Patent Application
20160067828
1. Field of the Invention
The present invention relates to a method for manufacturing a component of a turbomachine, in particular an aircraft engine, with the use of a generative or additive manufacturing method, as well as a corresponding manufactured component.
2. Prior Art
Additive manufacturing methods in which a component is built up layer by layer from a powder material, such as powder hardfacing, selective laser melting, selective laser sintering, selective electron-beam melting, selective electron-beam sintering, and the like are manufacturing methods of interest for components of turbomachines, such as stationary gas turbines or aircraft engines, since difficult-to-process materials, which are difficult to cast, for example, can be used with this method, and also components having near-final contours can be produced, so that complicated post-processing by means of machining methods such as milling can be dispensed with.
Of course, in additively manufactured components, there is the problem that the surface quality in part does not fulfill requirements with respect to roughness, in particular for application in turbomachines. Thus, components having surfaces that are too rough as flow surfaces, that is, surfaces over which a fluid flows, have a flow resistance that is too high or negatively affect the flow conditions due to undesired vortexing of the fluid flow. In addition, rough surfaces are in part unsuitable for ambient conditions, since rough surfaces can be subjected to an elevated oxidation and/or corrosion attack(s).
Therefore, it may be necessary to post-process corresponding surfaces in order to reduce the roughness, which brings with it, however, a high expenditure.
Object of the Invention
The object of the present invention is thus to provide a method for the manufacture of components of a turbomachine, which makes possible in an efficient way, with as small an expenditure as possible, the manufacture of components having suitable property profiles, and in particular, with surfaces having little roughness, wherein a multiple number of different materials, which are as variable as possible, will find use for the manufacture of the component.
Technical Solution
This object is achieved by a method and a component with the features of the present invention. Advantageous embodiments are discussed in detail below.
The invention proposes to provide a smoothing layer for components that have been at least partially additively manufactured, at least on a surface region of the at least additively manufactured part of the component on which it is necessary, this smoothing layer being deposited by vapor deposition, in order to thus obtain a smooth surface. It is possible in a simple way therewith to provide additively manufactured components with sufficiently smooth surfaces that are suitable for turbomachines, due to the fact that the flow surfaces on which a fluid flows are sufficiently smooth, on the one hand, in order to avoid a negative influencing on the flow, and, on the other hand, in order to avoid a corrosion attack due to a surface that is too rough.
A corresponding component, which is provided with a smoothing layer, can be additively manufactured either partially or entirely, and in fact, by different known methods for the additive manufacture of components, such as selective laser melting, selective laser sintering, selective electron-beam melting, selective electron-beam sintering, and powder hardfacing.
In particular, the entire region of the component that has been additively manufactured can be provided with a corresponding smoothing layer. Of course, it is also possible to provide a smoothing layer on only a part of the component, also only on a portion of the additively manufactured part of the component, or the entire component can be provided with a smoothing layer.
The smoothing layer can be deposited by different vapor deposition techniques, such as physical or chemical vapor deposition methods, for example. Physical vapor deposition (PVD) methods can comprise, for example, thermal vaporization, sputtering, pulsed laser deposition or electron-beam deposition, wherein individual physical vapor deposition methods can be plasma-supported, such as plasma-supported sputtering, for example. A plasma support can be employed also in chemical vapor deposition (CVD), (PECVD, plasma-enhanced chemical vapor deposition).
The smoothing layer can be introduced with a thickness of 5 μm to 200 μm, in particular 10 μm to 100 μm, so that with such a smoothing layer, the surface roughness of the component, which has been introduced by the additive manufacturing method, can be compensated, and the deposited smoothing layer itself can have a sufficiently smooth surface. The smoothing effect can be realized by means of a sufficiently thick smoothing layer, whereas the manufacturing expense can be reduced by minimizing the thickness of the smoothing layer.
The material of the smoothing layer can differ from the material or materials from which the component is built up. Of course, it may be advantageous if the smoothing layer comprises one or more chemical elements that are also contained in the material from which the component is fabricated (base material) and that will be coated with the smoothing layer. The adhesion of the smoothing layer to the component can be improved or assured in this way. The smoothing layer can be formed from a metal or an alloy or a chemical compound. For a turbomachine, in that alloys such as nickel alloys, nickel-based superalloys, titanium alloys, and the like are employed as base materials for corresponding components such as flow duct limiting walls, rotating blades, guide vanes, and the like, particularly metals that are also contained as a meaningful fraction in the base materials of the component to be coated can be used for the smoothing layer. For example, an aluminum layer can be selected for the smoothing layer for a component whose base material is composed of a nickel-based alloy such as IN718, which contains nickel, chromium, iron, molybdenum, titanium, aluminum, and other minor components.
After introducing the smoothing layer, the component with the smoothing layer can be subjected to a heat treatment, in particular a diffusion annealing, so that material from the smoothing layer can diffuse into the base material and/or material from the base can diffuse into the smoothing layer, so that a good adhesive strength of the smoothing layer and an equilibration of the chemical composition will result. Another additional functional layer can be deposited onto the smoothing layer. By introducing a smoothing layer, components can be produced, whose surface displays an average roughness Ra that is less than or equal to 10 μm, in particular less than or equal to 5 μm. The average roughness is determined by the average distance of a measurement point on the surface to a central line relative to the surface. In this case, the central line intersects the actual surface profile, so that the sum of the profile deviations referred to the central line is minimal. Correspondingly, the average roughness is the arithmetic mean of the deviation from the central line.
The appended drawings show in a purely schematic way, in:
Further advantages, characteristics and features of the present invention will be made clear in the following detailed description of an exemplary embodiment. Of course, the invention is not limited to this exemplary embodiment.
In a purely schematic cross-sectional view,
Such a built-up component 1 can have a relatively rough surface 3, which is unsuitable, for example, for use in turbomachines, since the rough surface 3 can negatively influence the flow conditions for surfaces along which a fluid flows, and secondly, the rough surface can be sensitive to corrosion attacks.
Correspondingly, the surface 3 of the component 1 according to
The component 1 with the smooth surface 4 can be used directly, for example, as a limiting wall element of the flow duct in a stationary gas turbine or an aircraft engine or as a rotating blade or guide vane of a corresponding turbomachine.
There is also the possibility that, after introducing the smoothing layer 2 on the smooth surface 4, an additional functional layer 6 will be introduced such as, for example, a layer for corrosion protection or a thermal barrier coating, or the like.
Although the present invention has been described in detail on the basis of the exemplary embodiment, it is obvious to a person skilled in the art that the invention is not limited to this exemplary embodiment, but that modifications are possible in a way that individual features or other kinds of combinations of features can be realized, as long as they are within the protective scope of the appended claims. The present disclosure includes all combinations of the individual features proposed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2014 217 858.4 | Sep 2014 | DE | national |
