Abstract:
A method of manufacturing a fiber reinforced metal disc comprises forming an annular groove in an axial face of a first metallic ring. A plurality of metal coated fibers are arranged in spiral preforms and a plurality of metallic wires are arranged in spiral preforms. The metal coated fiber preforms and the metallic wire preforms are arranged in the groove. An annular projection is formed on an axial face of a second metallic ring. The annular projection on the second metallic ring is aligned with the annular groove in the first metallic ring. Heat and pressure is applied to axially consolidate the metal coated fiber preforms and metallic wire preforms and to bond the first metal ring, the second metal ring, and the preforms to form a unitary composite disc. The use of metal coated fibers and metallic wires allows the mechanical properties to be tailored.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a method of manufacturing a fibre reinforced metal cylinder, in particular to a method of manufacturing a fibre reinforced metal ring or a fibre reinforced metal disc. 
     BACKGROUND OF THE INVENTION 
     In one known method of manufacturing a fibre reinforced metal ring, as disclosed in UK patent application No. GB2168032A, a fibre is wound spirally in a plane with a metal matrix spiral between the turns of the fibre spiral. The fibre spiral and metal matrix spiral are positioned between discs of metal matrix and this arrangement is pressed axially to consolidate the ring structure. This produces little or no breaking of the fibres. 
     A problem with this method is that it is difficult to wind the fibre and metal matrix unless the fibre and metal matrix have the same diameter. If the fibre and metal matrix wire have the same diameter the ring structure has a low volume fraction of fibre. 
     In another known method of manufacturing a fibre reinforced metal ring, as disclosed in UK patent application No. GB2198675A, a continuous helical tape of fibres and a continuous helical tape of metal foil are interleaved. The interleaved helical tapes of fibres and the metal foil are placed in an annular groove in a metal member and a metal ring is placed on top of the interleaved helical tapes of fibres and metal foil. The metal ring is pressed axially to consolidate the assembly and to diffusion bond the metal ring, the metal member and the interleaved helical tapes of fibres and metal foil together to form an integral structure. This method produces little or no breaking of the fibres. 
     In a further known method of manufacturing a fibre reinforced metal ring, as disclosed in our European patent No. EP0831154B1, a plurality of metal coated fibres are placed in an annular groove in a metal member and a metal ring is placed on top of the metal coated fibres. Each of the metal coated fibres is wound spirally in a plane and the metal coated fibre spirals are stacked in the annular groove in the metal member. The metal ring is pressed axially to consolidate the assembly and to diffusion bond the metal ring, the metal member and the metal coated fibre spirals together to form an integral structure. This method produces little or no breaking of the fibres. 
     The latter method suffers from several problems. Firstly the method of coating the fibres with metal may be costly. Secondly the choice of metals, or alloys, which may be coated onto the fibres is limited. Thirdly the fibre arrangement produced by the method is always the same and hence this limits the ability of the designer to tailor the properties of hoop strength, axial strength and radial strength to optimum for any particular fibre reinforced metal disc or fibre reinforced metal ring. 
     SUMMARY OF THE INVENTION 
     Accordingly the present invention seeks to provide a novel method of manufacturing a fibre reinforced metal component. 
     Accordingly the present invention provides a method of manufacturing a fibre reinforced metal component comprising the steps of:— 
     (a) forming a longitudinally extending groove in a face of a first metallic member, 
     (b) arranging at least one longitudinally extending metal coated fibre and at least one longitudinally extending metallic wire in the longitudinally extending groove in the first metallic member, 
     (c) forming a longitudinally extending projection on a face of a second metallic member, 
     (d) arranging the second metallic member such that the longitudinally extending projection of the second metallic member is aligned with the longitudinally extending groove of the first metallic member, 
     (e) applying heat and pressure such that the longitudinally extending projection moves into the longitudinally extending groove to consolidate the at least one longitudinally extending metal coated fibre and the at least one longitudinally extending metallic wire and to bond the first metallic member, the second metallic member, the at least one longitudinally extending metal coated fibre and the at least one longitudinally extending metallic wire to form a unitary composite component. 
