DE102012206087A1 - Making component e.g. turbine of aircraft engine, by preparing first component part, injecting second component part to the first compact part to form multi-component part, removing binder from part to form brown part and then sintering - Google Patents

Abstract

The method comprises preparing a first component part (40) made of a first injection-molding metal powder mixture comprising metal powder (11) and a binder (12), by metal powder injection molding in an injection molding machine, injecting a second component part (50) made of a second injection-molding metal powder mixture to the first compact part in an injection cycle to form a multi-component part from two metallic powder mixtures, removing binder from the multi-component part to form a brown part, and sintering (700) the brown part. The method comprises preparing a first component part (40) made of a first injection-molding metal powder mixture comprising metal powder (11) and a binder (12), by metal powder injection molding in an injection molding machine, injecting a second component part (50) made of a second injection-molding metal powder mixture to the first compact part in an injection cycle to form a multi-component part from two metallic powder mixtures, removing binder from the multi-component part to form a brown part, and sintering (700) the brown part. An adhesion between the first component part and the second component part is formed by melting the first component part during over molding of the second component part. The component parts comprise an enlarged contact surface, and form interlocking shapes present in the form of elevations and recesses. A positive connection is formed between the first and second component parts. The first and second component parts include first and second connectors respectively. The connectors are connected to each other. The recesses have a complementary mating shape. The second component part comprises a wear resistant material higher than the first component part. The first component part comprises an inexpensive and ductile material.

Description

The invention relates to a method for producing a component of an aircraft engine by metal powder injection molding of metal powder mixed with binder. The method is suitable for example for the production of components of a compressor or a turbine of an aircraft engine.

Components of an aircraft engine may be exposed to various damage mechanisms. For example, blades and rotor blades of aircraft engine compressors are often limited in life by erosion or foreign object damage (so-called "FOD Foreign Object Damage"). In order to protect such components against damage mechanisms in the engine, the use of cost-intensive, production-technically complex and / or constructive measures is known. These include the application of erosion control coatings, mechanical hardening of exposed areas, such as the leading edges of blades and blades, the application of erosion and FOD-compliant blade design, and the implementation of a particle separator in the engine.

The said application and solidification processes are completely separate from the actual production process of the engine components, for example the guide vanes and rotor blades, and are generally carried out by their own companies, which makes such processes very cost-intensive. As far as structural changes (for example, a thickening of the leading edges of the blades) or conceptual changes (for example the use of a particle separator in the compressor) are made to counteract erosion and FOD, in addition to higher costs this usually also has a negative effect on the performance of the overall system.

There is thus a need to inexpensively protect components such as e.g. guide vanes and blades of an aircraft engine.

Powder Metallurgy Injection Molding (also known as MIM ("Metal Injection Molding")) is widely used in high volume markets such as the automotive industry. Up to now, a leap in manufacturing technology to aviation has been at most selective, cf. R. MIM 2000: time to focus on value, not tonnage, in Metal Powder Report, Vol. 4. (May 2010) ,

The invention has for its object to provide a cost effective method for producing a component of an aircraft engine by metal powder injection molding.

The inventive solution according to claim 1 provides for this purpose that in a first process step, a first green component of the component to be produced from a first injection-moldable metal powder mixture containing mixed with a binder metal powder is produced in an injection molding machine. In a subsequent process step, the green compact component produced in the first process step is reused in an injection molding machine before debindering and before a heat treatment. There, a second greenware component made of a second injection-moldable metal powder mixture is injected onto the first greenware component or the second greenware component is injected around the first greenware component. This results in a multi-component green compact of two metal powder mixtures. Subsequently, the resultant multicomponent green compact is debinded, resulting in a browning of the component to be produced. The Bräunling is sintered in a conventional manner.

The solution according to the invention is thus based on the idea of producing a green compact of the component to be produced by means of at least two sequential injection molding cycles. This results in a multi-component green compact of at least two metal powder mixtures. In the subsequent debindering and sintering, this produces a metallic component which consists of different metals or metal alloys in different areas. This creates the possibility of realizing different properties as a function of the requirement profile of the component in different regions of the component. Since this is done by means of a powder metallurgy injection molding process, these different and tailored to the function of the component properties are provided in a cost effective manner.

In this case, material and design of the first greenware component, which represents an "injection molding blank", can be selected freely and adapted to the later requirements in the manufacturing process or in the application (for example, to requirements for long-term fatigue of the component). The insertion and removal of the finished injection-molded greenware components or by Injection molding produced multi-component green compact can be done fully automatically, which leads to a further cost reduction.

