Metal base material for wire type directive energy deposition method and method for manufacturing the same

Abstract

To provide a method for manufacturing a metal wire for a directive energy deposition method which enables high intensity and high moldability.SOLUTION: There is provided a metal wire raw material used in lamination molding (3D printing) by a directive energy deposition method using a wire as a base material, wherein when fine particles as a coagulated nucleus site are included in a metal wire, equiaxial crystal, micronization and homogenization of a molding structure can be achieved caused by increase in the number of nucleation sites in a molten pool formed by directive energy. Simultaneously, coagulated nuclear particles having high laser absorptivity are included, thereby provides a metal wire which enhances melting capacity by a laser, can simultaneously achieve high strength and high moldability, and is suitable for a directive energy deposition method. The coagulated nuclear particles have a melting point higher than that of base material metal, and has a parameter M represented by a predetermined expression of 12×10-3 or less.SELECTED DRAWING: Figure 20

Description

[Technical Field]

[0001] The present invention relates to a composite metal material for wire-type directed energy deposition, which has high strength and high formability, and a manufacturing method thereof. [Background technology]

[0002] Metal additive manufacturing (AM), also known as metal 3D printing, is a revolutionary manufacturing method that has the potential to change the face of manufacturing. It is capable of producing complex shapes that could not be produced using conventional methods. Additive manufacturing can be categorized into seven manufacturing methods: material extrusion, liquid vat photopolymerization, sheet lamination, binder jetting, material jetting, powder bed fusion, and directed energy deposition.

[0003] Metal additive processing can be broadly divided into powder bed fusion (powder bed method), which is currently mainstream and is leading the way in both research and social implementation, directed energy deposition (deposition method), which is suitable for social implementation because it is capable of additive manufacturing and is expected to grow rapidly in the future, and sintering, which applies metal powder injection molding (MIM) technology, in which the material is modeled using a resin printer and then debound and sintered. Of these, powder bed fusion and directed energy deposition are the only methods that can directly model metal products.

[0004] In directed energy deposition, a metal material is supplied to the substrate, and a focused heat source, such as a laser or electron beam, or arc plasma, is applied to the substrate. The metal material is then directly melted and deposited in a tiny molten pool formed on the substrate, and the metal is then deposited by solidification. The molten pool, also known as a melt pool, refers to a liquid pool of molten metal formed on the substrate directly below the heat source during welding. It is also used to refer to the tiny molten areas formed on the substrate during metal additive manufacturing. The molten substrate and droplets transferred from the deposited metal mix to form the molten metal.

[0005] The metal material is supplied by feeding metal powder or wire to the area where it is to be added. At the same time, high-energy beam or arc plasma irradiation is used to melt both the base material and the metal material to be added, and the material is deposited. By moving the material supply device and heat source relative to the base material and continuously moving the deposition position along the shape of the object, a three-dimensional object can be obtained.

[0006] There are several directed energy deposition techniques depending on the combination of heat source and material form. The three main types of heat sources used are laser, electron beam, and arc plasma, and the materials used are powder and wire. Figure 1 shows a schematic diagram of directed energy deposition when the heat source is a laser and the material form is wire. A heat source laser 1 is irradiated onto a substrate 2, forming a molten pool within the substrate. A material supply device 4 capable of supplying metal wire 3 supplies the metal wire to the molten pool, and the molten metal is deposited onto the substrate. The material supply device and beam source are then moved relative to a building platform 5 on which the substrate is placed, to form a three-dimensional part 6.

[0007] With additive manufacturing using directed energy deposition, material only needs to be supplied to the necessary areas, allowing for large layer thicknesses and fast building speeds, making it suitable for manufacturing large components. Wire-type directed energy deposition in particular can reduce material costs compared to powder-type directed energy deposition, which uses expensive metal powder.

[0008] Powder bed fusion and directed energy deposition (DEM) processes produce products by melting and solidifying metals in microscopic regions. In these processes, melting and solidification occur under large temperature gradients, resulting in the formation of columnar grains elongated in the build direction through epitaxial growth. Here, epitaxial growth refers to the growth pattern in which crystals grow on a substrate crystal and align with the crystal planes of the underlying substrate. Figure 2 shows a schematic diagram of solidification structure formation under a temperature gradient. When epitaxial growth occurs between solid phase 7 and liquid phase 8, the solid phase grows, inheriting the crystal orientation of the solid phase. The result is elongated columnar grains with a texture in the direction of solidification progression. Texture refers to the state in which the crystal grains constituting the material are preferentially aligned in a specific direction. Furthermore, in MAM, repeated exposure to high temperatures during the fabrication of each layer induces the growth of solid crystals. As a result, many of the structures produced by MAM exhibit columnar grains and texture. This is a hindrance when used as a structural member (Patent Document 1).

[0009] Furthermore, when using a laser as a directed energy heat source, the laser absorption capacity of metals becomes a major issue. Figure 3 shows the wavelength dependence of laser absorption capacity for steel 10, iron 11, molybdenum 12, copper 13, silver 14, and aluminum 15 (Non-Patent Document 1). Here, the wavelength of a carbon dioxide laser 16 and the wavelength of a fiber laser / YAG laser 17 are indicated by dotted lines. The laser absorption capacity of each metal exhibits a strong wavelength dependence, with long-wavelength lasers being largely reflected. Therefore, when attempting to melt a metal by irradiating it with a laser, most of the light is reflected, resulting in the problem of only a small amount of energy being used for melting.

[0010] Currently, welding wire is used as the material wire for wire-based directed energy deposition. Although it has the advantage of being relatively inexpensive and readily available, it cannot be said that it has the performance required for use as a material for directed energy deposition. In ordinary metal additive processing, columnar crystals elongated in the stacking direction are formed by epitaxial growth, resulting in a textured structure. Here, the preferred growth direction of the metal is determined by the crystal structure of the solidified phase. In the case of metals with bcc and fcc crystal structures, the rate-limiting factor for the formation of solid-phase crystals is the growth of the dense faces {110} and {111}, respectively, and therefore ... surrounded by them. <100> As a result, in metal additive processing, the stacking direction is <100> This results in anisotropy in mechanical properties, etc. (Non-Patent Document 2). This phenomenon, which is not a problem in welding, which deposits metal one-dimensionally, becomes prominent in wire-based directed energy deposition, which deposits metal three-dimensionally to obtain a product.

