Metal powder for additive manufacturing, method for manufacturing additive products using the same, and additive products

Abstract

The objective is to provide a method for manufacturing additive products using aluminum alloy powder, which is used to produce additive products made of aluminum alloys with excellent high-temperature strength. [Solution] The additive manufacturing process includes a first step of forming a powder layer containing a predetermined additive metal powder, a second step of forming a metal layer by irradiating the powder layer with laser light and solidifying the metal powder at the location of the laser light irradiation, and a third step of heat-treating the additive after the second step, and the first and second steps include a step of preheating the metal layer and the powder layer at a temperature of 50°C to 500°C, the first and second steps are repeated sequentially, and multiple metal layers are stacked and joined together to manufacture the product, and the volume energy density of the laser light irradiation conditions in the second step is 30 J / mm². 3 More than 150J / mm 3 The process is as follows: In the third step, the additive is heat-treated at a temperature of 200°C to 650°C for 1 hour to 30 hours to produce the additive.

Description

[Technical Field]

[0001] The present invention relates to aluminum alloy powder for producing an additive product made of an aluminum alloy having high relative density, excellent high-temperature strength, and high-temperature Young's modulus, a method for producing an additive product using the same, and the additive product itself. [Background technology]

[0002] Conventionally, Al-Si casting alloys, such as Al-10%Si-0.4%Mg (ISO-AlSi10Mg) alloy, have been mainly used as aluminum alloy materials for additive manufacturing (additive manufacturing). The additively manufactured products (formed bodies) exhibit an extremely fine cellular dendrite structure on the submicron order due to the effect of rapid solidification by irradiation with a laser, etc., and show excellent mechanical properties (strength and elongation at break) at room temperature.

[0003] As an example of using such Al-Si casting alloys in additive manufacturing, Patent Document 1 describes a metal powder for additive manufacturing that mainly consists of aluminum and contains a total of 10% by mass or less of silicon and magnesium, with a silicon content greater than 1% by mass. By additive manufacturing using this powder, it is possible to obtain an Al-Si alloy additively manufactured product that has high relative density, ductility and thermal conductivity, and excellent mechanical properties at room temperature.

[0004] Furthermore, Patent Document 2 describes a metal molded body made of an alloy containing a main metal element and an additive element, wherein the ratio of the atomic radius b of the main metal element to the atomic radius a of the additive element, 100(ab) / b, is -30% to +30%, and it is stated that the resulting molded body has excellent functional properties such as mechanical properties.

[0005] Furthermore, Non-Patent Document 1 examines the mechanical properties of fabricated objects using aluminum alloy powder containing silicon and magnesium. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] WO2017 / 203717 Brochure [Patent Document 2] Japanese Patent Publication No. 2016-053198 [Non-patent literature]

[0007] [Non-Patent Document 1] Journal of the Laser Processing Society of Japan: Takahiro Kimura, Vol.25, No.3 (2018), 164-173 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, although additively manufactured materials made from Al-Si alloys obtained in Patent Document 1 have excellent mechanical properties at room temperature, when exposed to temperatures above 150°C, their strength rapidly decreases due to the effects of coarsening and granulation of the microstructure caused by overaging, as disclosed in Non-Patent Document 1, for example. Therefore, additively manufactured materials using Al-Si alloy powder described in Patent Document 1 are difficult to use for components that require heat resistance.

[0009] Furthermore, while Patent Document 2 selects alloying elements with strengthening by solid solution into the aluminum matrix in mind, if elements with a fast diffusion rate are included, it is expected that coarse precipitates will form at high temperatures, significantly reducing the strength, making it unsuitable for use in high-temperature environments.

[0010] Therefore, the object of the present invention is to provide an aluminum alloy powder for producing an additive product made of an aluminum alloy with excellent high-temperature strength and high-temperature Young's modulus, as well as an additive product using the same and a method for producing the same. [Means for solving the problem]

[0011] In view of these problems, attention was paid to transition metals as alloying elements added to aluminum for improving heat resistance. Generally, transition metals have a low maximum solid solubility limit in aluminum and form compounds and solid solutions that are stable up to high temperatures. Further, since the diffusion rate of transition metal elements in aluminum is relatively slow, aluminum-transition metal alloys can stably maintain their microstructure for a long time in a high-temperature range. Therefore, improvement in high-temperature strength and high-temperature Young's modulus is expected in aluminum-transition metal alloys.

[0012] In the present invention, the above problems are solved by a metal powder for additive manufacturing that contains at least one selected from iron, manganese, chromium, nickel, and zirconium as an alloying element in aluminum at 0.20 mass% or more and 13 mass% or less, and in which the content of the iron is less than 4.5 mass%.

[0013] In a preferred embodiment of the metal powder for additive manufacturing according to the present invention, the total content of iron, manganese, chromium, nickel, and zirconium is 0.20 mass% or more and 13 mass% or less.

[0014] In a more preferred embodiment of the metal powder for additive manufacturing according to the present invention, the metal powder further contains silicon at less than 1 mass%.

[0015] Further, the above problems of the present invention are solved by a manufacturing method for an additive product that includes a first step of forming a powder layer containing the metal powder for additive manufacturing and a second step of forming a metal layer by solidifying the metal powder at a predetermined position in the powder layer, wherein the first step and the second step are sequentially repeated, and the metal layers are stacked and joined in a plurality of layers.

[0016] In a preferred embodiment of the manufacturing method for an additive product according to the present invention, the metal layer, the powder layer, and the additive product are preheated at a temperature of 50°C or higher and 500°C or lower in the first step and the second step.

[0017] In a preferred embodiment of the method for manufacturing an additive product according to the present invention, the method further includes a third step of performing heat treatment after the second step.

[0018] In a more preferred embodiment of the method for manufacturing an additive product according to the present invention, in the third step, the additive product is heat-treated at a temperature of 200°C or higher and 650°C or lower.

[0019] Furthermore, the above problems of the present invention are also achieved by an additive product containing at least any one of iron, manganese, chromium, nickel, and zirconium as alloy elements in aluminum at 0.20% by mass or more and 13% by mass or less, with the content of iron being less than 4.5% by mass and having a relative density of 95% or more and 100% or less.

[0020] In a preferred embodiment of the additive product according to the present invention, the total content of iron, manganese, chromium, nickel, and zirconium is 0.20% by mass or more and 13% by mass or less.