According to one embodiment of the invention, adhesion takes place between the first green component and the second green component by fusing the first green component during the application or extrusion coating of the second green component. It can be provided that the first green component and the second green component have an enlarged contact surface in order to improve their adhesion.

For this purpose, it can be provided, for example, that the greenware components form interlocking forms, at least in the area of contact with the respective other greenware component, for example in the form of elevations and depressions (for example in the form of a sawtooth pattern). Adhering the two greenware components to one another before the further process steps of debindering and sintering makes it possible to safely handle the multicomponent green body in the further process steps. In addition, this makes it easier to form a unitary component during the sintering process.

According to a further embodiment, a positive connection is realized between the first green compact component and the second green compact component, which firmly connects the multicomponent green compact prior to debindering and sintering. Such a positive connection can be realized, for example, by producing the first greenware component with first connecting elements which are surrounded or filled with material of the second greenware component when the second greenware component is applied or encapsulated, this material thereby forms second connecting elements, and wherein the first and second connecting elements engage in a form-fitting manner. Such a positive connection may be formed, for example in the form of interlocking projections and recesses. In this case, the projections may taper toward the contact surface between the two greenware components, for example, be dovetail-shaped or club-shaped, and the recesses have a matching complementary shape.

The provision of a positive connection between the greenware components of the multi-component green compact can also be advantageous for the strength of the finished sintered component, since an intimate connection has taken place in the transition region of the two components. It can be provided in accordance with a sub-aspect of the present invention that the different metal powder mixtures of the different greenware components undergo a different shrinkage during sintering, resulting in that the components are pressed together automatically during sintering. However, it is expressly pointed out that such a different shrinkage is provided only in one embodiment and by no means necessary for the invention, since by the inventive joining of the individual components already in the stage of greening in each case a single component of two or more different materials provided.

It can be provided that after spraying the second green compact component to the first green compact component, the resulting two-component green compact is supplied to one or more further injection molding cycles before debindering and before a heat treatment. For each additional injection cycle, another greenware component is added.

The method described is basically suitable for the production of any components of an aircraft engine. In this case, due to the use of the injection molding technique, components with geometrically complex structure can be produced. An embodiment of the present invention provides that the manufactured component is a rotor or vane of a compressor or a turbine of an aircraft engine. In this case, the first green component forms the soul of the later blade and the second green component components the region of the front and rear edge. It can be provided that the second green component has a harder and more wear-resistant material than the first green component, which consists of a less expensive and more ductile material.

Thus, in the second injection molding process, the particularly erosion and FOD loaded edges and edge areas of a blade are formed using a harder and more wear resistant material. The choice of this second material can be made from a wide range, which also takes into account the metallurgical compatibility of both materials.

For example, it may be provided that the first Greenware component comprises a metal powder having iron and nickel-based materials. It can further be provided that the second green component comprises a metal powder which a) consists of a nickel-based alloy which b) has iron and / or nickel materials which are reinforced with ceramic particles, and / or which c) dispersion-hardened by means of mechanical alloying is (so-called ODS alloys (ODS = "Oxid Dispersion Strengthening")).

According to a first embodiment, iron and nickel-based alloys are thus used as metal powder for the second green component, which have higher strength and hardness by means of precipitation and solid solution hardening, at the same time lower ductility, in comparison to the material of the first green component. According to a second embodiment, reinforced by ceramic particles reinforced iron and nickel alloys are used. According to a third embodiment, iron and nickel based ODS alloys are used. The difference between the second and the third embodiment variant is that in the second embodiment ceramic particles (on a micrometer scale) are introduced directly into the production process. The original metal powder is mixed with the ceramic particles and mixed before proceeding with the conventional processing of the feedstock. For ODS alloys, however, the starting powder already carries the hardening particles (usually Y2O3 dispersoids). The particles have nanometer-scale diameters and are previously introduced into the powder by mechanical alloying.

Following powder metallurgical injection molding, any post-processing methods known from conventional manufacturing can be used, such as machining, sandblasting, vibratory finishing or polishing. It can also be provided that heat treatment steps take place under atmosphere or vacuum, and an additional process step is carried out to fully compact the material produced in order to further improve the material properties. The latter can be done, for example, via a deformation of the component or the so-called hot isostatic pressing.

