Additive manufacturing process

Abstract

An additive manufacturing process in which a layer produced from a metal powder forms an xy-plane, which is solidified by means of an energy beam through the creation of melting points; a further layer produced from the metal powder and applied in the z-direction on the layer forms another xy-plane, which is solidified by the creation of further melting points; so that by repeating the aforementioned steps, a component with a predetermined shape is formed from the solidified layers, whereby a predetermined texture in the component is created from the crystal structure of the metal used to produce the metal powder. (a) determines a 2-dimensional point pattern for the xy-plane and (b) a rule for determining a spatial relationship between the 2-dimensional point pattern and at least one further 2-dimensional point pattern in the at least one further xy-plane, the melting points in the xy-plane are produced according to the 2-dimensional point pattern, and the further melting points in the further xy-plane following in the z-direction are produced according to a further 2-dimensional point pattern which results from applying the rule.

Description

[0001] The invention relates to an additive manufacturing process according to the preamble of claim 1.

[0002] Such a process is known, for example, from EP 3 482 853 A1. In this process, a layer made from a metal powder forms an xy-plane. This xy-plane is solidified by means of an energy beam through the creation of melting points. A further layer of the same metal powder, located in the z-direction, forms another xy-plane. This further xy-plane is solidified by the creation of additional melting points and bonded to the layer below. The melting points and subsequent melting points are staggered. The additional melting points solidify areas in the layer below that are not fully solidified.

[0003] Additive manufacturing has the disadvantage that, due to solidification oriented in the build direction or z-direction, mostly columnar crystals form that extend in the build direction. An anisotropic structure is formed. <001> The texture can be disadvantageous, for example, from a mechanical point of view. To overcome this disadvantage, the wall thickness of a component must be increased, at least in certain areas. This, in turn, increases the weight and manufacturing costs.

[0004] To improve the mechanical properties in particular, attempts are made to create an isotropic texture with small crystallites. It is known to add alloying elements that act as nucleation sites for this purpose. While this can alter the texture, it also changes the alloy itself, which is often undesirable.

[0005] From A. Plotkowsski, et al., A stochastic scan strategy for grain structure control in complex geometries using electron beam powder bed fusion, Additive manufacturing 46 (2021) 102092, it is known that a relatively large melting zone or melt pool can be produced by a high energy input. This enables a CET (columnar to equitaxed transition) transition and thus influences the texture. However, it requires a high energy input. This, in turn, necessitates the production of walls with a certain minimum thickness. The resulting texture is usually not completely isotropic.

[0006] It is also known that the texture can be influenced by the arrangement of melting points and / or melting lines (Dehoff et al.; Site specific control of crystallographic grain orientation through electron beam additive manufacturing, Materials Science and Technology 31(8) 2015 931-938).

[0007] The object of the invention is to eliminate the disadvantages of the prior art. In particular, it aims to provide an efficient additive manufacturing process for producing metallic components with a predetermined texture. Advantageously, the predetermined texture should only be producible in specific areas of the component. A further objective is to provide a device for carrying out the process.

[0008] The problem is solved by the features of claims 1 and 24. Advantageous embodiments result from the dependent claims.

[0009] According to the invention, in an additive process, it is proposed that a predetermined texture in the component is produced from the crystal structure of the metal used to produce the metal powder. (a) determines a 2-dimensional point pattern for the xy-plane and (b) a rule for determining a spatial relationship between the 2-dimensional point pattern and at least one further 2-dimensional point pattern in the at least one further xy-plane, the melting points in the xy-plane are produced according to the 2-dimensional point pattern, and The further melting points in the subsequent xy-plane following in the z-direction are produced according to a further 2-dimensional point pattern, which results from applying the rule.

[0010] The proposed method enables the particularly simple and cost-effective production of metallic components with a predefined texture. Furthermore, the texture can be adjusted within the component itself, depending on the specific requirements. This allows, for the first time, comprehensive material design of a component. The component's texture can be optimized, for example, with regard to its mechanical properties. Areas within the component can be created with isotropic textures and other areas with anisotropic textures. This makes it possible to optimally adapt the component to specific mechanical stresses, for example. This results in material savings and the production of lightweight components. Similarly, components with textures can also be manufactured to achieve predefined electrical, magnetic, or thermo-mechanical properties.

