Method and system for investment casting

Abstract

Methods and systems for investment casting with high performance aluminum alloys are described. The high performance aluminum alloy may be modified with nanoparticles to be compatible with an investment casting process. The nanoparticles are selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

Description

Technical Field

[0001] The present invention generally relates to methods and systems for investment casting of high-performance aluminum alloys; and more particularly to methods and systems for investment casting of high-performance aluminum alloys modified with nanoparticles. Background Art

[0002] Investment casting is an industrial process based on lost-wax casting. Investment casting can produce complex shapes that are difficult or impossible to achieve with other casting methods. It is also capable of producing products with excellent surface quality and low tolerances, and only requires minimal surface finishing or machining. While the investment casting process can produce a high-quality surface finish, it also results in a slow alloy cooling rate. High-performance aluminum alloys such as 2xxx series, 6xxx series, and 7xxx series aluminum alloys tend to form interdendritic microstructures and coarse microstructures at slow cooling rates. Such microstructures can cause cracks and tears in the finished product. Therefore, traditionally, high-performance aluminum alloys such as 2xxx series and 7xxx series aluminum alloys are not used in the investment casting process. It may be desirable to improve high-performance aluminum alloys to make them suitable for the investment casting process. Summary of the Invention

[0003] Methods and systems for investment casting of high-performance aluminum alloys modified with nanoparticles are described.

[0004] Some embodiments include a metal alloy for investment casting, comprising: an aluminum alloy selected from the group consisting of: 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys; and at least one type of nanoparticle dispersed in the aluminum alloy; wherein the metal alloy is compatible with the investment casting process.

[0005] In some embodiments, the metal alloy is selected from the group consisting of: A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0006] In some embodiments, the at least one type of nanoparticle is selected from the group consisting of: metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0007] In some embodiments, the at least one type of nanoparticle has a core-shell structure.

[0008] In some embodiments, the at least one type of nanoparticle comprises less than or equal to 30 volume % of the metal alloy.

[0009] In some embodiments, the at least one type of nanoparticle comprises 0.1 volume % to 2 volume % of the metal alloy.

[0010] In some embodiments, the metal alloy is configured for investment casting of a part having at least one thickness greater than or equal to 0.2 mm.

[0011] Some embodiments include a method of investment casting, the method comprising: ● melting an aluminum alloy modified with at least one type of nanoparticle; ● filling an investment casting mold with the molten aluminum alloy having at least one type of nanoparticle; and ● cooling the mold to solidify the molten aluminum alloy to form a part.

[0012] Some embodiments further include anodizing the part to have at least one color.

[0013] In some embodiments, the aluminum alloy is selected from the group consisting of: 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

[0014] In some embodiments, the aluminum alloy is selected from the group consisting of: A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0015] In some embodiments, the at least one type of nanoparticle comprises a material selected from the group consisting of: metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0016] In some embodiments, the at least one type of nanoparticle has a core-shell structure.

[0017] In some embodiments, the at least one type of nanoparticle comprises less than or equal to 30 volume % of the aluminum alloy.

[0018] In some embodiments, the at least one type of nanoparticle comprises 0.1 volume % to 2 volume % of the aluminum alloy.

[0019] In some embodiments, at least one cross-section of the part has a thickness greater than or equal to 0.2 mm.

[0020] Some embodiments include investment cast metal parts, comprising: an aluminum alloy; and at least one type of nanoparticle; wherein the at least one type of nanoparticle is distributed in the aluminum alloy; and wherein the aluminum alloy is selected from the group consisting of: 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

[0021] In some embodiments, the aluminum alloy is selected from the group consisting of: A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0022] In some embodiments, the at least one type of nanoparticle comprises a material selected from the group consisting of: metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0023] In some embodiments, the at least one type of nanoparticle has a core-shell structure.

[0024] In some embodiments, the nanoparticles account for less than or equal to 30 vol% of the aluminum alloy.

[0025] In some embodiments, the nanoparticles account for 0.1 vol% to 2 vol% of the aluminum alloy.

[0026] In some embodiments, the metal part is configured to be anodized to have at least one color.