[0021] In a more preferred embodiment of the additive product according to the present invention, the additive product further contains silicon and the content thereof is less than 1.0% by mass.

Effects of the Invention

[0022] By using the metal powder for additive manufacturing according to the present invention, an additive product with a high relative density, improved high-temperature strength and high-temperature Young's modulus, and excellent heat resistance can be manufactured.

Brief Description of the Drawings

[0023] [Figure 1A] A process diagram for explaining the steps of a method for manufacturing an additive product, which is an embodiment of the present invention. [Figure 1B] Following FIG. 1A, a process diagram for explaining the steps of a method for manufacturing an additive product, which is an embodiment of the present invention. [Figure 1C] Following FIG. 1B, a process diagram for explaining the steps of a method for manufacturing an additive product, which is an embodiment of the present invention. [Figure 2A] Following Figure 1C, this is a process diagram illustrating the steps of the manufacturing method for the additive product. [Figure 2B] Following Figure 2A, this is a process diagram illustrating the steps of the manufacturing method for the additive product. [Figure 2C] Following Figure 2B, this is a process diagram illustrating the steps of the manufacturing method for the additive product. [Figure 3] Following Figure 2C, this is a process diagram illustrating the steps of the manufacturing method for the additive product. [Figure 4] Plan view of a test specimen used in tensile testing. [Figure 5A] A photograph showing the shape of the manufactured add-on. [Figure 5B] A photograph showing the shape of a cylindrical appendage used to produce tensile test specimens. [Figure 6A] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 1-1). [Figure 6B] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 2-1). [Figure 6C] Optical microscope image of a vertical cross-section of a manufactured add-on (Reference Example 3-1). [Figure 6D] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 4-1). [Figure 7A] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 5-1). [Figure 7B] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 6-1). [Figure 7C] Optical microscope image of a vertical cross-section of a manufactured additive product (Reference Example 7-1). [Figure 7D] Optical microscope image of the vertical cross-section of the manufactured additive product (Example 8-1). [Figure 8A] Optical microscope image of the vertical cross-section of the manufactured additive product (Example 9-2). [Figure 8B] Optical microscope image of the vertical cross-section of the manufactured additive product (Example 10-2). [Figure 8C]Optical microscope image of the vertical cross-section of the manufactured additive product (Example 11-2). [Figure 8D] Optical microscope image of the vertical cross-section of the manufactured additive product (Example 12-2). [Figure 9A] Optical microscope image of the vertical cross-section of the manufactured additive product (Comparative Example 1-1). [Figure 9B] Optical microscope image of the vertical cross-section of the manufactured additive product (Comparative Example 2-1). [Figure 9C] Optical microscope image of the vertical cross-section of the manufactured additive product (Comparative Example 3-1). [Figure 10A] Optical microscope image of the vertical cross-section of the manufactured add-on (Comparative Example 4-1). [Figure 10B] Optical microscope image of the vertical cross-section of the manufactured additive product (Comparative Example 5-1). [Figure 11A] External photographs and optical microscope images of vertical cross-sections of adducts manufactured at preheating temperatures of 35°C and 200°C (Reference Example 9-1, Example 9-2). [Figure 11B] External photographs and optical microscope images of vertical cross-sections of adducts manufactured at preheating temperatures of 35°C and 200°C (Reference Example 10-1, Example 10-2). [Figure 11C] External photographs and optical microscope images of vertical cross-sections of adducts manufactured at preheating temperatures of 35°C and 200°C (Reference Example 11-1, Example 11-2). [Figure 11D] External photographs and optical microscope images of vertical cross-sections of adducts manufactured at preheating temperatures of 35°C and 200°C (Reference Example 12-1, Example 12-2). [Figure 12A] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 1-1). [Figure 12B] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 2-1). [Figure 12C] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 3-1). [Figure 12D]A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 4-1). [Figure 13A] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 5-1). [Figure 13B] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 6-1). [Figure 13C] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Reference Example 7-1). [Figure 13D] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Example 8-1). [Figure 14A] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Example 9-2). [Figure 14B] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Example 10-2). [Figure 14C] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Example 11-2). [Figure 14D] A graph showing the change in Vickers hardness of an additive product due to heat treatment (Example 12-2). [Figure 15A] Scanning transmission electron microscope (STEM) bright-field image of a horizontal cross-section of a manufactured additive product (Reference Example 1-1). [Figure 15B] Scanning transmission electron microscope (STEM) bright-field image of a horizontal cross-section of a manufactured additive product (Reference Example 2-1). [Figure 15C] Scanning transmission electron microscope (STEM) bright-field image of a horizontal cross-section of a manufactured adduct (Reference Example 5-1). [Figure 15D] High-angle annular dark-field scanning transmission electron microscope (STEM) image of a horizontal cross-section of a manufactured additive product (Reference Example 7-1). [Figure 15E] High-angle annular dark-field scanning transmission electron microscope (STEM) image of a horizontal cross-section of a manufactured additive product (Example 8-1). [Figure 15F] High-angle annular dark-field scanning transmission electron microscope (STEM) image of a horizontal cross-section of a manufactured additive product (Example 11-2). [Figure 15G] Scanning transmission electron microscope (STEM) bright-field image of a horizontal cross-section of a manufactured additive product (Example 12-2). [Modes for carrying out the invention]

[0024] Embodiments of the present invention will be described below. The present invention relates to aluminum alloy powder for manufacturing additive products (hereinafter referred to as "metal powder for additive manufacturing"), additive products using the same, and methods for manufacturing the same. However, the following description is not intended to limit the scope of the invention of this disclosure.

[0025] <Metal powders for additive manufacturing> The aforementioned additive manufacturing metal powder is equivalent to toner and ink in a typical two-dimensional printer. This additive manufacturing metal powder is an aluminum alloy powder mainly composed of aluminum (Al) and containing at least one selected from iron (Fe), manganese (Mn), chromium (Cr), nickel (Ni), and zirconium (Zr).

[0026] The content of at least one of the iron, manganese, chromium, nickel, and zirconium is 0.20% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and particularly preferably 7% by mass or more. It is also 13% by mass or less, more preferably 9% by mass or less, and even more preferably 8% by mass or less. By having the content within these ranges, the additive product made using the additive metal powder can achieve both high relative density and excellent high-temperature strength and high-temperature Young's modulus. If the content is higher than the above range, the melting point of the powder will rise, which may make it difficult to manufacture the additive metal powder. If the content is lower than the above range, there is a high possibility that the high-temperature strength, especially the 0.2% yield strength at high temperature, of the additive product made using the additive metal powder will not be sufficiently improved.

