Reactive Additive Manufacturing

Abstract

A reactive additive manufacturing method is provided. The additive manufacturing method can include the steps of: providing first and second materials (12, 14), the second material capable of reacting with the first material to form a reaction product; forming a first layer (32) from at least the first material; exposing at least a portion of the first layer to energy in the presence of a second material, the energy sufficient to initiate a reaction between the first and second materials to form a portion of an article, the portion of the article including the reaction product; forming a second layer (50) of at least the first material on the first layer; and exposing at least a portion of the second layer to energy in the presence of a second material, the energy sufficient to initiate a reaction between the first and second materials to form an additional portion of the article.

Description

[Technical Field]

[0001] The present invention relates generally to additive manufacturing, and more particularly to methods and apparatus for additive manufacturing using reactive materials. [Background technology]

[0002] Additive manufacturing techniques have been known for decades and are now used to produce a wide range of parts and articles suitable for a wide range of applications. The most common additive manufacturing processes can be divided into three main categories: powder bed sintering or melting, extrusion, and jetting or wire-fed directed energy deposition. One type of powder bed sintering or melting process (which can be called selective laser sintering or melting or direct metal laser sintering) uses a laser beam directed energy source to trace a pattern into a single layer of powder material. The heat from the laser sinters or melts the traced pattern into a solid piece of that layer's thickness. Using an appropriate material delivery device, another layer of powder can be applied on top of the just-sintered layer. This process can then be repeated until a three-dimensional object is formed. However, the energy required to create each layer of material limits production speeds and increases the cost of the equipment needed to produce the object; ceramic materials typically require more energy than metals, which in turn require more energy than plastics.

[0003] Another process for forming articles is reaction synthesis. Reaction synthesis is a chemical process that can be used to form sintered materials much faster than is possible with conventional sintering processes. A typical reaction synthesis process involves mixing two or more reactants (typically in powder form) with dissimilar chemical properties together. A press can be used to compress the mixed powder to form a compressed article or powder. Alternatively, a mold or crucible can be used to contain the powder mixture. Heat can then be applied to initiate a chemical reaction between the components. This process is often exothermic, resulting in the formation of one or more new phases. For example, heat from a furnace or flame can initiate a reaction in a mixture of titanium and carbon powders. The bonding reaction releases heat, resulting in the formation of a sintered ceramic phase of titanium carbide. The heat generated by this reaction spreads to the surrounding powder, causing a reaction that propagates through any reactants present. Some such processes involve the addition of one or more inert species (sometimes called diluents) to absorb heat and thereby control the reaction.

[0004] Reaction synthesis has been used to produce many types of materials, including ceramics, metals, intermetallics, polymers, and composites. However, most reaction synthesis processes require extensive processing steps, including the design and construction of dies and molds, and can typically only be used to produce articles of simple shapes with limited detail, thus limiting the usefulness of such processes. Summary of the Invention

[0005] One embodiment of an additive manufacturing method for producing an article can include the steps of: providing a first material; providing a second material, the second material capable of reacting with the first material to form a reaction product; forming a first layer from at least the first material; exposing at least a portion of the first layer to energy in the presence of the second material, the energy being sufficient to initiate a reaction between the first and second materials to form a portion of an article, the portion of the article including the reaction product; forming a second layer of at least the first material on the first layer; and exposing at least a portion of the second layer to energy in the presence of the second material. exposing the first and second materials to energy in the presence of the material, the energy being sufficient to initiate a reaction between the first and second materials to form an additional portion of the article.

[0006] Another embodiment of an additive manufacturing method for producing an article may include the following steps: providing a mixed powder including a first powder material and a second powder material, the first and second powder materials being capable of reacting with each other upon the application of energy to form a reaction product; forming a first layer from the mixed powder; exposing at least a portion of the first layer to energy sufficient to initiate a reaction between the first and second powder materials to form a reaction product, the reaction product in the first layer forming a portion of the article; forming an additional amount of the mixed powder on the first layer to form a second layer; and exposing at least a portion of the second layer to energy sufficient to initiate a reaction between the first and second powder materials to form a reaction product, the reaction product in the second layer also forming a portion of the article.

[0007] Also disclosed is a method of manufacturing an article, the method including the steps of: providing a first material in powder form; providing a second material in powder form, the second material capable of reacting with the first material to form a reaction product; combining the first and second materials with a third material to form a mixed paste, the mixed paste comprising a substantially homogeneous mixture of the first, second, and third materials; extruding the mixed paste; forming a green article from the extruded mixed paste; and heating the green article to a temperature sufficient to initiate a reaction between at least the first and second materials to form the article, the article comprising the reaction product.

[0008] Also disclosed is an additive manufacturing method for producing an article, the method including the steps of: providing a mixed paste, the mixed paste comprising a substantially homogeneous mixture of a first powder material, a second powder material, and a third material, wherein the first and second powder materials are capable of reacting with each other upon the application of energy to form a reaction product; extruding the mixed paste; forming a green article from the extruded mixed paste by building up individual layers of the mixed paste; and heating the green article to a temperature sufficient to initiate a reaction between the first and second materials to form the article, the article comprising the reaction product.

[0009] Another additive manufacturing method for producing an article can include the steps of: providing a mixed paste, the mixed paste comprising a substantially homogeneous mixture of a first powder material, a second powder material, and a third material, wherein at least the first and second powder materials are capable of reacting with each other upon the application of energy to form a reaction product; extruding the mixed paste to form at least a portion of an article; and exposing the mixed paste to energy during said extrusion, the energy being sufficient to initiate a reaction in said mixed paste to form a reaction product.

[0010] Also disclosed is a method of adding material to a pre-existing article, the method comprising the steps of: providing a first material; providing a second material, the second material capable of reacting with the first material to form a reaction product; forming at least the first material into a layer on at least a portion of the pre-existing article; and exposing at least a portion of the layer to energy in the presence of the second material, the energy being sufficient to initiate a reaction between the first and second materials to form a reaction product, the reaction product comprising an additional layer on at least a portion of the pre-existing article. [Brief explanation of the drawings]

[0011] Illustrative and presently preferred exemplary embodiments of the present invention are shown in the drawings. [Figure 1] FIG. 1 is a process flow diagram of a reactive additive manufacturing process according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a process flow diagram of a reactive additive manufacturing process according to a second embodiment of the present invention. [Figure 3] FIG. 3 is a process flow diagram of a third embodiment of a reactive additive manufacturing process. [Figure 4] FIG. 4 is a scanning electron micrograph of a portion of the article of Example 1 at 5000x magnification. DETAILED DESCRIPTION OF THE INVENTION

[0012] One embodiment of a reactive additive manufacturing process 10 is illustrated in FIG. 1 and can include providing supplies of at least a first material 12 and a second material 14. The first and second materials 12 and 14 can react with each other upon the application of energy to form a final article or product 16. In some embodiments, the first and second materials 12 and 14 can comprise powders; however, it is not necessary to provide the first and second materials 12 and 14 in powder form. For example, in another embodiment, the second material 14 can be provided in gaseous form (e.g., in the atmosphere surrounding the first material 12) and utilized to react with the first material 12 at an appropriate time during the process. Additionally, as described in more detail later herein, additional materials, such as additional reactant material 18, diluent 20, liquid 22, and binder 24, can be added depending on a wide range of factors, including the type of final product 16 to be produced.

[0013] In some embodiments, the particular material(s) used may be combined or mixed (e.g., in a mixer or blender 26) to form a mixed material 28. The mixed material 28 may then be formed (e.g., in step 30) into a first layer 32 on a suitable base 34. Alternatively, if only one major component is involved (e.g., in embodiments where the second material 14 is provided in gaseous form), the mixing step may be omitted and the first layer 32 may be formed solely from the first material 12. In some embodiments, the first layer 32 may be formed by compressing the material (e.g., either the first material 12 or the mixed material 28) in an optional compression process 36. Alternatively (and / or additionally), the various materials (e.g., the first material 12 or the mixed material 28) may be subjected to an optional evaporation process 38, thereby removing liquid components that may, in some cases, be present in either the first material 12 or the mixed material 28.

[0014] Regardless of the particular materials and processes used to form the first layer 32, the reactive additive manufacturing process 10 may then proceed to step 40, where at least a portion of the first layer 32 is exposed to energy sufficient to initiate a reaction between at least the first and second materials 12 and 14, thereby forming a reaction product. In some embodiments, the energy may be supplied by a directed energy beam 42, such as a laser beam 44. In other embodiments, the energy may be supplied by a localized energy source, such as a heater or hot filament 243 (FIG. 3). In embodiments where the energy is supplied by a directed energy beam 42, the directed energy beam 42 may be moved in a desired pattern over the first layer 32, resulting in the formation of a reacted portion or layer 32′ of the article 16 being manufactured. The reacted portion or layer 32' of article 16 will be composed primarily of the reaction products, but may also contain relatively minor amounts of other materials, such as unreacted amounts of first and second materials 12 and 14 and / or partially reacted products of first and second materials 12 and 14. Depending on the particular embodiment, step 40 may be performed in the presence of a process gas 46, such as a reactive gas (e.g., which may include second material 14 in some embodiments) or an inert gas. Alternatively, step 40 may be performed in a vacuum 48 or partial vacuum.