[0027] In some embodiments, the metal part has at least one cross-section with a thickness greater than or equal to 0.2 mm.

[0028] Additional embodiments and features are set forth in part in the following description, in part will be apparent to those skilled in the art upon reading the specification, or may be learned by practicing the present disclosure. A further understanding of the nature and advantages of the present disclosure can be realized by reference to the remaining portion of the specification as well as the drawings, which form a part of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] This specification will be more fully understood with reference to the following drawings, which are presented as exemplary embodiments of the invention and should not be construed as a complete recitation of the scope of the invention. It should be noted that the patent or application file contains at least one drawing executed in color. After request and payment of the necessary fee, the Patent Office will provide a copy of the patent or patent application publication with color drawings.

[0030] Figure 1 Shows the investment casting process.

[0031] Figure 2 Shows the investment casting process of a high-performance aluminum alloy modified with nanoparticles according to an embodiment of the present invention.

[0032] Figure 3A and 3B Shows an investment-cast nanoparticle-modified high-performance aluminum alloy part according to an embodiment of the present invention.

[0033] Figure 4 Shows investment-cast aluminum alloy parts with and without nanoparticle modification according to an embodiment of the present invention. Detailed Description

[0034] Turning now to the drawings, a method and system for investment casting using high-performance aluminum alloys are described. Many embodiments implement high-performance aluminum alloys modified with nanoparticles for the investment casting process. The investment casting process according to some embodiments produces high-performance aluminum alloy parts having properties including (but not limited to) the following: tight tolerances, smooth surface finish, complex geometries, and / or thin-wall cross-sections. Certain embodiments modify high-performance aluminum alloys with nanoparticles for the investment casting process, the high-performance aluminum alloys including (but not limited to) 2xx series, 2xxx series, 6xxx series, and / or 7xxx series. During the solidification step of the investment casting process, adding nanoparticles to high-strength aluminum alloys can refine the microstructure of the alloy. Nanoparticle-modified high-strength aluminum alloys can be investment cast to form parts with a desired surface finish and / or parts with complex structures without post-processing. Nanoparticle-modified high-performance aluminum alloys can resist hot cracking during investment casting.

[0035] For the purposes of the present invention, the term high-performance aluminum alloy shall be construed as 2xx series alloys, 7xx series alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, 7xxx series alloys, and / or any alloy that is difficult to cast conventionally, unless otherwise specified.

[0036] The investment casting process according to various embodiments of the present invention is further discussed below. Investment Casting

[0037] The investment casting process (also known as the lost-wax process) can be used as an industrial production method for metal parts. During the investment casting process, a pattern made of wax can be coated with a refractory material to create a mold. Then, the wax is melted before pouring the molten metal into the mold. Investment casting is known as a precision casting process that can produce high-precision parts with complex details.

[0038] The investment casting process has several advantages. The investment casting process can be used to cast parts with a high degree of complexity and intricacy. Investment casting can provide precise dimensional control and good surface finish. The wax can be recycled to reduce material waste. The investment casting process can be a net shape that does not require additional machining.

[0039] Figure 1 The process of investment casting is shown. Figure 1 Multiple steps of investment casting are shown. First, a wax pattern 101 of the desired shape can be made. Multiple wax patterns can be connected to a runner to form a pattern tree 102. Then, a thin layer of refractory material 103 can be applied to the pattern tree. A full mold is formed by covering the coated tree with enough refractory material to make it rigid 104. The mold coated with refractory material can be held in an inverted position and heated to melt the wax and allow the wax to drip out of the cavity 105. Then the hollow mold can be preheated to a high temperature. The molten material (such as metal and / or metal alloy) can be poured into the mold and solidified 106. Once the material has solidified, the mold can be separated from the final casting, and the part can be separated from the runner 107.

[0040] Parts produced by the investment casting process have various applications in fields such as consumer goods, power generation, aerospace, automotive, jewelry, etc. Various types of metal alloys can be used for investment casting, including (but not limited to) steel, aluminum alloys, and copper alloys. Aluminum alloys are widely used in fields such as consumer electronics, automotive, aerospace, and shipbuilding due to their good plasticity, corrosion resistance, and light weight. Commonly used aluminum alloys for investment casting include (but not limited to) 3xx series alloys such as A356, A360, A380, A383.

