WO2012097794A1

WO2012097794A1 - Generatively produced turbine blade and device and method for producing same

Info

Publication number: WO2012097794A1
Application number: PCT/DE2012/000019
Authority: WO
Inventors: Stefan NEUHÄUSLER; Bertram Kopperger; Josef WÄRMANN; Andreas Jakimov; Erwin Bayer; Wilhelm Meir
Original assignee: Mtu Aero Engines Gmbh
Priority date: 2011-01-19
Filing date: 2012-01-11
Publication date: 2012-07-26
Also published as: DE102011008809A1; EP2665570A1; US20130287590A1

Abstract

The invention relates to a method for producing gas turbine components, in particular aircraft turbine components, preferably low-pressure turbine blades made of a powder sintered selectively in layers by locally limited introduction of radiant energy, wherein the sintering is carried out in a closed first housing (2), so that a defined atmosphere can be set, wherein the powder or at least one part of the powder is generated in the same first housing (2) or in a second housing connected to the first housing in a gas-tight manner. The invention further relates to a corresponding device and to a gas turbine blade produced thereby.

Description

GENERATIVELY MANUFACTURED TURBINE SHOVEL AND DEVICE AND METHOD FOR THE PRODUCTION THEREOF

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to a process for the production of gas turbine components, in particular air turbine components, preferably low-pressure turbine blades made of a powder, which is selectively sintered in layers by localized introduction of radiant energy. Moreover, the invention relates to an apparatus for producing gas turbine components, in particular according to a corresponding method, and a gas turbine blade produced therewith, in particular low-pressure turbine blades made of a TiAl material.

STATE OF THE ART

So-called rapid prototyping or rapid manufacturing methods, ie methods for the rapid production of prototypes or for the rapid production of components, which utilize so-called generative manufacturing methods, are known from the prior art. In this case, three-dimensional structures are produced by selective sintering of powder, for example by means of laser or electron beams, which are guided over layered powder.

Such methods have been proposed for a variety of materials and for a variety of components, especially aircraft turbine components. Examples of this are in DE

103 19 494 AI, DE 10 2006 049 216 AI, DE 10 2004 057 865 AI, DE 10 2008 027 315 AI and

DE 109 03 436 C2 called.

However, the methods and devices described there have several disadvantages. For example, not all components can be made of all possible materials, because impurities can be introduced by the type of generative production, which lead to an unfavorable property profile, which is unacceptable for the intended application. Especially with titanium aluminide materials, for example, for

Low-pressure turbine blades can be used in aircraft engines Impurities lead to embrittlement, which make an employment in the aviation turbine construction impossible. Accordingly complicates or prevents in the worst case, the risk of

Incorporation of impurities a possible use of generative

Manufacturing process in the manufacture of turbine blades of titanium aluminides or alloys thereof.

In addition, it must be ensured at the same time that the production costs remain low in order to achieve economical production of the components. Especially with generative manufacturing processes, long processing times can mean that they can no longer be used economically.

DISCLOSURE OF THE INVENTION

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide a method for producing gas turbine components, in particular air turbine components, preferably low-pressure turbine blades made of titanium aluminide materials, which enables the production of a corresponding component with a desired property profile and at the same time is economical.

TECHNICAL SOLUTION

This object is achieved by a method having the features of claim 1, a device having the features of claim 8 and a gas turbine blade having the features of claim 9 or 10. Advantageous embodiments are the subject of the dependent claims.

The present invention is based on the idea that an advantageous production of gas turbine components, in particular turbine components, such as preferably low-pressure turbine blades made of very reactive materials, such as titanium aluminides, can be done in a generative manufacturing process, if it can be ensured that the starting powder used in generative manufacturing process has a corresponding purity. According to the invention, this is achieved in that the powder manufacturing process directly to the generative manufacturing process, ie a selective laser or electron beam sintered upstream, it being ensured that the produced starting powder is exposed between the powder production and the generative production of the component no unfavorable ambient atmosphere containing, for example, 5 oxygen. This avoids that the powder used, so for example, the very reactive Titanaluminide, can react with oxygen from the ambient atmosphere. This in turn means that the powder particles do not form oxide layers, such as thin alumina or titanium oxide layers in the case of TiAl, which would then lead to the introduction of oxygen into the device during sintering of the powder. Accordingly, it is provided that the powder production and the additive component manufacturing process be carried out in a defined atmosphere. This can be achieved if both

Sub-steps, namely powder production and generative manufacturing process in a single, gas-tight lockable housing or in two gas-tight interconnected housings are performed so that the powder produced in the first step does not have to leave the defined atmosphere before the production of the 15 component. This makes it possible to do that

To produce powder in very pure quality and to process it with the same purity by means of the generative manufacturing process to a component.