[0015] After the first layer 32 of the desired article 16 has reacted to form the reacted first layer 32', Step 30 may be repeated, forming a second layer 50 on the just-reacted first layer 32'. Step 40 may then be performed again, providing energy (e.g., from a directed energy beam 42) to second layer 50 in an amount sufficient to initiate a reaction between at least first and second materials 12 and 14 to form a reacted second layer 50' of article 16. Reacted second portion or layer 50' of article 16 will also be primarily composed of the reaction product of at least first and second materials 12 and 14, but may also include other materials. After determining that article 16 is complete (e.g., in step 52), process 10 may terminate.

[0016] Depending on the particular embodiment, the as-fabricated article 16 may be surrounded by unreacted portions of the first and second materials 12 and 14 used to form the various reacted layers (e.g., 32' and 50'). Such material may be removed (e.g., mechanically) to expose the final product or article 16.

[0017] A significant advantage of the present invention is that it can be used to produce articles encompassing a wide range of shapes, material compositions, and mechanical or structural properties. In particular, current additive manufacturing methods for producing high-strength parts typically use homogeneous powder materials with the same composition as the desired product. This approach limits the selection of materials that can be successfully utilized by current additive manufacturing processes to produce high-quality parts. Current material selection for the most commonly commercially available additive manufacturing processes is currently limited primarily to polymers and certain alloys. Because most current additive manufacturing processes rely on heating layers of a part to temperatures near or above the material's melting temperature, high-temperature materials, such as many ceramics, require high energy input and are difficult to manufacture with these processes. Due to the limitations of current processes, ceramics, intermetallics, and metal-ceramic composites are not widely available for use with additive manufacturing processes.

[0018] In the case of ceramic materials, the properties of ceramic articles produced by conventional ceramic processing methods can often be improved by using powders of ceramic components with small particle sizes (e.g., less than about 10 μm, and often less than about 1 μm in diameter) to produce fine-grained sintered ceramic articles. Such extremely fine particle sizes cannot be used in most current powder bed additive manufacturing processes because the poor flowability of the fine powders makes it difficult to obtain evenly spread layers.

[0019] In contrast to the various limitations, drawbacks, and disadvantages associated with known fabrication processes, the reactive additive manufacturing process of the present invention offers significant improvements and options in terms of material composition, energy requirements, and ease of manufacturing.

[0020] For example, in embodiments in which energy is released by an exothermic chemical reaction between various components (e.g., first and second materials 12 and 14), less external energy input is required to achieve the fusion of powder-form materials into a finished article 16. Lower external energy requirements allow for increased production rates and / or reduced equipment costs. The present invention enables additive manufacturing techniques to use materials not previously considered possible or practical in conventional additive manufacturing processes. Because the melting points of the reactants are often lower than the melting point of the product material, the in-situ product synthesis utilized by the present invention can result in improved product density compared to conventional additive manufacturing techniques that attempt to directly sinter or melt a hot product stage. Additionally, because the product stage is formed in-situ, relatively large reactant sizes can be used to form fine-grained product materials. This allows for improved product properties while maintaining optimal powder flow and dispersion characteristics for the compounded mixture.

[0021] The use of component reactants also allows for increased flexibility to easily modify the composition of the mixture by changing the ratio of the component materials. For example, a compounded mixture designed to produce a ceramic-metal matrix composite containing 20% ​​ceramic by volume could be easily modified to produce another ceramic-metal matrix composite containing 25% ceramic by volume. This flexibility is particularly useful for development research, but it may also be useful for easily customizing material properties based on the specific combination best suited to the manufactured article.

[0022] Having briefly described one embodiment 10 of a reactive additive manufacturing process according to the present invention, as well as some of the more prominent features and advantages, various embodiments, modifications, and alternative configurations possible with the present invention, are described in detail below. However, before proceeding with the detailed description, it should be recognized that various exemplary embodiments are shown and described herein because they can be utilized with particular starting materials to produce articles that include reactive components of those materials. However, as will become apparent to those skilled in the art after becoming familiar with the teachings presented herein, the present invention can be utilized with a wide variety of starting materials to form a wide variety of articles comprising a wide range of shapes, compositions, materials, and structural characteristics. Accordingly, the present invention should not be considered limited to the specific materials, processing steps, article shapes, compositions, and material properties shown and described herein.

[0023] 1 , a reactive additive manufacturing process 10 according to one embodiment of the present invention can include providing a supply of a first material 12 and a second material 14. At least the first and second materials 12 and 14 can react with each other upon the addition of energy to form a reaction product(s). As previously described, an optional reactant material 18 capable of reacting with materials 12 and 14 can be added to form a reaction product(s).

[0024] In some embodiments, one or more diluent materials 20 may be added to absorb heat and reduce the reaction rate, reaction temperature, and rate and / or extent of reaction. Additional diluent materials 20 may participate in the reaction as intermediate reactants, solvents, or catalysts that can reduce the energy input required to initiate the primary chemical reaction (e.g., the reaction between the first and second materials 12 and 14 and any additional reactant material 18). When adding one or more diluent materials 20, it may be desirable to use pre-synthesized product materials of the same composition as one or more reaction products. It may also be desirable to use a diluent material 20 (e.g., a metal or alloy) that imparts beneficial properties to the article 16 to serve as a matrix for the ceramic phase synthesized in the reaction. The diluent material 20 may also be selected to provide other benefits, such as an aid in sintering during manufacturing, or to inhibit grain growth.

[0025] Reaction equations may be used to determine stoichiometric ratios for the relative amounts of reactant species involved. Stoichiometric ratios can be readily converted to mass ratios using the molecular or atomic weights of the chemical species, as will be apparent to those skilled in the art after becoming familiar with the teachings presented herein. The chemical energy released or absorbed by the reaction can be calculated using tabulated chemical thermodynamic data tables (e.g., JANAF Thermochemical Tables), which are expressly incorporated herein by reference for all disclosures. The calculated energy of the reaction can be used, along with temperature-dependent heat capacity and phase change energy data, to calculate the temperature of the adiabatic reaction for the desired material system. The energy of the reaction can be used to estimate the adiabatic peak temperature that will be obtained during processing step 40. Energy, temperature dependent heat capacity data, and energy density input from a beam of directed energy 42 or localized energy (e.g., energy from a heater or filament 243 (FIG. 3)) can be used.

[0026] For exothermic chemical reactions, the heat input from the directed or localized energy source and the heat released by the chemical reaction will be conducted by the material to adjacent regions and will be sufficient to initiate the chemical reaction in those adjacent regions. If the heat released by the chemical reaction alone is sufficient to initiate the reaction in adjacent layers, the reaction may propagate throughout the contacting reactant materials. If the heat released by the chemical reaction alone is not sufficient to initiate the reaction in adjacent layers, limited localized reaction propagation may still occur with additional heat input from the directed energy source 42 or the localized energy source 243. The distance of propagation of the localized reaction is affected by the energy input from the directed energy source and the energy released by the chemical reaction. As previously mentioned, one or more diluent materials 20 may be utilized to control the degree and / or rate of propagation.

[0027] For powder bed embodiments (e.g., where the various layers 32, 50 are formed from powders), limited localized reaction propagation may be beneficial by increasing processing speed and favorable microstructures, but excessive propagation is generally undesirable as it will reduce the detail and tolerances achievable by the additive manufacturing process. Thus, for powder bed embodiments, it is generally preferred to design the reactant system to limit reaction propagation.

[0028] Additionally, in embodiments in which materials are provided in powder form, it may generally be desirable to use powders having a spherical or globular morphology due to their flowability. That is, the use of flowable powders improves the ability of the powder to be spread into a uniform layer. Powder flowability is also affected by particle diameter; too small particles and too large particles with poor flow properties limit the ability to form fine article details and hinder chemical activity.

[0029] The particle size of each of the component powders can be individually controlled by powder manufacturing techniques or classification processes (e.g., sieving) to provide powders of the desired size. The preferred size of each component powder will be based on the properties of the component materials, including density, morphology, hygroscopicity, oxygen affinity and oxide or hydroxide layer properties, and electrostatic interactions, and will also be apparent to one skilled in the art after becoming familiar with the teachings presented herein.

[0030] Referring again to FIG. 1 , it may also be desirable to add one or more liquids 22 and / or binders 24 to the mixture. The liquids 22 and / or binders 24 can be added to improve particle flow by binding fine particles (e.g., materials 12, 14, 18, and 20) into agglomerates or to form pastes, slurries, suspensions, colloidal suspensions, or plastically deformable composites. Any added liquids 22 and / or binders 24 may be selected to volatilize or decompose after forming the layer, either before or during the application of energy to initiate a chemical reaction. Such materials 22 and 24 may also participate in a chemical reaction, thereby forming a product phase within article 16.

[0031] By way of example, the liquid 22 and / or binder 24 may include any of a wide variety of waxes, polymers, or other low melting point materials that are liquid or viscous liquids or that can undergo viscous flow at room temperature or prior to or during the mixing process.