[0011] The proposed method requires no changes to the alloy, no particularly high energy input, and no use of crystal seeds. It is based solely on the surprising discovery that by arranging the melting points in a way that corresponds to the crystal structure of the respective metal, a predetermined texture can be produced in the component. Definitions

[0012] A microstructure, or structure, describes the arrangement and order of the constituents at the visible and microscopic level, regardless of the material (metal, ceramic, or polymer). The microstructural constituents, such as crystallites or grains, fillers, and amorphous regions, are typically very small and can be visualized qualitatively and quantitatively, for example, using a light microscope.

[0013] Texture refers to the totality of orientations of the crystallites in a given section of the produced polycrystalline solid.

[0014] An anisotropic texture refers to a polycrystalline solid in which the crystallites exhibit at least one preferred orientation. The preferred orientation is indicated by the direction of the surface normals according to the Miller indices.

[0015] Isotropic texture refers to a multicrystalline solid in which the crystallites do not exhibit a preferred orientation.

[0016] The term crystal structure refers to the crystal structure that forms during the solidification of a metal or alloy. The crystal structure is a three-dimensional periodic repetition of the basis (or a motif). Vectors that coincide with a lattice are called translation vectors t. They form a translationally symmetric point lattice. The points of this lattice do not represent atoms; they merely describe the periodicity of the crystal structure.

[0017] In the present invention, a translation vector t defines the displacement of superimposed point patterns in space. From the translation vector t, a displacement vector can expediently be determined by projecting the superimposed point patterns. This displacement vector extends along the xy-plane and describes only the displacement of the superimposed point patterns in the respective xy-planes.

[0018] A unit cell is the parallelepiped formed by three basis vectors. In metals, the unit cell exhibits either cubic or hexagonal symmetry. In this case, the unit cell can also be described as a "primitive unit cell". The basis vectors a v , b v , c vThe parameters are chosen such that the lattice they form corresponds to the lattice of a crystal. The coordinates of the crystal's lattice points are integers. The lattice is a geometric representation of a real crystal lattice. The distances between adjacent points in the unit cell are determined according to the basis vectors a. v , b v , c v The distances are denoted by a, b, and c. These are fictitious distances chosen in the invention to correspond to the distances between adjacent points in the two-dimensional dot pattern. A real crystal lattice is formed by atoms. The distance between atoms depends on several parameters, such as the size of the atoms involved.

[0019] x, y, z direction: Directions used to describe additive manufacturing or manufacturing equipment. The xy directions describe the horizontal xy build planes, while the z direction is perpendicular to the xy build planes and describes the build direction or build height.

[0020] According to an advantageous embodiment of the invention, to produce an anisotropic texture, a spatial arrangement of the melting points in the superimposed xy-planes is chosen such that they correspond to the symmetry of the unit cell.

[0021] To determine the two-dimensional dot pattern, a unit cell of the crystal structure can be oriented relative to the z-direction according to the texture to be produced. One of the basis vectors a is used. v , b v , c v chosen and the points of intersection of parallel to the basis vector a are selected. v , b v , c v The oriented straight lines are determined using the xy-plane. The basis vector is a.v , b v , c v The basis vector a will be used expediently. v , b v , c v The line with the largest component in the z-direction is chosen. The relative positions of the lines are determined by the unit cell. The distances between the lines are determined by the other basis vectors a. v , b v , c v This defines a family of parallel lines that intersect the xy-construction planes. The points of intersection define the location of the melting points to be produced.

[0022] The "rule for determining a spatial relationship between the 2-dimensional point pattern" can be given by a translation vector t, which determines the spatial position of the superimposed 2-dimensional point patterns relative to each other. The translation vector t extends parallel to the chosen basis vector a. v , b v , c vThe magnitude of the translation vector t can be determined as a function of the thickness d of the layers. Using such a translation vector t, the position of the melting points in the superimposed layers can be calculated quickly and easily as a function of the thickness d of the layers.

[0023] Especially in the production of <110> or <111> Textures can be used when a predetermined value for the translation vector t is reached, with another translation vector t1 having a changed direction, where the changed direction is parallel to one of the other basis vectors a v , b v , c v This is the case. By changing the direction of the translation vector in this way, the spatial symmetry can be improved.