By avoiding exposure of the powder to ambient atmosphere, and in particular avoiding contact of the powder with oxygen or other gases of the normal ambient atmosphere and the associated avoidance of the formation of oxide layers or other reaction products, it is also possible to process very fine powder due to its high surface area in conventional

Manufacturing process to a high impurity or oxygen content of

would lead to the component to be manufactured.

For the method according to the invention and a correspondingly constructed device, the selective laser beam sintering or electron beam sintering can be used as a generative production method.

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In both methods, multiple radiation beams can be generated simultaneously, thereby ensuring short process times, which increases the economics of the process. In addition, radiation of high power density is generated in both types of radiation, so that only short irradiation times for the corresponding sintering of the powder are required. This also promotes the efficiency of the process, the process can be carried out under vacuum or in inert gas atmosphere or in appropriate

Combinations of vacuum and inert gas atmosphere are performed. For example, the electron beam can sinter sintered in a vacuum, while the powder preparation can be carried out in an inert gas atmosphere to a cooling medium for the inert gas through the

To provide cooled powder particles in powder production.

In the method, a wide variety of powders, in particular different metallic powders can be used, wherein the powder particles can be formed from pure metal or from alloys. The powder may be formed, for example, from titanium aluminide alloys or components for producing titanium aluminide alloys, that is, for example, titanium powder, aluminum powder or powder of alloying ingredients such as niobium or the like. In particular, several devices for powder production can be provided to produce different powders. These powder manufacturing devices may be provided in several separate rooms or housings or in a housing with or without corresponding partitions. Only with respect to the ambient atmosphere completed transport to the place of generative component production must be guaranteed.

The powder can be mechanically alloyed, so it can be processed accordingly with appropriate additional powders. In addition, a certain particle size distribution can be set for the powder particles,

The inventive method also makes it possible that differently alloyed powder and / or with respect to the powder size differently adjusted powder in the

generating components is provided in different areas _» so that a component can result in a material gradient.

The powder can be prepared in different ways by known methods.

In particular, atomization of a molten material, for example by rotary dusting, can be used. In a device according to the invention, various devices for powder production and generative production of components may be provided in a housing or in gas-tight connected housings or rooms. These devices include devices for powder production by means of atomizing, for example rotary atomizers, corresponding devices for processing the powders, such as sieves and the like, apparatus for mechanical alloying, ie mixers and the like, as well as devices for supplying additional powder externally or means for storing Powder in the gas-tight sealed device. In addition, one can

Device according to the invention in addition to the beam generating device and devices for guiding the beam via a powder layer aids for transporting and handling of the powder as well as means for gas supply and for evacuating the device.

According to the present invention, gas turbine blades, in particular low-pressure turbine blades, can thus be produced from TiAl materials, which can be designed as hollow blades with an inner support structure. According to the invention, these components, which can only be produced by generative methods in a complicated cavity structure, can be produced from the material TiAl or TiAl alloys which is difficult to handle since fine-grained powders can be used and the generation of impurities, in particular the introduction of oxides, is prevented becomes. Accordingly, they are distinguished

Gas turbine blades produced according to the invention by fine-grained microstructure with low impurities, in particular low oxygen content. In addition, the gas turbine blades may have locally different alloy compositions and / or have grain size distributions. In addition, corresponding components are distinguished by the avoidance of segregation, as can be observed in cast components.

BRIEF DESCRIPTION OF THE FIGURES The invention will be clarified with reference to the accompanying drawings, which are purely schematic in FIG

Fig. 1 is an illustration of a device for the generative production of

Air turbine blades according to the invention; and in -

6

Fig. 2 is a perspective view of an inventively prepared

Show turbine blade.

EMBODIMENTS

Further advantages, characteristics and features of the present invention will become apparent from the following detailed description of an exemplary embodiment.

