition is deposited on a surface. In step 230, a cyclic process is initiated to cycle at least a portion of the deposited layer at a temperature above a beta transus temperature greater than or equal to the pre-alloyed composition. The cyclic step may include heating to a temperature greater than or equal to the beta transus temperature and cooling to a temperature less than or equal to the beta transus temperature. In step 240, a beta phase of beryllium is precipitated in the layer. Steps 220-240 are repeated for each layer of the beryllium-based article. Steps 220-240 may be repeated depending on the number of layers of the beryllium-based article.

[0044] In one embodiment, the method can be started by depositing an initial layer in a build box. Preferably, the pre-alloyed composition is transferred to the build box under minimal loss or surrounding area contamination. The build box comprises a surface, such as a build platform, and a sidewall. The build platform is typically a flat surface on which subsequent layers are deposited. The build platform can move along the vertical z-axis based on a signal provided by a computer-operated controller. The sidewall cooperates with the build platform to form a "box" containing the deposited pre-alloyed composition. Typically, the sidewall remains in a fixed position, and the build platform moves downward to allow the next layer of the pre-alloyed composition to be deposited.

[0045] The initial layer can be deposited on the surface with a predetermined pattern. In some embodiments, the layer based on the computer-aided design (CAD) model determines the preset pattern. Any suitable technology for depositing the initial layer is applicable to the method, including spreading, coating, brushing, roller coating, spraying or dispensing. In one embodiment, one or more deposition heads are used and moved in the horizontal xy plane. A controller can be used to move the one or more deposition heads specified by the design. The horizontal xy plane is a plane defined by an x-axis and a y-axis, wherein the x-axis, the y-axis and the z-axis are orthogonal to each other.

[0046] In some embodiments, the deposition is carried out under an inert gas atmosphere. In one embodiment, the deposition can be carried out in a reducing atmosphere to reduce the formation of oxides. After the layers of beryllium and stabilizer are deposited, energy can be applied in a reducing atmosphere. In one embodiment, the reducing atmosphere contains less than 20% oxygen by volume, such as less than 15% by volume, less than 10% by volume, or less than 5% by volume.

[0047] In one embodiment, each layer can be deposited in a uniform manner. The initial layer can have a thickness of 20 to 200 microns, for example 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 layer can be formed by compacting the deposited material with an optional compacting method. It may be necessary to use a mechanical compactor such as a scraper or double rolling or electrostatic force to compact the powder to provide a thin layer. In some embodiments, these layers can be deposited.

[0048] After depositing the initial layer, the method uses a cyclic process to heat the initial layer to a temperature above the beta transformation temperature of the pre-alloy composition, and then cools the layer. In one embodiment, the cyclic process can be fast to improve productivity and efficiency. In one embodiment, the cycle further includes exposing the deposited initial layer to an energy source. The cycle transforms through a thermal gradient at a high rate to solidify the beryllium product. In one embodiment, the energy source can be directed to 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 heat the layer to a temperature above the beta transformation temperature of the pre-alloy composition. The energy source can be a 10 3 W / mm 2 Up to 10 7 W / mm 2 , for example 10 4 W / mm 2 Up to 10 7 W / mm 2 , or 10 5 W / mm 2 Up to 10 6 W / mm 2 The power density of the electron beam or laser beam is less than 10 7 W / mm 2The energy source is operated at a power sufficient to induce heating to a temperature above a beta transition temperature greater than or equal to the pre-alloyed composition. In one embodiment, the effective diameter of the energy source may be 10 to 200 microns, such as 25 to 150 microns, or 35 to 100 microns. The scanning speed of the energy source may be 10 mm / s to 2000 mm / s, such as 50 mm / s to 1500 mm / s or 100 mm / s to 1000 mm / s. The raster width of the energy source may be 50 to 500 microns, such as 75 to 450 microns, 75 to 400 microns, or 100 to 350 microns. In one embodiment, the layer thickness may be 20 to 200 microns, such as 25 to 175 microns or 50 to 150 microns.

[0049] In one embodiment, the energy source and / or another source heats the initial layer to a temperature above the beta transus temperature. In one embodiment, the beta transus temperature may be 1050°C to 1250°C, such as 1075°C to 1225°C, 1100°C to 1200°C, or 1100°C to 1175°C. In one embodiment, the cycling process may be rapid to limit exposure of the pre-alloyed composition to temperatures above the beta transus temperature to less than 300 seconds, such as 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 rapid cycle can be 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. Long exposure times above the beta transition temperature can cause decomposition of the beta phase and formation of a lamellar microstructure.

