KR20070115952A - Apparatus and method for mixing, agitating and transporting molten or semi-solid metallic or metal-matrix composite materials - Google Patents

Abstract

An apparatus 2 and method for mixing, agitating and transporting a slurry of molten or semi-solid metal or metal-matrix composite material including a casing 1 for containment of the slurry. An electrical conductor means 10 applies to the slurry a moving magnetic field to induce flow thereof. A component 7,8 is secured and located within the casing to modify the flow pattern of the slurry induced by the moving magnetic field.

Description

APPARATUS AND METHOD FOR MIXING, AGITATING AND TRANSPORTING MOLTEN OR SEMI-SOLID METALLIC OR METAL-MATRIX COMPOSITE MATERIALS

The invention described herein relates to a method and apparatus for processing and pumping slurry of molten metal or semisolid metal or alloy or metal-matrix composite (MMC) material, and also relates to the manufacture of metal matrix composites. In order to mix the additives, all of which in particular pertain to die casting and similar processes.

Many consumer goods and many industrial equipment include components manufactured by some form of casting, such as sand casting, die casting, so-called thixocasting, and the like. Such processes include solidification in a mold or die of a molten or semi-melt pure metal, metal alloy or metal containing composite material.

Various methods have been attempted to perform the agitation required to form and maintain thixotropic slurries. In the "Thixomat" process described in US Pat. No. 5,040,589 (Bradley et al.), The shearing or stirring of the slurry is a rotating screw auger that fits perfectly into a cylindrical casing or barrel. screw auger). The auger also transports the slurry to the nozzle end of the barrel and finally pushes the slurry accumulated therein into a die or mold. Both achieving a sufficiently high shear rate to break the dendritic particle formation and using the auger to eject the slurry into the die require fitting the auger to the barrel. Thus, the thixomat machine suffers a considerable wear of the auger. Erosion by the slurry (for example, when the slurry contains aluminum) can exacerbate the above problem. See also PCT Publication WO 01/21343 (fan) and similar devices disclosed in US Pat. Nos. 5,501,266 (King et al.) And 6,065,526 (Kono).

   Mechanical stirring is continuously being developed as a means of shearing slurry (see, eg, US Pat. Nos. 4,771,818 (Kennedy), 5,186,236 (Gabasuller), and 6,470,955 (Richard et al.)). electromagnetic stirring has been introduced.

U.S. Patent No. 4,321,958 (Delasus) discloses an electromagnetic field inductor that directly provides a helically moving field in a mold.

US Pat. No. 4,434,837 (Winter et al.) Describes a stator, similar to a stator of an induction motor, to generate a rotating field which is used to stir the slurry of the mold around the axis of rotation. The use of is being started.

U.S. Patent No. 4,877,079 (Long et al.) Discloses a "counterflow" for a continuous casting mold using two groups of coils arranged and excited to produce two separate field patterns. An electromagnetic field stirring device is disclosed. The end result is, for example, types of induced metal movement in the mold that are more complex than those produced by a simple rotational field. Improved shear and mixing movements are claimed.

U. S. Patent No. 5,219, 018 (Meyer) discloses the use of a number of annular coils arranged coaxially with the mold along the length of the mold. When properly connected to a polyphase alternating current (AC), a moving field is created that tends to linearly move the molten and / or semi-molten metal of the mold along its length direction. In practice, an annular circulation is formed and centered on the longitudinal axis of the mold.

U. S. Patent No. 5,135, 564 (Fujikawa et al.) Discloses a cylindrical tank in which molten metal is cooled and stirred to form a non-dendritic slurry. Agitation is provided by rotation under the influence of a rotating magnetic field (as in a multiphase induction motor stator). A smooth, generally cylindrical core member is introduced into the container and is preferably coaxial with the container. The slurry is contained in an annular space between the inner container wall and the core. The core eliminates "dead zones" with limited agitation in the center of the container and increases the uniformity of the agitation.