[0027] Furthermore, the total content of iron, manganese, chromium, nickel, and zirconium is 0.20% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and particularly preferably 10% by mass or more. Also, it is 13% by mass or less, preferably 12.5% ​​by mass or less, and more preferably 12% by mass or less. By having the total content within these ranges, the additive product made using the additive metal powder can achieve both high relative density and excellent high-temperature strength and high-temperature Young's modulus. If the content is higher than the above range, the melting point of the powder will rise, which may make it difficult to manufacture the additive metal powder. On the other hand, if the content is lower than the above range, there is a high possibility that the high-temperature strength, especially the 0.2% yield strength at high temperature, of the additive product made using the additive metal powder will not be sufficiently improved.

[0028] The iron content of this additive metal powder is preferably less than 4.5% by mass, more preferably 3% by mass or less, and even more preferably 2% by mass or less. If the iron content is 4.5% by mass or more, the additive product made using the metal powder will become significantly brittle, and there is a risk of cracking such as interlaminar cracking.

[0029] Furthermore, the metal powder for additive manufacturing may also contain silicon. The silicon content is preferably less than 1% by mass, and less than 0.5% by mass. If the silicon content is 1% by mass or more, the high-temperature strength and ductility of the additive product made using the metal powder may decrease, and there is also a risk of cracking such as solidification cracking.

[0030] The metal powder used for additive manufacturing may contain small amounts of impurity elements. These impurity elements may be elements that are inevitably mixed in during the production of aluminum alloy powder (unavoidable impurities), or they may be modifying elements that are intentionally added. The content of impurity elements is not particularly limited, but is preferably 2% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less.

[0031] Specific examples of the aforementioned impurity elements include magnesium (Mg), copper (Cu), zinc (Zn), lithium (Li), silicon (Si), iron (Fe), manganese (Mn), chromium (Cr), nickel (Ni), titanium (Ti), calcium (Ca), sodium (Na), strontium (Sr), yttrium (Y), niobium (Nb), molybdenum (Mo), tungsten (W), antimony (Sb), beryllium (Be), phosphorus (P), vanadium (V), tin (Sn), lead (Pb), bismuth (Bi), cobalt (Co), silver (Ag), gallium (Ga), scandium (Sc), cerium (Ce), boron (B), carbon (C), nitrogen (N), oxygen (O), and the like.

[0032] The content of each element in the metal powder used for additive manufacturing can be measured by ICP emission spectroscopy and inert gas fusion-infrared absorption spectroscopy, etc.

[0033] The particle size of the metal powder for additive manufacturing is not particularly limited, but the volume-based average particle size (median diameter d50) is preferably 1 μm or more, more preferably 5 μm or more, even more preferably 10 μm or more, and particularly preferably 15 μm or more. If the average particle size is less than 1 μm, the fluidity of the powder will decrease, and there is a risk that a uniform powder layer cannot be formed in the manufacturing process of the additive product. On the other hand, the average particle size is preferably 200 μm or less, more preferably 150 μm or less, even more preferably 100 μm or less, and particularly preferably 60 μm or less. If the average particle size exceeds 200 μm, there is a risk that the powder will get caught in the squeegee during additive manufacturing, making it difficult to spread evenly.

[0034] The average circularity of the metal powder used for additive manufacturing is not particularly limited, but it is preferably between 0.9 and 1.0. If the average circularity falls below 0.9, the fluidity of the powder decreases, and there is a risk that a uniform powder layer cannot be formed in the additive manufacturing process.

[0035] The amount of oxygen contained in the metal powder for additive manufacturing is not particularly limited, but is preferably 0.001% by weight or more. It is also preferably 0.5% by weight or less, and more preferably 0.2% by weight or less. If the amount of oxygen exceeds this range, oxygen-related defects may occur in the additive product, potentially degrading its mechanical properties. If the amount of oxygen is below this range, there is a risk of the powder spontaneously igniting.

[0036] The moisture content in the metal powder used for additive manufacturing is not particularly limited, but is preferably 0.001% by weight or more. It is also preferably 0.5% by weight or less, and more preferably 0.2% by weight or less. If the moisture content exceeds this range, gas defects may occur in the additive product, potentially degrading its mechanical properties. It is industrially very difficult and impractical to reduce the moisture content below this range.

[0037] The aforementioned metal powder for additive manufacturing can be produced, for example, by gas atomization or water atomization, but it can also be produced by other methods such as the rotating electrode method, plasma atomization, centrifugal atomization, mechanical alloying, and chemical processes.

[0038] <Method of manufacturing additive products> Next, a method for producing an additive product using the aforementioned additive metal powder will be described. The additive product of the present invention comprises a first step of forming a powder layer containing the additive metal powder, and a second step of forming a metal layer by solidifying the additive metal powder at predetermined positions in the powder layer, wherein the first and second steps are repeated sequentially, and the product is manufactured by stacking and joining multiple metal layers. In this invention, powder bed fusion bonding, a type of additive manufacturing method, is used. However, other additive manufacturing methods may be used, such as directed energy deposition. Furthermore, indirect additive manufacturing methods such as binder injection or fused deposition may also be used.

[0039] Specifically, as shown in Figure 1A, the first step involves supplying additive manufacturing metal powder a onto a substrate 11 placed on a stage 14 in the chamber 10 by moving the squeegee 12 horizontally (in the direction of arrow A), thereby forming a powder layer P containing additive manufacturing metal powder a on the substrate 11. At this time, by adjusting the position of the vertically movable stage 14, a powder layer P of a desired thickness t can be formed.

[0040] Next, as shown in Figure 1B, the laser scanning device 13 irradiates a laser beam onto an arbitrary area of ​​the surface of the metal powder layer P, heating the metal powder in the irradiated area. As a result, the metal powder in the laser-irradiated area melts or sintersects and solidifies, and then, as shown in Figure 1C, a second step is performed in which the metal layer M is formed by irradiating the laser beam along a desired scanning path.