[0050] Unless preheating is used, the initial layer can be deposited at room temperature (20 to 25° C.). In some embodiments, the deposited initial layer can be preheated in the build box to a temperature of at least 100° C., such as at least 120° C., or 150° C., at least 200° C., at least 400° C., at least 450° C., or at least 500° C.

[0051] Operating the method at reduced atmospheric pressure or under vacuum can provide quality control for the layer and beryllium article material. Nevertheless, in some embodiments, the method can be operated at atmospheric pressure.

[0052] As part of the cyclic process, the method also cools the deposited layer. In one embodiment, the minimum cooling rate may be greater than 10°C / min, such as greater than 15°C / min or greater than 20°C / min. In some embodiments, the cooling rate may be greater than 1000°C / min, such as greater than 10,000°C / min, to achieve solidification. Cooling or supercooling can be achieved at a cooling rate of 10°C / min to 10,000°C / min, such as 20°C / min to 5,000°C / min, 50°C / min to 3,000°C / min, or 100°C / min to 1000°C / min. In one embodiment, cooling can be in the building direction of the layer. During solidification, the beta phase of beryllium can be precipitated. The beta phase of beryllium is stabilized by the presence of a stabilizer, and the beta phase of beryllium contributes to grain refinement.

[0053] A coolant can be used to achieve the desired cooling by removing excess energy applied to the layer. The coolant can further reduce the temperature gradient in the layer that tends to form columnar grains and thereby improve 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 gaseous stream at a temperature of less than or equal to 100°C, such as less than or equal to 75°C, less than or equal to 50°C, less than or equal to 25°C, less than or equal to 0°C, less than or equal to -10°C, less than or equal to -25°C or less than or equal to -50°C. In terms of range, the coolant can be applied at a temperature of -200°C to 100°C, such as -150°C to 50°C or -100°C to 25°C, including sub-ranges therein. The flow rate of the coolant may be adjusted while the layer is deposited, and may be less than 500 L / min, such as less than 250 L / min or less than 100 L / min.

[0054] 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.

[0055] The method can be repeated in a similar manner to one or more subsequent layers, thereby circulating each deposited pre-alloyed composition layer and precipitating the beta phase of beryllium in the layer. After leaving enough time for precipitation, one or more subsequent layers can be deposited in a predetermined pattern on at least a portion of the initial layer opposite to the surface. This continues to build a beryllium product, wherein each subsequent layer is deposited on at least a portion of the previously deposited layer. In one embodiment, the subsequent layers are deposited to achieve complex shapes, such as three-dimensional shapes. The subsequent layers can be deposited at room temperature, or can be preheated similarly to the initial layer. In a similar manner, an energy source is directed to at least a portion of the subsequent layers, to cycle at a temperature greater than (above) the beta transition temperature of the pre-alloyed composition. In one embodiment, the energy source is controlled within operating parameters similar to the initial layer. Depending on the product, the pattern of each subsequent layer can be different. In some embodiments, the subsequent layers can be deposited on at least a portion of the previous layer or the initial layer.

[0056] In some embodiments, the surface or build plate can be lowered by the thickness of the next subsequent layer. The thickness of the subsequent layer may vary, and in one embodiment, the subsequent layer may have a thickness of 20 to 200 microns, such as 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 subsequent layer may have a similar thickness, or the thickness may be adapted to the beryllium product. The method may continue to repeat deposition, circulation, and precipitation until the desired beryllium product is formed. In one embodiment, a three-dimensional object is formed. In one embodiment, the beryllium product may be formed by one or more subsequent layers, such as at least 5 subsequent layers, at least 10 subsequent layers, or at least 20 subsequent layers. For some products, hundreds of layers may be used, so the number of layers is not limited. The method may be repeated for each subsequent layer.

[0057] Each subsequent layer may include a pre-alloy composition to provide a stabilizer for each layer. In one embodiment, a portion of the layers may include a stabilizer that can be used to stabilize the beta phase of beryllium across the layers.

[0058] The orientation of the microstructure is not limited to the build direction of the subsequent layers. The microstructure of the beryllium article may contain multiple dendrite layers with different primary growth direction angles relative to each other. This provides a crack-free beryllium article.