1 shows a purely schematic representation of a device 1, which can be used for the production of turbine blades by the method according to the invention. The device 1 has a housing 2, which encloses two chambers or chambers 3 and 4, which are partitioned off by an unspecified partition with a passage opening 15 in the housing 2. In the one space 4 powder production takes place while in the other room 3, the sintering of the component 27 takes place.

The rooms 3 and 4 each have a vacuum pump 5 and 6, so that the rooms 3 and 4 can be pumped separately from each other. Alternatively, however, it can be provided to provide only a single pump for pumping off the entire interior of the housing 2.

In addition, several gas supply lines 7, 8, 9 are provided, which in turn allow the separate flooding of the rooms 3 and 4 with gas. Again, only a single gas supply for flooding the entire interior of the housing 2 may be provided. The flooding with gas can only serve to clean the room or the setting of an inert gas atmosphere.

In space 4 of the housing 2 there is further provided a melt supply 10 or, alternatively, a device for melting a metal or alloy (not shown) which comprises a nozzle device from which the melt is produced. Powder can escape. Here, known methods can be used, such as rotational atomization of the melt to produce fine-grained powder.

The powder thus produced can be collected on a table 11, whereby a pushing device 13 can laterally push off the powder and transport it in the direction of the space 3. In the simplest case, for example, located on the table 11 powder with the Slider 13 along the table 11 and the connecting plate 22 are moved through the opening 15 in the direction of the powder container 25 in the space 3 to there in the

Powder container or on the powder container as Pul publishers to be stored. Of the

Powder container 25 has a double bottom 26 which is adjustable in height according to the double arrow, so that at the beginning of the process, the double bottom 26 at the level of

Connection plate 22 is moved to receive a first Pul publishers.

This first powder layer is formed by an electron or laser beam 24 passing through the

Beam generating device 23 is generated locally selectively sintered according to the contour to be produced, wherein the electron beam or laser beam is moved over the powder layer on the double bottom 26. Where the electron or laser beam hits the powder and melts or melts it, the powder is locally sintered together, so that a component 27 is produced. Thereafter, the double bottom 26 is lowered by a certain height to allow the slider 13 to apply a new powder layer. This powder layer is then correspondingly sintered again by the beam bundles 24 of the laser or electron radiation and the process is continued until the component 27 to be produced is ready. The component 27 is then in a powder bed 28, which in the powder container 25th

is included. From there, the finished component 27 can be removed and removed through an opening 29 from the housing 2.

If a certain powder size is to be selected, an opening 21 can be opened in the connecting plate 22 or the table 11, so that the powder 12 enters a funnel 16 with a sieve 17 through which, however, only the powder having the determined powder size passes can. The powder is then collected in a powder container 18 with a double bottom 19, which can then be raised in the region of an opening 30 of the connecting plate 22 so that the powder contained in the powder container 18 by means of the double bottom 19 in the plane of the table 11 and ., The connecting plate 22 can be raised and there to be moved by the slider 13 in the direction of the Pul e-container 25. For this purpose, a hydraulic lifting device 20 is provided, which can move the powder container 18 upwards, as indicated by the double arrow.

In addition, opposite the opening 30, there is provided a feed hopper 14 with a lock through which additional powder externally generated can be introduced into the apparatus. With the lock, a gas supply 8 may be connected to For example, introduce inert gas in the lock area. In the same way, a corresponding vacuum pump (not shown) may be provided in the region of the lock of the input hopper 14. By the additional powder which can be introduced into the device 1 via the feed hopper 14, a mechanical alloying of the powder can be provided, for example by externally supplying alloy components.

Moreover, it is also possible, for example in the space 4 of the housing 2 to provide powder storage, are stored in the different powders to then mechanically alloy them in a powder mixing device, not shown, in order to produce desired compositions of the powder can. In addition, other devices for powder production and corresponding spaces can be provided. In the mixture of different powders, both powders of different chemical composition and also powders with different grain sizes can be mixed or alloyed.

In this respect, it is possible with the presented device 1 not only to directly process melts of alloys into powders and to use them in the generative production process, but it is also possible to mechanically alloy powders having different particle sizes and / or particle size distributions and chemical

To realize compositions in the device 1. In particular, it is thereby possible to provide different powders per layer, and thus to adjust gradients with regard to the composition and / or the grain size in the component 27 to be produced.

