JP2016502589A - Additive manufacturing of turbine components with multiple materials - Google Patents

Abstract

This is a method of additive manufacturing using a plurality of materials. First region shape (73), second region shape (74), and third region shape (75) of adjacent final material (30, 44, 45) at a given cut surface of component (20), respectively The first adjacent powder layer (48), the second adjacent powder layer (50), and the third adjacent powder layer (52) are supplied onto the work surface (54A). The first powder may be a structural metal supplied in the cross-sectional shape of the airfoil substrate (30). The second powder may be a bonding paint material supplied in a cross-sectional shape of the bonding paint (45) on the substrate. The third powder may be a thermal barrier ceramic supplied to the cross-sectional shape of the thermal barrier coating (44). By applying a specific laser intensity (69A, 69B) to each layer, the layer is melted or sintered. An integrated interface (57, 77, 80) may be formed between adjacent layers by overlapping gradient materials and / or alternating protrusions.

Description

  The present invention relates to additive manufacturing, and in particular to the production of multi-material metal / ceramic gas turbine components by selective laser sintering and selective laser melting of adjacent powder layers of different materials.

  This application is filed on Oct. 8, 2012 of US Provisional Patent Application No. 61 / 710,995 (Attorney Docket No. 2012P24077US) and US Provisional Patent Application No. 61 / 711,813 (Attorney Docket No. No. 2012P24278US), the benefit date of October 10, 2012, both of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Selective additive manufacturing builds a stack of components by selective laser melting (SLM) and selective laser sintering (SLS) of a powder bed to achieve a net shape or an approximate net shape. A powder bed of the final or precursor material of the component is deposited on the work surface. Creating a layer or flake of a component by selectively guiding laser energy to the powder bed according to the cross-sectional area shape of the component then becomes the new work surface for the next layer. Conventionally, the powder bed has spread over the entire work surface in the first step, and in subsequent steps the component cross-sectional area on the floor is defined or “painted” with a laser, for example by raster scanning.

  In a related process, often referred to as microcladding, the powder is deposited on the component by a feeding device such as a moving nozzle. As the powder is melted simultaneously at the deposition point by the laser, a material bead is formed on the component as the feeder moves. Continuous passes also allow the construction of one or more material layers for component repair or manufacturing.

  The inventors of the present invention have devised an additive manufacturing method for components having a plurality of adjacent materials having different characteristics. In this way, a net shape or an approximate net shape is obtained that strongly joins adjacent materials ranging from metal to ceramic. This is particularly beneficial for the manufacture of gas turbine components such as superalloy blades and vanes with ceramic thermal barrier coatings. Such airfoils are difficult to manufacture due to the complex shape with serpentine cooling channels lined with turbulators and film cooling holes.

  In the following description, the present invention will be described with reference to the drawings.

It is sectional drawing of the gas turbine blade of a prior art. It is sectional drawing of the powder supply apparatus which forms an adjacent powder layer on a working surface. It is sectional drawing of the laser beam which fuse | melts and sinters an adjacent powder layer. FIG. 7 shows a pattern of scan paths for powder supply and / or laser supply parallel to a nonlinear cross-sectional profile of a component. It is the figure which showed another scan pattern which has a parallel linear path. FIG. 5 is a diagram showing a scan path perpendicular or substantially perpendicular to a component wall. FIG. 3 shows a second flake formed on a first flake of a component. It is the figure which showed the adjacent powder layer deposited by different thickness. It is the figure which showed the interface which interlock | cooperates between adjacent materials. 3 is a flowchart illustrating aspects of one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a leading edge 22, a trailing edge 24, a pressure side 26, a suction side 28, a metal substrate 30, a cooling channel 32, a partition wall 34, a turbulator 36, a film cooling discharge hole 38, a cooling pin 40, and 2 is a cross-sectional view of a typical gas turbine airfoil 20 having a trailing edge discharge hole 42. FIG. The outside of the airfoil substrate is covered with a ceramic thermal barrier coating 44. A metal bonding paint 45 may be applied between the substrate and the thermal barrier coating. Turbulators are protrusions, depressions, ridges, or depressions in the cooling channel 32 that increase the surface area and stir the fluid boundary layer of the refrigerant flow.

  FIG. 2 illustrates the first adjacent powder layer 48, first, second, and third region shapes of the first, second, and third adjacent final materials at a given cut surface of the component. 2 illustrates a process and apparatus for supplying two adjacent powder layers 50 and a third adjacent powder layer 52 onto a work surface 54A. For example, the first powder layer 48 may be a structural metal supplied to the region shape of the airfoil substrate 30 shown in FIG. The second powder layer 50 may be a bonding paint supplied adjacent to the first powder 48 in the region shape (FIG. 1) of the bonding paint 45 on the substrate. The third powder layer 52 may be a thermal barrier ceramic supplied adjacent to the second powder in the region shape of the thermal barrier coating 44 (FIG. 1).

