JPH04231169A - Cone shape-object reinforced with filament and its manufacture - Google Patents

Abstract

PURPOSE: To obtain a composite structure having high strength and durability by being reinforced with a filament having non-uniform cross-section. CONSTITUTION: A layer of matrix metal is formed on a mandrel 10 with a nearly conical shape by plasma spraying. A spiral groove is formed in the surface of the layer by machining. A reinforcing filament 20 is wound in the groove. The second layer of matrix metal is formed on the wound layer by spraying to embed the filament. A reinforced composite structure containing laminated filament is formed by repeating this procedure.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD This invention relates generally to the production of filament-reinforced metal articles of very high strength and durability, and more particularly to the production of conically shaped filament-reinforced metal articles; and the method by which it can be manufactured.

0002

BACKGROUND OF THE INVENTION It is known that filament-reinforced articles can be produced by plasma spray techniques. A number of patents have been issued to the assignee of this application relating to such filament reinforced structures. The manufacture of foils, sheets and other similar articles based on titanium alloys and reinforced structures with silicon carbide fibers embedded in titanium-based alloys is described in U.S. Pat. No. 4,775,547; , No. 782,884, No. 4,786,566,
No. 4,805,294, No. 4,805,833 and No. 4,838,337 (assigned to the assignee of this application). The disclosures of these patents are hereby incorporated by reference.

The manufacture of the composites described in these patents has been the subject of much research because these composites have extremely high strength properties relative to their weight. One particularly desirable property is the high tensile properties imparted to the structure by the high tensile properties of the silicon carbide fibers or filaments. The tensile properties of this structure are related to the law of mixture. According to this rule, the proportion of properties such as tensile properties that are attributed to the filament as opposed to the matrix is determined by the volume percentage of the filament present in the structure and the tensile strength of the filament itself. Similarly, the proportion attributable to the matrix with the same tensile properties is determined by the volume percentage of the matrix present in the structure and the tensile strength of the matrix itself.

Prior to the development of the method described in the above-mentioned patent, such structures were manufactured by sandwiching reinforcing filaments between titanium-based alloys.
A laminate of alternating layers of alloy and reinforcing filament was pressed until a composite structure was formed. However, this prior art method is very satisfactory when attempting to form articles of various shapes, such as ring structures, where the filament is an internal reinforcement throughout the ring or other structure. It wasn't.

The structures and methods of fabrication taught in the above-mentioned patents represent a significant improvement over the previous technique of forming matrix and reinforcing filament sandwiches by compression.

[0006] Although later structures produced as described in the above-mentioned patents had greatly improved properties over earlier structures, the potentially extremely high limits of these structures It was found that the tensile strength did not reach the theoretically possible value. Testing of composites formed according to the method taught in the above-mentioned patents has shown that although the modulus values are generally in good agreement with those expected from the mixing rule, the ultimate tensile strength is generally proved to be much lower than the values predicted by the fundamental properties of the components. A number of patent applications have been filed in an attempt to overcome this problem of lower than expected tensile properties, and several of these applications are currently pending. See, for example, U.S. Patent Application No. 445,203, filed December 4, 1989, U.S. Patent Application No. 459,894, filed January 2, 1990, and
U.S. Patent Application No. 455,041 filed February 22nd
No. 455,048. The specifications of these applications are hereby incorporated by reference.

One structure that has been found to be particularly desirable when using the technology of these patents has a metal matrix with silicon carbide filament reinforcement surrounding the entire annulus. It is a circular article. Rings and tubes ranging from several inches to several feet in diameter have been manufactured using such reinforcing filaments. Such ring and tube structures have very high tensile properties relative to their weight, especially when compared to structures made entirely of metal.

[0008] This fiber-reinforced ring can be used, for example, as a reinforcing ring structure for compressor discs in jet engines. Many layers of reinforcement are required to provide reinforcement for the disks in the compressor stage of jet engines. Continuing to add more layers of filamentary reinforcement to the ring structure has proven extremely difficult due to differences in coefficients of thermal expansion and other factors.