[0041] Next, as shown in Figure 2A, the first step is repeated in which the position of the stage 14 is moved downward by a predetermined thickness, and the squeegee 12 is moved horizontally (in the direction of arrow A) to supply the additive manufacturing metal powder a onto the metal layer M, thereby forming a powder layer P containing the additive manufacturing metal powder a on the substrate 11. Next, as shown in Figure 2B, the laser scanning device 13 irradiates a laser beam onto an arbitrary area of ​​the surface of the metal powder layer P, heating the metal powder in the irradiated area. As a result, the metal powder in the laser-irradiated area melts or sintersects and solidifies, and as shown in Figure 2C, the metal layer M is formed by irradiating the laser beam along a desired scanning path, and the second step is repeated. At this time, when the powder layer P solidifies by melting or sintering to form the metal layer M, it is joined to the previously formed lower metal layer M, so the newly formed metal layer M becomes integrated with the lower metal layer M.

[0042] By sequentially repeating these first and second steps, an additive product M1 is manufactured in which multiple metal layers M are stacked and joined together, as shown in Figure 3. This additive manufacturing product, which is made by stacking and joining multiple layers, can be fabricated, for example, based on slice data converted from the three-dimensional shape data of the target additive manufacturing product using 3D CAD. The slice data is the shape data of each cross-section obtained by dividing the three-dimensional shape data of the additive manufacturing product into multiple layers, one above the other, with a predetermined stacking thickness t. By moving the base material 11 up and down using the stage 14 based on the predetermined stacking thickness t, and irradiating a predetermined area of ​​each of the multiple metal powder layers P stacked in the vertical direction with laser light based on the slice data, the metal powder is locally melted or sintered and solidified, thereby fabricating an additive manufacturing product with the desired shape.

[0043] In the second step, the irradiation conditions when irradiating the metal powder layer P with laser light, that is, the laser light output, scanning speed, scanning interval, etc., can be appropriately adjusted, for example, within a range of 10,000 W or less for the output, within a range of 30,000 mm / s or less for the scanning speed, and within a range of 50 mm or less for the scanning interval. In addition, the layer thickness t can be appropriately adjusted, for example, within a range of 10 mm or less.

[0044] Based on the inventors' research, the following formula was found using the laser beam output P (W), scanning speed V (mm / s), scanning interval s (mm), and layer thickness t (mm): E d =P / (V·s·t) The volume energy density E calculated by d (J / mm 3 It has been found that by irradiating metal powder with conditions optimized for each powder characteristic such as the composition, particle size distribution, and powder shape of the metal powder, additive products with high relative density can be obtained.

[0045] The optimal volume energy density under laser irradiation conditions for manufacturing the additive product of the present invention, which is dense (high relative density), is not particularly limited, but is 30 J / mm². 3 More than 150J / mm 3 The following is preferable: 40 J / mm 3 More than 120J / mm 3More preferably, it is as follows, and further 45 J / mm 3 or more and 100 J / mm 3 or less is particularly preferable. If it is lower than the above range, there is a risk of void defects due to unmelted parts inside the added product. Also, if it is higher than the above range, there is a risk of spherical gas pores occurring inside the added product by entraining hydrogen derived from moisture adhering to the atmospheric gas or powder.

[0046] Note that laser light can be used as a heat source for melting and solidifying the metal powder, but this means is not limited to laser light, and for example, electron beams, plasmas, etc. may also be used.

[0047] In the manufacturing method of the present invention, the metal layer, the powder layer, and the added product may be preheated in the first and second steps. The preheating temperature is preferably 50°C or higher, more preferably 150°C or higher. Also, it is preferably 500°C or lower, more preferably 400°C or lower, and even more preferably 250°C or lower. With preheating below 50°C, the effect of suppressing cracks (interlayer peeling) cannot be sufficiently obtained, and with preheating at a temperature exceeding 500°C, the microstructure of the added product disappears and the mechanical properties deteriorate. Usually, an electric heater attached to the bottom of the shaping platform or base plate is used for preheating, but a ceramic heater, high-frequency heating, etc. may also be used. Also, a heat source such as laser light or an electron beam may be scanned and heated.

[0048] The manufacturing method of the present invention may further include a third step of heat-treating the adduct after the second step. In the heat treatment step of the third step, a temperature of 200°C or higher is preferred, and 250°C or higher is more preferred. Also, a temperature of 650°C or lower is preferred, 500°C or lower is more preferred, and 450°C or lower is even more preferred. Heat treatment below 200°C does not sufficiently improve strength, and heat treatment at temperatures above 650°C may cause the microstructure of the adduct to disappear, degrading its mechanical properties, or cause a change in the shape of the adduct due to partial melting. In the third step, solution treatment (solid solution heat treatment) may be performed before the heat treatment. The furnace used for heat treatment is usually an atmospheric furnace, but an atmospheric furnace may be used, for example, in an inert gas atmosphere such as nitrogen or argon, or in a reducing gas atmosphere such as hydrogen.

[0049] Furthermore, the time for the heat treatment is preferably 0.1 hours or more, more preferably 0.5 hours or more, and more preferably 1 hour or more. Also, it is preferably 1000 hours or less, more preferably 500 hours or less, more preferably 100 hours or less, and even more preferably 30 hours or less. If it is shorter than 0.1 hours, the strength of the additive may not improve sufficiently. On the other hand, if it is longer than 1000 hours, there is a risk that the strength of the additive will decrease due to over-aging.

[0050] <Additive Products> The additive product of the present invention is composed of an aluminum alloy of a specific composition that constitutes the metal powder for additive manufacturing described above. Specifically, this additive product contains aluminum with at least one of the following alloying elements: iron, manganese, chromium, nickel, and zirconium. The content of at least one element selected from iron, manganese, chromium, nickel, and zirconium is 0.20% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and particularly preferably 7% by mass or more. It is also 13% by mass or less, more preferably 9% by mass or less, and even more preferably 8% by mass or less. By having the content within these ranges, the adducted product can achieve both high relative density and excellent high-temperature strength and high-temperature Young's modulus. If the content is higher than the above range, the melting point of the alloy will rise, making it difficult to manufacture the adducted product, and the ductility of the adducted product will decrease significantly. If the content is lower than the above range, there is a high possibility that the high-temperature strength of the adducted product, especially the high-temperature 0.2% yield strength, will not be sufficiently improved.

[0051] Furthermore, the total content of iron, manganese, chromium, nickel, and zirconium in the adduct is 0.20% by mass or more, preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 4% by mass or more, even more preferably 5% by mass or more, and particularly preferably 10% by mass or more. Also, it is 13% by mass or less, preferably 12.5% ​​by mass or less, and more preferably 12% by mass or less. By having the total content within these ranges, the adduct can achieve both high relative density and excellent high-temperature strength and high-temperature Young's modulus. If the content is higher than the above range, the melting point of the alloy will rise, making it difficult to manufacture the adduct, and the ductility of the adduct will decrease significantly. If the content is lower than the above range, there is a high possibility that the high-temperature strength of the adduct, especially the high-temperature 0.2% yield strength, will not be sufficiently improved.