[0024] According to a first simple embodiment of the invention, the 2-dimensional dot pattern can exhibit quadratic point symmetry, wherein the points have a first distance A1, where A1 = a. To form a <100> In the texture in the z-direction, the translation vector t is aligned parallel to the z-direction in this case.

[0025] According to a second, simpler variant, the 2-dimensional point pattern can exhibit rectangular point symmetry, where the points have a first distance A1 in a first direction and a second distance A2 in a second direction, where A2 = √2a. To form a <110> In this case, the texture in the z-direction is the translation vector t inclined at 45° to the z-axis.

[0026] According to a third simple variant, the 2-dimensional dot pattern can exhibit hexagonal point symmetry, where adjacent points of the hexagon have a distance of the second A2. To form a <111> In this case, the texture is the translation vector t in the z-direction relative to the z-axis by 50° to 60°, preferably by 53° to 57°, particularly preferably by 54.7°.

[0027] In addition to the simple variants shown above, a variety of other variants can be implemented - depending on requirements - by choosing a unit cell and its orientation relative to the z-axis.

[0028] For a symmetrical two-dimensional dot pattern, the radius r of a melting point is advantageously chosen to be smaller than the smallest of the distances to the next-but-one melting point. This ensures sufficient hardening of the layers. Simultaneously, this allows the desired texture to be created.

[0029] A particular advantage of the method according to the invention is that the production of melting points according to a symmetrical two-dimensional dot pattern can be carried out with minimal effort in at least one predetermined surface area of ​​the xy-plane. It is only necessary to produce the melting points according to the selected two-dimensional dot pattern in the predetermined surface area. A different texture can be produced in an adjacent surface area using the method according to the invention.

[0030] An isotropic texture can also be produced according to the inventive method. For the production of an isotropic texture, an asymmetrical dot pattern deviating from the symmetry of the unit cell is advantageously selected as the two-dimensional dot pattern. This prevents the random formation of symmetrical arrangements of melting points. A nearly completely isotropic texture can be produced reliably and safely. With conventional additive manufacturing processes, the production of nearly completely isotropic textures is either impossible or only possible with a very high degree of effort. In most cases, conventionally produced isotropic textures are not completely formed, i.e., areas with undesirable anisotropic textures remain.

[0031] To create the asymmetric 2-dimensional dot pattern, the points of a symmetric 2-dimensional dot pattern can be stochastically shifted by a fraction of the distance A1, A2. Alternatively, a different 2-dimensional dot pattern can be chosen.

[0032] It has proven advantageous to create an isotropic texture by choosing a larger radius r of the melting points in the respective xy-point pattern than the distance to the next-but-one neighboring point. Using the above measures, an isotropic texture can be reliably and safely generated across the desired volume.

[0033] In the method according to the invention, an electron beam or a laser beam can be used as the energy beam. The distances A1, A2 between the adjacent points in the xy plane are advantageously 50 to 500 µm.

[0034] The unit cell is advantageously a cubic, face-centered cubic, body-centered cubic or hexagonal unit cell.

[0035] The method described herein can be carried out using an additive manufacturing device for metallic components, which is configured for this purpose. The device may include a computer equipped with a program for controlling the energy beam, such that the melting points are produced according to the previously calculated two-dimensional point patterns. General examples

[0036] A process for producing a specified anisotropic texture can, for example, be carried out by the following steps when using a specified metal or alloy: (i) Determining the desired texture. (ii) Selection of the unit cell of the metal or alloy. (iii) Determining the position of the unit cell relative to the z-direction. (iv) Selection of a basis vector a v , b v , c v of the unit cell. Preferably, the basis vector a v , b v , c v selected with the largest component in the z-direction. (v) Determination of distances and the position of lines parallel to the basis vector a v , b v , c v are oriented. (vi) Determination of a 2-dimensional point pattern by identifying the points of intersection of the lines with an xy-planar plane. (vii) Optional: Specifying a displacement vector to determine the position of another 2-dimensional point pattern in another xy-plane relative to the symmetric 2-dimensional point pattern.

[0037] To determine the position of the unit cell, in particular its rotation angle around the z-axis and the angle of an edge with respect to the z-axis are specified.

[0038] To generate the symmetrical two-dimensional dot pattern for the melting points, the point spacing or the distances between the lines can be appropriately chosen. In simple cases, the symmetrical two-dimensional dot pattern may also be known beforehand.

[0039] The distance between two melting points is typically between 50 and 500 µm. The radius of a melting point is usually between 50 and 300 µm. The distance d between two successive xy build planes is usually between 50 and 100 µm.

[0040] The displacement vector conveniently describes the relative displacement of the melting points in directly superimposed construction planes. Its magnitude depends on the distance d between the xy construction planes. To generate a further symmetrical 2-dimensional point pattern, the displacement vector can be used, for example, to shift the symmetrical 2-dimensional point pattern by a predetermined amount in the x and / or y direction.

[0041] Exemplary embodiments of the invention are explained below with reference to the drawing. The drawing shows: Fig. 1 a cubic unit cell and a first projection into an xy-plane, Fig. 2 a cubic unit cell and a second projection into an xy-plane, Fig. 3. the cubic unit cell according to Fig. 2 and projections into multiple xy-planes, Fig. 4 a cubic unit cell and a third projection into an xy-plane, Fig. 5 a hexagonal unit cell and a fourth projection into an xy-plane, Fig. 6 a top view of an xy-plane with a transition from the projection of a cubic unit cell to a hexagonal unit cell, Fig. 7 a projection of the cubic unit cell onto the xy-plane, wherein the cubic unit cell is tilted in the

[111] direction, Fig. 8 the projection according to Fig. 7, wherein the cubic unit cell tilted in the

[111] direction is additionally rotated about the x-axis by 11.8 degrees (rotation about the y-axis is equal to 0 degrees), Fig. 9 the projection according to Fig. 7, where the rotation about the x-axis is 23.5 degrees (rotation about the y-axis is equal to 0 degrees), Fig. 10 the projection according to Fig. 7, where the rotation about the x-axis is 35.3 degrees (rotation about the y-axis is equal to 0 degrees), Fig. 11 a projection of a cubic unit cell tilted in the

[111] direction, which is tilted about the x-axis by 35.3 degrees and about the y-axis by 22.5 degrees, Fig. 12 a projection of a cubic unit cell tilted in the

[111] direction, wherein the rotation about the x-axis is 35.5 degrees and the rotation about the y-axis is 45 degrees, Fig. 13 a first pole diagram, and Fig. 14 a second pole diagram, and Fig. 15 a third pole diagram. production of a <100> Texture in the z-direction or building direction (see Fig. 1)

[0042] To manufacture a component from a metal with cubic symmetry, a point pattern with quadratic point symmetry is chosen as the two-dimensional point pattern. Such a point pattern is generally known and does not need to be determined by intersecting the xy-plane with the unit cell. The points have a first spacing A1 in the x and y directions, where A1 = a. A suitable distance is chosen for a. This distance corresponds to the spacing of the melting points. This results in a symmetrical two-dimensional point pattern for creating the melting points in the xy-plane. To create another two-dimensional melting point pattern in the next xy-plane, the already generated symmetrical two-dimensional melting point pattern can be used. It is created in the next xy-plane in the z-direction in an identical arrangement. n denotes the normal vector.In this simple case, the displacement vector is zero, since there is no displacement of the 2-dimensional point pattern in the next xy-plane in the x- and / or y-direction. Continuing these steps results in a component where the crystals have a predominant orientation in the z-direction. <100> exhibit texture. production of a <110> Texture in the z-direction or building direction (see Fig. 2)

[0043] To manufacture a component from a metal with cubic symmetry, a point pattern with rectangular point symmetry is chosen as the 2-dimensional point pattern. The points in the y-direction have a first spacing A1 and in the x-direction a second spacing A2, where A2 = √2a. Such a point pattern is generally known; it does not need to be determined by an intersection of the xy-plane with the unit cell. This results in a symmetrical 2-dimensional melting point pattern for creating the melting points in the xy-plane. n denotes the normal vector. To create another 2-dimensional point pattern in the next subsequent xy-plane, the already generated symmetrical 2-dimensional point pattern can be used. To generate the further 2-dimensional point pattern, the melting points in the next xy-plane are shifted, for example, by a translation vector by a predetermined amount in the x- and / or y-direction.The specified amount depends on the distance d of the further xy-construction plane from the underlying xy-construction plane and the angle, here 45°, which the selected basis vector a. v , b v , c v with the z-direction.