  By providing an interface 56 between the first and second powder layers, an overlapping region 57 that provides a material gradient transition between the two adjacent powder layers 48 and 50 may be formed. In addition, by supplying an interface 58 between the second and third powders 50 and 52, an engineered mechanical interlocking unit such as alternating fingers protruding alternately from the second and third powders is formed. You may make it (it mentions later). The powder supply device 60 may have one or more nozzles 62 that supply a powder spray 64 to the focal point 66.

  The powder feeder 60 incorporates a multi-axis movement 61 relative to the work surface 54A so that the nozzle follows a non-linear cross-sectional profile in a given horizontal plane and moves to different planes or distances relative to the work surface 54A at various angles. It may be possible to supply the powder. These axes may be realized by movement of the worktable 55 and / or the powder supply device 60 via a track and rotary bearing under computer control. In addition, powder supply parameters such as nozzle translation speed, mass supply speed, and spray angle may be determined in advance by discrete particle modeling simulation to optimize the final flake shape. The sprayed powder may be compressed and stabilized by means such as electromagnetic energy and / or mechanical or acoustic vibration prior to laser heating.

  The powder may be kept in the desired form until it is agglomerated flakes of the component by laser melting or laser sintering by wetting with water, alcohol, lacquer or binder before or during spraying. By including a flux material in the powder material, as detailed in US Patent Application Publication No. 2013/0140278 A1 (Attorney Docket No. 2012P22347US), a co-pending application incorporated herein by reference, The cladding process may be facilitated.

  FIG. 3 shows a process and apparatus for melting and / or sintering different powder layers 48, 50, 52 with different laser energies. For example, the substrate superalloy powder 48 and the bonding paint powder 58 are melted by the first and second laser energy, and the ceramic heat shielding powder 52 is sintered by the third laser energy that melts only a part of the ceramic particles. You may do it. Further, the different laser energies 69A and 69B may be supplied by a single laser emitter 68A having a variable output or a plurality of laser emitters 68A and 68B performing different outputs for different powder layers. The laser emitter follows a non-linear cross-sectional profile in a given plane by incorporating a multi-axis movement 70 relative to the work surface 54A and moves to a different plane or distance relative to the work surface 54A to achieve the desired angle and spot size. The laser beam may be positioned and guided.

  FIG. 4 shows the pattern of the path 72 following the non-linear cross-sectional profile 73, 74, 75 of the component 20. The powder supply focal point 66 of FIG. 2 may be controlled to follow such a path. Such a scan pattern 72 that is parallel to the cross-sectional profile enables the powder type to be changed for each of the powder layers 48, 50, 52.

  Further, the laser energies 69A and 69B (FIG. 3) may follow a non-linear scan path such as 72 in FIG. Such a path can minimize the number of laser intensity changes for different powder materials. The first laser energy is guided so as to follow the contour of the cross-sectional shape 73 of the first powder layer 48, and the second laser energy is followed so as to follow the contour of the cross-sectional shape 74 of the second powder layer 50. The third laser energy may be guided so as to follow the contour of the cross-sectional shape 75 of the third powder layer 52. The laser may be circulated off as it passes over areas that will remain as cavities in the formed component, such as film cooling holes 38.

  FIG. 5 shows another scan pattern having parallel linear paths 74 of laser energy. FIG. 6 shows a scan path 76 that is perpendicular or substantially perpendicular to the wall of the component. Patterns 74 and 76 may require an off / on circulation for cavity 38 as well as a change in laser intensity at each intersection with interfaces 56 and 58 for different powder layers. The spacing between the scans 72, 74, 76 is determined by the width or spot size of the laser beam at the powder surface. The number of scans may be reduced by using a plurality of laser emitters together to generate a wider area. Laser beam reduces scan spacing and spot size by adjusting the width by changing the distance of the light emitter from the work surface and / or adjusting the size and shape with an adjustable lens, mirror, or mask Rather, it may better define small, sharp, or curved elements of components such as fillets.

  FIG. 7 shows a first solidified flake 74 of a component that provides a new work surface 54B, and a second flake 76 of the component is obtained by applying a powder layer 48, 50, 52 thereon.