The method of the present invention enables the performance of aircraft engine components to be improved, particularly with respect to erosion and FOD resistance, without sacrificing the benefits of a conventional MIM process. These advantages can be found in the large material and geometry flexibility and a high cost advantage over established manufacturing processes. Another advantage is that materials can be processed using MIM technology, which has a higher application temperature than previously used in a high-pressure compressor.

The invention will be explained in more detail with reference to the figures of the drawing with reference to its embodiments. Show it:

1 a schematic representation of the individual processes of a method according to the invention for producing a component of an aircraft engine by metal powder injection molding;

2 a blade of a compressor component as a green compact component made by metal powder injection molding and having an interface for connection to another green compact component;

3A the component of 2 after encapsulation with a further metal powder mixture, whereby a second green component is formed, which is connected to the first green component, wherein the two components form a two-component green compact of different metal powder mixtures;

3B a cut through in the 3A perspective component shown;

4 the components of 3A . 3B after completion of the sintering process;

5 the multi-component green compact of 3A . 3B in perspective and separate representation of the individual greenware components for improved representation of the contact area of these components;

6 the multi-component green compact of 5 in another perspective view;

7 a section through a multi-component green compact according to the 3B wherein the two greenware components form a first embodiment of an alternative mechanical interface; and

8th a section through a multi-component green compact according to the 3B wherein the two greenware components form a second embodiment of an alternative mechanical interface.

The 1 shows an embodiment of a method for producing a component of an aircraft engine by metal powder injection molding. The considered component is in the illustrated embodiment, a blade of a compressor component of a jet engine. However, the principles of the present invention may equally be applied to other components of an aircraft engine, such as turbine blades and blades.

According to step 100 of the 1 First, the starting materials for the process are provided. This is a first powder 11 and a first binder 12 and a second powder 21 and a second binder 22 , The powder 11 . 21 is in each case a metal powder, wherein the two metal powder 11 . 21 have different metals or metal alloys. The binders 12 . 22 consist for example of thermoplastics and / or waxes. The binders 12 . 22 may have an identical or a different composition.

It will each be the first powder 11 and the first binder 12 to a first processable in the injection molding material and the powder 21 and the binder 22 mixed into a second processable in an injection molding material. The resulting processable in injection molding materials are referred to as a feedstock, so that there is a first feedstock and a second feedstock. The actual mixing process is in the process step 200 indicated schematically. The respective feedstock is then in the process step 300 plasticized and granulated. This is done separately for each feedstock. The plasticizing and granulating takes place in a manner known per se.

The correspondingly plasticized and granulated first feedstock is then in the process step 400 in an injection molding machine 30 introduced for use in an injection molding process. The result of the injection molding process is the production of a first greenware component 40 , The first greenware component 40 Forms the soul of a later blade of a rotor or a stator of a compressor of an aircraft engine. The first greenware component 40 is determined by the 2 will be explained in detail.

After making the first greenware component 40 with the first feedstock becomes the first greenware component 40 inserted in a second injection molding machine, which in the schematic representation of 1 is not shown separately, cf. step 500 , This insertion of the first greenware component 40 in another injection molding machine before debinding and before any heat treatment of the first green component 40 , In the injection molding machine is attached to the first green component 40 using the second feedstock, a second greenware component 50 molded. This second green component 50 forms in the illustrated embodiment, the edges and edge near areas of the later blade. The second green component 50 and their connection with the first greenware component 40 be based on the 3A . 3B be explained in more detail.

The multi-component green compact produced by the two sequentially executed injection molding processes 40 . 50 will be in the following work step 600 that is, the organic binder is withdrawn from the brownling. In this case, a porous, metallic component, which is referred to as Braunling, back. The process of debinding takes place in a conventional manner. It can be a chemical leaching of the binder according to process step 610 and / or a thermal expulsion of the binder according to method step 620 include. Finally, in process step 700 a sintering of the brownling. In it, the component gets its final size and density. The remaining porosity of the component is minimal, with densities of over 97% can be achieved.

The finished component has different properties in different areas, depending on whether the considered area is formed with material of the first feedstock or with material of the second feedstock. It is thus possible to realize a homogeneous component with different material properties while optimizing the material properties of the different regions of the component.

The method described can be extended so that one or more further injection molding cycles with further feedstocks can be carried out before debinding. This makes it possible to produce a multicomponent green compact with additional metal powder mixtures, which enables additional differentiation of the material properties of the finished component.