[0052] The iron content of this adduct is preferably less than 4.5% by mass, more preferably 3% by mass or less, and even more preferably 2% by mass or less. If the iron content is 4.5% by mass or more, the adduct consisting of that composition will become significantly brittle, and there is a risk of cracking such as interlaminar cracking.

[0053] Furthermore, the adduct may also contain silicon. The silicon content is preferably less than 1% by mass, and less than 0.5% by mass. If the content is 1% by mass or more, the high-temperature strength and ductility of the adduct with that composition may decrease, and furthermore, cracks such as solidification cracks may occur.

[0054] The aforementioned additive product may contain small amounts of impurity elements. These impurity elements may be elements that are inevitably mixed in during the production of the aluminum alloy powder (unavoidable impurities), or they may be modifying elements that are intentionally added. The content of impurity elements is not limited, but is preferably 2% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less.

[0055] Specific examples of the aforementioned impurity elements include magnesium (Mg), copper (Cu), zinc (Zn), lithium (Li), silicon (Si), iron (Fe), manganese (Mn), chromium (Cr), nickel (Ni), titanium (Ti), calcium (Ca), sodium (Na), strontium (Sr), yttrium (Y), niobium (Nb), molybdenum (Mo), tungsten (W), antimony (Sb), beryllium (Be), phosphorus (P), vanadium (V), tin (Sn), lead (Pb), bismuth (Bi), cobalt (Co), silver (Ag), gallium (Ga), scandium (Sc), cerium (Ce), boron (B), carbon (C), nitrogen (N), oxygen (O), and the like.

[0056] The content of each element in the additive product can be measured using ICP emission spectroscopy and inert gas fusion-infrared absorption spectroscopy, etc., in the same manner as the method for measuring the content of each element in the metal powder used for additive manufacturing.

[0057] The adduct according to the present invention has a relative density of 95% or more and 100% or less. The relative density of the adduct is preferably 98% or more, more preferably 99% or more, and even more preferably 99.5% or more. If the relative density does not meet this range, the mechanical properties of the adduct will deteriorate significantly. This relative density is calculated by binarizing an optical microscope image (100x magnification) of an arbitrary vertical (parallel to the stacking direction) cross-section near the center of the additive product, and then determining the area ratio of the metal portion excluding the voids. Relative density is desirable as it increases for improving the mechanical strength, ductility, and thermal and electrical conductivity of the added product.

[0058] The aforementioned additive product has a high-temperature tensile strength of 140 MPa or more at a test temperature of 150°C, a high-temperature tensile strength of 130 MPa or more at a test temperature of 200°C, a high-temperature tensile strength of 115 MPa or more at a test temperature of 250°C, a high-temperature tensile strength of 95 MPa or more at a test temperature of 300°C, and a high-temperature tensile strength of 57 MPa or more at a test temperature of 350°C. By possessing such high-temperature tensile strength, the added material can exhibit superior heat resistance compared to conventional technologies.

[0059] The aforementioned additive product has a high-temperature 0.2% proof stress of 115 MPa or more at a test temperature of 150°C, a high-temperature 0.2% proof stress of 105 MPa or more at a test temperature of 200°C, a high-temperature 0.2% proof stress of 95 MPa or more at a test temperature of 250°C, a high-temperature 0.2% proof stress of 75 MPa or more at a test temperature of 300°C, and a high-temperature 0.2% proof stress of 30 MPa or more at a test temperature of 350°C. By possessing such a high-temperature 0.2% yield strength, the additive product can exhibit superior heat resistance compared to conventional technologies. In particular, a higher high-temperature 0.2% yield strength at a test temperature of 350°C tends to satisfy the above conditions, resulting in a more significant improvement in heat resistance.

[0060] Furthermore, the additive product has a high-temperature Young's modulus of 59 GPa or more at a test temperature of 200°C, a high-temperature Young's modulus of 52 GPa or more at a test temperature of 250°C, a high-temperature Young's modulus of 34 GPa or more at a test temperature of 300°C, and a high-temperature Young's modulus of 29 GPa or more at a test temperature of 350°C. By having such a high-temperature Young's modulus, the added product can exhibit superior rigidity in the high-temperature range compared to conventional technologies.

[0061] The high-temperature tensile strength, high-temperature 0.2% proof stress, and high-temperature Young's modulus of the additive-type product are measured by tensile testing in a high-temperature atmosphere. The tensile test specimen used in the high-temperature tensile test is the shape shown in Figure 4. This tensile test specimen is held at each measurement temperature for at least one hour before the test is performed. The strain rate in the high-temperature tensile test is 0.3% / min up to the 0.2% proof stress, and 7.5% / min from the 0.2% proof stress until fracture.

[0062] Furthermore, the adductor should preferably have a room-temperature elongation of 9% or more, and more preferably 15% or more, in terms of ductility. By setting it to 9% or more, sudden breakage of the adductor can be prevented when a load is applied, and good toughness and impact energy absorption characteristics can be achieved.

[0063] The room-temperature elongation at break of the additive product is measured by a tensile test at room temperature. The tensile test specimen used in the tensile test is the shape shown in Figure 4. The strain rate in the tensile test is 0.3% / min up to the 0.2% proof stress, and 7.5% / min from the 0.2% proof stress until fracture.

[0064] Incidentally, when aluminum-transition metal alloys, such as the aforementioned additive manufacturing metal powder, are formed by conventional methods such as casting or powder metallurgy, the slow cooling rate results in the formation of coarse plate-like / needle-like compounds, and the mechanical properties of the material deteriorate significantly. In contrast, when additive manufacturing methods such as laser additive manufacturing, which involve irradiation with lasers or electron beams, are used, the rapid cooling and solidification caused by irradiation with lasers or electron beams results in an extremely fast cooling rate (10 3 ~10 6Non-patent document 1, etc., discloses that fabrication can be performed at K / s. Therefore, when such an additive manufacturing method and rapid solidification process are applied to aluminum-transition metal alloy powder, supersaturated solid solutions and non-equilibrium phases are generated by forced solid solution of transition metal elements, and heat treatment after fabrication makes it possible to form a structure in which high-temperature stable transition metal compounds are finely dispersed. Furthermore, some transition metal elements can be stably dissolved in aluminum up to high temperatures. As a result, the additively manufactured products of the present invention can exhibit excellent mechanical properties at room temperature and high temperatures through dispersion and precipitation strengthening by transition metal compounds, structural composite strengthening and grain boundary strengthening, and solid solution strengthening of transition metal elements. [Examples]

[0065] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. First, the measurement method will be described.