[0011] Furthermore, in the wire-type directed energy deposition method using a laser as a heat source, when an attempt is made to melt the welding wire by irradiating it with a laser, most of the laser is reflected, and a large amount of energy is required to melt the wire. [Prior art documents] [Non-patent literature]

[0012] [Non-Patent Document 1] E. Schubert et al.: LIA Proc.ICALEO'98 Vol. 85 (1998) G111 [Non-patent document 2] Koji Hagiwara et al.: Materia Vol. 57 No. 4 (2018) 145 [Non-patent document 3] Masaharu Kato: Iron and Steel, Vol. 78, No. 2 (1992), 209 [Non-patent document 4] RGMunro: J. Res. Natl. Inst. Stand. Technol. Vol. 105 (2000), 709 [Non-Patent Document 5] Y. Watanabe et al.: Mater.Trans. Vol. 64 No. 6 (2023), 1083 [Patent Document 1] Yoshimi Watanabe, Sanshu Chiba, Takashi Sato, Masashi Sato, Hiroyuki Kanno, Zen Nakano, Naoko Sato: Patent application filed November 2017, No. 6997984 Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention relates to a technology for metal additive processing using wire as a material, using directed energy deposition. Adding fine particles that act as solidification nucleation sites to the wire used in directed energy deposition increases the number of nucleation sites in the molten pool formed by the directed energy, thereby achieving equiaxed crystallization, refinement, and homogenization of the shaped structure. At the same time, the wire contains heterogeneous solidification nucleation particles that have a higher laser absorption capacity than metal, which enhances laser absorption capacity. At the same time, the fine particles cause diffuse reflection of the laser, thereby enhancing laser absorption capacity. This allows the laser to be used efficiently as a heat source, and provides a metal wire suitable for directed energy deposition, which can simultaneously achieve high strength and high formability. [Means for solving the problem]

[0014] The metal wire according to one embodiment of the present invention is used for metal additive processing. The metal wire of the present invention includes a metal matrix and solidification nuclei particles. The solidification nuclei particles have a higher melting point than the matrix alloy, and the parameter M (Non-Patent Document 3) expressed by the formula (1) is 12 × 10 -3 The following is the result.

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[0015] In the metal wire of the present invention, the volume ratio of the solidification nucleus particles to the metal matrix may be 20% or less.

[0016] The metal matrix may also be an aluminum alloy, a titanium alloy, a steel material including stainless steel, a copper alloy, a nickel alloy, a magnesium alloy, or any of these metals.

[0017] In addition, the solidification nucleus particles were made into L12 crystal structure by adding TiC, TiB2, Al3Ti, and the third element Me (Al 1-x Me x ) 3Ti, and SrO.

[0018] In addition, the solidification nucleus particles may particularly be TiB2 particles.

[0019] Another aspect of the present invention, a method for manufacturing a metal wire containing solidification nucleus particles, is a technique for incorporating the solidification nucleus particles inside a metal wire by wiredrawing or extrusion processing a multi-phase metal material containing the solidification nucleus particles. [Effects of the Invention]

[0020] When metal additive processing is performed using the wire of the present invention by directed energy deposition, improved laser absorption makes it possible to melt metal even with a low laser output, and solidification occurs through solidification nuclei, achieving equiaxed, refined, and homogenized crystal grains, thereby increasing the strength of the shaped material. Furthermore, the use of this metal wire makes it possible to control the structure while keeping the process parameters fixed, resulting in a shaped material with equiaxed, refined, and homogenized crystal grains. This makes it possible to manufacture high-strength shaped bodies, even for products with complex shapes that are difficult to control with process parameters. [Brief explanation of the drawings]