[0041] For high mobility and energy-efficient applications, high-strength aluminum alloys are highly desirable. Compared to high-performance aluminum alloys including (but not limited to) 2xx series, 2xxx series, 6xxx series, and / or 7xxx series, 3xx series aluminum alloys have relatively low mechanical strength. However, due to the slow cooling rate of the process, it is difficult to use these high-performance aluminum alloys for investment casting of complex components. Refractory materials are commonly used in the investment casting process to make molds because they are tolerant to thermal decomposition. Due to the use of refractory molds, the cooling rate of the molten material can be very slow, for example, from about 0.21 °C / s to about 1.24 °C / s, and / or from about 0.32 °C / s to about 4.22 °C / s. (See, for example, Yu, J. et al., Int J Adv Manuf Technol, 105, 3531–3542 (2019); Nawrocki, J. et al., Key Engineering Materials, 641, 124-131 (2015); the disclosures of which are incorporated herein by reference). High-performance aluminum alloys can begin to form large dendritic grains at slow cooling rates. The change in the microstructure of the alloy reduces the strength and ductility of aluminum castings, making them unsuitable for high-performance structures. Due to the formation of dendrites, the microstructure of dendritic grains and the dendrite arm spacing (DAS) can be coarse. Coarse DAS may result in relatively poor tensile ductility and fracture resistance. In addition, the microstructure changes caused by slow cooling rates make high-performance alloys prone to thermal cracking and shrinkage, making it difficult to form thin structures and / or complex shapes.

[0042] Many embodiments achieve nanoparticle-modified high-strength aluminum alloys in the investment casting process. Nanoparticles in high-strength aluminum alloys can refine the microstructure of the alloy and eliminate thermal cracks during the slow solidification step of the investment casting process. High-performance aluminum alloys for investment casting

[0043] Many embodiments achieve nanoparticle-modified high-performance alloys in investment casting, including (but not limited to) 2xx series, 2xxx series, 5xxx series, 6xxx series, and / or 7xxx series. The high-performance aluminum alloys have good strength, ductility, and fatigue life, as well as thermal conductivity. Examples of high-performance alloys that can be modified with nanoparticles and used in the investment casting process include (but not limited to) A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068. It is understood that, in accordance with various embodiments of the present invention, any of a variety of high-performance aluminum alloys can be appropriately utilized according to the requirements of specific applications.

[0044] In several embodiments, adding nanoparticles to high-performance aluminum alloys enables a low-cost investment casting process to be used for conventional difficult-to-cast wrought aluminum alloys. According to some embodiments, the presence of nanoparticles in the aluminum alloy can effectively refine the grain structure during the slow cooling of investment casting. In multiple embodiments, the nanoparticles can limit grain growth, adjust intermetallic compounds, and / or eliminate thermal cracking at low cooling rates in investment casting. In many embodiments, after modification with nanoparticles, aluminum alloy systems that are traditionally difficult to investment cast can be made suitable for investment casting.

[0045] In many embodiments, the nanoparticles can be uniformly dispersed in the metal alloy matrix. In some embodiments, the materials included in the nanoparticles include (but are not limited to) ceramics, oxides, nitrides, borides, carbides, and other carbon-based particles, metals, and metal alloys. The nanoparticles can be core-shell particles. Examples of the types of nanoparticles that can be dispersed in the aluminum alloy matrix include alumina nanoparticles, aluminum nitride nanoparticles, silicon carbide nanoparticles, silicon nitride nanoparticles, titanium carbide nanoparticles, titanium boride nanoparticles, titanium carbonitride nanoparticles, and tungsten carbide nanoparticles. In several embodiments, carbon nanotubes can be dispersed in the aluminum alloy matrix to enhance the castability of high-performance aluminum alloys. Additionally, the nanoparticles can be core-shell type nanoparticles including a core material and a coating. Examples include SiC nanoparticles coated with SiO, and ceramic nanoparticles coated with metals such as nickel or silver (see, for example, U.S. Patent US 9,023,128B2 to Li et al., the disclosure of which is incorporated herein by reference in its entirety).