     The method preferably comprises forming a circumferentially extending groove in an axial face of the first metallic member, arranging the at least one circumferentially extending metal coated fibre and at least one circumferentially extending metallic wire in the circumferentially extending groove in the first metallic member, forming a circumferentially extending projection on a face of the second metallic member, 
     arranging the second metallic member such that the circumferentially extending projection of the second metallic member is aligned with the circumferentially extending groove of the first metallic member, applying heat and pressure such that the circumferentially extending projection moves into the circumferentially extending groove to consolidate the at least one circumferentially extending metal coated fibre and the circumferentially extending metallic wire and to bond the first metallic member, the second metallic member, the at least one circumferentially extending metal coated fibre and the circumferentially extending metallic wire to form a unitary composite component. 
     The method may comprise arranging the at least one circumferentially extending metal coated fibre and the at least one circumferentially extending metallic wire in the circumferentially extending groove in the first metallic member such that the at least one circumferentially extending metal coated fibre and the at least one circumferentially extending metallic wire are arranged in a common plane. 
     The method may comprise arranging the at least one circumferentially extending metallic wire at a greater radial distance than the at least one circumferentially extending metal coated fibre. 
     The method may comprise arranging the at least one circumferentially extending metal coated fibre and the at least one circumferentially extending metallic wire in the circumferentially extending groove in the first metallic member such that the at least one circumferentially extending metal coated fibre and the at least one circumferentially extending metallic wire are arranged in different planes. 
     Preferably the method comprises arranging a plurality of circumferentially extending metal coated fibres and a plurality of circumferentially extending metallic wires in the circumferentially extending groove in the first metallic member. 
     The method may comprise arranging the plurality of circumferentially extending metal coated fibres and the plurality of circumferentially extending metallic wires in the circumferentially extending groove in the first metallic member such that a first one of the plurality of circumferentially extending metal coated fibres and a first one of the plurality of circumferentially extending metallic wires are arranged in a first common plane, a second one of the plurality of circumferentially extending metal coated fibres and a second one of the plurality of circumferentially extending metallic wires are arranged in a second common plane and the first and second common planes are spaced apart axially of the first metallic member. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The present invention will be more fully described by way of example with reference to the accompanying drawings, in which:— 
     FIG. 1 shows a longitudinal cross-sectional view through a bladed compressor rotor made according to the method of the present invention. 
     FIG. 2 is a plan view of a metal coated fibre preform and a metal matrix preform used in the method of the present invention. 
     FIG. 3 is a cross-sectional view through the metal coated fibre preform and the metal matrix preform shown in FIG.  2 . 
     FIG. 4 is a plan view of a metal coated fibre preform used in the method of the present invention. 
     FIG. 5 is a cross-sectional view through the metal coated fibre preform shown in FIG.  4 . 
     FIG. 6 is a plan view of a metal matrix preform used in the method of the present invention. 
     FIG. 7 is a cross-sectional view through the metal matrix preform shown in FIG.  6 . 
     FIG. 8 is a longitudinal cross-sectional view through an assembly of fibre preforms and metal matrix preforms positioned between first and second metallic members. 
     FIG. 9 is a longitudinal cross-sectional view through an assembly of fibre preforms and metal matrix preforms positioned between first and second metallic members after consolidation and bonding to form a unitary composite structure. 
     FIG. 10 is an enlarged longitudinal cross-sectional view of part of FIG. 9 showing the fibres. 
     FIG. 11 is an enlarged longitudinal cross-sectional through part of an assembly of fibre preforms and metal matrix preforms positioned between first and second metallic members showing one stacking arrangement of preforms. 
     FIG. 12 is an enlarged longitudinal cross-sectional Through part of an assembly of fibre preforms and metal matrix preforms positioned between first and second metallic members showing an alternative stacking arrangement of preforms. 