[0032] The first and second materials 12 and 14, and any reactants, diluents, liquids, and / or binders 18, 20, 22, and 24, may be combined or mixed in a suitable mixer 26 to form a mixed material 28. The mixer 26 may include any of a wide variety of mixing devices known in the art or that may be developed in the future that are suitable (or that will become suitable) for the particular application (e.g., forming a slurry or colloidal suspension) and the materials involved, such as a tumbler, mixer, ball mill, or blender. The resulting mixed material 28 may be spread in step 30 to thereby form a first layer 32. The mixed material 28 may be so formed by any of a wide variety of spreading and forming devices (not shown), such as applicator blades, brushes, rollers, sprayers, or dispensers known in the art or that may be developed in the future that are suitable (or that will become suitable) for forming the desired layer.

[0033] First layer 32 can be spread or formed on a suitable substrate 34. Alternatively, first layer 32 may be formed on a pre-existing article 34', which may be composed of the same material as article 16. In such an embodiment, article 16 so formed may be welded or otherwise bonded to pre-existing article 34', although this is not required.

[0034] The materials (e.g., first material 12 alone or mixed materials 28) forming the various layers (e.g., 32, 50) may optionally be compressed or consolidated (e.g., in step 36) to form compressed layers. Such a compression step may be accomplished by any of a wide variety of compression devices, such as compression plates, dies, or rollers. Alternatively, the various layers (e.g., 32, 50) may be compressed or consolidated by isostatic pressure. If a liquid 22 and / or binder 24 has been added, the liquid 22 and / or binder material 24 may be evaporated or decomposed in step 38. Step 38 may include applying heat and / or reduced pressure (e.g., vacuum or partial vacuum) for a time sufficient to evaporate or decompose the liquid 22 and / or binder 24.

[0035] Thereafter, at least a portion of layer 32 can then be exposed to energy sufficient to initiate a reaction between at least some of the materials comprising layer 32 (i.e., during step 40). In some embodiments, the energy sufficient to initiate the reaction can be provided by a beam of directed energy 42, which can be directed in a desired pattern onto layer 32. The beam of directed energy 42 can include any of a wide range of directed energy beams, such as a laser (or similar type of electromagnetic radiation) beam 44, an electron (or other particle) beam, or an electric plasma arc. In other embodiments, the energy required to initiate the reaction can include a localized source of energy, such as a hot filament or heater 243 (FIG. 3) positioned adjacent to layer 32.

[0036] The temperature required to initiate a chemical reaction for a particular system (i.e., combination of materials in layer 32) can be determined experimentally, obtained from the literature, or estimated theoretically. The reaction initiation temperature can be converted to an energy requirement using heat capacity and phase change energy data for the reactants, as will be apparent to those skilled in the art after becoming familiar with the teachings presented herein.

[0037] In embodiments utilizing a beam of directed energy 42, sufficient energy is applied to a portion of layer 32 to initiate a reaction between materials in mixed material 28, thereby The beam of directed energy 42 can be configured or modified to form reaction products and fuse the materials together to form a reacted layer 32' in the article 16. If the first layer 32 is spread on a substrate 34 or a prefabricated article 34', the beam of directed energy 42 and / or the energy of the reaction can also fuse the reacted first layer 32' to the substrate 34 or article 34'.

[0038] As briefly mentioned above, and depending on the particular embodiment, step 40 may be performed in the presence of a process gas 46, such as a reactive gas (e.g., in some embodiments, this may include second material 14) or an inert gas. Alternatively, step 40 may be performed in a vacuum or partial vacuum 48, in which case step 40 may be performed in a suitable processing chamber 54.

[0039] As previously mentioned, the reacted portion or layer 32' of article 16 may primarily comprise an equilibrium phase including reactant products and any diluents, but it may also include minor amounts of non-equilibrium phases including unreacted reactant materials and intermediate compounds of first and second materials 12 and 14, and possibly additional reactant materials 18, diluent materials 20, and liquid and binder materials 22 and 24.

[0040] After the first layer 32' of the desired article 16 has been sufficiently formed, step 30 may be repeated, in which an additional amount of reactive material (e.g., first material 12 or composite material 28, depending on the particular embodiment) is spread or formed on the just-formed layer 32' of the article 16 to form a second layer 50. Step 40 may then be performed again, in which a source or beam of directed energy 42 is directed onto the second layer 50 to form a second reacted portion or layer 50' of the article 16. The second portion or reacted layer 50' of the article 16 may also comprise primarily equilibrium product phases, but may also include other non-equilibrium phases. The steps of adding additional layers (in step 30) and exposing them to directed energy (in step 40) may be repeated until the article 16 is determined to be complete in step 52. Once the article 16 is complete, the process 10 may be terminated.

[0041] In many embodiments, the manufactured article 16 will be surrounded by unreacted and unfused portions of the materials used to form the various layers, and such materials can be removed (e.g., mechanically) to expose the final product or article 16.

[0042] A second embodiment 110 of a reactive additive manufacturing process is illustrated in Figure 2 and may also include providing a supply of a first material 112 and a second material 114. However, in the second embodiment 110, the second material 114 may be supplied in gas form to a suitable processing chamber 154, such that the gaseous substance 114 forms an atmosphere around the various layers 132, 150. Thus, in this alternative, the second material 114 may be referred to as a process gas 146. The first material 112 may react with the gaseous substance 114 upon the addition of energy, thereby forming a reaction product or article.

[0043] Before proceeding, it should be appreciated that in other embodiments, second material 114 need not be provided in the form of a gas. For example, in other embodiments, second material 114 may be provided as a vapor, mist, spray, or liquid. In still other embodiments, second material 114 may be provided in the form of a wire, tube, or strip. In such embodiments, the wire, tube, or strip of second material 114 may be provided in the form of a consumable electrode to provide directed energy in the form of a plasma arc or electron beam.

[0044] As in the first embodiment 10, one or more additional reactant materials 118 may optionally be added that can react with the materials 112, 114 to form a reaction product or article. One or more diluent materials 120 may be added to absorb heat and reduce the reaction rate, reaction temperature, extent of reaction, or amount of reaction propagation. As previously mentioned, the additional diluent materials 120 may participate in the reaction as intermediate reactants, solvents, or catalysts that can reduce the energy input required to initiate the primary chemical reaction. When adding a diluent material 120, it may be desirable to use a pre-synthesized product material of the same composition as one or more reaction products. It may also be desirable to use a diluent material 120 (e.g., a metal or alloy) that imparts beneficial properties to the final article 116 to serve as a matrix for the ceramic phase synthesized in the reaction. The diluent material 120 may also be selected to provide other benefits, such as an aid in sintering during manufacturing, or to inhibit grain growth.

[0045] Again, as in the first embodiment 10, reaction equations may be used in the second embodiment 110 to determine stoichiometric ratios for the relative amounts of reactant species involved. Stoichiometric ratios can be readily converted to mass ratios using the molecular or atomic weights of the specific chemical species involved. The chemical energy released or absorbed by the reaction can be calculated using tabulated chemical thermodynamic data tables (e.g., JANAF Thermochemical Tables). This calculated energy of reaction can be used, along with temperature-dependent heat capacity and phase change energy data for all components, to calculate the adiabatic reaction temperature for the material system. The energy of reaction, temperature-dependent heat capacity data, and energy density input from a directed energy source can be used to estimate the adiabatic peak temperature that will be achieved during the processing step.

[0046] For exothermic chemical reactions, the heat input from the directional energy source and the heat released by the chemical reaction will be conducted by the material in layer 132 to adjacent regions and will be sufficient to initiate the chemical reaction in those adjacent regions. If the heat released by the chemical reaction alone is sufficient to initiate the reaction in an adjacent layer (e.g., second layer 150), the reaction may propagate throughout the contacting reactant materials. If the heat released by the chemical reaction alone is not sufficient to initiate the reaction in the adjacent layer, limited localized propagation may still occur with additional heat input from directional energy source 142. The distance of localized propagation is affected by the energy input from directional energy source 142 and the energy released by the chemical reaction. A diluent material 120 may be utilized to control the degree of propagation.

[0047] In most variations of the second embodiment 110, the first material 112 and optional materials 118 and 120 will comprise powders, although providing them in powder form is not required. Again, a spherical powder morphology is generally preferred to improve the ability to distribute the powder into a uniform layer (i.e., powder flowability). Powder flowability is also affected by particle diameter; too small particles and too large particles with poor flow properties limit the ability to form fine article details and hinder chemical activity. The particle size of each of the component powders can be individually controlled by powder manufacturing or separation techniques (e.g., sieving) to provide powders of the desired size. The preferred size of each component powder will be based on the properties of the component materials, including density, morphology, hygroscopicity, oxygen affinity and oxide or hydroxide layer properties, and electrostatic interactions.