[0059] In some embodiments, the method further includes solidifying the multiple layers before sintering the preform. In one embodiment, the beryllium product can be solutionized and then quenched. The beryllium product can be annealed for 6 to 12 hours, for example, 8 to 10 hours. The quenching rate can be greater than 25°C / min, for example, greater than 50°C / min or greater than 100°C / min. Quenching can be performed slowly at room temperature. The annealed product can be finished, for example, by polishing or electroplating. The surface roughness of the product can be reduced, for example, by bead blasting or barrel finishing. In some embodiments, the beryllium product made may have scattered or unfused particles in one or more layers. Unfused particles can be removed by blowing or vacuuming as needed.

[0060] The present disclosure has been described with reference to exemplary embodiments. Obviously, after reading and understanding the foregoing detailed description, others will think of modifications and variations. The present disclosure is intended to be interpreted as including all such modifications and variations as long as they fall within the scope of the appended claims or their equivalents.

[0061] As used hereinafter, any reference to a series of embodiments is understood to be a reference to each of those embodiments individually (eg "embodiments 1-4" is understood to be "embodiment 1, 2, 3 or 4").

[0062] Embodiment 1 is a method of grain refining a beryllium-based article, the method comprising combining beryllium and at least one stabilizer to form a pre-alloyed composition; depositing a layer comprising the pre-alloyed composition on a surface; cycling at least a portion of the layer at a temperature above a beta transus temperature greater than or equal to the beta transus temperature of the pre-alloyed composition; precipitating a beta phase of beryllium in the layer; and repeating the depositing / cycling / precipitation for one or more subsequent layers, wherein each subsequent layer comprises the pre-alloyed composition.

[0063] Embodiment 2 is an embodiment of embodiment 1, wherein the at least one stabilizer comprises at least one metal selected from the group consisting of cobalt, copper, nickel, and iron.

[0064] Embodiment 3 is the embodiment of either embodiment 1 or 2, wherein the beryllium-based article has an average grain size of 1 to 80 microns.

[0065] Embodiment 4 is the embodiment of any of embodiments 1-3, wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of the beta phase species based on the total beryllium in the beryllium-based article.

[0066] Embodiment 5 is the embodiment of any of embodiments 1-3, wherein the beryllium-based article comprises 10 atomic % to 60 atomic % of the beta phase species based on the total beryllium in the beryllium-based article.

[0067] Embodiment 6 is the embodiment of any of embodiments 1-5, wherein the combining of beryllium and the at least one stabilizer is performed by mixing, blending, atomizing, mechanical alloying, resonance mixing, or a combination thereof.

[0068] Embodiment 7 is an embodiment of any of embodiments 1-6, wherein the pre-alloy composition comprises 40 to 95 weight percent beryllium.

[0069] Embodiment 8 is an embodiment of any of embodiments 1-7, wherein the pre-alloy composition comprises 5 to 60 weight percent of the at least one stabilizer.

[0070] Embodiment 9 is the embodiment of any of embodiments 1-8, wherein the at least one stabilizer is cobalt and the pre-alloy composition comprises 15 to 25 weight percent cobalt.

[0071] Embodiment 10 is the embodiment of any of embodiments 1-8, wherein the at least one stabilizer is copper and the pre-alloy composition comprises 40 to 60 weight percent copper.

[0072] Embodiment 11 is the embodiment of any of embodiments 1-8, wherein the at least one stabilizer is nickel and the pre-alloy composition comprises 25 to 35 weight percent nickel.

[0073] Embodiment 12 is the embodiment of any of embodiments 1-8, wherein the at least one stabilizer is iron and the pre-alloy composition comprises 5 to 15 weight percent iron.

[0074] Embodiment 13 is the embodiment of any of embodiments 1-12, wherein the cycling further comprises exposing the deposited layer to an energy source.

[0075] Embodiment 14 is the embodiment of any one of embodiments 1-13, wherein the circulating further comprises cooling.

[0076] Embodiment 15 is the embodiment of any of embodiments 1-14, wherein the average grain size is 5 to 25 microns.

[0077] Embodiment 16 is an embodiment of any of embodiments 1-15, wherein the pre-alloyed composition is in the form of particles.

[0078] Embodiment 17 is a version of embodiment 16, wherein the particles have a D50 average particle size of 10 to 50 microns.

