JP2023031963A - Production method of three-dimensional molded object - Google Patents

Abstract

The object of the present invention is to control the metal structure and mechanical properties of a three-dimensional object by devising the shape of the three-dimensional object and suppressing heat conduction so as to maintain the material temperature at a high temperature during processing.
A method for manufacturing a three-dimensional object (10) by laminating object layers using a metal powder additive manufacturing apparatus, wherein the three-dimensional object (10) is connected to a base (20) and has a thermal resistance of a predetermined value. A thin rod support portion 30 having a shape, a shell-shaped main body portion 50, and a tapered portion 40 that structurally connects the main body portion 50 and the thin rod support portion 30, and the metal powder additive manufacturing apparatus is a step of forming a thin layer of a powder material containing metal particles, and selectively irradiating the thin layer with a laser beam to sinter or melt-bond the metal particles contained in the powder material. The method includes a step of forming a layer, and a step of stacking the model layer by repeating the step of forming the thin layer and the step of forming the model layer in this order a plurality of times.
[Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a three-dimensional object using a powder bed fusion method.

In the powder bed fusion method (PBF), a raw material powder is locally and instantaneously melted and solidified using a laser beam or an electron beam to produce a sample of any shape (for example, See Patent Documents 1 and 2). Compared to processes such as forging and casting, PBF is characterized by faster cooling and solidification rates. Due to the thermal history during such a process, the metallographic structure of the shaped sample tends to be fine, which also affects its mechanical properties.

In particular, since a metal structure having a fine structure is inferior in ductility, a heat treatment is generally performed in order to coarsen the crystal grains of a shaped sample manufactured by the powder bed fusion method. In addition, research cases have been reported in which the metal structure and mechanical properties of a shaped sample are changed depending on process conditions (e.g., heat source output, scanning speed, substrate temperature [e.g., see Non-Patent Document 1], etc.).

Japanese Patent No. 3010312 JP 2018-80393 A

R. Mertens et al. ``Application of base plate preheating during selective laser melting'' Procedia CIRP 74 (2018) 5-11, Science Direct

As described above, in the case of the conventional powder bed fusion method, the raw material powder is melted and solidified locally and instantaneously by using a laser beam or an electron beam. It is a process in which the raw material powder instantly solidifies. Therefore, there is room for improvement in the manufacturing process because the mechanical properties are improved by coarsening the metal structure, phase transformation, precipitation, etc. by heat treatment after the molding process.
The present invention is intended to solve the above-described problems, and by devising the shape of a three-dimensional model to suppress heat conduction, the material temperature of the metal powder during the modeling process is maintained at a high temperature, and the metal structure of the three-dimensional model is improved. And it aims at providing the manufacturing method of the three-dimensional molded article which can control a mechanical characteristic.

[1] The method for forming a three-dimensional object according to the present invention is, for example, a method for manufacturing a three-dimensional object 10 in which layers of the object are laminated using a metal powder layered modeling apparatus as shown in FIG. The modeled object 10 is connected to the base 20 and includes a thin rod support portion 30 having a shape with a predetermined value of thermal resistance, a shell-shaped main body portion 50, and the main body portion 50 and the thin rod support portion 30. a tapered portion 40 that structurally connects;
The metal powder additive manufacturing apparatus forms a thin layer of powder material containing metal particles;
a step of selectively irradiating the thin layer with a laser beam to form a modeled object layer in which metal particles contained in the powder material are sintered or melt-bonded;
The method includes a step of repeating the step of forming the thin layer and the step of forming the modeled object layer in this order a plurality of times to stack the modeled object layer.

[2] In the method for forming a three-dimensional object according to the present invention, preferably, the step of laminating the object layers includes forming a thin rod support portion 30, and forming a tapered portion 40 connected to the thin rod support portion 30. and a step of shaping the body portion 50 connected to the tapered portion 40 .
[3] In the method for forming a three-dimensional object according to the present invention, preferably, the tapered portion 40 has a shape that expands from the thin rod support portion 30 side to the main body portion 50 side, and the expansion angle is 60 in full angle. degree or more and 120 degrees or less.