[0021] [Figure 1] Schematic diagram of directed energy deposition when the heat source is a laser and the material is in the form of a wire. 1 is the heat source laser, 2 is the substrate, 3 is the metal wire, 4 is the material supply device, 5 is the build platform, and 6 is the three-dimensional part. [Figure 2] This is a schematic diagram of the formation of solidification structures under a temperature gradient. 7 is the solid phase, 8 is the liquid phase, and 9 is the solid phase. [Figure 3] This is a diagram showing the wavelength dependence of laser absorption for various metals. 10 indicates steel, 11 indicates iron, 12 indicates molybdenum, 13 indicates copper, 14 indicates silver, 15 indicates aluminum, 16 indicates the wavelength of a carbon dioxide laser, and 17 indicates the wavelength of a fiber laser / YAG laser. [Figure 4] This is a diagram showing a pseudo-binary phase diagram of an (Al-1%Mg) alloy and Zn. 18 indicates the liquid phase, and 19 indicates the α-Al aluminum solid solution. [Figure 5] This figure shows the crystal structure of TiB2, which is known as a solidification nucleus particle for aluminum alloys. 20 indicates the [2,-1,-1,0] TiB2 direction, 21 indicates the [-1,2,-1,0] TiB2 direction, and 22 indicates the [0,0,0,1] TiB2 direction. 23 indicates the (1,1,-2,0) TiB2 plane, 24 indicates the (2,-1,-1,2) TiB2 plane, and 25 indicates the (0,0,0,1) TiB2 plane. [Figure 6]This diagram shows the lattice correspondence between TiB2 and aluminum. (a) shows the lattice correspondence of (1,1,-2,0)TiB2 / / (1,1,0)Al, [-1,1,0,0]TiB2 / / [-1,1,0]Al, (b) shows the lattice correspondence of (2,-1,-1,2)TiB2 / / (1,1,0)Al, [-1,1,0,0]TiB2 / / [-1,1,0]Al, and (c) shows the lattice correspondence of (0,0,0,1)TiB2 / / (1,1,1)Al, [-1,2,-1,0]TiB2 / / [-1,1,0]Al. [Figure 7] (a) Temperature dependence of the lattice constants of aluminum 26, a-axis 27 and c-axis 28 of TiB2. (b) Temperature dependence of the value of parameter M. Region 31 shows a coherent interface. [Figure 8] 1 is a photograph showing the appearance of an example of a wire manufactured using the A7003 alloy. [Figure 9] (a) is a diagram showing the results of observing the structure of an additive-free wire produced by wiredrawing using an optical microscope. (b) is a diagram showing the results of observing the structure of a solidification nucleus particle-added wire produced by wiredrawing using an optical microscope. 32 indicates the wiredrawing direction. [Figure 10] This figure shows the results of analyzing wire material with solidification nuclei particles using an EPMA (electron probe microanalyzer). 33 is a zirconium image, 34 is a manganese image, 35 is a secondary electron image (SEI image), 36 is a COMPO image (backscattered electron composition image), 37 is a silicon image, 38 is a titanium image, 39 is a magnesium image, 40 is a zinc image, and 41 is an iron image. [Figure 11] This figure shows the results of analyzing a wire material with added solidification nuclei particles using an EPMA (electron probe microanalyzer). 42 is a zirconium image, 43 is a manganese image, 44 is a secondary electron image (SEI image), 45 is a COMPO image (backscattered electron composition image), 46 is a silicon image, 47 is a titanium image, 48 is a magnesium image, 49 is a zinc image, and 50 is an iron image. [Figure 12]This figure shows the appearance of single beads formed by varying the scanning speed and wire feed speed with a fixed laser output of 1550 W. 51 shows the appearance of single beads formed by varying the scanning speed and wire feed speed at a scanning speed of 300 mm / min and a wire feed speed of 833 mm3 / min, 52 shows the appearance of single beads formed by varying the scanning speed and wire feed speed at a scanning speed of 300 mm / min and a wire feed speed of 1667 mm3 / min, 53 shows the appearance of single beads formed by varying the scanning speed and wire feed speed at a scanning speed of 300 mm / min and a wire feed speed of 2500 mm3 / min, 54 shows the appearance of single beads formed by varying the scanning speed and wire feed speed at a scanning speed of 600 mm / min and a wire feed speed of 833 mm3 / min, and 55 shows the appearance of single beads formed by varying the scanning speed and wire feed speed at a scanning speed of 600 mm / min and a wire feed speed of 1667 mm3 / min. m3 / min, 56 indicates a bead with a scanning speed of 600 mm / min and a wire feed speed of 2500 mm3 / min, 57 indicates a bead with a scanning speed of 900 mm / min and a wire feed speed of 833 mm3 / min, 58 indicates a bead with a scanning speed of 900 mm / min and a wire feed speed of 1667 mm3 / min, and 59 indicates a bead with a scanning speed of 900 mm / min and a wire feed speed of 2500 mm3 / min, and arrow 60 indicates the laser scanning direction. [Figure 13] This is a diagram showing a process map for laser power, scanning speed, and wire feed speed. The hatched areas in the diagram indicate conditions under which a good bead can be obtained in the entire area. [Figure 14] 1A and 1B are diagrams showing the effect of wire feed speed on bead width in a material without additives and in a material with solidification nucleus particles added, respectively. [Figure 15] 1A and 1B are diagrams showing the effect of wire feed speed on bead height for a material without additives and a material with solidification nucleus particles added, respectively. [Figure 16](a) A cross-sectional structure photograph of an additive-free material linearly formed under conditions of a laser output of 1850 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (b) A cross-sectional structure photograph of an additive-free material linearly formed under conditions of a laser output of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (c) A cross-sectional structure photograph of a material with solidification nucleus particles linearly formed under conditions of a laser output of 1850 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (d) A cross-sectional structure photograph of a material with solidification nucleus particles linearly formed under conditions of a laser output of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. [Figure 17] (a) A magnified cross-sectional micrograph of an additive-free material linearly formed under conditions of a laser output of 1850 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (b) A magnified cross-sectional micrograph of an additive-free material linearly formed under conditions of a laser output of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (c) A magnified cross-sectional micrograph of a material with solidification nucleus particles linearly formed under conditions of a laser output of 1850 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (d) A magnified cross-sectional micrograph of a material with solidification nucleus particles linearly formed under conditions of a laser output of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. [Figure 18] (a) A diagram showing the structure of a single bead of additive-free material formed under conditions of laser power, scanning speed, and wire feed rate of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. (b) A diagram showing the structure of a single bead of solidification nucleus particle-added material formed under conditions of laser power, scanning speed, and wire feed rate of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. [Figure 19](a1) A diagram showing the structure near the center of a single bead of additive-free material formed under conditions of laser power, scanning speed, and wire feed speed of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. (a2) A diagram showing the structure near the interface of a single bead of additive-free material formed under conditions of laser power, scanning speed, and wire feed speed of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. (b1) A diagram showing the structure near the center of a single bead of solidification nucleus particle-added material formed under conditions of laser power, scanning speed, and wire feed speed of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. (b2) A diagram showing the structure near the interface of a single bead of solidification nucleus particle-added material formed under conditions of laser power, scanning speed, and wire feed speed of 2000 W, 300 mm / min, and 833 mm3 / min, respectively. [Figure 20] (a) A photograph of the appearance of a plate-shaped sample of a material without additives fabricated under the conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, a wire feed speed of 833 mm3 / min, a layer pitch of 0.63 mm, and an argon gas flow rate of 10 L / min. (b) A photograph of the appearance of a plate-shaped sample of a material with solidification nucleus particles fabricated under the conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, a wire feed speed of 833 mm3 / min, a layer pitch of 0.63 mm, and an argon gas flow rate of 10 L / min. Arrow 61 indicates a crack. [Figure 21] (a) A diagram showing the results of evaluation of a cross section perpendicular to the laser scanning direction and the stacking direction in a plate-shaped sample of an additive-free material using an X-ray CT scanner. (b) A diagram showing the results of evaluation of a cross section perpendicular to the laser scanning direction and the stacking direction in a plate-shaped sample of a material with solidification nucleus particles added using an X-ray CT scanner. Arrow 62 indicates a defect. [Figure 22](a) A microstructure photograph of the vicinity of the base plate of a plate-shaped sample of additive-free material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (b) A microstructure photograph of the vicinity of the base plate of a plate-shaped sample of solidification nucleus particle-added material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. 63 indicates the laser scanning direction, 64 indicates the interface between the base plate and the fabricated body, 65 indicates the layer interface, 66 indicates the interface between the base plate and the fabricated body, and 67 indicates the layer interface. [Figure 23] (a) A microstructure photograph of the center of the lamination direction of a plate-shaped sample of additive-free material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. (b) A microstructure photograph of the center of the lamination direction of a plate-shaped sample of solidification nucleus particle-added material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed speed of 833 mm3 / min. 68 indicates the laser scanning direction, and 69 indicates the lamination interface. [Figure 24] (a) A micrograph of the upper part of the lamination direction of a plate-shaped sample of additive-free material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed rate of 833 mm3 / min. (b) A micrograph of the upper part of the lamination direction of a plate-shaped sample of solidification nucleus particle-added material fabricated under conditions of a laser power of 2000 W, a scanning speed of 300 mm / min, and a wire feed rate of 833 mm3 / min. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, an embodiment of the present invention will be described. The metal wire of the present invention can be applied to, for example, titanium and titanium alloys, aluminum and aluminum alloys, steel materials including stainless steel, copper and copper alloys, nickel and nickel alloys, magnesium and magnesium alloys, etc., and solidification nucleus particles are encapsulated inside the wire of these alloys. The solidification nucleus particles have a higher melting point than the base alloy and the parameter M expressed by the above-mentioned formula (1) is 12 × 10 -3 The following is the result.