One of the problems that arises with continuing to add outer layers of filament-reinforced matrix to ring structures is the compression and compression of the outer filaments as normal consolidation occurs during HIP (hot isostatic pressing). This means that buckling is more likely to occur in the outer ring. Such buckling of the filament can cause damage to the filament and, therefore, to the ring of which it is a part. Such buckling tends to occur more easily as the number of fiber layers increases, and when the number reaches 20 or 30 layers, adding layers beyond these values causes HIP Filament buckling and damage can occur as the process consolidates the entire structure.

One way to solve this problem is to
Co-pending U.S. Patent Application No. RD-20,406 (Attorney Docket No. RD-20,406)
). The solution described in this application is to form a series of coaxial rings and combine them with each other to create a reinforced ring structure with over 100 layers of reinforcement. Although these ring structures can be very large, on the order of a foot or several feet in diameter, they must fit together within extremely narrow tolerances of only a few thousandths of an inch. .

Most of the prior art relating to forming articles on mandrels involves the production of generally tubular articles. The patent literature and related art relating to such structures teaches highly effective and efficient methods for manufacturing tubular articles having substantially uniform cross-sectional areas.

For some purposes, it may be desirable to have a tubular reinforcing structure that does not have a uniform cross-sectional area. For example, one such structure is a reinforcing structure in the form of a cone. Such a cone is not uniform in axial cross-section and is in fact tapered in shape.

[0013]

SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to
It is an object of the present invention to provide a method by which generally tubular metal articles reinforced with filaments having non-uniform cross-sections can be manufactured.

Another object is to provide a method of manufacturing a generally conically shaped filament reinforced metal article.

Another object is to provide a conically shaped filament reinforced metal article.

Some of the other objects will become apparent from the following description, and some will be pointed out from time to time.

In a broad aspect of the invention, the objects of the invention can be achieved by providing a conical mandrel having external dimensions that approximately match the desired internal dimensions of the conical article to be formed. . The conical mandrel is placed in a low pressure plasma deposition chamber and a matrix metal coating is formed on the mandrel surface by plasma deposition. The coated conical mandrel is cooled, removed from the chamber, and machined to provide a smooth surface and to provide a helical groove in the surface suitable for receiving and holding the reinforcing filament member in place. Provided for. The filament-wound conical mandrel with this surface coating is reintroduced into the low pressure plasma deposition chamber and a second coating of matrix metal is applied by plasma spraying onto the filament-bearing surface.

The coated article is then removed from the chamber and machined to provide a relatively smooth surface and a helix suitable for receiving the helically wound reinforcing filament. A shaped groove may be provided. The cone and mandrel carrying this filament are then reintroduced into the low pressure plasma deposition chamber;
A second overcoat of matrix metal can be provided over the surface by plasma spraying.

This machining, grooving, wrapping and spraying process can be repeated any number of times until a conical reinforced structural member with the desired number of layers of reinforcement is formed.

The reinforced article thus formed can be removed from the mandrel, such as by machining or chemical dissolution, and the conical reinforcement member can then be compacted by HIPing by processes well known in the industry. I can do it.

For convenience, this series of steps will be referred to as machining, grooving and winding steps. Surprisingly, by using this sequence of steps in producing structures with approximately circular cross-sections, dense structures are obtained and without detectable buckling of the filaments. It has been found that structures can be obtained with more layers of reinforcement than previously possible.

[0022]

DETAILED DESCRIPTION OF THE INVENTION Generally, it is desirable for filament-reinforced structures to have relatively uniform spacing between the individual strands of filaments in the structure. This is particularly desirable for structures formed by metal spraying techniques. Wrapping reinforcing filament over a generally cylindrical surface can be difficult, as unevenness in the surface to be wrapped may result in uneven spacing between the reinforcing filament strands, or in practice. Two or more strands may come into contact due to unevenness. When matrix metals are applied by thermal spraying, the presence of filament contact substantially prevents the sprayed metal from fully penetrating and enveloping such filaments, resulting in a matrix structure. It becomes impossible to obtain the best strengthening effect on the body and the highest density of the composite. One way to overcome this problem is to
The invention is disclosed and claimed in co-pending U.S. patent application Ser.