[0066] (Measurement method) [Content of each element in metal powder for additive manufacturing] Measured by ICP emission spectroscopy.

[0067] [Average particle size of metal powders used in additive manufacturing] The particle size distribution of the powder was measured using laser diffraction scattering, and the average particle size was defined as the particle size at which 50% of the volume-based particle size distribution was accumulated from the finest particles. The average particle size is defined as the median diameter "d 50 It is also written as "".

[0068] [Volume energy density (E) under laser irradiation conditions] d )] Volume energy density of laser light in additive manufacturing (E d (J / mm 3 )) was calculated using the following formula. E d =P / (V·s·t) The laser output power P (W), scanning speed V (mm / s), scanning interval s (mm), and layer thickness t (mm) are as follows. For each metal powder used in additive manufacturing, additive products were fabricated by varying the laser output P (W), scanning speed V (mm / s), and scanning interval s (mm). The density of the fabricated additive products was measured using the Archimedes method. The density obtained by the Archimedes method can be measured in accordance with "JIS Z 2501: Sintered metal materials - Test methods for density, oil content and open porosity". Based on these results, the optimal conditions for each metal powder used in additive manufacturing were determined to obtain the additive product with the highest density. Furthermore, the E under the optimal conditions was determined. d The value was calculated using the above formula.

[0069] [Formability (presence or absence of cracks)] Using an optical microscope, optical microscope images (magnification 100x) of the vertical cross-section of the cylindrical (8 mm diameter, 15 mm height) additive products obtained in each example and comparative example, as shown in Figure 5A, were captured. The results are shown in Figures 6A-6D, 7A-7D, 8A-8D, 9A-9C, and 10A-10B. The laser irradiation conditions used during the fabrication of the additive products were the optimal conditions determined for each metal powder used for additive manufacturing. Based on these images, the presence or absence of cracks in the additive products was determined.

[0070] [Relative density] The relative density of the added material was calculated by binarizing an optical microscope image (100x magnification) of an arbitrary vertical cross-section near the center of a cylindrical added material (8 mm in diameter, 15 mm in height), and then determining the area ratio of the metal portion excluding the void. Samples with cracks were not measured.

[0071] [Tensile strength, 0.2% yield strength, elongation at break] Tensile strength, 0.2% proof stress, and elongation at break were all measured using a tensile testing apparatus of Grade 1 or higher, based on "JIS B 7721: Tensile testing machines and compression testing machines - Calibration and verification methods for force measuring systems". Tensile tests at room temperature and high temperature were conducted based on "JIS Z 2241:2011: Tensile testing methods for metallic materials" and "JIS G 0567:2020: High-temperature tensile testing methods for iron and steel materials and heat-resistant alloys," respectively. The tensile test specimen used was prepared by turning the cylindrical appendix (12 mm in diameter, 80 mm in length), which was fabricated perpendicular to the lamination direction shown in Figure 5B, into the shape shown in Figure 4. The dimensions of each part of the test specimen 20 were as follows: the total length L of the test specimen 20 was 80 mm, the length L1 of the main body 22 was 30 mm ± 0.1 mm, the diameter D1 of the main body 22 was 6 mm ± 0.05 mm, the radius of curvature R of the shoulder 23 was 4.5 mm, the length L2 of the gripping part 21 was 15 mm, and the diameter D of the gripping part 21 was 10 mm. The test specimen 20 was then held at each test temperature for one hour before being subjected to the tensile tests at high temperatures.

[0072] (1) Tensile strength The room-temperature tensile strength was measured using the method described below after additive manufacturing, before heat treatment (as-formed), or after cooling to room temperature following heat treatment. Similarly, the high-temperature tensile strength was measured using the method described below after heating to 150°C, 200°C, 250°C, 300°C, and 350°C, either before or after heat treatment. The test specimen 20 was pulled using a tensile testing device until it fractured, and the tensile load was measured at various points during the test. The strain rate in the tensile test was set to 0.3% / min up to the 0.2% yield strength, and then to 7.5% / min from the 0.2% yield strength until fracture. At this time, the jig of the tensile testing device was adjusted to grip the gripping part 21 of the test specimen 20 and apply force in the axial direction of the test specimen 20. The tensile strength was then calculated by dividing the maximum tensile load by the cross-sectional area of ​​the main body 22 before the test (=π×D1×D1÷4).

[0073] (2)0.2% yield strength The 0.2% yield strength at room temperature was measured using the method described below after additive manufacturing, before heat treatment, or after heat treatment and cooling to room temperature. Similarly, the 0.2% yield strength at high temperatures was measured using the method described below after heating to 150°C, 200°C, 250°C, 300°C, and 350°C, either before or after heat treatment. The test specimen 20 was pulled using a tensile testing apparatus until it fractured, and the tensile load was measured at any time during the test. Simultaneously, the displacement of the gauge length between the test points of the test specimen was measured at any time using an extensometer. At this time, the flange portion 24 of the main body of the test specimen 20 for tensile testing was used as the gauge point, and the length L1 of the main body was used as the gauge length between the gauge points. The strain rate in the tensile test was set to 0.3% / min up to the 0.2% yield strength, and to 7.5% / min from the 0.2% yield strength until fracture. The jig of the tensile testing apparatus was adjusted to grip the gripping portion 21 of the test specimen 20 and to apply force in the axial direction of the test specimen 20. Based on the above data of tensile load and gauge length displacement, a nominal stress-nominal strain curve was obtained. The nominal stress was calculated by dividing the tensile load by the cross-sectional area of ​​the main body 22 before the test (=π×D1×D1÷4). The nominal strain was calculated as a percentage obtained by dividing the measured displacement of the gauge length by the initial gauge length measured before the test. The 0.2% yield strength was calculated using the offset method described in "JIS Z 2241:2011:Tensile Test Methods for Metallic Materials".

[0074] (3) Elongation at break After additive manufacturing, before heat treatment, or after cooling to room temperature following heat treatment, the room-temperature elongation at break was measured using the method described below. First, the flange portion 24 of the main body of the tensile test specimen 20 was used as the gauge point, and the length L1 of the main body was used as the gauge point distance. The gauge point distance before the test was measured and set as the initial gauge point distance. Then, after performing the tensile test on the specimen 20, the fracture surfaces were butted together, taking care to ensure that the centerlines of both fractured fragments of the specimen 20 were in a straight line, and the gauge point distance after fracture was measured. The elongation at fracture was calculated as a percentage obtained by dividing the difference between this post-fracture gauge point distance and the initial gauge point distance by the initial gauge point distance. The strain rate in the tensile test was 0.3% / min up to the 0.2% proof stress, and 7.5% / min from the 0.2% proof stress until fracture.

[0075] (4) Young's modulus After additive manufacturing, before heat treatment, or after heat treatment, the samples were heated to 150°C, 200°C, 250°C, 300°C, and 350°C, and the high-temperature Young's modulus was measured using the method described below. The test specimen 20 was pulled using a tensile testing apparatus until it fractured, and the tensile load was measured at any time during the test. Simultaneously, the displacement of the gauge length between the test points of the test specimen was measured at any time using an extensometer. At this time, the flange portion 24 of the main body of the test specimen 20 for tensile testing was used as the gauge point, and the length L1 was defined as the gauge length between the gauge points. The strain rate in the tensile test was set to 0.3% / min up to the 0.2% yield strength, and to 7.5% / min from the 0.2% yield strength until fracture. The jig of the tensile testing apparatus was adjusted to grip the gripping portion 21 of the test specimen 20 and to apply force in the axial direction of the test specimen 20. Based on the above data of tensile load and gauge length displacement, a nominal stress-nominal strain curve was obtained. The nominal stress was calculated by dividing the tensile load by the cross-sectional area of ​​the main body 22 before the test (=π×D1×D1÷4). The nominal strain was calculated as the percentage obtained by dividing the measured displacement between gauge points by the initial gauge point distance measured before the test. Young's modulus was calculated as the slope of the rising straight line in the nominal stress-nominal strain curve immediately after the start of the test.

[0076] [Heat treatment conditions and Vickers hardness] The additives produced in each example were heated in an atmospheric furnace to temperatures ranging from 200°C to 550°C for 1 to 30 hours. After 1, 3, 5, 7, 10, 20, and 30 hours at each temperature, the samples were removed from the furnace and cooled to room temperature. The Vickers hardness (Hv0.2) was then measured using the following method with a load of 0.2 kgf. The Vickers hardness (Hv0.2) was measured according to "JIS Z 2244:2009: Vickers hardness test - Test method".

[0077] [Metal structure in cross-section] The horizontal (perpendicular to the stacking direction) cross-sections of the additive products manufactured in the examples were observed using a scanning transmission electron microscope (STEM).

[0078] ( Reference Examples 1-1 to 7-1, 1-2 to 7-2, Examples 8-1, 8-2, Reference Examples 9-1 to 12-1, Examples 9-2 to 12-2, Comparative Examples 1-1 to 5-1, 1-2 to 5-2) Additive-formed products were fabricated using the various additive-formed metal powders shown in Table 1, employing a laser-based powder bed fusion additive manufacturing method (laser additive manufacturing). Each additive-formed metal powder was prepared by nitrogen gas atomization. The laser additive manufacturing system used was the EOSINT M280 from EOS GmbH of Germany, which is equipped with a ytterbium (Yb) fiber laser (laser wavelength: approximately 1070 nm) as its heat source, with a spot diameter of approximately 0.1 mm and an output of 400 W. Laser irradiation conditions during additive manufacturing (volume energy density (E) d For each powder, the conditions (optimal conditions) that yielded the highest density additive product were selected. Furthermore, the metal layer, powder layer, and additive manufacturing products were preheated to 35°C or 200°C before manufacturing using an electric heater attached to the bottom of the printing platform of the laser additive manufacturing apparatus. During manufacturing, the temperature was monitored and controlled to the same temperature using a thermocouple installed inside the printing platform. The characteristics of the manufactured adducts are shown in Tables 2 and 3.

[0079] Furthermore, examples of the shapes of the manufactured add-ons are shown in Figures 5A and 5B. Furthermore, optical microscope images of the vertical cross-section of the additive product with the shape shown in Figure 5A are shown in Figures 6A-6D, 7A-7D, 8A-8D, 9A-9C, and 10A-10B. Furthermore, in Reference Examples 9-1, 10-1, 11-1, 12-1, and Examples 9-2, 10-2, 11-2, and 12-2, Figures 11A to 11D show photographs of the appearance of the additive products with the shape shown in Figure 5A, manufactured at preheating temperatures of 35°C and 200°C. Furthermore, the change in Vickers hardness of the added product due to heat treatment is shown in Figures 12A-12D, 13A-13D, and 14A-14D. Note that the plots (black circles) at the leftmost position (0 hours) in Figures 12A-12D, 13A-13D, and 14A-14D represent the hardness values ​​of the added product in the as-formed state (without heat treatment). Furthermore, the manufactured additive products ( Reference example1-1, 2-1, 5-1, 7-1, Examples Scanning transmission electron microscope (STEM) bright-field or high-angle annular dark-field images of the horizontal cross-sections of 8-1, 11-2, and 12-2) are shown in Figures 15A to 15G. Furthermore, Reference Examples 9-1, 10-1, 11-1, and 12-1 became Examples 9-2, 10-2, 11-2, and 12-2 by setting the preheating temperature to 200°C. Therefore, from the viewpoint of their relationship to Examples 9-2, 10-2, 11-2, and 12-2, they were designated as Reference Examples rather than Comparative Examples, and their numbers were matched to those of the corresponding Examples.