U. S. Patent No. 6,637, 927 (Lou Nobil et al.) Discloses a stirring device in which a container is surrounded by a coil stack that generates both a rotating field and a longitudinal moving field (as in a multiphase induction motor). The net result of the influence of the field is that the metal adjacent to the container wall inside the container travels in a spiral path and is recycled along a roughly linear path inside that spiral.

The use of electromagnetic induction is also known in pumps for molten metal. However, these pumps are intended to provide a smooth flow that is not turbulent flow or mixing flow.

U.S. Patent No. 2,786,416 (Pennemore) discloses a plurality of spiral interleaved windings provided around an annular duct that receives liquid metal and the windings connected to a multiphase AC power source to provide a spiral moving field. A pump is started. See also US Pat. No. 3,885,890 (Davidson), in which a coil is provided in an annular duct-centered casing to provide a helical field. Flow straightening vanes or baffles may be provided in each case.

U.S. Patent No. 4,212,592 (Olich) discloses a pump in which a rotating field is applied to an annular duct concentric to the axis of rotation of the rotating field, the rotating field inducing metal flow to the duct. Flow calibration vanes are provided in the duct.

U.S. Patent 4,988,267 (Yamada) discloses a pump, in particular for supplying molten metal to the spray sleeve of a casting machine. Coils are provided around the duct where the metal is pumped to move the metal in the axial direction along the duct. All such pumps have an annular duct for molten metal with a ferromagnetic core that is provided concentrically with the annular portion to the protective enlcosure.

The specification of each patent publication of each patent is incorporated herein by reference in its entirety.

According to one aspect of the invention,

A casing for receiving a slurry (collectively "slurry") of molten or semisolid metal containing material or metal matrix composite material,

At least one electrical conductor means in magnetic communication with the slurry for generating a moving magnetic field for directing the flow of the slurry in the casing, and

A shaped component secured (preferably rigid) to at least one mold positioned in the casing and altering the flow pattern of the slurry induced by the moving magnetic field. An apparatus is provided for mixing, stirring and conveying a slurry (collectively “slurry”) of molten or semisolid metal containing material or metal matrix composite material.

The casing may be or include a duct having an inlet and an outlet, and the slurry flows from the inlet to the outlet. The casing may be or include a casing or container through which the slurry flows under the influence of the moving magnetic field.

The at least one electrical conductor means may comprise a set of windings which may be connected to an alternating current power source.

Optionally, the casing is at least partially surrounded by a fluid coolant jacket that allows fluid coolant to be circulated to transfer heat between the metal matrix metal or metal matrix composite material in the casing and the fluid coolant of the fluid coolant jacket. .

Preferably the component is one or more helical screw flights. The casing and the helical screw flight form at least one helical conduit for the flow of the slurry. Optionally, the helical conduit comprises at least one segment inclined in the induced movement direction of the slurry contained therein.

The casing and / or the component may be at least partially formed of titanium or a material comprising titanium. It is contemplated that the use of titanium or titanium containing materials may be particularly desirable. For example, the material may be a titanium matrix composite, such as a child Sergio methicillin (CermeTi ^®) developed by the four dynamic meth Technology of Burlington, Mass., USA emitter (Dynamet Technology Inc.). The ceramic or ceramic containing material may also be suitable for use in parts or for component (s) contacting the surface of the casing and / or the slurry contained in the casing.

Another aspect of the invention provides a system for casting a slurry in a die or mold. The disclosed apparatus transfers the slurry directly to a die or mold of a casting machine or thixoforging machine or directly to a shot sleeve of a die casting machine.

According to another aspect of the invention,

Placing the slurry into the casing,

Applying a moving magnetic field to the slurry to direct the flow of slurry to the casing by at least one electrical conductor means, and

And providing at least one component secured to and positioned in the casing that changes the flow of the slurry. For example, a flow can be induced and the pattern of the flow can be modified to control, prevent or limit the growth of dendritic solid particles in the slurry. The temperature of the slurry in the casing can be controlled by passing a fluid coolant through the coolant jacket surrounding the casing.