[0046] In some embodiments, the nanoparticles can include one or more ceramics, although other nanoparticle materials, including metals or other conductive materials, are also contemplated. Examples of nanoparticle materials include metal oxides (such as alkaline earth metal oxides, post-transition metal oxides, and transition metal oxides, such as aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), yttrium oxide (Y 2 O 3 ), magnesium aluminate (MgAl 2 O 4 ), and zirconium oxide (ZrO 2 ), non-metal oxides (such as silicon oxide (SiO 2 ), metal carbides (such as transition metal carbides, such as titanium carbide (TiC), niobium carbide (NbC), chromium carbide (Cr 3 C 2), nickel carbide (NiC), hafnium carbide (HfC), vanadium carbide (VC), tungsten carbide (WC) and zirconium carbide (ZrC)), non-metallic carbides (such as silicon carbide (SiC)), metal silicides (such as transition metal silicides, such as titanium silicide (Ti 5 Si 3 ))), metal borides (such as transition metal borides, such as titanium boride (TiB 2 ), zirconium boride (ZrB 2 ), hafnium boride (HfB 2 ), vanadium boride (VB 2 ), and tungsten boride (W 2 B 5 ))), metal nitrides (such as transition metal nitrides), metals (such as transition metals in elemental form, such as tungsten (W)), alloys, mixtures or other combinations of two or more of the above, and alloys, mixtures or other combinations of one or more of the above with other elements. Specific examples of suitable nanoparticle materials include transition metal-containing ceramics, where the presence of the transition metal can confer a larger Hamaker constant, closer to that of the metal matrix with a reduced van der Waals potential well, such as transition metal carbides, transition metal silicides, transition metal borides, transition metal nitrides, and other non-oxide transition metal-containing ceramics (see, for example, PCT application number PCT / US20 / 27775 by Li et al.; U.S. Patent No. US 9,322,084 B2 by Li et al.; U.S. Patent No. US11,040,395B2 by Li et al., the disclosures of which are incorporated herein by reference in their entirety). Nanoparticles containing ceramics, metals, or other conductive materials can be core-shell particles.

[0047] In many embodiments, the nanoparticles can have at least one dimension with an average size less than about 500 nm. In some embodiments, the nanoparticles can have at least one dimension with an average size as follows: between 1 nm and about 500 nm; between about 1 nm and about 400 nm; between about 1 nm and about 300 nm; between about 1 nm and about 200 nm; between about 1 nm and about 100 nm; between about 1 nm and about 70 nm; between about 1 nm and about 50 nm; between about 1 nm and about 30 nm. Some embodiments provide that the size distribution of the nanoparticles can be characterized by the standard deviation relative to the average diameter, which is at most about 100%, at most about 90%, at most about 80%, at most about 70%, at most about 60%, or at most about 50% of the average size. In certain embodiments, the nanoparticles can have a generally spherical or globular shape, although other shapes and configurations of the nanoparticles can also be considered (e.g., elliptical, polygonal, irregular shapes).

[0048] In some embodiments, the high-performance aluminum alloy may include nanoparticles in a volume percentage within the following ranges: from about 0.1% to about 2%; from about 0.25% to 2%; about 0.5% or greater; about 1% or greater; about 2% or greater; about 3% or greater; about 5% or greater; about 6% or greater; about 7% or greater; about 8% or greater; about 9% or greater; about 10% or greater; about 15% or greater; about 20% or greater; about 25% or greater; or about 30% or greater. In certain embodiments, a volume percentage (from about 0.1% to about 2%) of nanoparticles may be applied to investment cast aluminum alloys that are difficult to cast or conventionally cannot be investment cast. It can be readily understood that, in accordance with the various embodiments of the present invention, any concentration among the various nanoparticle concentrations can be used according to the requirements of a specific application.