[0079] Embodiment 18 is the embodiment of any of embodiments 1-17, wherein each subsequent layer is deposited over at least a portion of a previously deposited layer.

[0080] Embodiment 19 is an embodiment of any of embodiments 1-18, wherein the beta transition temperature is 1050°C to 1250°C.

[0081] Embodiment 20 is an embodiment of any of embodiments 1-19, wherein the beryllium-based article comprises beryllium; and at least one stabilizer comprising at least one metal selected from cobalt, copper, nickel, and iron, wherein the beryllium-based article has an average grain size of 1 to 80 microns, and wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of β-phase species based on the total beryllium in the beryllium-based article.

[0082] Embodiment 20 is a method for grain refining a beryllium-based article, the method comprising depositing a layer on a surface, the layer comprising a pre-alloyed composition, the pre-alloyed composition comprising beryllium and at least one stabilizer, the stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel and iron; cycling at least a portion of the layer at a temperature above or equal to the beta transus temperature of the pre-alloyed composition; precipitating a beta phase of beryllium in the layer; and repeating the deposition / cycling / precipitation for one or more subsequent layers, wherein each subsequent layer comprises the pre-alloyed composition, and wherein the beryllium-based article has an average grain size of 1 to 80 microns.

[0083] Embodiment 21 is an embodiment of embodiment 20, wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of beta-phase species based on the total beryllium in the beryllium-based article.

[0084] Embodiment 22 is the embodiment of either embodiment 20 or 21, further comprising combining beryllium and the at least one stabilizer to form the pre-alloy composition.

[0085] Embodiment 23 is the embodiment of any of embodiments 20-22, wherein the combining of beryllium and the at least one stabilizer is performed by mixing, blending, atomizing, mechanical alloying, resonance mixing, or a combination thereof.

[0086] Embodiment 24 is an embodiment of any of embodiments 20-23, wherein the pre-alloy composition comprises 40 to 95 weight percent beryllium.

[0087] Embodiment 25 is an embodiment of any of embodiments 20-24, wherein the pre-alloy composition comprises 5 to 60 weight percent of the at least one stabilizer.

[0088] Embodiment 26 is an embodiment of any of embodiments 20-25, wherein the at least one stabilizer is cobalt and the pre-alloy composition comprises 15 to 25 weight percent cobalt.

[0089] Embodiment 27 is an embodiment of any of embodiments 20-26, wherein the at least one stabilizer is copper and the pre-alloy composition comprises 40 to 60 weight percent copper.

[0090] Embodiment 28 is the embodiment of any of embodiments 20-27, wherein the at least one stabilizer is nickel and the pre-alloy composition comprises 25 to 35 weight percent nickel.

[0091] Embodiment 29 is the embodiment of any of embodiments 20-28, wherein the at least one stabilizer is iron and the pre-alloy composition comprises 5 to 15 weight percent iron.

[0092] Embodiment 30 is the embodiment of any one of embodiments 20-29, wherein the cycling further comprises exposing the deposited layer to an energy source.

[0093] Embodiment 31 is an embodiment of any one of embodiments 20-30, wherein the cycle further comprises cooling.

[0094] Embodiment 32 is an embodiment of any of embodiments 20-31, wherein the average grain size is 5 to 25 microns.

[0095] Embodiment 33 is an embodiment of any of embodiments 20-32, wherein the pre-alloyed composition is in the form of particles.

[0096] Embodiment 34 is a version of embodiment 30, wherein the particles have a D50 average particle size of 10 to 50 microns.

[0097] Embodiment 35 is the embodiment of any one of embodiments 20-34, wherein each subsequent layer is deposited on at least a portion of a previously deposited layer.

[0098] Embodiment 36 is an embodiment of any of embodiments 20-35, wherein the beta transition temperature is 1050°C to 1250°C.

[0099] Embodiment 37 is a beryllium-based article comprising beryllium; and at least one stabilizer comprising at least one metal selected from cobalt, copper, nickel, and iron, wherein the beryllium-based article has an average grain size of 1 to 80 microns, and wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of β-phase species based on the total beryllium in the beryllium-based article.

[0100] Embodiment 38 is an embodiment of embodiment 37, comprising 40 to 95 weight percent beryllium.

[0101] Embodiment 39 is the embodiment of any of embodiments 37 or 38, comprising 5 to 60 weight percent of the at least one stabilizer.