The 2 shows a first green component 40 according to the 1 , The first greenware component 40 forms the core of a later blade of a rotor or a stator of a compressor. It includes the actual compressor blade 41 (ie, the inner airfoil portion), which is an aerodynamically shaped body, and a vane ring radially adjacent thereto 42 , The shovel 41 has a mechanical interface at its leading edge and at its trailing edge 43 which serves to connect to a second greenware component, as indicated by the 3A . 3B will be executed. This interface 43 is in the 2 only shown schematically. Possible embodiments are particularly in the 3B . 5 . 7 and 8th shown.

It should be noted that the interface 43 does not necessarily have to have a deviating from a smooth surface geometry. Thus, the material of a second green component with the material of the first green component already combines by automatically melting the first green component in the injection molding machine during the overmolding with the feedstock of the second green component. An additional mechanical interface is thus not necessarily provided, but possible in embodiment variants.

The 3A shows a two-component green compact after carrying out the method step 500 of the 1 , where the first green component 40 with the second feedstock to form the second greenware component 50 has been overmoulded. The second green component 50 is formed at the edges and edge near areas of the later blade. It is envisaged that the second green component 50 is formed of a harder and more wear-resistant material than the first green component 40 ,

As the material of the second green compact component for forming the edges and edge-near portions of the blade, for example, a nickel-based alloy having a very high precipitation ratio is used, or various iron and / or nickel materials which can be reinforced with ceramic particles are used. The following table gives an example of material combinations for the first feedstock and the second feedstock or the first greenware component and the second greenware component: "Inner Soul" (1st Feedstock) Edges near edges (2nd feedstock) IN718 IN738LC Alloy 800H IN713LC HK30 PM2000 IN713LC PM1000

The sectional view of the 3B illustrates the training of the interface between the first green component 40 and the second greenware component 50 , After that, the first greenware component runs 40 towards the leading and trailing edges of the blades pointed or V-shaped in areas 44 out. The second green component 50 gets around these pointed areas 44 sprayed around.

This is also in the presentation of the 5 to recognize, on the one hand, the two green components 40 . 50 perspective and on the other hand in a schematic representation of their interface. It is based on the 5 good to realize that the second green component 50 is formed in two parts and two sections 50a . 50b exists at the same time in the injection molding process 500 to the first green component 40 be sprayed.

It should be noted that the 5 not to be misunderstood is that the second greenware component 50a . 50b in a separate step with the first greenware component 40 would be connected. The isolated illustration of first greenware component 40 and second greenware component 50 just to better represent the interface. The second green component 50 is created by overmolding the first green component with the second feedstock. Immediately and directly, a direct connection is formed between the respective injection-moldable metal powder mixtures. It allows the binders 12 . 22 surface-active additives are added, which is a sticking of the two greenware components 40 . 50 improve each other. The in the 5 recognizable serrated saving 51a . 51b the second greenware components 50a . 50b thus arises automatically when injecting the second feedstock to the first green component 40 ,

The 6 shows the described components in a further schematic, perspective view.

The further description goes with the 4 continued. This shows that in the 3B Green state component shown consisting of two green components 40 . 50 After completion of the manufacturing process, that is, after debindering the multi-component greenware of 3B resulting in a browning and after sintering of the browning, according to the process steps 600 and 700 of the 1 , The finished component 60 includes areas 61 . 62 , which consist of different materials and therefore have different properties. The properties can thereby be adapted to the functional tasks that have to be performed by the respective areas and, taking into account the possible damage, in particular by erosion and FOD, which they can experience, they are provided in a cost-optimized manner. In the transition between the areas 61 . 62 lie areas 63 which, due to diffusion processes, comprise material from both feedstocks, naturally having a concentration gradient between the regions 61 and 62 is present.

The formation of the interface between the first green component 40 and the second greenware component 50 according to the 3B is merely an example. The interface can basically have any structural design. A first alternative embodiment shows the 7 , Here are the first greenware component 40 and the second greenware component 50 through an interface 45 separated from each other, which has a sawtooth shape. This is with the advantage of an increased contact area between the first green component 40 and the second greenware component 50 connected. The increased contact surface provides improved adhesion between the two greenware components 40 . 50 provided. Instead of a sawtooth pattern, other interlocking shapes can be provided to increase the contact area, for example, elevations and depressions according to a wave pattern.

The 8th shows an alternative embodiment in which a connection between the first green component 40 and the second greenware component 50 is realized by a positive connection. This will be the first green component 40 in the process step 400 of the 1 shaped so that they are in the connecting region to the second green component 50 at least one projection 46 forms, which is the contact surface 47 between the two components 40 . 50 rejuvenated. When overmolding the first green component 40 These dovetails become tapered projections 46 automatically encapsulated by the second feedstock, with automatically a complementary recess in the second green component 50 formed.