By means of the gas feeds 7, 8, 9 and the pumps 5, 6 it is possible to set defined atmospheric conditions in the chambers 3 and 4 of the housing 2, wherein different atmospheres in the chambers 3 and 4 can also be set. Thus, in addition to vacuum conditions, it is also possible to generate atmospheres with defined gas compositions, for example inert gas atmospheres. In particular, it is possible in the housing 2 to set a substantially oxygen-free atmosphere in the technical framework, so that no Contamination of the component 27 takes place with unwanted oxygen levels. But other gases, such as nitrogen, which could lead to the formation of nitrides, can be excluded accordingly, for example when working under vacuum or inert gas atmospheres.

By defined adjustment of the atmosphere can thus be avoided that

Contaminants are contained in the manufactured component. At the same time can through

Use of multi-beam devices, ie beam generation devices such as laser or electron beam devices that can generate multiple beams or high

Have radiation performance, a high energy input into the powder can be achieved, so that the sintering can be realized in a very short process times. Accordingly, the inventive method can be operated very efficiently.

In particular, the apparatus and the corresponding method for producing gas turbine blades from titanium aluminide materials or alloys thereof can be used. Furthermore, it is possible hollow blades with complicated cavities, such as cooling channels, or

To produce cavities with complicated Smtzstrukturen in an economical manner.

In the components corresponding grain sizes can be adjusted. Also, segregations in alloys can be avoided and, in addition, graded components having defined compositions in different regions of the blade can be produced.

FIG. 2 shows an example of a low-pressure turbine blade for an aircraft turbine made of a titanium aluminide material, wherein the blade 50 has a blade root 55 and a hollow blade

Airfoil 51 has. The cavity 52 of the airfoil 51 is interrupted by stiffeners 53 and 54, which are shown in dashed lines. The stiffeners divide the cavity 52 into partial cavities 56, 57 and 58.

For example, in the regions of the partial cavities 56, 57 and 58, the blade airfoil 51 can have different compositions with respect to the chemical composition and / or the particle size distribution. The change in the composition can be carried out continuously or stepwise, so that sets a stepless or stepped gradient. Although the present invention has been described in detail with reference to the accompanying examples, it will be understood by those skilled in the art that the invention is not limited to these examples, but rather modifications are possible such that other combinations of the features presented are possible or individual Features can be omitted, as long as the scope of the appended claims is not abandoned.

Claims

claims

1. A method for producing gas turbine components, in particular turbine components, preferably low-pressure turbine blades from a powder which is selectively sintered in layers by localized introduction of radiant energy, wherein the sintering in a closed, first housing (2) is performed, so that a defined atmosphere adjustable is

characterized in that

in the same first housing (2) or a gas-tight connected to the first housing second housing, the powder or at least a portion of the powder is generated.

2. The method according to claim 1,

characterized in that

the sintering by means of laser or electron beam (24) takes place.

3. The method according to claim 1 or 2,

characterized in that

a plurality of radiation beams (24) for the introduction of radiant energy are used simultaneously for sintering.

4. The method according to any one of the preceding claims,

characterized in that

a substantially oxygen-free atmosphere or a vacuum is set.

5. The method according to any one of the preceding claims,

characterized in that

metallic powders (12), in particular powders from or for the production of TiAl alloys.

6. The method according to any one of the preceding claims,

characterized in that

the powder (12) is mechanically alloyed and / or adjusted in its size distribution, and in particular differently alloyed and / or powder-sized powder is sintered in a component in different regions.

7. The method according to any one of the preceding claims,

characterized in that

the powder is made by atomizing.

8. An apparatus for producing gas turbine components, in particular turbine components, preferably low-pressure turbine blades from a powder, in particular by the method according to one of the preceding claims, comprising a first housing (2) in which a container (25) for a powder bed (29) and a Radiation source (23) for generating at least one beam for introducing radiant energy into the powder bed and an arrangement (13) for applying thin powder layers are arranged on the powder bed,

characterized in that

A device (10) for generating powder is arranged in the first housing or in a second, gas-tight housing connected to the first housing (2).

9. Gas turbine blade, in particular low-pressure turbine blade made of a TiAl material, in particular produced by the method according to one of claims 1 to 7,

characterized in that

the blades (50) are designed as hollow blades with an inner support structure (53, 54).

10. Gas turbine blade according to claim 9 or the preamble of claim 9,

characterized in that

the gas turbine blade a fine-grained structure in which 95% of the grains have a particle size of less than 100 nm and or has a locally different alloy composition and / or particle size distribution.