[0080] [Table 1]

[0081] [Table 2]

[0082] [Table 3]

[0083] (result) From the optical microscope images of the vertical cross-section of the additive product (Figures 6A-6D, 7A-7D, 8A-8D, 9A-9C, 10A-10B), Reference examples 1~7, Examples 8 No cracks were observed in the additive products up to 12, and they were found to have a high relative density of over 99.7%. On the other hand, cracks and void defects were observed in Comparative Examples 1 to 3 and 5. As shown in Figures 11A to 11D, in Reference Examples 9-1 to 12-1 and Examples 9-2 to 12-2, in the additive products manufactured at a preheating temperature of 35°C (Reference Examples 9-1 to 12-1), cracks (delamination) occurred perpendicular to the lamination direction in both the external appearance and the internal cross-section. However, in the additive products manufactured at a preheating temperature of 200°C (Examples 9-2 to 12-2), crack occurrence was suppressed due to the release of residual stress and reduction of thermal strain, resulting in a high relative density. Furthermore, graphs showing the change in Vickers hardness of the additive products (Figures 12A-12D, 13A-13D, and 14A-14D) revealed that in each example, heat treatment within a specific temperature range increased the hardness. Furthermore, the results in Tables 2 and 3 show that the additive products of each example were high-density materials with a relative density of 99.5% or higher, exhibiting excellent high-temperature strength (high-temperature tensile strength, high-temperature 0.2% yield strength) and high-temperature Young's modulus in the high-temperature range of 150°C or higher, and also possessing sufficient room-temperature tensile strength, room-temperature 0.2% yield strength, and room-temperature elongation at fracture. On the other hand, Comparative Examples 1-3 and 5 clearly had cracks and lacked sufficient strength. Comparative Example 4 was a high-density material with no cracks and a relative density of 99.5% or higher, but its high-temperature tensile strength and high-temperature 0.2% yield strength above 300°C, high-temperature Young's modulus above 200°C, and room-temperature elongation at fracture were undesirable. Furthermore, as shown in Figures 15A to 15G, from the bright-field (BF) and high-angle annular dark-field (HAADF) images of the horizontal cross-section of the additive product obtained using a scanning transmission electron microscope (STEM), Reference example In 1-1 and 2-1, fine crystallized and precipitated phases are dispersed in the aluminum matrix at cell boundaries and grain boundaries, and are composed of aluminum and iron, respectively. Reference example 1-1), aluminum and manganese ( Reference example It can be determined that it is a transition metal compound as described in 2-1). Since the diffusion rate of transition metal elements in aluminum is slow, these transition metal compounds are thought to be able to exist stably up to high temperatures. Therefore, it is thought that the high-temperature strength and high-temperature Young's modulus were improved mainly through dispersion / precipitation strengthening, structural composite strengthening, and grain boundary strengthening, as these compounds suppress dislocation movement and grain boundary sliding in the high-temperature range. Reference example In 5-1, no clear precipitated phase was observed, and STEM-EDS analysis revealed that chromium tended to dissolve in the matrix. Since the diffusion rate of chromium in aluminum is even slower than that of iron and manganese, it is thought that the dissolved chromium can stably contribute to solid solution strengthening up to high temperatures, thereby improving high-temperature strength and high-temperature Young's modulus. Reference exampleIn 7-1, a compound of aluminum and zirconium (Al3Zr) was finely precipitated (~5 nm) in the aluminum matrix, and chromium was in solid solution, similar to Example 5. Therefore, it is thought that the high-temperature strength and high-temperature Young's modulus were improved mainly by solid solution strengthening of chromium and precipitation strengthening by Al3Zr. In Example 8-1, it is believed that the high-temperature strength and high-temperature Young's modulus were improved by dispersion and precipitation strengthening, structural composite strengthening and grain boundary strengthening by a network-like transition metal compound of aluminum and manganese crystallized and precipitated in the cell boundaries and aluminum matrix, as well as by solid solution strengthening with manganese and chromium. In Example 11-2, it is believed that the high-temperature strength and high-temperature Young's modulus were improved by dispersion and precipitation strengthening, grain boundary strengthening and structural composite strengthening with various petal-shaped, plate-shaped and granular transition metal compounds mainly containing aluminum, manganese, chromium, and iron, as well as solid solution strengthening with various transition metals. In Example 12-2, it is believed that the high-temperature strength and high-temperature Young's modulus were improved by dispersion and precipitation strengthening and structural composite strengthening by a network-like transition metal compound of aluminum and nickel crystallized and precipitated in the cell boundaries and aluminum matrix, as well as by precipitation strengthening by an aluminum-zirconium compound (Al3Zr). Also, Reference example 3-1, 4-1, 6-1, Examples Similarly, for 9-2 and 10-2, since they are addition products made from aluminum alloys containing transition metal elements, it is presumed that their high-temperature strength and high-temperature Young's modulus could be improved through dispersion and precipitation strengthening by transition metal compounds, structural composite strengthening and grain boundary strengthening, as well as solid solution strengthening by transition metal elements, as described above. [Explanation of Symbols]

[0084] 10 Chambers 11 Base material 12 squeegee 13. Laser scanning device 14 stages 20 test specimens 21 Gripping part 22 Main body 23 Shoulder 24 Brim a. Metal powder for additive manufacturing t thickness M Metal layer M1 Additive Products P powder layer L Total length of the test specimen L1 Length of the main body (distance between gauge points) L2 Length of the gripping part D. Diameter of the gripping part D1 Diameter of the main body R: Radius of curvature of the shoulder

Claims

[Claim 1] A first step of forming a powder layer containing the metal powder for additive manufacturing described below, A second step involves irradiating the powder layer with laser light to solidify the metal powder at the location of the laser light irradiation, thereby forming a metal layer. The process includes a third step of heat-treating the additive after the second step, The first and second steps include a step in which the metal layer and the powder layer are preheated to a temperature of 50°C or more and 500°C or less. The first and second steps are repeated sequentially, and the metal layers are manufactured by stacking and joining multiple layers. The volume energy density of the laser light irradiation conditions in the second step is 30 J / mm². ３ More than 150J / mm ３ The following: A method for manufacturing an additive, wherein in the third step, the additive is heat-treated at a temperature of 200°C to 650°C for 1 hour to 30 hours. • Metal powders for additive manufacturing: The aluminum contains at least one alloying element selected from iron, manganese, chromium, nickel, and zirconium in an amount of 0.20% to 13% by mass. The total content of the aforementioned iron, manganese, chromium, nickel, and zirconium is 9.72% by mass or more and 13% by mass or less. The iron content is less than 4.5% by mass, Furthermore, it contains silicon, and its content is less than 1% by mass. Furthermore, it contains magnesium, with a magnesium content of 2% by mass or less. The aforementioned alloying elements contain only unavoidable impurities other than the aforementioned iron, manganese, chromium, nickel, zirconium, silicon, and magnesium. A metal powder for additive manufacturing having a volume-based average particle size (median diameter d 50) of 1 μm or more and 200 μm or less.

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