[0048] In the second embodiment 110, it may also be desirable to add one or more liquids 122 and / or binders 124 to the first material 112. Again, the liquids 122 and The liquid 122 and / or binder 124 may be added to bind the first material 112 and / or any additional materials (e.g., materials 118 and 120) into a cohesive mass, thereby improving the flowability of the material, or to form a paste, slurry, suspension, colloidal suspension, or plastically deformable composite. Any added liquid 122 and / or binder 124 may be selected to volatilize or decompose after forming the layer, before or during the application of energy to initiate a chemical reaction. Such materials 122 and 124 may also participate in a chemical reaction, thereby forming a product phase within the article 116. The liquid 122 and / or binder 124 may include any of a wide range of waxes, polymers, or other low-melting materials that are liquid or viscous liquids, or that can undergo viscous flow at room temperature or before or during the mixing process.

[0049] First material 112 and any additional reactant, diluent, liquid, and / or binder substances 118, 120, 122, and / or 124 may be combined or mixed (e.g., in a suitable mixer 126) to form a mixed material 128. The resulting mixed material 128 can be spread onto a base 134 or pre-existing article 134′ in step 130, thereby forming a first layer 132. As with first embodiment 10, any of a range of spreading and forming devices can be used for this purpose, such as applicator blades, brushes, rollers, sprayers, or dispensers.

[0050] The materials forming the various layers (e.g., the first material 112 alone or the mixed material 128) may optionally be compressed or consolidated in step 136, thereby forming compressed layers. Again, any of a wide variety of compression devices, such as compression plates, dies, or rollers, may be used for this purpose. The layers may also be compressed or consolidated using isostatic pressure. If a liquid 122 or binder 124 has been added, such materials 122 and 124 may be evaporated or decomposed in an optional evaporation step 138. Optionally, step 138 may include applying heat and / or reduced pressure for a time sufficient to evaporate or decompose substantially all of the liquid and / or binder materials 122, 124. Again, the compression and evaporation steps 136 and 138 may be performed separately or in combination. Alternatively, neither of the compression and evaporation steps 136 and 138 need be performed.

[0051] In the second embodiment 110, a second material 114 (i.e., which may comprise a process gas 146) may be introduced into the processing chamber 154. The process gas 146 may consist of a single reactive gas type (e.g., the second material 114), multiple reactive gas types, or a reactive gas with one or more inert gases (e.g., argon).

[0052] The first layer 132 can then be exposed to energy during step 140, thereby forming a reacted portion or layer 132' of the article 116 to be manufactured. Again, the supplied energy may include directed energy (e.g., energy from a directed energy beam 142). Alternatively, the energy may include localized energy, such as energy from a hot filament or heater 243 (FIG. 3). To control the reaction products, rate, peak temperature, reaction propagation, or degree of completion during the reaction process, a process gas 146 (i.e., which may include the second reactant material 114) may be supplied at a controlled pressure, flow rate, and / or ratio. For embodiments including a processing chamber 154, an optional compression 136 and / or evaporation 138 step may be included to maintain an atmosphere of the process gas 146 between spreading the layer and exposure to energy in step 140. The processing chamber 154 may be referred to as a pressure vessel or a In any embodiment, the pressure of the process gas 146 may be selected to be maintained at any desired pressure, i.e., above or below ambient pressure. Alternatively, the process 140 may be carried out in a vacuum or partial vacuum 148.

[0053] In embodiments where the energy required to initiate a reaction is provided by directed energy, the directed energy beam 142 can be controlled or configured to impart sufficient energy to a portion of the layer 132 to initiate a reaction between the materials, thereby forming reaction products and fusing the materials together to form a reacted layer 132'. When the first layer 132 is spread on a compatible substrate 134 or prefabricated article 134', the directed energy beam 142 and / or the energy of the reaction can also fuse the first layer 132' to the substrate 134 or prefabricated article 134'. Reaction products may include products formed by reaction of components of the reactive materials in the blended mixture 128, products formed by reaction of components in the blended mixture 128 with various chemical species (i.e., second reactant 114) comprising the process gas 146, and products formed by reaction of components of the process gas 146 with other components in the process gas 146. The reacted layer 132' may include an equilibrium phase containing reactant products and any diluent materials, but it may also include non-equilibrium phases containing unreacted reactant materials and intermediate compounds of the components of the mixed material 128 and the process gas 146.

[0054] After the first layer 132' of the desired article 116 has been sufficiently formed, step 130 may be repeated, in which an additional amount of mixed material 128 is spread, formed, or (optionally) compressed onto the just-formed layer 132' of the article 116 to form a second layer 150. Step 140 may then be performed again, in which a beam of directed energy 142 is directed onto the second layer 150 to form a second reacted portion or layer 150' of the article 116 to be manufactured. The second portion or layer 150' of the article 116 may also include equilibrium product phases of the various components, but it may also include other non-equilibrium phases. Steps 130 and 140 of adding additional layers and exposing them to directed energy may be repeated until the article 116 is determined to be complete in step 152. Once the article 116 is complete, the process 110 may be terminated. In most ways of this second embodiment 110, the manufactured article 116 will be surrounded by unreacted and unfused portions of the mixed material 128 used to form the various layers (e.g., 132′, 150′). Such material can be removed (e.g., mechanically) to expose the final product or article 116.

[0055] Still other variations and modifications of the present invention are possible. For example, and now referring primarily to FIG. 3 , a third embodiment 210 of a reactive additive manufacturing process according to the present invention can include forming a mixed paste material 228, which can then be extruded in step 230 to form a “green” article 215. Depending on the particular final article 216 to be produced, the green article 215 can include substantially the entire final article 216. Alternatively, the green article 215 can include a smaller portion or individual layer 232 of the final article 216.

[0056] Once the green article 215 or layer 232 is sufficiently formed, it may then be heated (e.g., by heater 243), thereby initiating one or more chemical reactions and forming the final article 216. Alternatively, the green article 215 or layer 232 may be exposed to a beam of directed energy 242 before adding the next layer 250. The heat or directed energy may partially or completely fuse the layers 232, 250, which may or may not be sufficient to initiate one or more chemical reactions within the layers. In this embodiment, if the desired product phase has already formed by chemical reaction upon exposure of the layer to heat or directed energy, the fully formed article 216 will constitute the final article 216 without the need for further exposure to heat (e.g., during step 256). The most significant difference in this third embodiment 210 compared to the first embodiment 10 is that the mixed material 228 is applied only to the location of the layer where the article is to be formed, as opposed to spreading the mixed material over the entire layer in the first embodiment 10.

[0057] Specifically, method 210 can include providing first and second materials 212 and 214 and optional additional reactant and diluent materials 218 and 220. As with first and second embodiments 10 and 110, first and second materials 212 and 214 and optional reactant material 218 can react with one another upon the application of energy, thereby forming a desired reaction product or product to form article 216.

[0058] As with other embodiments 10 and 110, one or more diluents 220 may be added to absorb heat and / or reduce the reaction rate, reaction temperature, and amount of reaction propagation. Additional diluents 220 may participate in the reaction as intermediate reactants, solvents, or catalysts that can reduce the energy input required to initiate the primary chemical reaction. When adding a diluent 220, it may be desirable to use a pre-synthesized product of the same composition as one or more reaction products. It may also be desirable to use a diluent 220 (e.g., a metal or alloy) that imparts beneficial properties to the article to serve as a matrix for the ceramic phase synthesized in the reaction. The diluent 220 may also be selected to provide other benefits, such as an aid in sintering during manufacturing, or to inhibit grain growth.

[0059] In many embodiments, the first and second materials 212 and 214, and any additional reactants and diluents 218 and 220, can be provided in powder form, although providing these materials in powder form is not required. Once the first and second materials 212 and 214 and any additional reactants and / or diluents 218 and / or 220 are provided, they may be combined or mixed (e.g., in a suitable mixer 226) to form a mixed material 228. In many forms of this embodiment 210, the mixed material 228 should constitute a paste or pasty material (e.g., a slurry or colloid) suitable for subsequent extrusion. Accordingly, in certain embodiments shown and described herein, a liquid 222 and / or a binder 224 may be added during the mixing process to form the mixed paste or pasty material 228.

[0060] As with other embodiments 10 and 110, reaction equations may be used in embodiment 210 to determine stoichiometric ratios for the relative amounts of reactant species involved. Stoichiometric ratios can be easily converted to mass ratios using the molecular or atomic weights of the chemical species. The chemical energy released or absorbed by the reaction can be calculated using tabulated chemical thermodynamic data tables (e.g., JANAF Thermochemical Tables). This calculated energy of reaction can be used, along with temperature-dependent heat capacity and phase change energy data for all components, to calculate the adiabatic reaction temperature for the material system. The energy of reaction, temperature-dependent heat capacity data, and energy density input from the directed energy source can be used to estimate the adiabatic peak temperature that will be obtained during the processing step.

[0061] For exothermic chemical reactions, the heat input in step 240 (or step 256) and the heat released by the chemical reaction will be transferred by the reacting materials to adjacent regions and will be sufficient to initiate the chemical reaction in those adjacent regions. If the heat released by the chemical reaction alone is sufficient to initiate a reaction in an adjacent layer, the reaction may propagate throughout the reactant material. If the heat released by the chemical reaction alone is not sufficient to initiate a reaction in an adjacent layer, limited local propagation may still occur with additional heat input from the directed energy source 242 or heater 243. The distance of local propagation is affected by the energy input from the directed energy source 242 or heater 243 and the energy released by the chemical reaction. Again, one or more diluent materials 220 may be utilized to control the degree of propagation of the reaction. For extrusion-based embodiments (such as the third embodiment 210), sufficient propagation of the chemical reaction may be desirable.