    
    
     DESCRIPTION OF THE INVENTION 
     A finished ceramic fibre reinforced metal rotor  10  with integral rotor blades is shown in FIG.  1 . The rotor  10  comprises a metal ring  12  which includes a ring of circumferentially extending reinforcing ceramic fibres  14 , which are fully diffusion bonded to the metal ring  12 . A plurality of equi-circumferentially spaced solid metal rotor blades  16  extend radially outwardly from and are integral with the metal ring  12 . 
     The ceramic fibre reinforced metal rotor  10  is manufactured using a plurality of metal coated ceramic fibres and a plurality of metal matrix wires. Each ceramic fibre  14  is coated with metal matrix  18  by any suitable method, for example physical vapour deposition, sputtering etc. A first set  20 A of metal coated  18  ceramic fibre  14  are arranged to have a first length. A second set  20 B of metal coated  18  ceramic fibre  14  are arranged to have a second length which is longer than the first length. 
     Each of the metal coated ceramic fibres  14  of the first set  20 A is wound around a mandrel. A metal matrix wire  22  is then wound coaxially around each metal ceramic fibre  14  of the first set  20 A to form an annular disc shaped preform  24 A as shown in FIGS. 2 and 3. Each annular, or disc shaped, preform  24 A thus comprises a single metal coated  18  ceramic fibre  14  arranged in a spiral and a single metal matrix wire  22  arranged coaxially in a spiral with the metal matrix wire  22  arranged at a greater diameter than the metal coated  18  ceramic fibre  14 . A glue  26  is applied to the annular, or disc shaped, preform  24 A at suitable positions to hold the turns of the spirals together. 
     Each of the metal coated ceramic fibres  14  of the second set  20 B is wound around a mandrel to form an annular, or disc shaped fibre preform  24 B as shown in FIGS. 4 and 5. Each annular, or disc shaped, preform  24 B thus comprises a single metal coated  18  ceramic fibre  14  arranged in a spiral. A glue  26  is applied to the annular, or disc shaped, preform  24 B at suitable positions to hold the turns of the spirals together. 
     The glue is selected such that it may be completely removed from the annular, or disc shaped, preforms  24 A and  24 B prior to consolidation. The glue may be for example polymethyl-methacrylate in di-chloromethane or perspex in di-chloromethane. 
     A first annular ring, or metal disc,  30  is formed and an annular axially extending groove  32  is machined in one axial face  34  of the first metal ring  30 , as shown in FIG.  8 . The annular groove  32  has straight parallel sides, which form a rectangular cross-section. A second metal ring, or a metal disc,  36  is formed and an annular axially extending projection  38  is machined from the second metal ring  36  such that it extends from one axial face  40  of the second metal ring  36 . The second metal ring  30  is also machined to form two annular grooves  42  and  44  in the face  40  of the second metal ring  36 . The annular grooves  42  and  44  are arranged radially on opposite sides of the annular projection  38  and the annular grooves  42  and  44  are tapered radially from the axial face  40  to the base of the annular projection  38 . It is to be noted that the radially inner and outer dimensions, diameters, of the annular projection  38  are substantially the same as the radially inner and outer dimensions, diameters, of the annular groove  32 . 
     One or more annular preforms  24 A and one or more annular preforms  24 B are positioned coaxially in the annular groove  32  in the axial face  34  of the first metal ring  30 . The radially inner and outer dimensions, diameters, of the annular preforms  24 A and  24 B are substantially the same as the radially inner and outer dimensions, diameters, of the annular groove  32  to allow the annular preforms  24 A and  24 B to be loaded into the annular groove  32  while substantially filling the annular groove  32 . A sufficient number of annular preforms  24 A and  24 B are stacked one upon the other in a predetermined arrangement in the annular groove  32  to partially fill the annular groove  32  to a predetermined level. 
     The second metal ring  36  is then arranged such that the axial face  40  confronts the axial face  34  of the first metal ring  30  and the axes of the first and second metal rings  30  and  36  are aligned such that the annular projection  38  on the second metal ring  36  aligns with the annular groove  32  in the first metal ring  30 . The second metal ring  36  is then pushed towards the first metal ring  30  such that the annular projection  38  enters the annular groove  32  and is further pushed until the axial face  40  of the second metal ring  36  abuts the axial face  34  of the first metal ring  30 . 
     The radially inner and outer peripheries of the axial face  34  of the first metal ring  30  are sealed to the radially inner and outer peripheries respectively of the axial face  40  of the second metal ring  36  to form a sealed assembly. The sealing is preferably by TIG welding, electron beam welding, laser welding or other suitable welding processes to form an inner annular weld seal and an outer annular weld seal. 
     The sealed assembly is evacuated using a vacuum pump and pipe connected to the chambers  42  or  44 . The sealed assembly is then heated, while being continuously evacuated to evaporate the glue from the annular preforms  24 A and  24 B and to remove the glue from the sealed assembly. 
     After all the glue has been removed from the annular preforms  24 A and  24 B and the interior of the sealed assembly is evacuated the pipe is sealed. The sealed assembly is then heated to diffusion bonding temperature and isostatic pressure is applied to the sealed assembly, this is known as hot isostatic pressing. This results in axial consolidation of the annular preforms  24 A and  24 B and diffusion bonding of the first metal ring  30  to the second metal ring  36  and diffusion bonding of the metal on the metal coated  18  ceramic fibres  14  to the metal on other metal coated  18  ceramic fibres  14  to the first metal ring  30 , the second metal ring  36  and to the metal matrix wire  22 . During the hot isostatic pressing the pressure acts equally from all directions on the sealed assembly, and this causes the annular projection  38  to move axially into the annular groove  32  to consolidate the annular preforms  24 A and  24 B. 
     The resulting consolidated and diffusion bonded ceramic fibre reinforced component  60  is shown in FIGS. 9 and 10, which shows the ceramic fibres  14  and the diffusion bond region  62 . Additionally the provision of the grooves, or chambers  42  and  44  allows the annular projection  38  to move during the consolidation process and in so doing this results in the formation of a recess  63  in the surface of what was the second metal ring. The recess  63  indicates that successful consolidation and diffusion bonding has occurred. 
     After consolidation and diffusion bonding the component is machined to remove at least a portion of what was originally the second metal ring and at least a portion of the diffusion bonded region. 
     The component may then be machined for example by electrochemical machining or milling to form the integral compressor blades or the component may be machined to form one or more slots to receive the roots of compressor blades. Alternatively compressor blades may be friction welded, laser welded or electron beam welded onto the component. 
     The length of the metal coated  18  ceramic fibres  14  and the length of the metal matrix wires  22  in the annular preforms  24 A may be preselected so as to obtain fibre reinforcement at the appropriate diameters in the component. Additionally it may be possible to wind the metal matrix wire  22  around the mandrel first and then to wind the metal coated ceramic fibre  14  coaxially around the metal matrix wire  22  so as to obtain fibre reinforcement at the appropriate diameters in the component. Furthermore, it may be possible to have two or more predetermined lengths of metal coated ceramic fibre and two or more predetermined lengths of metal matrix wire sequentially wound coaxially around each other in a common plane. 
     In FIG. 8, there are two preforms  24 A between two preforms  24 A to provide less ceramic fibre reinforcement in the central area at the outer diameter region as shown in FIG.  10 . The preforms  24 A and  24 B may be stacked in any predetermined arrangement. The preforms  24 A and  24 B may be arranged alternately, as shown in FIG. 11, or there may a plurality of preforms  24 A between adjacent preforms  24 B or a plurality of preforms  24 B between adjacent preforms  24 A or there may a combination of any of these in the stack of preforms  24 A and  24 B. 
     In an alternative embodiment the ceramic fibre reinforced metal rotor  10  is manufactured using a plurality of metal coated ceramic fibres and a plurality of metal matrix wires. 
