DD259163A1 - METHOD FOR PRODUCING COMPOSITE WORKPIECES - Google Patents

Abstract

The invention relates to a method for the production of composites whose functional parts are exposed to very different types of loads in the application. The type of load in the application calls for adapted material properties. This can be achieved by connecting geometrically determined parts of the pile to an informal mixture of substances and / or directional or non-directional fibers. The final total cohesion is created by joining the composite work piece. The shapeless substance mixture or the fibers are therefore first brought into their desired geometric final shape during the joining process itself. The joining process is realized mainly by diffusion welding or hot isostatic pressing. By this method, it is possible to combine the mixture and / or fibers with each other or with geometrically determined parts in one operation. By this way of joining, the constructive possibilities for the production of composites are substantially increased. Fig. 1

Description

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Field of application of the invention

The invention relates to a method for producing composite workpieces, wherein the output parts to be connected have a different structure structure. In use, these composite workpieces are subjected to various loads resulting from physically different types of stress.

The production of these composite workpieces should preferably be carried out by diffusion welding or hot isostatic pressing. The composite workpieces are mainly used in the fields of precision engineering, the glass and ceramics industry, mechanical and tool engineering, electrical engineering and electronics.

Characteristic of the known technical solutions

It is known to use thermal joining methods for joining solid, geometrically determined bodies. Diffusion welding and hot isostatic pressing are processes in which the material combinations to be joined are very diverse.

The starting workpieces generally have a geometrically solid state which does not change during the joining process in the macroscopic range or is subject to a specific forming process, the consistency of the substance remaining the same (general state of the art).

A disadvantage of this method is that no informal fabric particles or fibers can be connected to the solid geometric structures.

As described in "American Machinist", issue 10/1983, it is further known to use diffusion bonding coupled with superplastic forming to make honeycomb structures.

The disadvantage here is that only superplastic materials can be used and that the size of the honeycomb structures can not be arbitrarily minimized.

Furthermore, it is known to add oriented fibers by fusion bonding, usually by electrical discharges or gas discharges, as described in DE-PA 3014451, DE-OS 3133002 and DE-OS 3211848.

The disadvantage here is that the glass fiber structure at the edge, d. H. in the joining zone, is subjected to a high thermal load, wherein the initial structure of the fiber changes at this point.

In DE-PS 2231680 and DE-OS 3316001 ways of connecting directional fiber materials by mechanical integration or folding are described. These methods have the disadvantage that the packing density does not increase arbitrarily and the connection of the individual fibers with each other is not cohesive nature.

Object of the invention

The aim of the invention is to provide a solution which makes it possible, in joining processes such as diffusion bonding and high-temperature soldering, to produce composite parts whose starting parts have a different structural configuration. The aim is to produce workpieces that have special properties that are tailored to the particular application in use.

The essence of the invention

The invention has for its object to develop a manufacturing technology to produce composite workpieces whose individual Ausgangsbestandteile have a different structure structure, so specifically tailored to the application properties of the resulting composite workpiece can be realized.

According to the invention the object is achieved in that one or more geometrically determined body with an informal mixture, for. As powder and / or be connected with directional or non-directional fibers. The manufacturing methods preferably used for the production of these composite workpieces are diffusion welding and hot isostatic pressing. The technological cycle must proceed in such a way that both the joint of geometrically determined body and substance mixture and the entire volume of the informal mixture of substances heated to bonding temperature and this temperature over a certain period of time (joining time) is maintained. The heating of the entire formless mixture of substances is required in order to proceed to the atomic or molecular bonding processes necessary for the strength of the composite material.

In diffusion bonding and hot isostatic pressing, a working pressure is necessary for connecting the other, which approaches the individual components of the composite workpiece to be produced as closely as possible. When using the method according to the invention, it is therefore necessary, when using informal substance mixtures, to use a joining part shape (joining tool) corresponding to the final state of the composite workpiece. The working pressure necessary for the method, the joining temperature and the joining time are chosen so that there is no difference between geometrically determined body and the joining pressure from the formless mixture with respect to the degree of space filling or the joining product of the formless material has a certain porosity. This effect can be achieved in particular by a targeted pressure or temperature field over the Gesamttwerkstück to be produced.

The connection with each other or with geometrically determined bodies also has to be done in a tool in order to achieve the best possible approximation of the individual fibers (normally line contact). The degree of space filling when joining fibers depends on the already mentioned technological parameters, the fiber material and the fiber geometry.

By the method according to the invention it is possible to add coated or uncoated workpieces. Whether a coating is necessary depends on the material parameters, the miscibility of the substances and the technological cycle.

embodiment

The invention will be explained in more detail with reference to the embodiments illustrated in Figures 1, 2 and 3. Showing:

Figure "!: shaft with bearing shell

Figure 2: Filter made of fiber material with metal edge

Figure 3: Filter made of fiber material without metal edge

As can be seen from FiguM, the bearing of a rotating shaft 1 is formed such that the bearing shell consists of two different materials. Inside, i. on the friction surface between shaft and bearing, a porous cast iron 2 is used, which ensures certain emergency running properties. On this casting 2 sits as a connector to adjacent equipment parts a pressure piece 3 made of a corrosion-resistant and high temperature resistant Pneudolegierung. The bearing shell, consisting of parts 2 and 3, was manufactured by diffusion welding. The cast iron and pseudo alloy version was specially adapted to the application, i. once the emergency running procedure of the bearing shell could be improved and on the other hand the outside of the bearing shell could be protected by a highly wear-resistant material against the very aggressive external operating conditions.

FIG. 2 shows the possibility of connecting fiber parts 5 and 6 with a geometrically determined body, the metal ring 4. The position and the number of fibers varies greatly depending on the desired application. A similar example is shown in FIG. 3, in which 2 differently oriented fibers are joined without metal cladding. Again, the type, number and orientation of the fibers can be different depending on the purpose. For undirected fibers to be joined, only the type and number (packing density) is interesting for the later application.

Claims (3)

1. A process for the production of composite parts whose functional parts are exposed in the application physically very different types of stress, in particular by diffusion welding or hot isostatic pressing, characterized in that the starting materials of geometrically determined bodies and Puivergemischen consist, being in a tool under the action of the working parameters ( Pressure, temperature, time) run simultaneously 2 manufacturing processes, to the effect that a compact body is formed by sintering from the powder mixture and a combination of geometrically existing body and powder mixture is realized, for the coupling of these methods, only one manufacturing device is needed. 2. The method according to claim 1, characterized in that by varying one or more operating parameters, the density of the powder mixture which connects to a solid body is varied so that a defined porosity is formed. 3. The method according to claim 1, characterized in that in place of the powder mixture directed or non-directional fiber structures are connected.