[0062] After the various component materials are combined and mixed, the resulting mixed paste material 228 can be extruded in step 230 to form a portion or layer 232 of the green article 215 or the article to be manufactured. Any added liquid and / or binder substances 222 and / or 224 may optionally be evaporated or decomposed from the extruded material by applying heat and / or reduced pressure for a sufficient period of time in step 238. In step 240, the extruded layer 232 may optionally be exposed to heat from a directed energy beam 242 or heater 243 to partially or completely fuse the materials together to form a fused or reacted layer 232′. It should be recognized that in this embodiment, the energy imparted by the directed energy beam 242 or heater 243 during step 240 may or may not be sufficient to initiate one or more chemical reactions within the green article 215 or layer 232. In this embodiment, if the desired product phase has already formed by chemical reaction upon exposure of the various layers (e.g., 232, 250) to heat or directed energy, the fully formed article will be the final article 216 without the need for further exposure to heat in step 256.

[0063] Depending on the particular materials involved and / or the final article 216 to be produced, step 240 may be performed in the presence of a process gas 246. The process gas 246 may include a reactive gas or an inert gas. In that case, process 240 may be performed in a suitable processing chamber 254. Alternatively, step 240 may be performed in a vacuum or partial vacuum 248.

[0064] Additional extruded layers (e.g., second layer 250) may be added until the article is fully formed (as determined, for example, in step 252). In a variation of third embodiment 210, the extrusion process may proceed in a continuous manner, without discontinuities in the extrusion process between layers. In such a continuous extrusion process, the optional application of heat or directed energy may also proceed in a continuous manner until article 216 is fully formed. If the layers of the article are not exposed to sufficient heat or directed energy to initiate chemical reactions to form the desired product phases (during step 240), the formed or produced article will continue to comprise “green” article 215, which will include unreacted materials (e.g., first and second materials 212 and 214 and optional additional reactant 218) that make up mixed paste 228, diluent material 220, and any liquid and / or binder materials 222 and / or 224.

[0065] The green article 215 may then be heated in step 256 to initiate a reaction between the first and second materials 212 and 214 and any additional reactants 218, diluent material 220, and any liquid and / or binder materials 222, 224. The temperature and time required to initiate and complete a chemical reaction for a particular system can be determined experimentally, obtained from the literature, or estimated theoretically. The reaction initiation temperature can be converted to an energy requirement using heat capacity and phase change energy data for the reactants. It is possible.

[0066] The result will be a final article 216 comprised primarily of the reaction product of first and second materials 212 and 214, any additional reactants 218, and liquid and / or binder substances 222 and / or 224, and any optional diluent substances 220. Depending on the particular materials involved, any liquid and / or binder substances 222 and / or 224 used to form the mixed paste 228 can be removed either during optional evaporation step 238 or during heating steps 240 or 256. Alternatively, the liquid and / or binder substances 222 and / or 224 may be completely evaporated or decomposed instead of participating in a chemical reaction to contribute to the product phase. [Example]

[0067] Reaction scheme example : A wide range of product materials can be produced by the method described in this invention. The invention can be used to produce materials including metals, intermetallics, ceramics, composites, and polymers. Examples of suitable reactions are provided below to illustrate the versatility of the process, but the invention should not be limited by these examples. The stoichiometric coefficients (1 if not shown) represent the number of moles of each chemical species. The variables x and y are used to represent dilution factors that can be varied to adjust the reaction temperature and / or product composition. The calculated adiabatic combustion temperature T for a solid-state reaction with the stoichiometric coefficients shown, assuming a starting temperature of 298 K, is: ad is shown.

[0068] [Table 1]

[0069] [Table 2]

[0070] [Table 3]

[0071] Examples of items : Example 1 - TiB 2 -TiC-85Al : An exothermic reaction mixture containing 76.8% aluminum, 16.8% titanium, and 6.5% boron carbide powders by weight was prepared to produce a product with an aluminum matrix and a ceramic reinforcement phase containing 85% aluminum, 10.75% titanium diboride, and 4.25% titanium carbide by volume. The mixture has a calculated adiabatic reaction temperature of 933 Kelvin. A mixture with a total weight of 4000 g was prepared by weighing the component powders according to the above percentages. The powders were mixed using a motorized tumbler. The mixed powder was then placed in the dispenser tray of an EOS M290 direct metal laser sintering (DMLS) machine available from EOS of North America, Inc. (Novi, Michigan, USA).

[0072] A three-dimensional model of the article to be manufactured was designed using a computer-aided design (CAD) software program and digitally sliced ​​into layers equivalent in thickness to one layer of the powder to be spread. The digital information was sent to an EOS M290 DMLS machine.

[0073] The processing chamber of the M290 DMLS machine was filled with argon gas and heated to approximately 30 μm. A layer of the powder mixture having a thickness of 1 / 4" was spread across the entire aluminum substrate using a recoater blade. This first slice of the article was traced over the powder layer with an M290 ytterbium fiber laser, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to initiate the exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, thereby fusing itself and the aluminum alloy to the build plate. A second layer of the powder mixture was then spread over the first layer using a recoater blade, and this second slice of the article was traced with the laser, thereby initiating a chemical reaction in this layer. The laser and chemical reaction energy fused the traced area of ​​the second layer to itself and the first layer. This process was then repeated layer by layer until the complete article was produced. The finished article was then removed from the build plate by cutting with a band saw.

[0074] A total of 20 articles were produced on the build plate in a single production run, using either one or two laser exposures per layer, with each part having its own unique combination of laser power and travel speed settings. The product phases of the articles were examined by X-ray diffraction and scanning electron microscopy (SEM), revealing primarily titanium diboride and titanium carbide in an aluminum matrix. An SEM micrograph of one of the articles from Example 1 is reproduced in Figure 4.

[0075] The density of the part is determined to be 3.00 g / cm using the Archimedes method. 3 measured against the theoretical density of The parts were found to have a theoretical density ranging from about 92.04% to about 99.63%, depending on the combination of laser exposure, laser power, and travel speed used. Hardness values ​​were measured using the Rockwell B scale (HRB), and measurements were found to average 62.9 HRB (approximately 1100 MPa) for the parts with high relative density. The measured hardness of the aluminum matrix composite compares favorably to literature values ​​for commercially pure aluminum, which has a reported Brinell hardness of 30BHN500 (approximately 294 MPa), which is less than zero on the HRB scale.

[0076] Example 2 - (Ti-V)B 2, C-85Al-Mg matrix : By weight, it is 75.19% aluminum / 4.5% magnesium alloy powder, 18.23% titanium tungsten / 6% aluminum / 4% vanadium powder and 6.58% boron carbide powder An exothermic mixture containing 85% aluminum and 4.5% magnesium by volume was prepared. A product was produced with a matrix of titanium and a ceramic reinforcement phase containing 15% by volume of titanium, vanadium diboride, and carbides. The mixture has a calculated adiabatic reaction temperature of 933 Kelvin. A mixture with a total weight of 4000 g was prepared by weighing out the component powders according to the above percentages. The powders were mixed using a motorized tumbler. The mixed powder was then placed in the dispenser tray of an EOS M290 Direct Metal Laser Sintering (DMLS) machine.

[0077] A three-dimensional model of the article to be manufactured was designed using a computer-aided design (CAD) software program and digitally sliced ​​into layers equivalent in thickness to one layer of the powder to be spread. The digital information was sent to an EOS M290 DMLS machine.

[0078] The processing chamber of the DMLS machine was filled with argon gas, and a layer of powder mixture approximately 30 μm thick was spread across an aluminum build plate using a recoater blade. This first slice of the article was traced onto the powder layer with an M290 ytterbium fiber laser, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, fusing itself and the aluminum alloy to the build plate. A second layer of the powder mixture was then spread onto the first layer using a recoater blade, and this second slice of the article was traced with the laser, thereby initiating a chemical reaction in this layer. The energy from the laser and the chemical reaction fused the traced area of ​​the second layer to itself and the first layer. This process was then repeated layer by layer until the complete article was produced. The finished article was then removed from the build plate by wire electrical discharge machining (EDM).

[0079] A total of 20 articles were fabricated on the build plate in a single production run, using either one or two laser exposures per layer, with each part having its own unique combination of laser power and travel speed settings. Examination of the product phases of the articles by X-ray diffraction and SEM revealed primarily titanium diboride and titanium carbide, with minor amounts of vanadium diboride and carbide, within an aluminum-magnesium alloy matrix. The density of the parts was determined to be 2.95 g / cm using the Archimedes method. 3 Measured density against theoretical density The hardness was measured and found to range from about 97.7% to about 100% of theoretical, depending on the laser exposure and the combination of laser power and travel speed used on the part. Hardness values ​​were measured using the Rockwell B scale (HRB) and found to average 90.4 HRB (approximately 1900 MPa) for parts with 100% relative density. The measured hardness of the aluminum matrix composite compares favorably with literature values ​​for commercially pure aluminum, which has a hardness of 30BHN500 (approximately 294 MPa), which is less than zero on the HRB scale. This hardness value also compares favorably with that of the pure aluminum matrix composite described in Example 1.

[0080] Example 3 - NiTi : An exothermic reaction mixture containing 55.5% nickel and 44.5% titanium by weight was prepared to produce a product consisting of an intermetallic nickel-titanium shape memory alloy. The mixture had a calculated adiabatic reaction temperature of 1438 Kelvin. A mixture with a total weight of 2500 g was prepared by weighing out the component powders according to the above percentages. The powders were mixed using a motorized tumbler. The mixed powder was then placed in the dispenser tray of an EOS M290 direct metal laser sintering (DMLS) machine.

[0081] A three-dimensional model of the article to be manufactured was designed using a computer-aided design (CAD) software program and digitally sliced ​​into layers equivalent in thickness to one layer of the powder to be spread. The digital information was sent to an EOS M290 DMLS machine.

[0082] The processing chamber of the DMLS machine was flooded with argon gas, and a layer of powder mixture approximately 40 μm thick was spread across a 316L stainless steel build plate with a recoater blade. This first slice of the article was traced on top of the powder layer with an M290 ytterbium fiber laser, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, fusing itself and the 316L alloy to the build plate. A second layer of the powder mixture was then spread over the first layer with a recoater blade, and this second slice of the article was traced with the laser, thereby initiating a chemical reaction in this layer. The laser and chemical reaction energy fused the traced area of ​​the second layer to itself and the first layer. This process was then repeated layer by layer until the entire article was produced. The finished article was then removed from the build plate by cutting with a band saw.

[0083] A total of 12 articles were fabricated on the build plate in a single production run, using either one or two laser exposures per layer, with each part having its own unique combination of laser power and travel speed settings. The product phase of the articles was examined by X-ray diffraction and SEM and found to be primarily a 1:1 nickel-titanium intermetallic compound. The density of the parts was determined to be 6.5 g / cm using the Archimedes method. 3 Theoretical density of The measured tensile strength was found to range from about 86.7% to about 97.2%, depending on the laser exposure and the combination of laser power and travel speed used on the parts. These parts were suitable for subsequent shape setting using heat treatment and mechanical deformation.

[0084] Example 4 - Extrusion : An exothermic reactive mixture containing 55.12% titanium, 13.83% carbon, and 31.06% aluminum by weight was prepared to produce a product with a 45% aluminum matrix and 55% titanium carbide particles by volume. The mixture had a calculated adiabatic reaction temperature of 2368 Kelvin. A mixture with a total weight of 200 g was prepared by weighing out the component powders according to the above percentages. The powder was shaken by hand in a Nalgene-type bottle and poured into a glass beaker, to which 80 g of propylene glycol was then added. The powder was mixed with the liquid propylene glycol by manual stirring using a stainless steel stirring tool. The mixed powder and propylene glycol slurry was then placed in a flexible polymer bag equipped with a nozzle suitable for extruding the material by applying pressure to the bag containing the material.

[0085] Three steel sheet metal build plates were placed on the surface of an electric hot plate to maintain a temperature of approximately 210°C. Individual articles were extruded onto each of the three sheet metal build plates, with the propylene glycol evaporating during the extrusion process due to the elevated temperature of the build plates. The extrusion of the first article was completed by continuously extruding material to produce a green part consisting of 15 successively fed, interconnected layers of extruded material. A second article was produced by continuously extruding one layer of the article and then cutting away the extruded material before starting the next layer. A third green article was completed by extruding a series of segments onto each layer, cutting away between the ends of one segment, and starting the next, cutting away between each layer. While the extrusion process was performed manually in this example, this process could also be performed computer-assisted. Suitable for computer-based automation.

[0086] The green article was then reacted by locally contacting it with an oxyacetylene flame, locally initiating an exothermic chemical reaction that then self-propagated throughout the article. The high-temperature chemical reaction rapidly transformed the reactants into a product phase, thereby fusing and strengthening the article while evaporating any volatile impurities, such as residual propylene glycol. The reacted article maintained the shape developed during extrusion and was shown to have high wear resistance due to the hardness of the titanium carbide product phase.

[0087] Example 5 - SiC : A silicon carbide product was produced by preparing an exothermic reactive mixture containing 70.0% silicon and 30.0% carbon by weight. The mixture has a calculated adiabatic reaction temperature of 1852 Kelvin. A mixture with a total weight of 10 g was prepared by weighing the component powders according to the percentages listed above. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0088] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to include a steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch). The die height was set using an adjustable height positioning table, and a cylindrical press rod was threaded through the hole and leveled at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, which was filled with argon gas. The height of the positioning table was adjusted to allow for a gap of approximately 2 mm between the press rod and the top of the die. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was manually scraped flat with a steel scraping blade so that the top of the layer was level with the top of the die.

[0089] A two-dimensional rectangular article measuring approximately 12.7 mm by approximately 9.5 mm (approximately 0.5 in. by 0.375 in.) was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraver, and a rectangular pattern was traced with the laser onto the powder layer, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, thereby fusing together. The height of the positioning table was then raised one step equivalent to approximately 200 μm, while the press rod position remained stationary. A second layer of the powder mixture was then manually spread over the first layer and scraped off flush with the top of the die using a steel scraping blade. The rectangular article was then traced again with the laser, thereby initiating the chemical reaction in this layer. The energy from the laser and the chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article was produced having a thickness or height of approximately 1 mm. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0090] The product phase of the article was examined by X-ray diffraction and found to be primarily silicon carbide, however, silicon and carbon peaks were also present. The presence of residual silicon and carbon is believed to be due to the layer thickness of approximately 200 μm being too large for the laser processing conditions.

[0091] Example 6 - WC-Co : An exothermic mixture containing 75.1% tungsten, 4.9% carbon, and 20.0% cobalt by weight was prepared to produce a product consisting of a matrix of 80% tungsten carbide and 20% cobalt by weight. The mixture had a calculated adiabatic reaction temperature of 876 Kelvin. The temperature was set at 10 g. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0092] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to include a steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch). The die height was set using an adjustable height positioning table, and a cylindrical press rod was threaded through the hole in the positioning table to level the die at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, which was filled with argon gas. The height of the positioning table was adjusted to allow for a gap of approximately 2 mm between the press rod and the top of the die. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was manually compressed so that the top of the layer was level with the top of the die, then scraped flat using a steel plate.

[0093] A two-dimensional square article measuring approximately 12.7 mm (approximately 0.5 inches) square was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraving machine, and a square pattern was traced with the laser onto the powder layer, heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, resulting in fusion. The height of the positioning table was then raised one step equivalent to approximately 200 μm, while the press rod position remained stationary. A second layer of the powder mixture was then manually spread over the first layer, compressed, and scraped off flush with the top of the die using a steel scraping blade. The square article was then traced again with the laser, thereby initiating the chemical reaction in this layer. The energy from the laser and chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article with a height or thickness of approximately 1 mm was produced. The finished article was then removed from the surrounding unreacted powder using tweezers.

[0094] The product phase of the article was examined by X-ray diffraction and found to be primarily tungsten carbide and cobalt, however, tungsten and carbon peaks were also present. The presence of residual tungsten and carbon is believed to be due to the layer thickness of approximately 200 μm being too large for the laser processing conditions.

[0095] Example 7 - TiB 2 -TiC-glass matrix : An exothermic mixture containing 50.0% by weight glass powder (approximately 74.5% silica, 13.5% soda, 10.5% lime, and 1.5% alumina), 36.1% titanium, and 13.9% boron carbide was prepared to produce a product composed of titanium diboride and titanium carbide in a 50% percent by weight glass matrix. A mixture with a total weight of 5 g was prepared by weighing the component powders according to the above percentages. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0096] An Epilog Zing laser engraver equipped with a 40 watt carbon dioxide laser was modified to have a steel die with a cylindrical hole of approximately 25.4 mm (approximately 1 inch), and the die height was set by an adjustable height positioning table, where a cylindrical press rod was threaded through the hole and flattened at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, and the glove box was filled with argon gas. The press rod and die were then placed in a controlled atmosphere glove box. The height of the positioning table was adjusted so that there was a gap of about 2 mm between the tops. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was compressed by hand so that the top of the layer was level with the top of the die, and then scraped flat with a steel plate.

[0097] A two-dimensional rectangular article measuring approximately 12.7 mm by approximately 9.5 mm (approximately 0.5 in. by 0.375 in.) was designed using a CAD computer software program. The digital information was sent to an Epilog Zing 40-watt laser engraving machine, and a rectangular pattern was traced with the laser onto the powder layer, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, thereby fusing together. The positioning table was then raised two steps, equivalent to approximately 200 μm, while the press rod position remained stationary. A second layer of the powder mixture was then manually spread over the first layer, compressed, and scraped flush with the top of the die using a steel scraping blade. The rectangular article was again traced with the laser, thereby initiating the chemical reaction in this layer. The energy from the laser and the chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article was produced having a height or thickness of approximately 0.8 mm. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0098] The product phases of the article were examined by X-ray diffraction and found to contain primarily titanium diboride, titanium carbide, and amorphous material, along with small amounts of reactant and intermediate phases. The presence of these additional phases is believed to be due to the layer thickness of 200 microns being too large for the laser processing conditions.