  FIG. 8 shows the powder layers 48, 50, 52 supplied at different heights depending on the respective process shrinkage in order to finally achieve a uniform flake thickness. The powders of the first adjacent layer 48 and the second adjacent layer 50 may be deposited in the overlapping region 57 so as to overlap and form a gradient material transition. The overlapping width may be at least 0.2 mm, for example. Further, the powders of the second adjacent layer 50 and the third adjacent layer 52 may also be deposited in the overlapping region 77 so as to overlap and cause a gradient material transition. The overlap width may be for example at least 0.2 mm or 0.4 mm, or a maximum of 1 mm or a maximum of 2 mm.

  FIG. 9 shows the second layer 50 and the third layer 52 in which an engineering interlocking mechanism 80 such as an alternating profile forming a three-dimensional alternating finger protruding alternately from the bonding layer 50 and the ceramic layer 52 is formed. The interface is shown. Such a mechanically interlocking interface may be provided as an alternative or addition to the gradient material region 77 shown in FIG. A crack 82 may be formed in the ceramic layer 52 to relieve the tension during operation by circulating the laser energy off / on when the ceramic layer 52 is scanned. Further, the material of the ceramic layer 52 may include a hollow ceramic sphere 84 to suppress thermal conductivity. When a hollow ceramic sphere is included in the heat-insulating layer 52, since the cavities of the sphere are not reduced by sintering during operation, the thermal conductivity is permanently suppressed.

FIG. 10 is a flowchart of a method 84 illustrating aspects of an embodiment of the present invention,
86. Providing a plurality of adjacent powder layers of different materials on the work surface at each region shape representing a given cut surface of the multi-material component;
88. Forming a gradient material transition region between at least two adjacent powder layers by superimposing on at least two of the adjacent powder layers;
90. Applying a specific laser energy to each of the powder layers to melt or sinter the layers, wherein at least two of the layers receive different laser intensities;
92. Producing a component by selective additive manufacturing by repeating from step 86 on successive cut surfaces;
including.

  In some embodiments, the sintering temperature of the ceramic layer can be as low as 350 ° C. by including nanoscale ceramic particles. This facilitates co-sintering and joining of the metal and ceramic layers. The temperature drop occurs particularly when particles having an average diameter of less than 100 nm are contained in the ceramic powder at least 2% by volume and at most 100% by volume, particularly when the particles have an average diameter of less than 50 nm. According to this method, sintering can be performed only by partially melting such nanoparticles. This is not possible when applying ceramic coatings by thermal spray techniques. This is because smaller particles tend to melt completely.

  Nickel-based superalloys used in hot gas turbine components are often strengthened with a gamma prime precipitant phase in a gamma phase matrix. These superalloys are difficult to manufacture and repair due to their high temperature environmental durability. However, according to the method described herein, it is possible to manufacture and bond to adjacent layers of different materials such as ceramics. Casting gas turbine blades having serpentine channels with turbulators and film cooling and discharge holes is difficult and expensive. The method reduces costs while more fully bonding different material layers. This allows the entire multi-material component, such as a turbine blade, to be manufactured in a single process, instead of coating the superalloy blade after a separate process such as thermal spraying.

  While various embodiments of the present invention have been illustrated and described above, it will be apparent that these embodiments have been provided as examples only. Various modifications, changes and substitutions can be made without departing from the invention. Accordingly, the invention is limited only by the spirit and scope of the appended claims.

20 Gas Turbine Airfoil 22 Leading Edge 24 Trailing Edge 26 Pressure Side 28 Suction Side 30 Metal Substrate 32 Cooling Channel 34 Bulkhead 36 Turbulator 38 Film Cooling Discharge Hole 40 Cooling Pin 42 Trailing Edge Discharge Hole 44 Ceramic Thermal Barrier Coating 45 Metal Bonding Paint 48 First Adjacent Powder Layer 50 Second Adjacent Powder Layer 52 Third Adjacent Powder Layer 54A Work Surface 54B Work Surface 55 Work Table 56 Interface 57 Superposition Area 58 Interface 60 Powder Supply Device 61 Multiaxial Movement 62 Nozzle 64 Powder Spray 66 Focus 68A Laser emitter 68B Laser emitter 69A Laser energy 69B Laser energy 70 Multi-axis movement 72 Scan pattern 73 Non-linear cross-sectional shape profile 74 Non-linear cross-sectional shape profile 75 Non-linear cross-sectional shape profile 76 Thin piece 77 Overlapping region 80 Interlocking mechanism 2 crack 84 hollow ceramic spheres

Claims (20)