     Each ceramic fibre  14  is coated with metal matrix  18  by any suitable method, for example physical vapour deposition, sputtering etc. The metal coated  18  ceramic fibres  14  are arranged to have a predetermined length. Each of the metal coated ceramic fibres  14  is wound around a mandrel to form an annular, or disc shaped fibre preform  24 B as shown in FIGS. 4 and 5. Each annular, or disc shaped, preform  24 B thus comprises a single metal coated  18  ceramic fibre  14  arranged in a spiral. A glue  26  is applied to the annular, or disc shaped, preform  24 B at suitable positions to hold the turns of the spirals together. 
     The metal matrix wires  28  are arranged to have a predetermined length. Each of the metal matrix wires  28  is wound around a mandrel to form an annular, or disc shaped preform  24 C as shown in FIGS. 6 and 7. Each annular, or disc shaped, preform  24 C thus comprises a single metal matrix wire  28  arranged in a spiral. A glue  26  is applied to the annular, or disc shaped, preform  24 C at suitable positions to hold the turns of the spirals together. 
     In this embodiment one or more annular preforms  24 B and one or more annular preforms  24 C are positioned coaxially in the annular groove  32  in the axial face  34  of the first metal ring  30 , as shown in FIG.  12 . The radially inner and outer dimensions, diameters, of the annular preforms  24 B and  24 C are substantially the same as the radially inner and outer dimensions, diameters, of the annular groove  32  to allow the annular preforms  24 B and  24 C to be loaded into the annular groove  32  while substantially filling the annular groove  32 . A sufficient number of annular preforms  24 B and  24 C are stacked one upon the other in a predetermined arrangement in the annular groove  32  to partially fill the annular groove  32  to a predetermined level. 
     The preforms  24 B and  24 C are arranged alternately, as shown in FIG.  12 . However, the preforms  24 B and  24 C may be stacked in any predetermined arrangement. There may be a plurality of preforms  24 B between adjacent preforms  24 C or a plurality of preforms  24 C between adjacent preforms  24 B or there may a combination of any of these in the stack of preforms  24 B and  24 C. 
     The diameter of the metal matrix wire  28  of the annular preforms  24 C may the same diameter, or a different diameter to the diameter of the metal coated  18  ceramic fibres  14  of the annular preforms  24 B. 
     The annular preforms  24 C may also comprise two or more metal matrix wires having different diameter wound together around a mandrel. The annular preforms  24 A may also comprise one or more metal matrix fibres and one or more metal matrix wires having different diameters wound together around a mandrel. 
     The reinforcing fibre may comprise alumina, silicon carbide, silicon nitride, boron, or other suitable fibre. 
     The metal coating on the ceramic fibre may comprise titanium, titanium aluminide, an alloy of titanium or any other suitable metal, alloy or intermetallic which is capable of being bonded. 
     The metal matrix wire may comprise titanium, titanium aluminide, an alloy of titanium or any other suitable metal, alloy or intermetallic which is capable of being bonded. 
     The first metal ring and the second metal ring comprise titanium, titanium aluminide, an alloy of titanium or any other suitable metal, alloy or intermetallic which is capable of being bonded. 
     The present invention has enables the ceramic fibre reinforced metal component to be produced at a lower cost by using metal matrix wires and metal coated ceramic fibres. The use of metal matrix wires enables the amount of metal to be deposited on the metal coated ceramic fibres to be reduced and hence reduces the cost of depositing metal onto the ceramic fibres. 
     The present invention allows different metals, or alloys to be used for the metal matrix wires and the metal coating on the ceramic fibres. 
     The present invention allows the radial strength of the ceramic fibre reinforced component to be improved without limiting hoop strength. 
     Thus each spirally wound metal coated ceramic fibre preform is arranged in a different, parallel, plane to the spirally wound metal matrix wire or some of the spirally wound metal coated ceramic fibre preforms are arranged in the same plane as the spirally wound metal matrix wire.