[0099] Example 8-B 4 C : A boron carbide product was produced by creating an exothermic mixture containing 78.3% boron and 21.7% carbon by weight. The mixture has a calculated adiabatic reaction temperature of 957 Kelvin. A mixture with a total weight of 10 g was prepared by weighing the component powders according to the percentages listed above. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0100] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to include a steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch). The die height was set using an adjustable height positioning table, and a cylindrical press rod was threaded through the hole in the positioning table to level the die at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, which was filled with argon gas. The height of the positioning table was adjusted to allow for a gap of approximately 2 mm between the press rod and the top of the die. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was manually compressed so that the top of the layer was level with the top of the die, then scraped flat using a steel plate.

[0101] A two-dimensional rectangular article having dimensions of approximately 12.7 mm by approximately 9.5 mm (approximately 0.5 inches by 0.375 inches) was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraver, and a rectangular pattern was traced with the laser onto the powder layer, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area caused the material in the article to sinter and melt, resulting in fusion. The height of the positioning table was then raised two steps, equivalent to approximately 400 μm, while the press rod remained stationary. A second layer of the powder mixture was then manually spread over the first layer, compressed, and scraped off flush with the top of the die using a steel scraping blade. The rectangular article was again traced with the laser, thereby initiating a chemical reaction in this layer. The energy of the laser and chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article with a height or thickness of approximately 5.6 millimeters was produced. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0102] Examination of the product phase of the article by X-ray diffraction revealed that it contained boron carbide, and boron and carbon peaks were also present. The presence of residual boron and carbon is believed to be due to the layer thickness of approximately 400 μm being too large for the laser processing conditions.

[0103] Example 9-B 4 C-TiB 2 -SiC eutectic : An exothermic reaction mixture containing 61.3% boron, 25.1% carbon, 11.1% silicon, and 2.5% titanium by weight was prepared to produce a ternary eutectic ceramic product consisting of boron carbide, silicon carbide, and titanium diboride. The mixture has a calculated adiabatic reaction temperature of 1408 Kelvin. A mixture with a total weight of 10 g was prepared by weighing the component powders according to the above percentages. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0104] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to include a steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch). The die height was set using an adjustable height positioning table, and a cylindrical press rod was threaded through the hole and leveled at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, which was filled with argon gas. The height of the positioning table was adjusted to allow for a gap of approximately 2 mm between the press rod and the top of the die. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was manually scraped flat with a steel scraping blade so that the top of the layer was level with the top of the die.

[0105] A two-dimensional rectangular article measuring approximately 12.7 mm by approximately 9.5 mm (approximately 0.5 in. by 0.375 in.) was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraver, and a rectangular pattern was traced with the laser onto the powder layer, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product material to sinter and melt, thereby fusing together. The height of the positioning table was then raised one step equivalent to approximately 200 μm, while the press rod position remained stationary. A second layer of the powder mixture was then manually spread over the first layer and scraped off flush with the top of the die using a steel scraping blade. The rectangular article was then traced again with the laser, thereby initiating the chemical reaction in this layer. The energy from the laser and the chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article was produced having a height or thickness of approximately 1.4 mm. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0106] Example 10 - TiC-TiC Diluent : An exothermic reactive mixture was prepared containing, by weight, 40.0% titanium, 10.0% carbon, and 50.0% titanium carbide diluent to produce a product comprised of titanium carbide. Titanium carbide was added to reduce the reaction temperature, preventing the reaction from propagating outside the area intended to constitute the engineered article. The mixture has a calculated adiabatic reaction temperature of 2076 Kelvin. A mixture with a total weight of 10 g was prepared by weighing the component powders according to the percentages listed above. The powders were mixed by shaking and then manually pulverized using a mortar and pestle.

[0107] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to accommodate a removable steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch) in diameter. Within the die, a layer of mixed powder was compressed between two press rods with a force of 1 metric ton, and the upper press rod was pushed out, with the compressed powder remaining within the die. The die and compressed powder were placed into the laser engraver, and the processing chamber was flooded with argon gas.

[0108] A two-dimensional rectangular article measuring approximately 12.7 mm by approximately 9.5 mm (approximately 0.5 inches by 0.375 inches) was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraver, and a rectangular pattern was traced with a laser onto the powder layer, thereby heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product's materials to sinter and melt, thereby fusing them together. A total of 0.1 g of additional mixed powder was added on top of the first layer and compressed again using 1 metric ton of force, and the die and compressed powder were placed in the laser engraver. The processing chamber was refilled with argon gas, and the rectangular article was again laser traced, thereby initiating the chemical reaction in this layer. The energy from the laser and chemical reaction fused the traced area of ​​the second layer to itself and to the first layer. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0109] The product phase of the article was examined by X-ray diffraction and found to contain primarily titanium carbide, with small amounts of titanium and carbon present. The presence of residual boron and carbon is believed to be due to incomplete removal of the surrounding powder and a layer height that was too high for the laser processing conditions.

[0110] Example 11 - Ti-TiN : A powder containing 100% titanium by weight was prepared and reacted exothermically with nitrogen gas at 1 atmosphere pressure in an atmosphere consisting of 90% argon gas and 10% nitrogen gas, thereby producing a product consisting of titanium nitride and titanium metal.

[0111] An Epilog Zing laser engraver equipped with a 40-watt carbon dioxide laser was modified to include a steel die with a cylindrical hole approximately 25.4 mm (approximately 1 inch). The die height was set using an adjustable height positioning table, and a cylindrical press rod was threaded through the hole and leveled at a fixed height on the machine base. The Epilog Zing laser engraver was placed inside a controlled atmosphere glove box, which was filled with a mixture of argon and nitrogen gases. The height of the positioning table was adjusted to allow approximately 2 mm of clearance between the press rod and the top of the die. A layer of mixed powder was placed on top of the press rod in the die, and the powder layer was manually scraped flat with a steel scraping blade so that the top of the layer was level with the top of the die.

[0112] A two-dimensional rectangular article having dimensions of approximately 12.7 mm x 9.5 mm (approximately 0.5 in x 0.375 in) was designed using a CAD software program. The digital information was sent to an Epilog Zing 40-watt laser engraver, and a rectangular pattern was engraved on the powder bed. The line was traced with a laser, heating the traced area to a temperature sufficient to initiate an exothermic chemical reaction with nitrogen gas. The rate and extent of the reaction were kinetically limited by the availability of nitrogen. The combined energy from the laser and the chemical reaction in the traced area was sufficient to cause the product's materials to sinter and melt, resulting in fusion. A total of 0.1 g of additional mixed powder was added on top of the first layer and compressed again using 1 metric ton of force. The die and compressed powder were then placed in a laser engraving machine. The processing chamber was refilled with argon gas, and the rectangular article was again traced with a laser, thereby initiating the chemical reaction in this layer. The laser and chemical reaction energy fused the traced area of ​​the second layer to itself and to the first layer. This process was then repeated layer by layer until a complete article with a height or thickness of approximately 1 mm was produced. The completed article was then removed from the surrounding unreacted powder using tweezers.

[0113] The product had the golden color characteristic of titanium nitride and was found to also contain unreacted titanium metal. The amount of product phase converted to titanium nitride can be increased by increasing the nitrogen concentration and pressure, as well as by decreasing the titanium particle size and layer thickness.

[0114] While preferred embodiments of the invention have been presented herein, it is anticipated that suitable modifications may be made to those embodiments, and such would still fall within the scope of the invention. Accordingly, the present invention should be construed solely in accordance with the claims. [Mode of Invention] [1] 1. A method for manufacturing an article, comprising the steps of: Preparing the first material; providing a second material, said second material capable of reacting with said first material to form a reaction product; forming a first layer from at least said first material; exposing at least a portion of the first layer to energy in the presence of the second material, the energy being sufficient to initiate a reaction between the first material and the second material to form a portion of the article, the portion of the article comprising the reaction product; forming at least a second layer of the first material on the first layer; and exposing at least a portion of said second layer to energy in the presence of said second material, said energy being sufficient to initiate a reaction between said first material and said second material to form an additional portion of said article; The method comprising: [2] [1] The method of [1], wherein exposing at least a portion of the first layer to energy comprises exposing at least a portion of the first layer to directed energy sufficient to initiate a reaction between the first material and the second material, and exposing at least a portion of the second layer to energy comprises exposing at least a portion of the second layer to directed energy sufficient to initiate a reaction between the first material and the second material. [3] [1] The method of [1], wherein exposing at least a portion of the first layer to energy comprises exposing at least a portion of the first layer to localized energy sufficient to initiate a reaction between the first material and the second material, and wherein exposing at least a portion of the second layer to energy comprises exposing at least a portion of the second layer to localized energy sufficient to initiate a reaction between the first material and the second material. . [4] The method of any one of [1] to [3], further comprising mixing the first material and the second material to form a mixed material, wherein the mixed material comprises a substantially homogeneous mixture of the first material and the second material, and forming the first layer and the second layer comprises forming the first layer and the second layer from the mixed material. [5] The method according to any one of [1] to [4], wherein the forming step includes compressing the mixed material to form the first layer and the second layer. [6] The method according to any one of [1] to [5], wherein the first material and the second material include powders, and the mixed material includes powders. [7] The method of any one of [1] to [6], further comprising combining the mixed material with a third material to form a mixed paste, the mixed paste comprising a substantially homogeneous mixture of the first material, the second material, and the third material, and forming the first layer and the second layer comprises extruding the mixed paste to form the first layer and the second layer. [8] The method according to any one of [1] to [7], wherein the third material includes a liquid. [9] The method according to any one of [1] to [7], wherein the third material includes a binder.