The positive connection between the two greenware components 40 . 50 can lead to a particularly strong connection already in the green state and to the formation of larger transition areas 63 between areas of different materials 61 . 62 in the finished manufactured component 60 lead, compare 4 ,

The invention is not limited in its embodiment to the embodiments shown above, which are to be understood only as examples. In particular, the nature and form of the illustrated greenware components and the interfaces formed between them are to be understood merely as examples.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• R. MIM 2000: time to focus on value, not tonnage, in Metal Powder Report, Vol. 4. (May 2010) [0005]

Claims (16)

Method for producing a component ( 60 ) of an aircraft engine by metal powder injection molding of metal powder mixed with binder, characterized in that - a first green component ( 40 ) of the component ( 60 ) from a first injection-moldable metal powder mixture containing metal powder mixed with a binder by metal powder injection molding ( 400 ) in an injection molding machine ( 30 ), - the first greenware component ( 40 ) before debinding and a heat treatment is re-used in an injection molding machine and a second green component ( 50 ) from a second injection-moldable metal powder mixture to the first green component ( 40 ) is sprayed or injected around it ( 500 ), whereby a multi-component green compact of two metal powder mixtures is formed, - then the resulting multi-component green compact is debindered ( 600 ), wherein a Braunling of the component ( 60 ) is formed, and - the Bräunling is sintered ( 700 ). Method according to claim 1, characterized in that adhesion between the first green component ( 40 ) and the second greenware component ( 50 ) by melting the first green component ( 40 ) during the application or extrusion coating of the second greenware component ( 50 ) he follows. Method according to claim 2, characterized in that the first green component ( 40 ) and the second greenware component ( 50 ) thereby have an enlarged contact surface such that they intermesh with one another at least in the contact region with the respective other green component (FIG. 45 ) form, for example in the form of elevations and depressions. Method according to claim 1, characterized in that between the first green component ( 40 ) and the second greenware component ( 50 ) a positive connection ( 46 ) is realized. A method according to claim 4, characterized in that a positive connection between the first green component ( 40 ) and the second greenware component ( 50 ) is realized by the fact that the first green component ( 40 ) with first connecting elements ( 46 ) produced during the molding or encapsulation of the second greenware component ( 50 ) are surrounded or filled with material of the second green component, thereby forming second connecting elements, wherein the first and the second connecting elements ( 46 ) interlock positively. A method according to claim 5, characterized in that the connecting elements of the greenware components in the form of form-fitting interlocking projections ( 46 ) and recesses are formed. Method according to claim 6, characterized in that the projections ( 46 ) to the contact surface ( 47 ) between the two greenware components ( 40 . 50 ), for example, dovetail-shaped or club-shaped, and the recesses have a matching complementary shape. Method according to one of the preceding claims, characterized in that after injection of the second green component ( 50 ) to the first greenware component ( 41 ) the resulting two-component green compact is supplied to at least one further injection molding cycle before debindering, with a further greenware component being added to each further injection molding cycle. Method according to one of the preceding claims, characterized in that the manufactured component ( 60 ) is a blade of a rotor or a stator of a compressor or a turbine of an aircraft engine. Method according to claim 9, characterized in that the first green component ( 40 ) a soul of the later scoop ( 60 ) and the second greenware component ( 50 ) forms the areas of the leading edge and the trailing edge of the blade. Method according to one of the preceding claims, characterized in that the second green component ( 50 ) has a harder, more wear resistant material than the first green component ( 40 ). Method according to claim 11, characterized in that the first greenware component ( 40 ) has a cheaper and more ductile material than the second green component ( 50 ). Method according to one of the preceding claims, characterized in that the second green component ( 50 ) are formed in several parts, wherein all parts ( 50a . 50b ) of the second greenware component ( 50 ) in the same injection molding process to the first green component ( 40 ) are injected. Method according to one of the preceding claims, characterized in that the first green component ( 40 ) has a metal powder containing iron and / or nickel-based materials. Method according to one of the preceding claims, characterized in that the second green component ( 50 ) comprises a metal powder which - consists of a nickel-based alloy, and / or - which has iron and / or nickel materials which are reinforced with ceramic particles, and / or - which is dispersion-hardened by means of mechanical alloying. Method according to one of the preceding claims, characterized in that the component ( 60 ) after sintering ( 700 ) undergoes a re-densification by forming and / or by hot isostatic pressing.

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