[0023] In the present invention, based on solidification nucleation theory, a composite metal material suitable for directed energy deposition is provided in which solidification nuclei particles that have a higher melting point than the material alloy of the metal wire used and have a well-matched atomic arrangement with the phase that will become the primary crystal of the metal are mixed into the wire in advance.

[0024] When this metal wire is used as a material for directed energy deposition (DE), it contains fine solidification nuclei particles with higher laser absorption than metal materials, resulting in enhanced laser absorption. As a result, the metal wire can be melted with a low laser power. Additionally, the solidification nuclei particles supplied to the melt pool act as nuclei for crystal growth. When the wire has good wettability with the molten alloy, optimizing the size and distribution of the solidification nuclei promotes uniform solidification in various locations compared to when conventional metal wire is used under the same conditions. This allows for the production of materials with fewer internal defects and suppresses the development of columnar crystals elongated in the build direction and uneven internal structures.

[0025] As an index for selecting and evaluating solidification nuclei particles that exhibit the above-mentioned effects of the present invention, there is a parameter M, which is approximately proportional to elastic strain. Parameter M is calculated using the following formula (1), and the smaller this value, the smaller the energy required for nucleation, and therefore it is considered that the particles function as effective solidification nuclei.

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[0026] Also, ε x and ε y is calculated using the following formulas (2) and (3).

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[0027] The parameter M can be considered for all crystal orientation relationships, not just low-index planes and orientations. Furthermore, since the parameter M is approximately proportional to the elastic strain energy due to the misfit strain introduced at the interface between different phases, it is a parameter with physical meaning.

[0028] In the present invention, solidification nuclei particles that act as effective nuclei for the base metal are selected based on two factors: the melting point and the parameter M, which is an evaluation parameter for the consistency of atomic arrangement. These are then mixed with the base metal to provide a composite metal material for directed energy deposition. In this case, the composite metal material has a melting point higher than the primary crystal of the alloy, and the parameter M at the solidification temperature is 12 × 10 -3 The following materials are selected as solidification nuclei:

[0029] There are countless possible crystal orientation relationships at the interface between the solidifying metal / alloy and the solidification nuclei. In the present invention, for example, low-index planes are considered, and the one with the smallest value can be used as the parameter M of the material for the solidifying metal / alloy.

[0030] In the metal wire, the volume fraction of solidification nuclei particles relative to the base alloy is preferably 20% or less, and more preferably 10% or less. The manufacturing process of the metal wire may be any type, such as a drawing method, an extrusion method, or a rolling method. Therefore, as long as the metal wire has enough deformability to be wrapped around a bobbin, any type of manufacturing method for the metal wire may be used.

[0031] The solidification nuclei particles have a melting point higher than that of the metal material and the parameter M is 12 × 10 -3 The following materials can be used: For example, TiB2, TiC, Al3Ti, and a third element Me are added to aluminum and aluminum alloys to make the crystal structure L12 (Al 1-x Me x )3Ti. Among these, TiB2 particles are preferred because they have a small parameter M and are highly compatible with the matrix metal.

[0032] As described above, the solidification nucleus particles can be composed of one or more substances. In order to fully exert the effects of the solidification nucleus particles, the solidification nucleus particles are preferably manufactured so as to be uniformly distributed inside the metal wire during the metal wire manufacturing process.

[0033] The above-mentioned metal wire shaping method can be used for directed energy deposition using a laser as well as directed energy deposition using arc plasma as a heat source. It can also be applied to welding as well as additive processing.

[0034] (Example) The present invention will now be described with reference to examples. Here, A7003 aluminum alloy is used as the metal to be shaped. A7003 aluminum alloy is an Al-Zn-Mg alloy for welded structures, characterized by excellent extrusion properties and used for vehicle and motorcycle rims, etc. Its composition is Si 0.30 or less, iron 0.35 or less, copper 0.20 or less, manganese 0.30 or less, magnesium 0.5 to 1.0, chromium 0.20 or less, zinc 5.0 to 6.5, zirconium 0.05 to 0.25, titanium 0.20 or less, other components each 0.05 or less, other components total 0.15 or less, and the balance is aluminum. The reason for selecting A7003 aluminum alloy is that it does not contain copper and has reduced magnesium content, which allows it to maintain strength while providing excellent weldability and extrusion processability. However, any alloy can be used as long as it does not deviate from the scope of the present invention.