[10] The method of any one of [1] to [9], further comprising providing a supply of a diluent material, wherein the diluent material inhibits reaction between the first material and the second material.

[11] The method of any one of [2] and [4] to

[10] , wherein exposing the first layer and the second layer to directed energy includes directing a laser beam at the first layer and the second layer.

[12]

[11] The method of

[11] , wherein directing a laser beam at the first layer and the second layer includes directing a laser beam having a wavelength in an infrared wavelength range at the first layer and the second layer.

[13] The method of any one of [2] and [4] to

[10] , wherein exposing the first layer and the second layer to directional energy includes directing an electron beam at the first layer and the second layer.

[14] The method of any one of [2] and [4] to

[10] , wherein exposing the first layer and the second layer to directed energy comprises exposing the first layer and the second layer to an electric plasma arc.

[15] The method according to any one of [4] to

[14] , wherein the mixing, forming, and exposing steps are carried out in an inert atmosphere.

[16] The method according to any one of [1] to

[15] , wherein the second material contains a process gas, and the exposing step is carried out in an atmosphere containing the process gas.

[17] The method of

[16] , wherein the process gas comprises nitrogen gas.

[18] The method of any one of [1] to

[17] , further comprising exposing the article to energy after formation to react any unreacted material remaining in the article.

[19]

[18] The method of

[18] , wherein exposing the article to energy after formation includes heating the article in a furnace to react any unreacted material remaining in the article.

[20] 1. An additive manufacturing method for producing an article, comprising the steps of: a) providing a mixed powder including a first powder material and a second powder material, the first powder material and the second powder material being capable of reacting with each other to form a reaction product upon application of energy; b) forming a first layer from the mixed powder; c) exposing at least a portion of the first layer to energy sufficient to initiate a reaction between the first powder material and the second powder material to form the reaction product, the reaction product in the first layer forming at least a portion of the article; d) providing an additional amount of the mixed powder on the first layer to form a second layer; and e) exposing at least a portion of the second layer to energy sufficient to initiate the reaction between the first powder material and the second powder material to form the reaction product, the reaction product in the second compressed layer also forming a part of the article. [twenty one]

[20] The method of

[20] , further comprising repeating steps d) and e) until the article is completely formed. [twenty two]

[20] or

[21] . The method of

[20] or

[21] , wherein exposing at least a portion of the first layer to energy comprises exposing at least a portion of the first layer to directed energy sufficient to initiate a reaction between the first material and the second material, and wherein exposing at least a portion of the second layer to energy comprises exposing at least a portion of the second layer to directed energy sufficient to initiate a reaction between the first material and the second material. [twenty three]

[20] or

[21] . The method of

[20] or

[21] , wherein exposing at least a portion of the first layer to energy comprises exposing at least a portion of the first layer to localized energy sufficient to initiate a reaction between the first material and the second material, and wherein exposing at least a portion of the second layer to energy comprises exposing at least a portion of the second layer to localized energy sufficient to initiate a reaction between the first material and the second material. [twenty four] The method according to any one of

[20] to

[23] , further comprising compressing the mixed powder to form a first compressed layer. [twenty five] The method of any one of

[21] to

[24] , further comprising exposing the article to energy after formation to react any unreacted material remaining in the article.

[26] 1. A method of manufacturing an article, comprising the steps of: providing a first material in powder form; providing a second material in powder form, said second material capable of reacting with said first material to form a reaction product; combining the first material and the second material with a third material to form a mixed paste, the mixed paste comprising the first material, the second material, and the third material; a substantially homogeneous mixture of ingredients; extruding the mixed paste to form a green article; and heating the green article to a temperature sufficient to initiate a reaction between the first material and the second material to form the article, the article comprising the reaction product; The method comprising:

[27]

[26] The method of

[26] , wherein forming a green article from the extruded mixed paste comprises forming a layered structure by depositing individual layers of the extruded mixed paste adjacent to one another.

[28]

[26] or

[27] , wherein the third material comprises water, and the combining comprises combining the first material and the second material with the water to form the mixed paste.

[29] The method of any one of

[26] to

[28] , wherein the third material includes a binder, and the combining includes combining the first material and the second material with the binder to form the mixed paste.

[30] 1. An additive manufacturing method for producing an article, comprising the steps of: providing a mixed paste, the mixed paste comprising a substantially homogeneous mixture of a first powder material, a second powder material, and a third material, wherein at least the first powder material and the second powder material are capable of reacting with each other upon the application of energy to form a reaction product; extruding the mixed paste; forming a green article from the extruded mixed paste by building up individual layers of the mixed paste; and heating the green article to a temperature sufficient to initiate a reaction between the first material and the second material to form the article, the article comprising the reaction product; The method comprising:

[31] 1. An additive manufacturing method for producing an article, comprising the steps of: providing a mixed paste, the mixed paste comprising a substantially homogeneous mixture of a first powder material, a second powder material, and a third material, wherein at least the first powder material and the second powder material are capable of reacting with each other upon the application of energy to form a reaction product; extruding the mixed paste to form at least a portion of the article; and exposing the mixed paste to energy during said extrusion, said energy being sufficient to initiate a reaction in said mixed paste to form said reaction product; The method comprising:

[32] 1. A method of adding material to a pre-existing article, comprising the steps of: Preparing the first material; providing a second material, said second material capable of reacting with said first material to form a reaction product; forming a layer of at least the first material over at least a portion of the pre-existing article; and exposing at least a portion of said layer to energy in the presence of said second material, said energy being sufficient to initiate a reaction between said first material and said second material to form said reaction product, said reaction product forming at least one of said pre-existing articles; Including an additional layer on top of a portion; The method comprising:

Claims

1. 1. A method for manufacturing an aluminum article, comprising the steps of: a) providing a supply of aluminum alloy in powder form; b) providing one or more feeds selected from the group consisting of TiC and B4C; c) mixing said aluminum alloy powder and one or more selected from the group consisting of TiC and B4C to form a mixture; d) forming the mixture into a first layer. e) exposing at least a portion of said first layer to energy sufficient to initiate an exothermic chemical reaction between said aluminum alloy powder and said one or more selected from the group consisting of TiC and B4C; g) forming a second layer of the mixture on the first layer; and h) repeating said exposing step e) and said forming step g) on ​​said second layer to form additional portions of said article. The method comprising:

2. 10. The method of claim 1, further comprising providing a supply of binder, and wherein said mixing step comprises mixing said binder, said aluminum alloy, and one or more selected from the group consisting of TiC and B4C to form said mixture.

3. The method of claim 1 , wherein said exposing step e) comprises exposing said first layer and said second layer to directed energy.

4. 4. The method of claim 3, wherein step e) of exposing the first layer and the second layer to directed energy comprises directing a laser beam at the first layer and the second layer.

5. 2. The method of claim 1, wherein the mixing step further comprises mixing the aluminum alloy powder and the one or more selected from the group consisting of TiC and B4C with a liquid to form a mixed paste, the mixed paste being a substantially homogeneous mixture of the aluminum alloy powder and the one or more selected from the group consisting of TiC and B4C, and wherein the step d) of forming a first layer and the step g) of forming a second layer comprise extruding the mixed paste to form the first layer and the second layer.

6. 10. The method of claim 1, wherein said first layer refers to "layer" and said second layer refers to "subsequently formed layer," and further comprising repeating steps d), e), and g) until the aluminum article is fully formed.

7. The method of claim 6 further comprising subjecting the aluminum article to a heat treatment process.

8. 1. A method of manufacturing an article, comprising the steps of: a) providing a supply of aluminum alloy in powder form; b) providing a supply of one or more powders selected from the group consisting of TiC and B4C; c) mixing said aluminum alloy powder and said one or more powders selected from the group consisting of TiC and B4C to form a mixture; d) forming the mixture into a first layer; e) exposing at least a portion of said first layer to sufficient energy to initiate an exothermic chemical reaction between said aluminum alloy powder and said one or more selected from the group consisting of TiC and B4C; g) repeating the forming step d) and exposing step e) on successively formed layers until the article is completely formed; The method comprising:

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