[0049] According to some embodiments, investment-cast high-performance aluminum alloys modified with nanoparticles exhibit high mechanical strength suitable for structural applications. Examples of such aluminum alloys include (but are not limited to) A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068. Any of the above nanoparticles can be used to modify the high-performance aluminum alloy. Investment casting of such high-strength aluminum alloys can open up application spaces for investment-cast aluminum alloys.

[0050] The investment casting process can produce parts with thin walls and complex structures. Many embodiments produce investment-cast high-strength aluminum parts having a thickness between about 0.2 mm and about 0.5 mm; between about 0.2 mm and about 0.3 mm; between about 0.2 mm and about 0.4 mm. Several embodiments produce investment-cast high-strength aluminum parts having a thickness greater than or equal to about 0.2 mm; greater than or equal to about 0.3 mm; greater than or equal to about 0.4 mm; greater than or equal to about 0.5 mm; greater than or equal to about 0.6 mm; greater than or equal to about 0.7 mm; greater than or equal to about 0.8 mm; greater than or equal to about 0.9 mm; greater than or equal to about 1.0 mm. The hot-cracking resistance of the nanoparticle-modified high-performance aluminum alloy according to some embodiments enables the production of thin-walled structures using the investment casting process.

[0051] Some embodiments provide that post - processing can be applied to investment - cast aluminum alloys with nanoparticles, however, it should be clear that this is not necessary. Adding nanoparticles enables the investment casting of high - performance aluminum alloy parts, and they have a surface finish of high quality (e.g., smooth with minimal cracks and / or defects). In several embodiments, investment - cast aluminum parts with nanoparticles may not require post - processing such as machining. In many embodiments, anodization can be applied to the investment - cast parts to add a desired color. Investment - cast metal parts with nanoparticle - modified aluminum alloys can be anodized to add any selected color, including (but not limited to) red, blue, green, yellow, silver, gold, and any combination thereof. It can be readily understood that, in accordance with various embodiments of the present invention, any of the various post - processing treatments can be appropriately used according to the requirements of the specific application.

[0052] Many embodiments employ high - performance aluminum alloys infused with nanoparticles to achieve the investment - casting process. Figure 2 The investment - casting process according to an embodiment of the present invention is shown. Prepare (201) a metal alloy (such as an aluminum alloy) with nanoparticles for investment casting. The following aluminum alloys can be prepared for investment casting, including (but not limited to) A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068. Many embodiments provide that the aluminum alloy mixed with nanoparticles has high mechanical strength. In some embodiments, the nanoparticles can be uniformly incorporated and dispersed in the aluminum - alloy matrix. In several embodiments, the content of nanoparticles in the metal alloy can be from about 0.1 vol% to about 2 vol%. Some embodiments provide that the nanoparticles can be made of the following materials, including (but not limited to): metal oxides (e.g., alkaline - earth metal oxides, post - transition metal oxides, and transition metal oxides such as aluminum oxide (Al 2 O 3 ), magnesium oxide (MgO), titanium oxide (TiO 2 ), yttrium oxide (Y 2 O 3 ), magnesium aluminate (MgAl 2 O 4 ), and zirconium oxide (ZrO 2 ), non - metal oxides (e.g., silicon oxide (SiO 2 ), metal carbides (e.g., transition - metal carbides such as titanium carbide (TiC), niobium carbide (NbC), chromium carbide (Cr 3 C 2) nickel carbide (NiC), hafnium carbide (HfC), vanadium carbide (VC), tungsten carbide (WC), and zirconium carbide (ZrC)), non-metallic carbides (such as silicon carbide (SiC)), metal silicides (such as transition metal silicides, such as titanium silicide (Ti 5 Si 3 ))), metal borides (such as transition metal borides, such as titanium boride (TiB 2 ), zirconium boride (ZrB 2 ), hafnium boride (HfB 2 ), vanadium boride (VB 2 ), and tungsten boride (W 2 B 5 ))), metal nitrides (such as transition metal nitrides), and metals (such as transition metals in elemental form, such as tungsten (W)). The nanoparticles can be core-shell particles.

[0053] Software such as computer-aided design (CAD) software can be used to design the desired product. High-performance aluminum alloys modified with nanoparticles can be formed into various shapes and / or structures. A model of the product (203) is formed using wax and / or polymer. These models can be 3D printed for rapid manufacturing. A metal mold can also be used to injection mold a wax pattern. A pattern tree (203) having a plurality of patterns connected to runners and gates is formed. If investment casting is to be performed on a single pattern, the pattern tree may not be necessary. The pattern tree can be coated (204) with a molten refractory material, such as a ceramic material or a ceramic slurry. Examples of refractory materials include (but are not limited to): silica, silica sand, magnesite, zircon, various aluminosilicates, and alumina. A binder can be mixed with the refractory material to obtain a smooth and thin coating. Once the refractory coating dries, the refractory coating forms a mold covering the pattern. The coated pattern tree is heated to melt the wax and remove (205) the wax and / or polymer to leave a hollow shell (also known as a mold). Heating can be achieved by various methods, such as induction heating, convective heating, or baking.

[0054] The prepared metal alloy mixed with nanoparticles can be melted to form (206) a molten metal alloy. The molten aluminum alloy can be poured into (207) the ceramic mold. Once the molten alloy cools and solidifies (208), the metal part (209) can be retrieved. Various cooling rates can be employed for cooling. The part can be cooled at room temperature (about 10 °C to about 25 °C), or other cooling methods (such as using a fan) can be applied to accelerate cooling. Post-processing such as anodizing can be performed on the investment-cast metal part to add a desired color, and / or machining can be performed to improve the details (not shown). Post-processing can be optional.

[0055] Figure 3A and Figure 3BShows the investment casting process of a high-performance aluminum alloy sample according to an embodiment of the present invention. Figure 3A Shows the process of investment casting an air compressor. The process starts with the CAD design of the air compressor 301. Then a wax or polymer model can be formed 302. A wax tree with multiple models can be formed 303. A ceramic mold (not shown) can be formed using the wax or polymer model and used as the mold for the molten alloy (not shown). The solidified metal part 304 shows an investment casting of an air compressor made of AA6061 alloy modified with about 1 vol% of TiC nanoparticles. The investment casting air compressor with nanoparticle-modified AA6061 can be anodized to be red 305. The solidified metal part 306 shows an investment casting of an air compressor made of AA7075 alloy modified with about 1 vol% of TiC nanoparticles. Although specific nanoparticles and aluminum alloys are shown in the figure, it is understood that any suitable nanoparticles and metal alloys can be used in the investment casting process.

[0056] Figure 3B Illustrates the process of investment casting an eyeglass frame. The process starts with the CAD design of the eyeglass frame 311. A model of wax or polymer can be formed based on the design 312. A wax tree with multiple models can be formed 313. A ceramic mold (not shown) can be formed using the wax mold and used as the mold for the molten alloy (not shown). The solidified metal part 314 shows an eyeglass frame investment cast with AA7075 modified with about 1 vol% of TiC nanoparticles. Although specific nanoparticles and aluminum alloys are shown in the figure, it is understood that any suitable nanoparticles and metal alloys can be used in the investment casting process.

[0057] Figure 4 Shows investment casting samples with and without nanoparticle modification according to an embodiment. Figure 4 Shows a comparison of investment casting samples with AA7075 alloy. 401 shows investment casting AA7075 without nanoparticle modification. Several cracks are visible in the sample. 402 shows investment casting AA7075 with about 1 vol% of TiC nanoparticle modification, and no cracks are observed in the sample. The investment casting sample with nanoparticles enables the AA7075 alloy to have a smooth surface. Equivalent principle

[0058] From the above discussion, it can be inferred that according to the embodiments of the present invention, the above concepts can be implemented in various arrangements. Therefore, although the present invention has been described in certain specific aspects, many other modifications and variations will be apparent to those skilled in the art. Therefore, it should be understood that the present invention can be practiced in a manner different from the specific description. Therefore, the embodiments of the present invention should be considered illustrative rather than restrictive in all respects.

[0059] As used herein, the singular terms "a", "an", and "the" may include plural referents unless the context clearly dictates otherwise. References to a singular object are not intended to mean "one and only one" but rather "one or more" unless explicitly stated.

[0060] As used herein, the terms "about" and "approximately" are used to describe and account for small variations. When used in conjunction with an event or circumstance, these terms can refer to instances where the event or circumstance occurs precisely as well as instances where it occurs approximately. When used in conjunction with a numerical value, these terms can refer to variations that are within ±10% of that numerical value, such as within ±5%, within ±4%, within ±3%, within ±2%, within ±1%, within ±0.5%, within ±0.1%, or within ±0.05%.

[0061] In addition, quantities, ratios, and other numerical values may sometimes be presented herein in a range format. It should be understood that this range format is used for convenience and brevity and should be interpreted flexibly as including the numerical values explicitly specified as the limits of the range as well as all individual numerical values or sub-ranges subsumed within that range as if each numerical value and sub-range were explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200 as well as individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and the like. Examples

[0062] Example 1: A metal alloy for investment casting, comprising: an aluminum alloy selected from the group consisting of 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys; and at least one type of nanoparticle dispersed in the aluminum alloy; wherein the metal alloy is compatible with the investment casting process.

[0063] Example 2: The example metal alloy of Example 1, wherein the metal alloy is selected from the group consisting of A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0064] Example 3: The example metal alloy of Example 1 or 2, wherein the at least one type of nanoparticle is selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0065] Example 4: The example metal alloy of Example 1, 2 or 3, wherein the at least one type of nanoparticles has a core-shell structure.

[0066] Example 5: The example metal alloy of any one of Examples 1 to 4, wherein the at least one type of nanoparticles accounts for less than or equal to 30% by volume of the metal alloy.

[0067] Example 6: The example metal alloy of any one of Examples 1 to 5, wherein the at least one type of nanoparticles accounts for 0.1% to 2% by volume of the metal alloy.

[0068] Example 7: The example metal alloy of any one of Examples 1 to 6, wherein the metal alloy is configured for investment casting a part having at least one thickness greater than or equal to 0.2 mm.

[0069] Example 8: An investment casting method, comprising: melting an aluminum alloy modified with at least one type of nanoparticles; filling an investment casting mold with the molten aluminum alloy having at least one type of nanoparticles; and cooling the mold to solidify the molten aluminum alloy to form a part.

[0070] Example 9: The example method of Example 8, wherein the aluminum alloy is selected from the group consisting of: 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

[0071] Example 10: The example method of Example 8 or 9, wherein the aluminum alloy is selected from the group consisting of: A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0072] Example 11: The example method of Example 8, 9 or 10, wherein the at least one type of nanoparticles comprises a material selected from the group consisting of: metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0073] Example 12: The example method of any one of Examples 8 to 11, wherein the at least one type of nanoparticles has a core-shell structure.

[0074] Example 13: The example method of any one of Examples 8 to 12, wherein the at least one type of nanoparticles accounts for less than or equal to 30% by volume of the aluminum alloy.

[0075] Example 14: The example method of any one of Examples 8 to 13, wherein the at least one type of nanoparticles accounts for 0.1% to 2% by volume of the aluminum alloy.

[0076] Example 15: The example method of any one of Examples 8 to 14, wherein at least one cross-section of the part has a thickness greater than or equal to 0.2 mm.

[0077] Example 16: The example method of any one of Examples 8 to 15, further comprising anodizing the part to have at least one color.

[0078] Example 17: An investment-cast metal part, comprising: an aluminum alloy; and at least one type of nanoparticles; wherein the at least one type of nanoparticles is distributed in the aluminum alloy; and wherein the aluminum alloy is selected from the group consisting of 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

[0079] Example 18: The example metal part of Example 17, wherein the aluminum alloy is selected from the group consisting of A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

[0080] Example 19: The example metal part of Example 17 or 18, wherein the at least one type of nanoparticles comprises a material selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

[0081] Example 20: The example metal part of Example 17, 18 or 19, wherein the at least one type of nanoparticles has a core-shell structure.