A method of making a component,
Providing a plurality of adjacent powder layers of different powder materials on the work surface, with each region shape representing each final material at a given cut surface of the multi-material component;
Forming a material gradient region between the at least two adjacent powder layers by overlapping at least two of the adjacent powder layers;
A first laser energy having a first intensity is applied to the first powder layer of the powder layer, and a second laser energy having a second different laser intensity is applied to the second powder layer of the powder layer. And steps to
Producing the component by repeating from the supplying step on successive cut surfaces of the component;
Including methods.   The first powder layer includes a metal, the second powder includes a thermal barrier ceramic, and the first powder layer follows a first plurality of scan paths parallel to a non-linear outer periphery of the first powder layer. 2. The method of claim 1, wherein the second laser energy is guided to follow a second plurality of scan paths parallel to a non-linear outer periphery of the second powder layer.   Forming a channel through the first and second final materials by cycling the first and second laser energies while following the first and second scan paths. The method of claim 2 comprising.   The method of claim 2, further comprising forming a strain relaxation crack in the second final material by cycling the second laser energy on and off while following a second scan path.   Supplying the first and second powder materials onto the work surface via alternating profiles to form a mechanically interlocking interface between the first and second final materials; The method of claim 1, further comprising forming alternating fingers throughout.   The first and second powder layers are deposited on the work surface at first and second thicknesses, respectively, and the laser energy is predetermined to thereby determine the final at the given cut surface. The method of claim 1, further comprising thinning the powder layer to a uniform thickness of material.   Providing the first and second laser energies by a laser beam guided along a continuous linear scan path that respectively passes over the first and second powder layers; and The method of claim 1, further comprising: providing the first and second intensities by changing the intensity of a laser beam.   A product formed by the method of claim 1. A method of making a component,
Each powder of the first, second, and third adjacent layers of different materials in a first, second, and third region shape that represents a given multi-material cut surface of the component in combination. Supplying on the work surface,
The first powder layer comprises a structural metal material, the second powder layer comprises a bonding paint material, and the third powder layer comprises a thermal barrier ceramic;
Melting or sintering the layer by applying specific laser energy to each of the powder layers, wherein at least two of the layers are each subjected to different laser intensities;
Producing the component by selective additive manufacturing by repeating from the supplying step on a continuous cut surface;
Including methods.   The method of claim 9, further comprising forming a channel in the component by cycling the laser energy on and off while following a scan path parallel to each profile of the region shape.   Guide the first laser energy to follow a scan path parallel to the profile of the first shape and guide the second laser energy to follow a scan path parallel to the profile of the second shape. The method of claim 9, further comprising guiding a third laser energy to follow a scan path parallel to the profile of the third shape.   The method of claim 11, further comprising forming a strain relief crack in the thermal barrier ceramic by cycling the third laser energy on and off.   By supplying the second and third powders onto the work surface via an alternating profile, a mechanically interlocking interface is formed between the second and third layers, thereby providing an alternating finger at the interface. The method of claim 11, further comprising: forming.   The method of claim 9, further comprising forming a gradient material region by overlapping the first and second powders by at least 0.2 mm.   The method of claim 11, further comprising forming a gradient material region by overlapping the second and third powders by at least 0.4 mm.   The first and third layers are deposited on the work surface with first and second different thicknesses, respectively, and the three powders are made to a uniform material thickness by defining respective intensities of the laser energy. The method of claim 11, further comprising thinning the layer.   Providing the first, second, and third laser energy by a laser beam guided along a continuous line that respectively passes over the first, second, and third layers; 12. The method of claim 11, further comprising providing the specific energy of each powder layer that intersects the line by changing the intensity of the laser beam along the line. A method of making a gas turbine component comprising:
First, second, and third adjacency in first, second, and third region shapes of first, second, and third adjacent final materials at a given cut surface of the component Supplying a powder layer on the work surface;
The first material comprises a structural metal, the second material comprises a bond paint metal, and the third material comprises a thermal barrier ceramic;
Melting the first and second powder layers with first and second laser energies, respectively, and melting only a portion of the third powder layer with third laser energies, Forming a new work surface by solidification;
Producing the component of the structural metal with a porous ceramic thermal barrier layer by repeating from the supplying step on a continuous cut surface;
The first laser energy is guided to follow the contour of the first shape, the second laser energy is guided to follow the contour of the second shape, and the third shape of the third shape is guided. Guiding the third laser energy to follow a contour; and
Including methods. Forming a gradient material interface between the first and second layers by overlapping at least 0.2 mm on the first and second powders;
By supplying the second and third powders onto the work surface via an alternating profile, a mechanically interlocking interface is formed between the second and third layers, thereby alternating the entire interface. Forming fingers,
The method of claim 18, further comprising:   20. A product formed by the method of claim 19.

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