[0102] Embodiment 40 is an embodiment of any of embodiments 37-39, wherein the at least one stabilizer is cobalt and the pre-alloy composition comprises 15 to 25 weight percent cobalt.

[0103] Embodiment 41 is the embodiment of any of embodiments 37-40, wherein the at least one stabilizer is copper and the pre-alloy composition comprises 40 to 60 weight percent copper.

[0104] Embodiment 42 is the embodiment of any of embodiments 37-41, wherein the at least one stabilizer is nickel and the pre-alloy composition comprises 25 to 35 weight percent nickel.

[0105] Embodiment 43 is an embodiment of any of embodiments 37-42, wherein the at least one stabilizer is iron and the pre-alloy composition comprises 5 to 15 weight percent iron.

[0106] Embodiment 44 is the embodiment of any of embodiments 37-43, wherein the average grain size is 5 to 25 microns.

[0107] Embodiment 45 is the embodiment of any of embodiments 37-44, wherein the beryllium-based article comprises beryllium compound.

[0108] Although the present invention has been described in detail, based on the above discussion, relevant knowledge in the art and the references discussed above in connection with "background" and "detailed description" (the disclosures of which are all incorporated herein by reference), it is easy for those skilled in the art to see modifications within the spirit and scope of the present invention. In addition, it should be understood that aspects of the present invention and parts of various embodiments and various features listed below and / or in the appended claims may be combined or interchanged in whole or in part. In the previous description of various embodiments, those embodiments with reference to another embodiment may be appropriately combined with other embodiments as recognized by those skilled in the art. In addition, it will be appreciated by those of ordinary skill in the art that the previous description is only by way of example and is not intended to be limiting.

Claims

1. A method for refining the grains of a beryllium-based product, the method comprising: combining beryllium and at least one stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel, and iron to form a pre-alloyed composition; depositing a layer comprising the pre-alloyed composition on a surface; cycling at least a portion of the layer above a temperature greater than or equal to a beta transus temperature of the pre-alloyed composition; precipitating a beta phase of beryllium in the layer; and The depositing / cycling / precipitation is repeated for one or more subsequent layers, wherein each subsequent layer comprises the pre-alloyed composition, and wherein the beryllium-based article has an average grain size of 1 to 80 microns.

2. The method of claim 1, wherein the beryllium-based article comprises 1 atomic % to 99 atomic % of beta-phase species based on total beryllium in the beryllium-based article.

3. The method of any one of claims 1 or 2, wherein the combining of the beryllium and the at least one stabilizer is performed by mixing, blending, atomizing, mechanical alloying, resonance mixing, or a combination thereof.

4. The method of any one of claims 1 to 3, wherein the pre-alloy composition comprises 40 to 95 weight percent beryllium and 5 to 60 weight percent of the at least one stabilizer.

5. The method according to any one of claims 1 to 4, wherein: The at least one stabilizer is cobalt, and the pre-alloy composition comprises 15 to 25 weight percent cobalt; The at least one stabilizer is copper, and the pre-alloy composition comprises 40 to 60 weight percent copper; The at least one stabilizer is nickel and the pre-alloy composition comprises 25 to 35 weight percent nickel; or The at least one stabilizer is iron, and the pre-alloy composition comprises 5 to 15 weight percent iron.

6. The method of any one of claims 1-5, wherein the cycling further comprises exposing the deposited layer to an energy source.

7. The method according to any one of claims 1 to 6, wherein the circulation further comprises cooling.

8. The method according to any one of claims 1 to 7, wherein the average grain size is 5 to 25 microns.

9. The method according to any one of claims 1 to 3, wherein the pre-alloyed composition is in the form of particles.

10. The method of claim 9, wherein the particles have a D50 average particle size of 10 to 50 microns.

11. A method according to any one of claims 1 to 10, wherein each subsequent layer is deposited over at least a portion of a previously deposited layer.

12. The method according to any one of claims 1 to 11, wherein the beta transus temperature is 1050°C to 1250°C.

13. The method of any one of claims 1 to 12, wherein the beryllium-based article comprises beryllium; and at least one stabilizer comprising at least one metal selected from the group consisting of cobalt, copper, nickel and iron, wherein the beryllium-based article has an average grain size of 1 to 80 microns, and The beryllium-based article comprises 1 atomic % to 99 atomic % of β-phase species based on the total beryllium in the beryllium-based article.

Images