[0082] Example 21: The example metal part of any one of Examples 17 to 20, wherein the nanoparticles account for less than or equal to 30% by volume of the aluminum alloy.

[0083] Example 22: The example metal part of any one of Examples 17 to 21, wherein the nanoparticles account for 0.1% to 2% by volume of the aluminum alloy.

[0084] Example 23: The example metal part of any one of Examples 17 to 22, wherein the metal part is configured to be anodized to have at least one color.

[0085] Example 24: The example metal part according to any one of Examples 17 to 23, wherein the metal part has at least one cross-section with a thickness greater than or equal to 0.2 mm.

Claims

1. A metal alloy for investment casting, comprising: an aluminum alloy selected from the group consisting of 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys; and at least one type of nanoparticles dispersed in the aluminum alloy; wherein the metal alloy is compatible with the investment casting process.

2. The metal alloy according to claim 1, wherein the metal alloy is selected from the group consisting of A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

3. The metal alloy according to claim 1, wherein the at least one type of nanoparticles is selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

4. The metal alloy according to claim 1, wherein the at least one type of nanoparticles has a core-shell structure.

5. The metal alloy according to claim 1, wherein the at least one type of nanoparticles accounts for less than or equal to 30% by volume of the metal alloy.

6. The metal alloy according to claim 1, wherein the at least one type of nanoparticles accounts for 0.1% to 2% by volume of the metal alloy.

7. The metal alloy according to claim 1, wherein the metal alloy is configured to investment cast a part having at least one thickness greater than or equal to 0.2 mm.

8. An investment casting method, comprising: melting an aluminum alloy modified with at least one type of nanoparticles; filling an investment casting mold with the molten aluminum alloy having at least one type of nanoparticles; and cooling the mold to solidify the molten aluminum alloy to form a part.

9. The method according to claim 8, further comprising anodizing the part to have at least one color.

10. The method according to claim 8, wherein the aluminum alloy is selected from the group consisting of 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

11. The method according to claim 8, wherein the aluminum alloy is selected from the group consisting of A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

12. The method according to claim 8, wherein the at least one type of nanoparticles comprises a material selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

13. The method according to claim 8, wherein the at least one type of nanoparticles has a core-shell structure.

14. The method according to claim 8, wherein the at least one type of nanoparticles accounts for less than or equal to 30% by volume of the aluminum alloy.

15. The method according to claim 8, wherein the at least one type of nanoparticles accounts for 0.1% to 2% by volume of the aluminum alloy.

16. The method according to claim 8, wherein the part has at least one cross-section with a thickness greater than or equal to 0.2 mm.

17. An investment-cast metal part, comprising: an aluminum alloy; and at least one type of nanoparticles; wherein the at least one type of nanoparticles is distributed in the aluminum alloy; and wherein the aluminum alloy is selected from the group consisting of 2xx series aluminum alloys, 2xxx series aluminum alloys, 6xxx series aluminum alloys, and 7xxx series aluminum alloys.

18. The metal part according to claim 17, wherein the aluminum alloy is selected from the group consisting of A201, AA2024, AA2219, A206, AA2618, AA5083, AA6013, AA6061, AA6063, AA6069, AA6110A, AA7034, AA7050, AA7075, and AA7068.

19. The metal part according to claim 17, wherein the at least one type of nanoparticles comprises a material selected from the group consisting of metal oxides, non-metal oxides, metal carbides, non-metal carbides, metal silicides, metal borides, metal nitrides, and any combination thereof.

20. The metal part according to claim 17, wherein the at least one type of nanoparticles has a core-shell structure.

21. The metal part according to claim 17, wherein the nanoparticles account for less than or equal to 30% by volume of the aluminum alloy.

22. The metal part according to claim 17, wherein the nanoparticles account for 0.1% to 2% by volume of the aluminum alloy.

23. The metal part according to claim 17, wherein the metal part is configured to be anodized to have at least one color.

24. The metal part according to claim 17, wherein the metal part has at least one cross-section with a thickness greater than or equal to 0.2 mm.

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