[4] In the method for forming a three-dimensional object of the present invention, preferably, the shape in which the thermal resistance of the thin rod support portion 30 is a predetermined value is obtained in the step of forming the main body portion 50 by the metal powder layered modeling apparatus. It is preferable that the temperature rise of the model layer in the step of forming the model layer by light irradiation is determined so as to satisfy the heat treatment temperature and the heat treatment time of the model layer.
[5] In the method for forming a three-dimensional object of the present invention, preferably, the heat treatment temperature and the heat treatment time of the object layer are such that the crystal grain shape of the powder material of the object layer maintains a predetermined crystal grain size. should be defined as The crystal grain shape of the powder material may be, for example, 60 or more and 180 μm or less, which corresponds to an ASTM grain size range of 2-5.
[6] In the method for forming a three-dimensional object according to the present invention, the main body 50 is preferably a turbine stationary blade or a turbine rotor blade.

[7] Preferably, the three-dimensional object modeling method of the present invention further includes a step of removing the tapered portion 40 from the body portion 50 or a step of removing the thin rod support portion 30 from the tapered portion 40. good.

In the method for forming a three-dimensional object of the present invention, by structurally connecting the tapered portion and the thin rod support portion to the body portion, heat conduction to the base can be suppressed. The build sample can be kept at a high temperature during the build process of the build. Therefore, the metallographic structure and mechanical properties of the shaped sample can be controlled.
The shape of the tapered part and thin rod support part is the part where the cross-sectional area of the modeled sample (the area of the cross section parallel to the base material) becomes smaller, and when the body part is modeled by the powder bed fusion method , the heat transfer to the base through the tapered portion and thin rod support portion can be suppressed, and the main body portion can be kept at a high temperature. Depending on how much the cross-sectional areas of the tapered portion and thin rod supporting portion are reduced, the holding temperature of the main body changes, and the metal structure and mechanical properties of the main body can also be controlled.

In the powder bed fusion method of the present invention, since the metal powder material can be kept at a high temperature during the shaping process, the formation of crystal grains can be controlled by slowing down the cooling rate and solidification rate. Therefore, by maintaining a high temperature during the molding process, it is possible to replace the coarsening of the metal structure, phase transformation, precipitation, etc. due to the conventional heat treatment after the molding process, eliminating the need for heat treatment after the molding process and simplifying the manufacturing process. Become.

1 is a front view of a molded article showing an embodiment of the present invention; FIG. 1 is an overall functional block diagram showing an embodiment of a metal powder 3D printer used in the powder bed fusion method of the present invention; FIG. It is a flow chart of the molding method of the three-dimensional molded article showing one embodiment of the present invention. It is a flow chart of the molding method of the three-dimensional molded article showing one embodiment of the present invention. The base 20 is shown in a photographic view showing the microstructure of the cut surface of the modeled product by a scanning electron microscope (SEM), which shows one embodiment of the present invention. The tapered portion 40 is shown in the photographic view showing the microstructure of the cut surface of the modeled product taken by a scanning electron microscope (SEM), showing one embodiment of the present invention. A main body part 50 is shown in a photographic view showing a microstructure of a cut surface of a modeled product by a scanning electron microscope (SEM), which shows one embodiment of the present invention. The base 20 is shown in the photographic view showing the crystal grains of the cut surface of the shaped article by backscattered electron diffraction (EBSD), which shows one embodiment of the present invention. A photographic view showing crystal grains of a cut surface of a modeled object by backscattered electron diffraction (EBSD), showing an embodiment of the present invention, showing a tapered portion 40 . The main body part 50 is shown in a photographic view showing the crystal grains of the cut surface of the shaped article by backscattered electron diffraction (EBSD), which shows one embodiment of the present invention. The width and length of the crystal grain obtained from the EBSD image are illustrated with respect to the height of the model. The width and length of the crystal grain obtained from the EBSD image are illustrated with respect to the height of the model. It is a figure which shows the result of the hardness test which shows one Example of this invention, and shows distribution of the height direction of the modeled object. FIG. 2 is an explanatory diagram of the temperature distribution of a modeled object measured by an infrared camera, showing an embodiment of the present invention, showing each part of the modeled object. FIG. 2 is an explanatory diagram of the temperature distribution of a modeled object measured by an infrared camera, showing the distribution in the height direction of the modeled object, according to an embodiment of the present invention. FIG. 4 is an explanatory diagram of the measured temperature distribution of a modeled object using thermal analysis by the finite element method, showing the distribution in the height direction of the modeled object. FIG. 10 is an explanatory diagram of the measured temperature distribution of a modeled object using thermal analysis by the finite element method, and is shown for each part of the modeled object.

The present invention will be described below with reference to the drawings.
FIG. 1 is a front view of a molded article showing one embodiment of the present invention. A method for forming a three-dimensional object according to the present invention is a method for manufacturing a three-dimensional object 10 in which object layers are laminated using a metal powder layered modeling apparatus. The three-dimensional object 10 includes a base 20, a thin rod support portion 30, a tapered portion 40, and a body portion 50, and the body portion 50 is the final manufacturing object. Therefore, in order to obtain the body portion 50 which is the final product to be manufactured, a step of removing the tapered portion 40 from the body portion 50 or a step of removing the thin rod support portion 30 from the tapered portion 40 is required. good.

The base 20 is a portion where one end of the thin rod support portion 30 is coupled, and is provided to facilitate handling of the three-dimensional object 10 in a state where the thin rod support portion 30 and the tapered portion 40 are connected. In this embodiment, the shape of the base 20 is disk-shaped, with an outer diameter Φ2 of 14 mm and a thickness (H0-H1) of 5 mm, but it is not limited to this shape.

The thin rod support portion 30 is a rod-shaped member whose one end is connected to the base 20, and has a shape with a predetermined value of thermal resistance. is 10 mm. The shape in which the heat resistance of the thin rod support portion 30 is a predetermined value is the shape of the object layer in the step of forming the object layer by laser light irradiation by a metal powder layered modeling apparatus in the step of forming the body portion 50. It is preferable that the temperature rise is determined so as to satisfy the heat treatment temperature and heat treatment time of the model layer. It is preferable that the heat treatment temperature and heat treatment time of the model layer are determined so that the crystal grain shape of the powder material of the model layer maintains a predetermined crystal grain size.

The tapered portion 40 structurally connects the main body portion 50 and the thin rod support portion 30. For example, at a height H2, the tapered portion 40 has the same cross-sectional shape as the thin rod support portion 30, and at a height H3. It has the same cross-sectional shape as the body portion 50 at the position. The length (H2-H3) of the tapered portion 40 is 5 mm. The umbrella shape of the tapered portion 40 has a shape that expands from the thin rod support portion 30 side to the main body portion 50 side, and the expansion angle is preferably 60 degrees or more and 120 degrees or less in full angle, and here is about 98 degrees. It has become.

In this embodiment, the body portion 50 has a round bar shape with a circular cross section, and has an outer diameter Φ2 of 14 mm and a length (H4-H3) of 30 mm. It may have a shell shape with a concave curved surface such as a turbine stationary blade or a turbine rotor blade.

A modeled object having such a shape is manufactured, for example, using a metal powder additive manufacturing apparatus called SLM280 manufactured by SLM Solution Co., Ltd. located in Lubeck, Federal Republic of Germany. A metal powder additive manufacturing apparatus is known, for example, from the above-mentioned Patent Document 2 and the like.

[Overview of Laser Metal Powder Additive Manufacturing Equipment]
FIG. 2 is an overall functional block diagram showing an embodiment of a metal powder 3D printer used in the powder bed fusion method of the present invention. With reference to FIG. 2, the lamination-molding apparatus 100 is a laser lamination-molding apparatus, for example. The layered manufacturing apparatus 100 includes a laser device 110 , a galvanomirror 120 , a control device 130 and a chamber 200 .

The laser device 110 emits laser light. Laser device 110 is, for example, a fiber laser, a CO ₂ laser, or the like. Laser device 110 may be provided with a lens system (not shown). The lens system receives laser light from laser device 110 and focuses the laser light to form laser 112 . The galvanomirror 120 performs irradiation operation of the laser 112 . That is, the galvanomirror 120 adjusts the position where the laser 112 is irradiated.

The chamber 200 includes a layer forming chamber 210 , a modeling table 230 , a powder supply chamber 220 and a recoater 250 . In order to prevent the metal powder particles 140 from being oxidized during the irradiation operation of the laser 112, the inside of the chamber 200 is kept filled with an inert gas (argon, nitrogen, etc.) or is kept in a vacuum state. maintained.

The layer forming chamber 210 has a housing shape with an opening at the upper end. The modeling table 230 is accommodated in the layer forming chamber 210 and supported so as to be vertically movable. The modeling table 230 is moved up and down by a motor (not shown).

The powder supply chamber 220 is arranged next to the layer formation chamber 210 . The powder supply chamber 220 has a housing-like shape, and includes a vertically movable piston 240 therein. Metal powder particles 140 are layered on the piston 240 . The metal powder particles 140 serve as raw materials for a modeled object. A layer of the metal powder particles 140 is discharged from the upper opening of the layer forming chamber 210 by raising the piston 240 . The metal powder particles 140 are, for example, metal powders of nickel superalloy, cobalt superalloy, or iron superalloy having high heat resistance, and there is Hastelloy as a trade name, for example. Instead of the metal powder particles 140, ceramics such as Al ₂ O ₃ may be used together with the metal powder particles 140, or inorganic powder particles such as ceramic particles may be used alone.

The recoater 250 is arranged near the upper opening of the powder supply chamber 220 . The recoater 250 is moved in a specific direction (horizontal direction) by a motor (not shown) and reciprocates between the powder supply chamber 220 and the layer forming chamber 210 . In FIG. 2, the recoater 250 reciprocates in the X direction.
By moving in the X direction, the recoater 250 horizontally moves the layer of the metal powder particles 140 discharged from the powder supply chamber 220 and supplies it to the layer forming chamber 210 . A metal powder layer 260 made of the metal powder particles 140 is formed on the modeling table 230 by the metal powder particles 140 deposited on the modeling table 230 in the layer forming chamber 210 . By moving the recoater 250 in the X direction, the metal powder particles 140 move in the horizontal direction, and the surface of the metal powder layer 260 is flattened.

The control device 130 includes a central processing unit (CPU) (not shown), a memory, and a hard disk drive (hereinafter referred to as HDD). The HDD stores well-known CAD (Computer Aided Design) applications and CAM (Computer Aided Manufacturing) applications. The control device 130 uses a CAD application to create three-dimensional shape data of a modeled object to be manufactured.

The control device 130 also uses a CAM application to create processing condition data based on the three-dimensional data. In the layered manufacturing method, a plurality of modeled object parts formed by the laser 112 are layered to form a modeled object. The processing condition data includes processing conditions for forming each modeled object portion. In other words, the processing condition data is created for each molded object portion. The control device 130 controls the laser device 110, the lens system and the galvanomirror 120 based on the processing condition data to adjust the output of the laser 112, scanning speed, scanning interval and irradiation position.

[Details of manufacturing process]
3 and 4 are flow charts of a method for forming a three-dimensional object according to one embodiment of the present invention. In the metal powder additive manufacturing apparatus, the above-mentioned modeled object is manufactured in the following steps according to the flow charts shown in FIGS.
As a preparatory step for the metal powder additive manufacturing apparatus, a vacuum pump is used to evacuate the chamber 200 . After the inside of the chamber 200 is evacuated, an inert gas (argon, nitrogen, etc.) is supplied inside the chamber 20 . Note that the modeling table 230 in the layer forming chamber 210 may be preheated.

Next, a metal powder layer 260, which is a thin layer of powder material containing metal particles, is formed (S100). Next, the thin layer is selectively irradiated with a laser beam to form a model layer in which metal particles contained in the powder material are sintered or melt-bonded (S110). The step of forming the thin layer and the step of forming the modeled object layer are repeated in this order multiple times to stack the modeled object layer (S120).

In the step of stacking the modeled object layers (S120), first, the base 20 is modeled (S122). Next, thin rod support portions 30 are shaped (S124). Subsequently, the tapered portion 40 connected to the thin rod support portion 30 is formed (S126). Next, the body portion 50 connected to the tapered portion 40 is shaped (S128). In the step of forming the body portion, the temperature rise of the modeled object layer in the step of forming the modeled object layer by laser beam irradiation by the metal powder additive manufacturing apparatus satisfies the heat treatment temperature and heat treatment time of the modeled object layer. As a result, the crystal grain shape of the powder material of the modeled article layer positioned in the body portion 50 maintains a predetermined crystal grain size (S129).
Then, the tapered portion 40 is removed from the main body portion 50, or the thin rod support portion 30 is removed from the tapered portion 40 (S130) to obtain the intended shape of the main body portion 50 (S132).
In this way, the desired three-dimensional object shape is obtained (S140).

In this example, Hastelloy X alloy is used as the raw material powder of the metal powder. For this metal powder, the manufacturer's Hayes International documentation lists the hardness and grain size of the material solution heat treated at 1177°C. A typical ASTM grain size of 2-5 corresponds to an average grain size of 60-180 μm.

FIG. 5 is a photographic diagram showing the microstructure of the cut surface of the modeled product observed by a scanning electron microscope (SEM), showing one embodiment of the present invention. , (C) shows the body portion 50 .
6A and 6B are photographic diagrams showing crystal grains of a cut surface of a modeled product obtained by backscattered electron diffraction (EBSD), showing an embodiment of the present invention. Part 40 , (C) shows the body part 50 .

FIG. 7 shows the grain width and length obtained from the EBSD image against the height of the model. In addition, in the measurement of grains, the number of intersections between one straight line and grain boundaries is counted in the same manner as in "JIS G 0551: 2020 Steel-Microscopic test method for grain size", and the line length is calculated by the number of intersections. obtained by subtracting Since the crystal grains grew long and thin in the molding direction (height direction), lines were drawn in the horizontal direction of the image (perpendicular to the molding direction) and the vertical direction of the image (parallel to the molding direction). bottom.
From FIG. 7, the crystal grains of the base 20 have a width of 25 μm or less and a length of 50 μm or less. In the tapered portion, the grain width increases from 27.5 μm to 33.2 μm and the length increases from 55.7 μm to 84.5 μm as the modeling height increases from 15 mm to 20 mm. On the other hand, the crystal grains of the model positioned at the main body portion of 50 μm have a width of 30 μm or more and 50 μm or less and a length of 60 μm or more and 155 μm or less. That is, compared with the base 20, the body portion 50 and the tapered portion 40 have a coarser structure.

FIG. 8 is a diagram showing the results of a hardness test, showing an example of the present invention, showing the distribution of the molded object in the height direction. At a height of 20-50 mm, which indicates the range of height (H4-H3) corresponding to the body portion 50, the Vickers hardness Hv is 190-220. On the other hand, the Vickers hardness Hv is 210-250 at a height of 15-20 mm, which indicates the range of height (H2-H3) corresponding to the tapered portion 40. FIG. Moreover, at a height of 5-15 mm, which indicates the range of height (H1-H2) corresponding to the thin rod supporting portion 30, the Vickers hardness Hv is 265-275. At a height of 0-5 mm, which indicates the range of height (H0-H1) corresponding to the base 20, the Vickers hardness Hv is 265-275. That is, the material of the body portion 50 is softened compared to the tapered portion 40 and the thin rod support portion 30 .

FIG. 9 is an explanatory diagram of the temperature distribution of a modeled object measured by an infrared camera, showing an embodiment of the present invention, showing each part of the modeled object. The infrared camera is a Telops FAST M350. The measured temperature distribution was measured at a frame rate of 4 Hz and an exposure time of 100 μs. The figure shows the measured temperature distribution of each layer immediately after laser irradiation.
In this example, the number of layers laminated by the metal powder additive manufacturing apparatus was 1668, the height was 50 mm, and the elapsed time required for processing from the first layer was 5 hours, 32 minutes and 57 seconds. The build height and the number of layers were 4.98 mm and 167th layer for H1 in FIG. The molding time was 33 minutes and 13 seconds until H1, 1 hour, 39 minutes and 50 seconds until H2, and 2 hours, 13 minutes and 1 second until H3.

FIG. 10 is an explanatory diagram of the temperature distribution measured on the outermost surface of the modeled object by an infrared camera, showing an embodiment of the present invention, showing the distribution in the height direction of the modeled object. The vertical axis is temperature distribution, and the horizontal axis is modeling time. The frame rate is 4 Hz, and the temperature measurements represent a moving average every 20 frames (5 seconds).
The base 20 had a time range of 0-1993 seconds and a measured temperature distribution of 50-300°C. The thin rod support portion 30 had a time range of 1994-5990 seconds and a measured temperature distribution in the range of 50-200°C. In the tapered portion 40, the measured temperature distribution ranged from 100 to 1100° C. for a time period of 5991-7981 seconds, and the temperature was lower on the side closer to the thin rod support portion 30 and increased as it approached the main body portion 50. On the other hand, in the body part 50, the measured temperature distribution is as high as 1000-1100° C. , the measured temperature distribution decreased slightly to 800-900°C.

FIG. 11 is an explanatory diagram of the measured temperature distribution of the molded object using thermal analysis by the finite element method, showing the distribution in the height direction of the molded object.
At the portion corresponding to the base 20, the temperature distribution was 50-400.degree. The temperature distribution was 100-400° C. at the portion corresponding to the thin rod supporting portion 30 . At the portion corresponding to the tapered portion 40, the temperature distribution was 150-1300.degree. At these parts, the energy generated by the laser beam irradiation from the metal powder additive manufacturing apparatus also diffuses to the base 20 side, and the temperature of the processed parts does not rise.
The surface temperature distribution was 1150-1250.degree. At these parts, the energy generated by the laser beam irradiation by the metal powder additive manufacturing apparatus is prevented from diffusing toward the base 20 side due to the high thermal resistance of the thin rod support part 30, and the main body part, which is the processed part, is prevented. 50 processing temperature is maintained at 1150-1250°C.

FIG. 12 is an explanatory diagram of the measured temperature distribution of the molded object using thermal analysis by the finite element method, showing each part of the molded object.
The finite element method used software ABAQUS 2019 manufactured by Dassault Systems. A thermal analysis per layer was performed using the finite element method using a metal powder additive manufacturing system. According to the surface temperature calculation by the finite element method, the temperature distribution in the layer corresponding to the base 20 was 50-250.degree. In the layer corresponding to the thin rod supporting portion 30, the temperature distribution ranged from 50 to 850.degree. The temperature distribution was 800-950° C. at a portion of the body portion 50 near the tapered portion 40 .

In the above-described embodiment, the energy generated by the laser beam irradiation by the metal powder additive manufacturing apparatus is retained in the processed portion of the main body 50, and the heat diffusion to the base side is caused by the high thermal resistance of the thin rod support portion 30. Although the case of prevention is shown, the present invention is not limited to this embodiment, and various embodiments are possible within the scope obvious to those skilled in the art.

According to the powder bed fusion method of the present invention, the energy generated by the laser beam irradiation by the metal powder layered modeling apparatus is retained in the processed portion of the main body 50, and the heat diffusion toward the base side is caused by the thin rod supporting portion 30. This is prevented by high thermal resistance, so that the crystal grain shape of the powder material of the molding layer that constitutes the main body 50 maintains a large crystal grain size. For example, post-processing such as improvement of mechanical properties can be omitted.

10: Three-dimensional object 20: Base 30: Thin rod support part 40: Tapered part 50: Body part 100: Layered modeling device 110: Laser device 112: Laser 120: Galvanomirror 130: Control device 140: Metal powder particles 200 : Chamber 210: Layer forming chamber 220: Powder supply chamber 230: Molding table 250: Recoater 260: Metal powder layer

Claims (7)

A method for manufacturing a three-dimensional object by laminating object layers using a metal powder additive manufacturing apparatus, the three-dimensional object comprising:
A thin rod support portion connected to the base and having a shape with a predetermined thermal resistance;
a shell-shaped main body;
a tapered portion that structurally connects the main body portion and the thin rod support portion;
with
The metal powder additive manufacturing apparatus is
forming a thin layer of powder material comprising metal particles;
a step of selectively irradiating the thin layer with a laser beam to form a modeled object layer in which metal particles contained in the powder material are sintered or melt-bonded;
a step of repeating the step of forming the thin layer and the step of forming the modeled object layer a plurality of times in this order to stack the modeled object layer;
A method of forming a three-dimensional object including The step of laminating the modeled object layer includes:
a step of shaping the thin rod support;
A step of shaping the tapered portion connected to the thin rod support portion;
a step of shaping a body portion connected to the tapered portion;
The method for forming a three-dimensional object according to claim 1. The tapered portion has a shape expanding from the thin rod supporting portion side to the main body portion side, and the expanding angle is 60 degrees or more and 120 degrees or less in full angle.
The method for forming a three-dimensional object according to claim 1 or 2. The shape in which the thermal resistance of the thin rod support portion is a predetermined value is
In the step of forming the body portion, the temperature rise of the modeled object layer in the step of forming the modeled object layer by laser light irradiation by the metal powder additive manufacturing apparatus is determined by the heat treatment temperature and the heat treatment time of the modeled object layer. determined to satisfy
The method for forming a three-dimensional object according to any one of claims 1 to 3. The heat treatment temperature and heat treatment time of the model layer are determined so that the crystal grain shape of the powder material of the model layer maintains a predetermined crystal grain size.
The modeling method of the three-dimensional molded article according to claim 4. The method for forming a three-dimensional object according to any one of claims 1 to 5, wherein the main body is a turbine stationary blade or a turbine rotor blade. Further, a step of removing the tapered portion from the main body portion, or a step of removing the thin rod support portion from the tapered portion,
The method for forming a three-dimensional object according to any one of claims 1 to 6.

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