It has been recognized that in certain applications it may be desirable to form a filament reinforced structure on an intentionally textured surface. For example, a typical cylinder has a constant, uniform diameter along its length. However, in some articles of cylindrical construction, an indentation is provided at one or both ends or somewhere in the middle of the cylinder to enable the reinforced structure to be used for the specific intended use. There is. One simple problem that illustrates the unique peculiarity of the present invention is to form a generally cylindrical structure having a generally conical shape, with a reinforcing material wrapped around the conical portion, assuming a conical spiral shape. This is the case. However, in the case of such conically shaped surfaces, the problems described above regarding movement of the reinforcement strands on surfaces that are not regular or smooth become even more critical.

[0024] Filaments wound on a conical surface tend to move very easily over the surface, which can cause undesired contact of some strands. This is because such filaments tend to collect on the smaller diameter portion (tip portion) of the mandrel that supports them.

By preparing a mandrel having a generally conical shape, as illustrated in FIG. can get. The tendency of the individual strands of such filamentary reinforcement to come into contact together and form a surface that cannot be penetrated by metal spraying is quite evident in such structures. To the applicant's knowledge, no filament-reinforced structure has ever been made in this configuration.

What we have done is to enable the production of approximately cylindrical structures whose longitudinal cross-section is not uniform, but in which the filamentary reinforcement is uniformly distributed along the surface. It is.

To accomplish this, a helical groove is machined into the tapered surface to serve as a guide for receiving the filamentary reinforcement and to provide reinforcement along the surface. determine the interval in advance.

The helical grooves can be machined directly into the surface of the as-deposited matrix metal, or the deposited matrix metal can first be machined into a smooth cone and then the cone can be machined directly into the surface of the as-deposited matrix metal. It can also be machined into a smooth surface. If the deposited matrix is first machined to smooth it and then grooved, the filament volume fraction will be high.

[0029] Each step by which the method of the invention can be carried out can be explained with reference to the accompanying drawings.

First, reference is made to FIG. A mandrel 10 having the shape of a truncated cone is prepared. The mandrel 10 has a handle 12 extending axially from its large diameter end to allow manipulation and rotation of the mandrel within a low pressure plasma deposition chamber (not shown).

The mandrel 10 is introduced into a chamber as described above, and a surface layer 14 of a matrix metal, such as a titanium-based alloy, is plasma sprayed onto the conical surface.

After spraying the surface layer 14 of matrix metal,
The cone is removed from the chamber and at least one helical groove 16 is machined into the deposited matrix surface. Preferably, a single groove is machined to provide a guideway for wrapping the reinforcing filament around the surface. In order to be effective as a reinforcing filament, a high volume fraction of the filament must be placed on the surface to be reinforced. The filament is extremely thin, so
To increase the volume fraction of filament reinforcement, wrap more than 100 strands per inch. It will be appreciated that maintaining proper spacing between filaments wound with strand densities of 100 or more per inch can be very difficult. Surprisingly, the inventors have found that the volume fraction of reinforcing filaments allows the filaments to be maintained at a nearly uniform spacing with the high strand density required to form a reinforced structure. . A detail of the generally V-shaped groove machined into the conical surface is shown in the enlarged partial view of FIG. The filament 20 remains within this V-shaped groove after being wrapped into a cone as shown in FIG.

After winding the filament onto the cone, the cone is reintroduced into the plasma deposition chamber and a second coating 22 is applied by plasma spraying a matrix metal onto the surface around which the filament is wound. embedded within the matrix metal.

This process of grooving, wrapping and spraying can be repeated several times to build up the reinforcing layer on the conical mandrel. The resulting structure 20 is HIPed to consolidate the structure and increase its density to near the theoretical maximum density for the article.