 According to another aspect of the present invention there is provided a method of mixing an additive into a slurry to produce a metal matrix composite (MMC).

Thus, the invention disclosed herein relates to the manufacture of components from metals (including metal alloys) and metal matrix composites (MMCs), in which a die is used and the material entering the die is in the form of a thixotropic slurry. . Or such a slurry may be known as a semi-solid metal (SSM). This term is understood here to include metal matrix composites.

1 is a flow chart comparing the rheocasting process and the thixocasting process.

2 is a flow chart showing alternative steps in carrying out this process.

 3 is a cross-sectional view of a duct comprising the device according to the invention, cut in a plane comprising a longitudinal axis in the center of the duct comprising the device according to the invention.

4 is a cross-sectional view cut in the "4-4" position of FIG. 3 of the duct shown in FIG.

5 is a developed view of a portion of the inner surface of the wall of the duct shown in FIGS. 3 and 4.

FIG. 6 shows the same type as FIG. 5 showing possible variations.

7 is a longitudinal cross-sectional view of a duct comprising an alternative embodiment of a device constructed in accordance with the present invention.

8 is a longitudinal cross-sectional view of a closed cylindrical vessel incorporating another alternative embodiment of a device constructed in accordance with the present invention.

9 is a schematic diagram of an application example of an apparatus manufactured according to the present invention.

10 is a schematic diagram of another example of application of a device made in accordance with the present invention.

11 is a schematic diagram of an alternative application of a device made according to the invention.

12 is a schematic diagram of another alternative application of an apparatus constructed in accordance with the present invention.

13 is a schematic diagram of another alternative application of an apparatus constructed in accordance with the present invention.

1 and 2 are flow charts of processes illustrating possible applications of the present invention disclosed herein. 1 shows the steps in a process known as "Rheological Casting" and "Fluid Casting", for example, described in US Pat. No. 6,432,160 and incorporated herein by reference. In each of these processes, the metal alloy is first melted in a known manner, usually with controlled ambient atmosphere (step 1). At this point, the alloy liquid is at a temperature above its liquidus temperature.

In step 2 ("conditioning and receiving"), the molten material is cooled below the liquidus temperature and cooled above its solidus temperature and vigorously stirred. Due to cooling, dendritic solid particles begin to aggregate and grow. If the molten material is not sufficiently agitated, the particles will be gradually linked to gradually increase the viscosity of the mixture and the solidification of the normal pathway. The effect of the agitation is to modify the microstructure of the solidifying alloy by allowing the dendritic particles to be modified into discrete degenerate dendritic particles in approximately spheroidal form. As the proportion of these particles increases, the viscosity increases. By solid stirring (eg shear) and precise control of the temperature maintained between the solid and liquid phase temperatures, a semisolid slurry is produced. Non-dendritic forms of metal alloys and their application to casting substantially are described in US Pat. No. 3,902,544 (Fleming et al.), Which is incorporated herein by reference.

Step 2 usually takes place in a container separate from the container in which the initial melting took place. The slurry may be contained in the container for some time while remaining in that state. The slurry is thixotropic in that the slurry remains fluid as long as stirring and proper temperature are maintained, but loses fluidity if stirring stops or the temperature drops below the solid phase temperature. In step 3 ("feed") the slurry is ejected from the container in which the state of the slurry has been so controlled.

In thixotropic casting, the slurry is then solidified into a billet (shown in step 4a). They are then remelted in slurry form (step 5a) and cast (step 6a). In fluid casting, the slurry is not cast after solidifying and remelting, but is used directly for casting.