[0035] The pseudobinary phase diagram of an (Al-1%Mg) alloy with Zn obtained using the integrated thermodynamic calculation software Thermo-Calc and the TCAL3:Al-Alloys v3.0 database is shown in Figure 4. During the solidification process of an alloy containing 5.0 to 6.5% zinc, shown by the hatched area in the figure, α-Al aluminum solid solution 19 first crystallizes as primary crystals from the liquid phase 18 at approximately 656°C.

[0036] Therefore, when A7003 aluminum alloy is selected as the material for molding, a foreign substance can be selected as the solidification nucleus material, which has a melting point higher than the melting point of A7003 aluminum alloy, which is approximately 656°C, and has a highly consistent atomic arrangement at approximately 656°C with the primary α-Al aluminum solid solution of A7003 aluminum alloy.

[0037] Next, we will select solidification nuclei particles that are effective for the A7003 aluminum alloy. The crystalline structure of TiB2, which is known as a solidification nuclei particle for aluminum alloys, is shown in Figure 5. The 20 in the figure is [2,-1,-1,0]. TiB2 Direction, 21 is [-1,2,-1,0] TiB2 direction, and 22 is [0,0,0,1] TiB2It indicates the direction. Also, 23 is (1,1,-2,0) TiB2 Face, 24 is (2,-1,-1,2) TiB2 face, and 25 is (0,0,0,1) TiB2 Shows the surface.

[0038] Next, consider the lattice correspondence between TiB2 and aluminum. (1,1,-2,0) shown in Figure 6(a) TiB2 / / (1,1,0) Al , [-1,1,0,0] TiB2 / / [-1,1,0] Al For the lattice correspondence of , the value of the parameter M at room temperature is 57.4 × 10 -3 Also, as shown in Figure 6(b), (2,-1,-1,2) TiB2 / / (1,1,0) Al , [-1,1,0,0] TiB2 / / [-1,1,0] Al For the lattice correspondence of , the value of the parameter M at room temperature is 10.7 × 10 -3 Furthermore, (0,0,0,1) shown in Figure 6(c) TiB2 / / (1,1,1) Al , [-1,2,-1,0] TiB2 / / [-1,1,0] Al For the lattice correspondence of , the value of the parameter M at room temperature is 9.95 × 10 -3 As can be seen, the lattice correspondence shown in Figure 6(c) shows that the atomic arrangement is highly consistent.

[0039] However, these values ​​were calculated based on the lattice constant at room temperature, and solidification actually occurs at the melting point. Therefore, the temperature dependence of the lattice constant of aluminum26, the temperature dependence of the lattice constant of the a-axis of TiB227, and the temperature dependence of the lattice constant of the c-axis of TiB228 (Non-Patent Document 4) are shown in Figure 7(a). The value of parameter M calculated using these lattice constants is shown in Figure 7(b). The (2, -1, -1, 2) shown in Figure 6(b) TiB2 / / (1,1,0) Al , [-1,1,0,0] TiB2 / / [-1,1,0] AlThe value of the parameter M for the lattice of the lattice does not change significantly with temperature. TiB2 / / (1,1,1) Al , [-1,2,-1,0] TiB2 / / [-1,1,0] Al In the case of the value of the lattice correspondence parameter M30, the value of the parameter M decreases with increasing temperature, and a coherent interface 31 is shown at high temperatures (Non-Patent Document 5). It is found that the coherence of the atomic arrangement becomes higher as the temperature increases. Therefore, in this example, TiB2 was selected as the solidification nucleus material.

[0040] Next, the wire is produced. First, an A7003 alloy containing TiB2 solidification nuclei particles was produced using an Al-Ti-B alloy. This was extruded into a round bar measuring 25 mm in diameter and 130 mm in length. The titanium concentration in the extruded material was 0.2 mass%. Similarly, an extruded material of an unaltered A7003 alloy without the addition of solidification nuclei particles was also produced. This extruded material was then drawn into a wire with a diameter of 1.2 mm.

[0041] The appearance of an example of the produced wire is shown in Figure 8. Both the extruded material of the A7003 alloy without solidification nuclei particles and the extruded material of the A7003 alloy with solidification nuclei particles could be processed into wire that could be wound around a bobbin.

[0042] The structure of the wire produced by wiredrawing was observed using an optical microscope, and the results are shown in Figure 9. The arrow in the figure indicates the wiredrawing direction 32. Figure 9(a) shows the structure of a material without solidification nuclei particles, and Figure 9(b) shows the structure of a material with solidification nuclei particles. From these microstructure photographs, it was found that no major defects were generated within the samples when extruded materials of A7003 alloy without solidification nuclei particles and A7003 alloy with solidification nuclei particles were wiredrawn. Therefore, this series of processes made it possible to provide materials that can be used in wire-type directed energy deposition.

[0043] Figure 10 shows the results of an EPMA (electron probe microanalyzer) analysis of wire material with added solidification nuclei particles, with (from the top left) a zirconium image 33, a manganese image 34, and an SEI image (secondary electron image) 35, (from the middle left) a COMPO image (backscattered electron composition image) 36, a silicon image 37, and a titanium image 38, and (from the bottom left) a magnesium image 39, a zinc image 40, and an iron image 41. This figure shows no signs of titanium segregation or aggregation.

[0044] Figure 11 shows the results of EPMA (electron probe microanalyzer) analysis of wire material with solidification nuclei particles added in different fields of view. From the top left, there is a zirconium image 42, a manganese image 43, and an SEI image (secondary electron image) 44; from the middle left, there is a COMPO image (backscattered electron composition image) 45, a silicon image 46, and a titanium image 47; and from the bottom left, there is a magnesium image 48, a zinc image 49, and an iron image 50. Even when the field of view was changed, no segregation or aggregation of titanium was observed, and it can be concluded that a structure with dispersed solidification nuclei particles was obtained.

[0045] Next, a process map was created by linear modeling using a Mitsubishi Electric wire-type directed energy deposition system. At this time, the laser power was set to 1550W, 1700W, 1850W, and 2000W, the scanning speed was set to 300mm / min, 600mm / min, and 900mm / min, and the wire feed speed was set to 833mm. 3 / min, 1667mm 3 / min and 2500mm 3 / min.

[0046] As an example, Fig. 12 shows beads formed by changing the scanning speed and wire feed speed while fixing the laser output at 1550 W. Here, when the scanning speed is 300 mm / min and the wire feed speed is 833 mm / min, 3 / min bead 51, scanning speed 300mm / min and wire feed speed 1667mm 3 / min bead 52, scanning speed 300mm / min and wire feed speed 2500mm 3 / min bead 53, scanning speed 600mm / min and wire feed speed 833mm3 / min bead 54, scanning speed 600mm / min and wire feed speed 1667mm 3 / min bead 55, scanning speed 600mm / min and wire feed speed 2500mm 3 / min bead 56, scanning speed 900mm / min and wire feed speed 833mm 3 / min bead 57, scanning speed 900mm / min and wire feed speed 1667mm 3 / min bead 58, scanning speed 900mm / min and wire feed speed 2500mm 3 / min bead 59 is shown, and the arrow indicates the laser scanning direction 60.

[0047] For example, the scanning speed is 300 mm / min and the wire feed speed is 833 mm. 3 When the scanning speed was 900 mm / min, a good bead was formed over the entire length. 3 Therefore, the bead appearance was divided into three regions, and the bead appearance in each region was classified as "good (sm)," "droplet-like (dr (drop)")," and "insufficient fusion (st (stub)."

[0048] Figure 13 shows the process map for laser power, scanning speed and wire feed speed. This is particularly noticeable with solidification nucleus particle materials, but it can be seen that increasing the wire feed speed results in insufficient melting. The hatched conditions in the figure produce good beads in all areas. From this figure, it can be seen that when the laser power is 1850W, the scanning speed is 300mm / min and the wire feed speed is 833mm, 3 / min, and the laser power was 2000W, the scanning speed was 300mm / min, and the wire feed speed was 833mm 3 It was found that good molding was possible under the condition of / min, regardless of the presence or absence of solidification nuclei particles.

[0049] The effect of wire feed speed on bead width for the alloy without additives and the alloy with solidification nuclei particles is shown in Figures 14(a) and (b), respectively. As can be seen from these figures, there was no strong correlation between wire feed speed and bead width.

[0050] In contrast, Figures 15(a) and (b) show the effect of wire feed speed on bead height for the alloy without additives and the alloy with solidification nuclei particles, respectively. As shown in the figure, increasing the wire feed speed increases the bead height, while decreasing the scanning speed increases the bead height. This is due to the amount of wire feed.

[0051] In Figure 16(a), the laser output is 1850W, the scanning speed is 300mm / min, and the wire feed speed is 833mm. 3 / min, the laser output was 2000W, the scanning speed was 300mm / min, and the wire feed speed was 833mm. 3 / min, the laser power is 1850W, the scanning speed is 300mm / min, and the wire feed speed is 833mm. 3 / min, and Fig. 16(d) shows the solidification nucleus particle additive material linearly shaped under the conditions of laser power 2000W, scanning speed 300mm / min, and wire feed speed 833mm. 3 The cross-sectional structure of the material with solidification nuclei particles added was linearly formed at a rate of 1 / min. In the material without solidification nuclei particles, the interface between the bead and the base plate was a beautiful arc, whereas in the material with solidification nuclei particles added, the center of the interface was slightly concave.

[0052] In Fig. 17(a), the laser output is 1850W, the scanning speed is 300mm / min, and the wire feed speed is 833mm. 3 Figure 17(b) shows the additive-free material linearly formed under the conditions of laser power 2000W, scanning speed 300mm / min, and wire feed speed 833mm. 3 / min, the laser power is 1850W, the scanning speed is 300mm / min, and the wire feed speed is 833mm. 3 / min, and Fig. 17(d) shows the solidification nucleus particle additive material linearly shaped under the conditions of laser power 2000W, scanning speed 300mm / min, and wire feed speed 833mm. 3 The enlarged cross-sectional micrograph of the material with solidification nuclei particles added was linearly formed under the condition of / min. Compared to the material without solidification nuclei particles, the material with solidification nuclei particles has a finer microstructure.

[0053] Therefore, the laser power, scanning speed and wire feed speed were set to 2000 W, 300 mm / min and 833 mm 3 The structure of a single bead formed under conditions of 0.1 / min was observed using EBSD (electron backscatter diffraction). EBSD is a technique in which a sample is irradiated with an electron beam, the resulting EBSD pattern is photographed with a camera, and the pattern is indexed to obtain information on crystal orientation. Figure 18 shows an inverse pole figure orientation map (IPF map) in which the plane index of the crystal plane perpendicular to an arbitrary direction was determined at each point and displayed according to a color key. As can be seen from this figure, the crystal grains of the material with solidification nuclei particles added (Figure 18(b)) are significantly finer than those of the material without solidification nuclei particles (Figure 18(a)).

[0054] Next, Figures 19(a1) and 19(a2) show enlarged views of the material without solidification nuclei particles at positions 447 μm from the base plate (near the bead center) and 100 μm from the base plate (near the interface), respectively. Figures 19(b1) and 19(b2) show enlarged views of the material with solidification nuclei particles at positions 447 μm from the base plate (near the bead center) and 100 μm from the base plate (near the interface), respectively. It can be seen that the crystal grains of the material with solidification nuclei particles are finer than those of the material without solidification nuclei particles.