[0035]

DESCRIPTION OF EXAMPLES The implementation of the method of the invention is illustrated in the following examples. The structure actually formed in this example has a constant diameter rather than a decreasing diameter. However, as will be readily apparent, the method illustrated in this example can be easily converted to be suitable for use with structures of decreasing diameter or conical structures. Example 1 A mild steel metal mandrel for matrix metal layer deposition was manufactured by first providing a 0.002" thick layer of Al2O3 by plasma spraying in air. This mandrel was then deposited on top of the The titanium-based alloy was introduced into a low-pressure radio frequency (RF) plasma deposition chamber suitable for depositing a titanium-based alloy as a matrix metal.The titanium-based alloy actually used was Ti-6242 (Ti-6Al).
-2Sn-4Zr-2Mo). After depositing a layer of approximately 0.125 inch on the mandrel surface, the mandrel was allowed to cool and the Ti-6242 peeled off the mandrel, which was removed from the chamber. This Ti-6242
The ring was approximately 4 inches in diameter and approximately 4 inches long. The Ti-6242 ring was machined on a lathe to remove the rough surface of the deposited metal. After removing rough surfaces, machining creates spiral grooves (
112 filaments per inch). Silicon carbide filaments, specifically Textron
Specialty Materials Company (Textron)
Specialty Materials Corporation
After an SCS-6 filament, available from A. cation), was attached and secured to one end of the mandrel, the filament was wrapped onto the mandrel along the grooves that had been previously machined into the matrix metal surface. Once the groove was completely filled, the other end of the filament was clamped to keep it in place for the next step.

Ti-6 supporting this filament
The 242 ring was again placed in the low pressure plasma deposition chamber and a second layer of matrix metal was deposited over and around the fibers and on the surface of the ring using low pressure RF plasma deposition. After deposition, the ring was allowed to cool and removed from the chamber. The second layer of matrix metal was machined to a smooth surface within 0.010 inch radially of the previous layer, and the surface was machined with helical grooves. The process of wrapping the reinforcing filament into the groove formed in the ring surface and spraying additional matrix metal over it was repeated until eight layers of reinforcing material and matrix metal were formed on the mandrel.

Another feature of the present invention is the ability to adapt such composites for certain applications where it is desirable to vary the properties of the composite along the length of the article around which the surface filament is wound. In order to vary the properties along the length, it is possible to vary the spacing between the individual strands of reinforcement along its length. To change such spacing, change the spacing between the grooves around which the filament is wound.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conical mandrel suitable for use in practicing the invention.

FIG. 2 is a schematic diagram showing the mandrel after depositing a layer of matrix metal on the mandrel.

3 is a schematic illustration of the coated mandrel of FIG. 2 machined to form a smooth surface and a helical groove formed in the surface; FIG.

FIG. 4 is a detailed view of the grooves cut into the surface of FIG. 3;

FIG. 5 is a schematic explanatory diagram of a state in which a filament is wound within the spiral groove of the mandrel in FIG. 3;

6 is a schematic illustration of the structure of FIG. 5 coated with a layer of matrix metal with reinforcing filaments embedded within the surface of the matrix; FIG.

[Explanation of symbols]

10 Mandrel, 14　Matrix metal surface layer, 16 groove, 20 filament, 22 Second coating of matrix metal.

Claims (2)

[Claims] 1. A plurality of rows of filamentary reinforcing material are embedded within a matrix of titanium-based alloy, and the spacing between filaments of the reinforcing material within the matrix is uniform and is 1/100 inch. A filament-reinforced composite structure that is anchored within. 2. In order to form a composite structure thereon, a mandrel having a substantially conical shape is prepared, a layer of matrix metal is provided on the mandrel by plasma spraying, and the surface of this layer is machined. A spiral groove is provided, a reinforcing filament is wound in the groove on the surface, a second layer of the matrix metal is provided by thermal spraying on the layer around which the filament is wound, and the filament is embedded in this second layer. A method for manufacturing a filament-reinforced composite structure, comprising: