METHOD FOR THE LAYER-BY-LAYER ADDITIVE MANUFACTURING OF A COMPOSITE MATERIAL

Abstract

A method for the layer-by-layer additive manufacturing of a composite material having the selective irradiation of a base material to produce a first, dense material phase and to produce a second, porous material phase, wherein the production of the first material phase and the production of the second material phase take place alternately. A correspondingly produced composite material and to a component has the composite material.

Claims

1. A method of layer-by-layer additive manufacture of a composite material, comprising: selectively irradiating a base material for production of a first, dense material phase, and for production of a second material phase having a porosity, wherein the production of the first material phase and the production of the second material phase alternate, and wherein the first material phase and the second material phase are produced alternately within a layer for the composite material.

2. The method as claimed in claim 1, wherein the first material phase is produced by complete melting of the base material, and the second material phase is produced by sintering of the base material.

3. The method as claimed in claim 1, wherein the first material phase and the second material phase are produced alternately in a build direction of the composite material.

4. The method as claimed in claim 1, wherein both the first material phase and the second material phase are metallic.

5. The method as claimed in claim 1, wherein the composite material is produced by selective laser melting.

6. The method as claimed in claim 5, wherein an energy input during the production of the composite material is altered at the changeover from the production of the first material phase to the production of the second material phase.

7. The method as claimed in claim 5, wherein an energy input during the production of the composite material is reduced at the changeover from the production of the first material phase to the production of the second material phase.

8. The method as claimed in claim 1, wherein the production of the second material phase is effected only by a subsequent heat treatment.

9. A composite material, produced by a method as claimed in claim 1, comprising: the first material phase and the second material phase, wherein regions of the second material phase connect regions of the first material phase in at least one direction of expansion of the material.

10. The composite material as claimed in claim 9, wherein the regions of the first material phase are largely or effectively in the form of hexagonal platelets, and wherein the regions of the second material phase are present in the interstices in the regions of the first material phase.

11. The composite material as claimed in claim 9, wherein the base material is a nickel- or cobalt-based superalloy.

12. A component comprising: the composite material as claimed in claim 9, wherein the component is a turbine blade or another component in the hot gas path of a gas turbine.

13. A turbine comprising: the component as claimed in claim 12.

14. The composite material as claimed in claim 11, wherein the base material comprises Mar M 247 or In939.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 shows a schematic section view of an additive manufacturing system, indicating an additive, powder bed-based build process.

[0047] FIG. 2 shows, in a simplified schematic section view, a composite material of the invention.

[0048] FIG. 3 shows, in a simplified schematic top view, a composite material of the invention.

[0049] FIG. 4 indicates, by a schematic diagram, process steps of the invention.

[0050] FIG. 5 indicates, in a simplified view, a turbine component comprising the composite material of the invention.

DETAILED DESCRIPTION OF INVENTION

[0051] In the working examples and figures, elements that are identical or have the same effect may each be given the same reference numerals. The elements shown and their size ratios to one another should fundamentally not be considered as being to scale; instead, individual elements, for better illustratability and/or for better understanding, may be shown as being excessively thick or in oversized form.

[0052] FIG. 1 shows a plant or apparatus (not indicated explicitly) for layer-by-layer or additive manufacture of a component or workpiece 10.

[0053] The component 10 may be a three-dimensional body produced or producible according to any predetermined geometry, which is built by a multitude of individual layers (cf. reference sign L in FIG. 2), for example by means of a beam melting method, such as selective laser melting (SLM), selective laser sintering (SLS) or electron beam melting (EBM).

[0054] Component 10 may be a turbine component, for example a part used in the hot gas path of a gas turbine, especially made from a nickel- or cobalt-based superalloy.

[0055] In FIG. 1, component 10 is advantageously built up produced only partly and not to completion, i.e. is shown during its additive manufacture.

[0056] The system further comprises a coating device 4 for layer-by-layer provision of a powder or base material P for the component 10. The system further comprises vessels (see left and right in the drawing) in which the base material P is advantageously kept for layer-by-layer production of the component 10 and for the corresponding supply and removal.

[0057] The system comprises a build platform 5. The build platform 5 is advantageously configured so as to be lowerable.

[0058] The system also includes an irradiation device 3, for example a laser or an electron beam device.

[0059] In the method of additive manufacture which is also described with reference to FIG. 4, there is layer-by-layer application of base material P and solidification of the (applied) starting material 8, advantageously in succession, such that the component 10 is built/produced step by step in a build direction Z.

[0060] The base material P is advantageously a metallic base material. Alternatively, it may be a ceramic material. In addition, the material may be a material having metallic and ceramic material properties and/or what is called an MCrAlY alloy or a “cermet” material.

[0061] After the production or the build of a single layer for the workpiece 1, the build platform 5 is further lowered, advantageously by a measure corresponding to the layer thickness L, followed by individual melting, for example with a laser beam, and solidification. Typically, in the case of such powder bed-based processes, a layer thickness may be between 20 and 40 μm. According to the predetermined dimension, selective irradiation of several thousand or several tens of thousands of individual layers may thus be necessary.

[0062] In the SLM method, in the course of solidification, a powder bed is especially scanned point by point, line by line, or over its area, and/or is advantageously irradiated according to a defined irradiation geometry comprising a multitude of irradiation vectors. Corresponding data for the exposure geometry are advantageously taken from a CAD file or a corresponding dataset.

[0063] As an alternative to the SLM method, the layer-by-layer production method may relate to selective laser sintering (SLS) or electron beam melting (EBM).

[0064] FIG. 2 shows a schematic side view or section view of a component 10. The component 10 has, at its top end or tip, a composite material V. The composite material V is advantageously additively manufactured by the method described with reference to FIG. 4.

[0065] This configuration of the component 10 or composite material V may, for example, represent a turbine blade or part thereof.

[0066] The composite material V has a first material phase 1 and the second material phase 2, with regions of the second material phase 2 connecting regions of the first material phase 1 in at least one direction of expansion, in the present configuration the vertical z direction.

[0067] Without restriction of generality, the sequence of layers or material phases 1 and 2 may be arranged or formed in any other spatial direction or main direction of extension (cf. reference signs X, Y) of the corresponding component.

[0068] More particularly, component 10 may accordingly comprise a layer stack of layers 1 and 2. A layer thickness is identified by way of example by reference sign L. Even though this is not shown explicitly, the layer thickness of layers 1 may differ from that of layers 2. Moreover, the layer thicknesses of the layers in the stack may vary overall.

[0069] The layers 1 are advantageously the first material phase 1. The layers 2 are advantageously the second material phase 2. Accordingly, the layers and the material phases may be referred to synonymously. Advantageously, a layer at least partly or completely comprises the correspondingly identified material phase.

[0070] The layer stack shown may, for example, be a sandwich structure at the tip of a turbine blade.

[0071] The second material phase or arrangement thereof may correspond to that of a matrix into which the first material phase is embedded.

[0072] In the diagram of FIG. 2, the matrix of the second material phase may be an interlamellar matrix.

[0073] The first material phase 1 advantageously has a dense material structure without significant porosity.

[0074] The second material phase advantageously has a certain porosity.

[0075] In other words, the blade tip described advantageously alternately has completely or largely dense and porous layers, with the dense layers 1 having been produced by complete melting with an energy beam (cf. reference numeral 3 in FIG. 1), and the porous layers 2 by merely partial melting, sintering or partial sintering. This appropriately leaves a certain porosity in the layers 2.

[0076] Even though the turbine blade tip described can have reduced strength, for example by comparison with a volume material with a completely molten structure, crack propagation characteristics in particular in radial (vertical) direction are improved. In addition, in the case of a correspondingly chosen alloy, for example what is called “Alloy247” Mar-M247, In939 (“Inconel 939”), In738 or Rene 80, it is possible to achieve improved oxidation stability or improved high-temperature stability.

[0077] An advantageous application may, as shown, be a turbine blade tip in the high-temperature sector, for example the first or second turbine stage.

[0078] FIG. 3 indicates, by a schematic top view, an alternative configuration of the composite material V of the invention. Again, regions of the first material phase 1 and of the second material phase 2 are shown.

[0079] By contrast with the diagram of FIG. 2, the regions of the first material phase 1 are largely or effectively in the form of hexagonal platelets, and the regions of the second material phase 2 are disposed in interstices of the regions of the first material phase 1, and connect them.

[0080] The technical advantages of the composite materials presented in the embodiments described so far, or correspondingly formed hierarchical structures of material phases, are that the intrinsic stresses that occur in the additive building process, and also those that occur only subsequently in the operation as intended or the use of the component, can advantageously be reduced.

[0081] More particularly, it is possible by suitable mutual arrangement of the first and second material phases to create anisotropic, tailored or improved crack propagation characteristics. The typical effects of the shear strengthening that are utilized in composite materials, for example comprising a crack deflection, crack attenuation or crack bridging function, what is called “pullout” of the (completely) dense regions and sliding of the corresponding layers, can advantageously likewise be utilized in the material created in the present context.

[0082] The configuration indicated by way of example by FIG. 3 may especially be designed similarly to a natural mother-of-pearl material or emulated correspondingly.

[0083] For example, a proportion by volume or mass of the first material phase 1 may be between 80% and 95% of the composite material V. Accordingly, the corresponding proportion of the second material phase 2 may be between 5% and 20% in the composite material V. The first material phase 1 may—as shown—be in the form of regions of hexagonal platelets having dimensions or diameters of 5 to 15 μm and heights corresponding to one or more layer thicknesses L.

[0084] According to the diagram in FIG. 3, the matrix of the second material phase may be an intertabular matrix.

[0085] FIG. 4 indicates, by a schematic diagram, a method of the invention for layer-by-layer additive manufacture of a composite material V. The method comprises a), the selective irradiating of the base material P for production of the first dense material phase 1, and for production of a second porous material phase 2, wherein the producing of the first material phase 1 and the producing of the second material phase 2 are effected alternately or successively.

[0086] Method step aa) is supposed to indicate that an energy input, which can be established by way of the additive methods described, for example, via regulation or control of the radiative output or of the energy density correspondingly introduced in time or space in the process, can be altered at the changeover from the production of the first material phase 1 to the production of the second material phase 2.

[0087] In method step ab), an energy input can especially be reduced during the production of the composite material V at the changeover from the production of the first material phase 1 to the production of the second material phase 2 (see above).

[0088] More particularly, by way of the described production of the second material phase 2, this can be solidified only in a step downstream of the actual additive build, especially by a subsequent heat treatment (cf. reference sign ac)).

[0089] The fixing of irradiation parameters, comprising the described energy input into a powder bed composed of the base material P mentioned, can be effected directly by way of a preparation step for the actual additive manufacture. Especially the fixing or assignment of specific build parameters, such as the layer thickness L or the energy input mentioned (not identified explicitly) relative to geometric data (CAD) of the component 10, can be effected by way of a CAM method.

[0090] The advantages of the invention are thus possibly manifested even in a preparation for manufacture, and can be distributed and utilized in the form of functional CAM data. Accordingly, the method specified, indicated by the reference sign CPP, may be at least partly computer-implemented.

[0091] FIG. 5 indicates, by a schematic view, a component 10 in a further configuration. What is shown more particularly is that the component described may relate to a housing portion of a turbo machine, for example a gas turbine. The advantageous anisotropic crack propagation characteristics described, or improved material characteristics with regard to crack propagation, may be exploited in at least one fixed direction of the component, for example in radial direction or in circumferential direction.

[0092] It is apparent that a curved portion of the housing consists of or comprises the composite material V. The structures identified by dotted lines in this portion, in the present context, are intended to identify the first material phase 1, which, in the embodiments described in FIGS. 2 and 3, may be arranged either in layers one top of another or in one and the same layer alternately with an otherwise unspecified second material phase.

[0093] This configuration advantageously enables improvement of propagation of cracks that are possibly already initiated during the additive manufacture, both in circumferential direction of the arc identified in FIG. 5 and radially thereto.

[0094] Alternatively, the component 10 may be another component of a turbo machine, for example a component which is used in the hot gas path of a turbo machine, for example a gas turbine. In particular, the component may refer to a blade or vane, a ring segment, a burner part or a burner tip, a shroud, a shield, a heat shield, a nozzle, a seal, a filter, an opening or probe, a resonator, a ram or a cyclone, or a corresponding transition or insert or a corresponding retrofitted part.

[0095] The invention is not limited to the working examples by the description with reference thereto, but encompasses any novel feature and any combination of features. This especially includes any combination of features in the patent claims, even if this feature for this combination is not itself specified explicitly in the patent claims or working examples.