[0044] In the further xy-plane, another 2-dimensional melting point pattern is created in the z-direction. This pattern is identical to the first 2-dimensional melting point pattern, but shifted relative to the first by the amount specified by the displacement vector in the x- and / or y-direction. Continuing these steps results in a component where the crystals in the z-direction predominantly form a <110> exhibit texture.

[0045] Fig. Figure 3 shows the construction of several layers s, s+1, s+2 using the diagram in Fig. The 2-dimensional pattern shown is shown in Figure 2. t describes the translation vector, n the normal vector.

[0046] The Fig. 4 and Fig. 5 show analogous to the Fig. 1 and Fig. 2 two-dimensional dot patterns. Fig. Figure 4 shows a third projection into an xy-plane for a cubic unit cell, Fig. Figure 5 shows a fourth projection into an xy-plane for a hexagonal unit cell.

[0047] production of a <111> Texture in the z-direction or building direction (see Fig. 7)

[0048] To manufacture a component from a metal with cubic symmetry, a point pattern with hexagonal point symmetry is chosen as the two-dimensional point pattern. Adjacent points in the hexagon have a second distance A2 = v2a. Such a point pattern is generally known and does not need to be determined by intersecting the xy-plane with the unit cell. This results in a symmetrical two-dimensional point pattern for creating the melting points in the xy-plane.

[0049] To create another 2-dimensional point pattern in the next subsequent xy-plane, the already generated symmetrical 2-dimensional point pattern can be used. To generate the additional 2-dimensional point pattern, the points of the symmetrical 2-dimensional point pattern are shifted, for example, by a translation vector, by a predefined amount in the x- and / or y-direction. The predefined amount depends on the distance d of the additional xy-plane from the underlying xy-plane and the angle formed by the selected basis vector a. v , b v , c v with the z-direction. Here, it is inclined at 54.74 degrees relative to the x-, y- and z-axes.

[0050] In the further xy-plane, a further 2-dimensional melting point pattern is produced in the z-direction. This pattern is identical to the 2-dimensional melting point pattern, but is shifted in the xy-projection by an amount in the x- and y-directions determined by the translation vector t. Continuing these steps results in a component in which the crystals predominantly form a [missing information - likely a specific pattern or configuration] in the z-direction. <111> exhibit texture.

[0051] In the process for manufacturing the <110> Texture can be the basis vector a v , b v , c v be inclined at +45° or -45° with respect to the z-direction. In the method for manufacturing the <111> Texture can be the basis vector a v , b v , c v be directed parallel to the 3 spatial directions of the cube diagonals ( Fig. 7) In these cases, one direction of the basis vector a can be v , b v, c, e.g., depending on the progress of construction, especially when a predetermined layer thickness is reached, may be changed.

[0052] The proposed method allows the creation of textures with virtually any orientation. This is achieved by rotating the unit cell in space around the x- and / or y-axis. The resulting symmetrical two-dimensional point patterns can be determined by the intersection points of the respective unit cell with the xy-plane or computationally (see Fig. 8 to 11).

[0053] A process for producing an isotropic texture can, for example, be carried out by the following steps: (i) Selection of a unit cell of the metal or alloy. (ii) Determining the position of the unit cell relative to the z-direction (iii) Determination of at least one symmetric 2-dimensional point pattern by an intersection of the xy-planar plane with the unit cell, (iv) Transformation of the symmetric 2-dimensional point pattern into an asymmetric 2-dimensional point pattern, e.g. by stochastic translation of at least a subset of the points, (v) Generating a further asymmetric point pattern for the next following xy-plane such that at least a further subset of the points of the further asymmetric point pattern are not congruent with the points of the symmetric point pattern in the z-direction.

[0054] The generation of the further asymmetric point pattern can be achieved, for example, by arranging its points in the gaps in the z-direction with respect to the asymmetric point pattern in such a way as to avoid the formation of a 3-dimensional symmetry.

[0055] The generation of the further asymmetric point pattern can also be achieved, for example, by translating the asymmetric point pattern into a non-coincident position relative to the asymmetric point pattern using a translation vector t. Advantageously, the direction of the translation vector t is changed from one xy-plane to the next xy-plane, thus ensuring an asymmetric arrangement of the points in 3-dimensional space.

[0056] The generation of a specific texture using the proposed method can be limited to at least a predetermined volume fraction. Different textures can also be produced in different volume fractions. This allows, for the first time, specific properties to be set in components within predetermined volume fractions. These properties can include mechanical properties, such as stiffness in the direction of load, magnetic properties, vibration properties, etc. Electron Beam-Based Additive Manufacturing (PBF-EB)

[0057] In the following embodiments, the nickel-based superalloy IN718 was processed using electron beam additive manufacturing (PBF-EB). The experiment was performed on a 15 kW PBF-EB system (PB-EBM 30S) from pro-beam GmbH & Co. KGaA (Gilching, Germany) at an acceleration voltage of 150 kV. The starting material used was a plasma-atomized powder of the nickel-based superalloy IN718 from Tekna Plasma Europe (Mäcon, France) with a particle size distribution between 45 µm and 105 µm. The chemical composition is listed in Table 1. Table 1 Chemical composition of IN718 powder Element Ni Cr Mo Nb Ti Al Fe Konzentration(Gew.%) 51,70 17,68 2,90 5,99 0,97 0,48 Balance.

[0058] The manufacturing process took place under a controlled, protective gas-free vacuum atmosphere at a pressure of 2×10 -5mbar. The process temperature was measured during manufacturing using a thermocouple attached to the underside of a base plate; a control system maintained a constant process temperature of 900 °C. Maintaining the process temperature was achieved primarily by a rapidly deflected and expanded electron beam during a preheating step. For the subsequent melting of the powder layer, the beam was focused to a full width at half maximum (FWHM) between 174 µm and 380 µm, between 174 µm and 380 µm. Texture analysis using electron backscatter diffraction (EBSD)

[0059] Electron backscatter diffraction (EBSD) is a microstructural crystallographic technique used in scanning electron microscopy (SEM) to determine the crystallographic orientation of materials. An electron beam is directed onto a tilted sample, causing backscattered electrons to form so-called Kikuchi patterns, which are detected by a phosphor screen detector. The Kikuchi patterns result from intersecting lines formed by constructive interference of the electrons scattered from the crystal lattice and satisfy Bragg's law. The Kikuchi patterns are analyzed to determine the crystal orientation at each scanned point.

[0060] EBSD provides detailed information about grain orientation, phase identification, and crystal structure. EBSD data were acquired using a NordlysNano detector from Oxford Instruments and visualized with AZTec software. Acceleration voltage was 20 kV, beam current 0.69 nA, and a step size of 5 µm with a sample tilt of 70°. EBSD data processing was performed using the open-source Matlab library MTEX. Orientation density function (ODF) polar figures were used to visualize textures. These represent the volume fraction ΔV(g) of crystals in a polycrystalline sample whose orientation g lies within a volume element dg of g relative to the total number of grains V in the measurement volume, according to equation (1). ODF(g)=ΔV(g) / Vdg

[0061] To make a quantitative comparison between the characteristics of different textures, the so-called texture index J is used. ODF used according to equation (2). JODF=∫|ODF(g)|2dg

[0062] A texture index of J means ODF = 1 a completely random distribution of grain orientations in the measurement volume (= isotropy). The larger J ODF The more pronounced the texture, the more pronounced the respective texture becomes. Example of a <111> Texture in the direction of build-up (see Fig. 7)

[0063] For the creation of the xy-dot pattern, a dot spacing of a = 200 µm was chosen. According to the rules of the invention, tilting the cubic unit cell by phi = 45° and theta = 35° (space diagonal of the cube in the build direction) results in a hexagonal dot pattern with a dot spacing of 282.84 µm. Furthermore, with a selected layer thickness d of 50 µm, a translation vector t = (35.36 µm, 61.24 µm, 50 µm) is obtained. The magnitude of the displacement vector in the xy-plane is 70.71 µm.

[0064] The individual points are melted at a point energy of 169 mJ, a point residence time of 308 µs and a beam width at half maximum of approximately 170 µm.

[0065] In Fig. Figure 13 shows the resulting texture as the first pole diagram or first ODF pole figure. It is a clear <111> Texture with threefold symmetry can be observed, corresponding to the dot pattern. The texture index J ODFis 1.67. The direction-dependent modulus of elasticity calculated from the ODF pole figure is 234 GPa in the assembly direction.

[0066] Example of a <100> Texture in the direction of construction (see Fig. 14) For the production of the xy-dot pattern, a dot spacing of a = 280 µm was chosen. The layer thickness d is 50 µm. According to the rules of the invention, a cubic dot pattern with a dot spacing of 280 µm results from the tilting of the cubic unit cell by phi = 0° and theta = 0° (surface normal of the cube in the build direction). The translation vector is t = (0 µm, 0 µm, 50 µm). Thus, the displacement vector in the xy-plane is (0 µm, 0 µm). The individual dots are melted at a dot energy of 261 mJ, a dot residence time of 348 µs, and a beam width at half maximum of approximately 380 µm.

[0067] In Fig. Figure 14 shows the resulting texture as the second pole diagram or second ODF pole figure. It is a clear <100> Texture can be observed. The texture index J ODF is 3.96. The direction-dependent modulus of elasticity calculated from the ODF pole figure is 129 GPa in the assembly direction. Example of an isotropic sample

[0068] For the production of the xy-dot pattern, a dot spacing of a = 141.4 µm was chosen. According to the rules of the invention, tilting the cubic unit cell by phi = 45° and theta = 35.3° (space diagonal of the cube in the build direction) results in a hexagonal dot pattern in the xy-build plane with a dot spacing AS2 = 200 µm. The translation vector t = (100 µm, 57.74 µm, 50 µm) chosen here differs significantly from the values ​​t = (35.36 µm, 61.24 µm, 50 µm) calculated according to the rules for the anisotropic case, each with a layer thickness of 50 µm.

[0069] The individual points are melted at a point energy of 65 mJ, a point residence time of 68 µs and a beam half-width of approximately 174 µm.

[0070] In Fig. The resulting texture is represented in Figure 15 as the third pole diagram or third ODF pole figure. The texture index J ODF The calculated value is 1.03. A texture index of 1 indicates a completely random distribution of grain orientations within the measurement volume. The direction-dependent Young's modulus calculated from the ODF is 202 GPa. This corresponds approximately to the literature value for IN718 in the isotropic state. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 3 482 853 A1

[0002] Cited non-patent literature

[0000] A. Plotkowsski, et al., A stochastic scan strategy for grain structure control in complex geometries using electron beam powder bed fusion, Additive manufacturing 46 (2021) 102092

[0005] Dehoff et al.; Site specific control of crystallographic grain orientation through electron beam additive manufacturing, Materials Science and Technology 31(8) 2015 931-938

[0006]

Claims

[1] Additive manufacturing process in which a layer made from a metal powder forms an xy-plane, which is solidified by means of an energy beam through the creation of melting points, A further layer, made from metal powder and applied in the z-direction on the layer, forms another xy build plane, which is solidified by creating further melting points. so that by repeating the aforementioned steps a component with a predetermined shape is formed from the solidified layers, characterized by , that to produce a predetermined texture in the component from the crystal structure of the metal used to produce the metal powder (a) determines a 2-dimensional point pattern for the xy-plane and (b) a rule for determining a spatial relationship between the 2-dimensional point pattern and at least one further 2-dimensional point pattern in which at least one further xy-plane is defined, the melting points in the xy plane are produced according to the 2-dimensional point pattern, and The further melting points in the subsequent xy-plane following in the z-direction are produced according to a further 2-dimensional point pattern, which results from applying the rule. [2] Additive manufacturing process according to claim 1, wherein, for the production of an anisotropic texture, a spatial arrangement of the melting points in the superimposed xy build planes is selected such that they correspond to the symmetry of the unit cell. [3] Additive manufacturing process according to one of the preceding claims, wherein, to determine the 2-dimensional dot pattern, a unit cell of the crystal structure is oriented relative to the z-direction according to the texture to be produced, one of the basis vectors a v , b v , c v is chosen and the intersection points of parallel to the basis vector a v , b v , c v , oriented lines with the xy-planar plane are determined, whereby the relative positions of the lines are determined by the unit cell and the distances between the lines are determined by the further basis vectors a v , b v , c v be defined. [4] Additive manufacturing process according to claim 3, wherein a is the basis vector v , b v , c v the basis vector a v , b v , c v The one chosen is the one with the largest component in the z-direction. [5] Additive manufacturing process according to one of the preceding claims, wherein the rule is given by a translation vector t which determines a position of the superimposed 2-dimensional point patterns relative to each other. [6] Additive manufacturing process according to one of the preceding claims, wherein one direction of the translation vector t is parallel to the selected basis vector a v , b v , c v is [7] Additive manufacturing process according to one of the preceding claims, wherein an amount of the translation vector t is determined as a function of a thickness d of the layers. [8] Additive manufacturing process according to one of the preceding claims, wherein, upon reaching a predetermined value for the translation vector t, a further translation vector t1 with a changed direction is used, wherein the changed direction is parallel to one of the further basis vectors a v , b v , c vis. [9] Additive manufacturing process according to one of the preceding claims, wherein the 2-dimensional dot pattern has a square point symmetry, wherein the points have a first distance A1, wherein A1 = a. [10] Additive manufacturing process according to any one of the preceding claims, wherein to form a <100> The texture in the z-direction is aligned with the translation vector t parallel to the z-direction. [11] Additive manufacturing process according to one of the preceding claims, wherein the 2-dimensional dot pattern has a rectangular point symmetry, wherein the points have a first distance A1 in a first direction and a second distance A2 in a second direction, wherein A2 = √2a. [12] Additive manufacturing process according to any one of the preceding claims, wherein to form a <110> The texture in the z-direction has the translation vector t inclined at 45° to the z-axis. [13] Additive manufacturing process according to one of the preceding claims, wherein the 2-dimensional dot pattern has a hexagonal point symmetry, wherein adjacent points of the hexagon have the second distance A2. [14] Additive manufacturing process according to one of the preceding claims, wherein to form a <111 >texture in the z-direction the translation vector t is inclined relative to the z-axis by 50° to 60°, preferably by 53° to 57°, particularly preferably by 54.7°. [15] Additive manufacturing process according to one of the preceding claims, wherein in the symmetrical 2-dimensional dot pattern a radius r of a melting point is chosen to be smaller than the smallest of the distances to the melting point two times further along. [16] Additive manufacturing process according to one of the preceding claims, wherein the production of the melting points according to a symmetrical 2-dimensional dot pattern takes place only in at least one predetermined surface section of the xy-building plane. [17] Additive manufacturing process according to one of the preceding claims, wherein an asymmetric dot pattern deviating from the symmetry of the unit cell is chosen to produce an isotropic texture as a 2-dimensional dot pattern. [18] Additive manufacturing process according to one of the preceding claims, wherein to produce the asymmetric 2-dimensional dot pattern the points of a symmetric 2-dimensional dot pattern are stochastically shifted by a fraction of the distance a. [19] Additive manufacturing process according to claim 18, wherein a further 2-dimensional dot pattern is selected which is different from the asymmetric 2-dimensional dot pattern. [20] Additive manufacturing process according to one of the preceding claims, wherein, to form an isotropic texture, the radius r of the melting points in the respective xy-point pattern is chosen to be larger than the distance to the next-but-one neighboring point. [21] Additive manufacturing process according to one of the preceding claims, wherein an electron beam or a laser beam is used as the energy beam. [22] Additive manufacturing process according to one of the preceding claims, wherein the distances between the adjacent points in the xy-plane are 50 to 500 µm. [23] Additive manufacturing process according to any of the preceding claims, wherein the unit cell is a cubic, face-centered cubic, body-centered cubic or hexagonal unit cell. [24] Device for the additive manufacturing of metallic components, prepared for carrying out the method according to one of the preceding claims.

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