[0055] When the grain size near the center of the bead was measured, it was 62.9 μm for the material without additives, while it was 17.4 μm for the material with solidification nuclei particles added. Furthermore, when the grain size near the interface was measured, it was 30.3 μm for the material without additives, while it was 18.7 μm for the material with solidification nuclei particles added. These results are summarized in Table 1. That is, Table 1 shows the results for the laser power, scanning speed, and wire feed speed of 2000 W, 300 mm / min, and 833 mm / min, respectively. 3 This table summarizes the grain size of single beads formed under the conditions of 0.1 / min. As shown above, it was found that the addition of solidification nuclei particles significantly contributes to grain refinement in beads formed by wire-type directed energy deposition. (Table 1) JPEG2025169606000008.jpg2276

[0056] Therefore, the laser output was 2000W, the scanning speed was 300mm / min, and the wire feed speed was 833mm. 3 Plate-shaped samples were fabricated under the conditions of a feed rate of 1 / min, a layer pitch of 0.63 mm, and an argon gas flow rate of 10 L / min. Figures 20(a) and 20(b) are photographs of the appearance of plate-shaped samples fabricated using a material without additives and a material with solidification nuclei particles added, respectively. In the material without additives, cracks 61 indicated by the arrows had occurred. In contrast, no such cracks occurred in the material with solidification nuclei particles added. In this way, it was found that the addition of solidification nuclei particles improves fabrication properties even in wire-type directed energy deposition (deposition method).

[0057] Next, defect evaluation was performed using X-ray CT. CT stands for computed tomography, which irradiates a material with X-rays from multiple directions and analyzes the captured images using a computer to generate a three-dimensional X-ray image. The X-ray CT imaging conditions were: SID (the distance from the sample to the image detector) value of 600 mm, number of views of 1200, slice thickness of 0.378 mm, metal filter of 0.5 mm thick copper, scaling coefficient for brightness value conversion coefficient of 10, image size of 512 x 512, pixel dimension of 0.148 mm / voxel, X-ray detector size in inches of 9.0 inches, and data accumulation average number per frame of 4.

[0058] As examples of X-ray CT imaging results, Fig. 21(a) and Fig. 21(b) show the results of evaluating cross sections perpendicular to the laser scanning direction and lamination direction for an additive-free material and a material with solidification nuclei particles added, respectively. The laser power was 2000 W, the scanning speed was 300 mm / min, and the wire feed speed was 833 mm. 3 / min. A defect 62 was observed at the edge of the sample in the additive-free material, which corresponds to the location near where the crack had occurred. On the other hand, apart from this defect, no significant defects were observed in either the additive-free material or the material with solidification nuclei particles, indicating that good molding was achieved.

[0059] Laser output: 2000W, scanning speed: 300mm / min, wire feed speed: 833mm 3 The density of the plate-shaped sample formed under the conditions of laser output of 2000 W, scanning speed of 300 mm / min, and wire feed speed of 833 mm was evaluated by Archimedes' method. Here, Archimedes' method is a method for determining the density of a sample by using the fact that a solid in a liquid is subjected to buoyancy equal to the weight of the liquid of the same volume (Archimedes' principle). The results are shown in Table 2. That is, Table 2 shows the density evaluated by Archimedes' method under the conditions of laser output of 2000 W, scanning speed of 300 mm / min, and wire feed speed of 833 mm. 3 This is a table showing the density of plate-shaped samples molded under the conditions of 0.15 Mg / m3 / min. The density of the additive-free material is 2.780 Mg / m3. 3 and the density of A7003 (2.790 Mg / m 3) was used to calculate the relative density, which was 99.6%. In contrast, the density of the solidification nucleus particle additive was 2.777 Mg / m 3 The relative density is 99.5%. As can be seen, there is no significant difference in overall density due to the addition of solidification nuclei. This is because the main defects that occurred in the additive-free material were cracks, and it can be confirmed that high-density molding was achieved for both samples. (Table 2) JPEG2025169606000009.jpg2286

[0060] Laser output: 2000W, scanning speed: 300mm / min, wire feed speed: 833mm 3 Figures 22(a) and 22(b) show microstructure photographs near the base plate of plate samples made from additive-free material and solidification nuclei particle-added material, fabricated under conditions of 1 / min. They were etched for 30 seconds in an etching solution consisting of 10% hydrofluoric acid and 90% water. 63 indicates the laser scanning direction, 64 the interface between the base plate and the formed body, 65 the layer interface, 66 the interface between the base plate and the formed body, and 67 the layer interface. It can be seen that the structure exhibits elongated columnar crystal structure in the layer direction, tilted toward the laser direction. Compared to the additive-free material, it can be seen that the crystal grains in the solidification nuclei particle-added material are significantly refined.

[0061] Laser output: 2000W, scanning speed: 300mm / min, wire feed speed: 833mm 3 Figures 23(a) and 23(b) show microstructure photographs of the center of the stacking direction of plate-shaped samples made from additive-free material and solidification nuclei particle-added material, fabricated under conditions of 1 / min. The samples were etched for 30 seconds in an etching solution consisting of 10% hydrofluoric acid and 90% water. 68 indicates the laser scanning direction, and 69 indicates the stacking interface. It can be seen that the structure exhibits elongated columnar crystal structure in the stacking direction, and that the structure is tilted toward the laser. This figure also shows that the crystal grains in the solidification nuclei particle-added material are significantly refined compared to the additive-free material.

[0062] Laser output: 2000W, scanning speed: 300mm / min, wire feed speed: 833mm3 Figures 24(a) and 24(b) show microstructure photographs of the upper part of the stacking direction of plate specimens made from additive-free material and solidification nuclei particle-added material, fabricated under conditions of / min. They were etched for 30 seconds in an etching solution consisting of 10% hydrofluoric acid and 90% water. This figure also shows that the crystal grains in the solidification nuclei particle-added material are significantly finer than those in the additive-free material.

[0063] In this way, it has been discovered that even in wire-type directed energy deposition, the addition of solidification nuclei particles improves shaping properties and refines crystal grains, thereby improving mechanical properties.

[0064] In the above-described example, TiB2 particles were used as solidification nuclei particles, but the parameter M was 12 × 10 -3 It is believed that similar results can be obtained by using the following particles. Although A7003 was used as the metallic material, similar solidification nuclei particles can be used, and similar results can be obtained, even when aluminum or other aluminum alloys are used. Furthermore, in addition to aluminum and aluminum alloys, titanium alloys, steel materials including stainless steel, copper alloys, nickel alloys, magnesium alloys, and the individual metals mentioned above can also be used as metallic materials.

[0065] The present invention is not limited to the above-described embodiments (examples), and may be embodied in various forms without departing from the scope of the present invention. For example, the function of one component in the above-described embodiments may be distributed among multiple components, or the functions of multiple components may be integrated into one component. Also, part of the configuration of the above-described embodiments may be omitted. Furthermore, at least part of the configuration of the above-described embodiments may be added to or substituted for the configuration of another of the above-described embodiments. Note that all aspects included in the technical concept specified by the wording of the claims are embodiments of the present invention. [Explanation of symbols]

[0066] 1...heat source laser, 2...substrate, 3...metal wire, 4...material supply device, 5...build platform, 6...three-dimensional part, 7...solid phase, 8...liquid phase, 9...solidified phase, 10...steel, 11...iron, 12...molybdenum, 13...copper, 14...silver, 15...aluminum, 16...carbonate laser wavelength, 17...fiber laser / YAG laser wavelength, 18...liquid phase, 19...α-Al aluminum solid solution, 20...[2,-1,-1,0] TiB2 Direction, 21…[-1,2,-1,0] TiB2 Direction, 22…[0,0,0,1] TiB2 Direction, 23…(1,1,-2,0) TiB2 Surface, 24…(2,-1,-1,2) TiB2 Surface, 25…(0,0,0,1) TiB2 26...Temperature dependence of the lattice constant of aluminum 27...Temperature dependence of the a-axis lattice constant of TiB2 28...Temperature dependence of the c-axis lattice constant of TiB2 29...(2,-1,-1,2) TiB2 / / (1,1,0) Al , [-1,1,0,0] TiB2 / / [-1,1,0] Al The value of the parameter M corresponding to the grid, 30...(0,0,0,1) TiB2 / / (1,1,1) Al , [-1,2,-1,0] TiB2 / / [-1,1,0] Al lattice correspondence parameter M value, 31...coherent interface, 32...wire drawing direction, 33...zirconium image, 34...manganese image, 35...SEI image (secondary electron image), 36...COMPO image (backscattered electron composition image), 37...silicon image, 38...titanium image, 39...magnesium image, 40...zinc image, 41...iron image, 42...zirconium image, 43...manganese image, 44...SEI image (secondary electron image), 45...COMPO image (backscattered electron composition image), 46...silicon image, 47...titanium image, 48...magnesium image, 49...zinc image, 50...iron image, 51...scanning speed 300 mm / min, wire feed speed 833 mm 3 / min bead, 52...Scanning speed is 300mm / min and wire feed speed is 1667mm 3 / min bead, 53...Scanning speed is 300mm / min and wire feed speed is 2500mm 3 / min bead, 54...Scanning speed is 600mm / min and wire feed speed is 833mm 3 / min bead, 55...Scanning speed is 600mm / min and wire feed speed is 1667mm 3 / min bead, 56...Scanning speed is 600mm / min and wire feed speed is 2500mm 3 / min bead, 57...Scanning speed is 900mm / min and wire feed speed is 833mm 3 / min bead, 58...Scanning speed is 900mm / min and wire feed speed is 1667mm 3 / min bead, 59...Scanning speed is 900mm / min and wire feed speed is 2500mm 3 / min bead, 60...laser scanning direction, 61...crack, 62...defect, 63...laser scanning direction, 64...interface between base plate and molded body, 65...layer interface, 66...interface between base plate and molded body, 67...layer interface, 68...laser scanning direction, 69...layer interface

Claims

1. A composite metal material characterized in that at least one type of solidification nucleus particles are contained within a metal base material, and the metal is in a wire shape.

2. 2. The composite metal material according to claim 1, wherein the metal wire is in the form of a wire produced by a drawing method, an extrusion method, or a rolling method.

3. The wire-shaped composite metal material according to claim 2, characterized in that the composite metal material is an aluminum alloy, titanium alloy, steel material including stainless steel, copper alloy, nickel alloy, magnesium alloy, or any of these simple metals produced by drawing, extrusion, or rolling.

4. 4. The composite metal material according to claim 3, characterized in that it is used as a wire-shaped composite metal material for additional processing by directed energy deposition.

5. A composite metal material for directed energy deposition (DE) is characterized in that at least one type of solidification nuclei particles are contained inside a metal wire, and the metal wire is in a wire shape manufactured by a drawing method, an extrusion method, or a rolling method, and the solidification nuclei particles have a higher melting point than the metal base material, and a parameter M expressed by formula (1) is 12×10 －３ Composite metal material: [Equation 1] (In the formula, ε ｘ and ε ｙ are the principal axial strains along the principal axes x and y, which are perpendicular to each other in the lattice of the solidification nucleus phase and the lattice of the solidification phase, respectively, and ε ｘ and ε ｙ is calculated using the following formulas (2) and (3): [Equation 2] [Equation 3] (In the formula, x ｉ , y ｉ and x ｊ , y ｊ are the principal axial strain directions of material i and material j, respectively, and a ｉ and a ｊ are the lattice constants of material i and material j, respectively.)

6. The solidification nucleus particles are TiB ２ , TiC, Al ３ Adding Ti and a third element, Me, changes the crystal structure to L1 ２ (Al １－ｘ Me ｘ ) ３ 5. The composite metal material according to claim 1, wherein the particles are particles of one or more compounds selected from the group consisting of Ti and SrO.

7. The solidification nucleus particles are TiB ２ The composite metal material of claim 6, which is a particle.

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