In fluid casting, the slurry ejected in step 3 is cast almost immediately. The casting process may take two forms, which are distinguished in FIG. 1. In one form, the transfer / jetting (step 3) is done directly to the die, so the casting step (step 4b) consequently simply means the slurry is injected into the die and the solidification in the die. In the other form, the transfer (step 3) is done in an intermediate container, such as an injection (shot) sleeve of a cold chamber type die casting machine. Step 4c has two steps: spraying the slurry into the shot sleeve and then spraying into a die or mold prior to solidification.

Essentially, thixotropic casting and fluid casting processes for pure metal alloys can be applied to metal matrix composites, including those based on aluminum alloys and fly ashes. See, for example, US Pat. No. 4,888,054 (Pond I), which is incorporated herein by reference. The main difference is that a mixing step is included.

FIG. 2 is similar to FIG. 1 except that it includes a mixing step (shown in FIG. 1A) where the additive (such as fly ash) is mixed into the molten alloy to produce a metal matrix composite. The remaining steps are numbered the same as the corresponding steps in FIG. 1. For metal matrix composite materials such as alloys, stirring and cooling (first) to the temperature between the liquid and solid phases are required to control the material into a suitable solid semisolid slurry for the casting step (s). .

The term "fly ash" as used herein denotes a byproduct of coal combustion. The material consists mainly of complex aluminosilicate glass, mullite, hematite, magnetite spinel and quartz. The proportion of fly ash quartz (crystallin silica) depends on the quartz content of the coal. The term also used herein includes products known as pozzolan, fly ash, Class F fly ash and Class C fly ash. In the past, fly ash has been used as a supplementary cementitious material for concrete or concrete products. Fly ash has also been used for soil stabilization and as a fine filler for asphalt and other products.

With continued reference to FIG. 2, a first object of the present invention is the provision of an apparatus capable of carrying out steps 1a and 2 and additionally step 3 (in the case of step 3), at least, conveying to billet casting equipment. Or shot sleeve of a cold chamber casting machine. Alternatively, the equipment described above can be used when the ejection (step 3) is done directly to the die or mold (ie, at a relatively high pressure). Another object is to provide an improved method for the formation, control and use of metal alloys and metal matrix composites such as thixotropic slurries.

Returning to FIG. 1, the invention can also be used to carry out steps 2 and 3, which are described in the same manner as described in the previous paragraph with respect to FIG. 3.

3 is a cross-sectional view of the duct 1 and the device 2 according to one embodiment of the invention. The cross section was cut in the plane including the longitudinal axis 3 in the center of the duct 1. Preferably the duct 1 has a circular cross section. 4 is a cross-sectional view at the “4-4” position of FIG. 3 of the device 2 shown in FIG. 3, cut in a plane perpendicular to the axis 3. The long central body 4 is fixed in the duct 1 and coaxial with the duct. The body 4 and the wall 5 of the duct form between them a space 6 which is annular in the preferred embodiment. Multiple, preferably one or two interleaved Archimedean screw flights (7, 8) are arranged in the annular space (6), wherein the screw flights (if there are two such flights) E) Separated by an angle of 180 ° around the axis (3). The flights 7, 8 are fixed to the wall 5 and the central body 4 and extend therebetween. The flights therefore do not rotate in the duct 1 and thus avoid the problem of wear in the particular prior art approach mentioned previously. However, the flights modify the direction of the axial flow and add a helical component to the flow with turbulent agitation.

A fluid coolant jacket 9 capable of cooling the molten slurry or slurry in the duct surrounds the duct 1. In this kind of device the design of a liquid coolant jacket, such as the jacket 9 for cooling, is itself a complex technique. The jacket 9 may comprise additional components or may be different from the jacket 9 shown.

A plurality of, preferably three, solenoid type coils 10, designated R, Y, and B (in the illustrated embodiment) surround the duct and water jacket. By connecting one phase to each of the jaws R, Y and B, a three phase AC power source can be connected to the coils 10 in a known manner. When a current is supplied to the coils, the effect is to induce a eddy current and associated magnetic field in the duct 1 to move the molten metal or slurry in the duct 1 in the longitudinal direction as indicated by arrow "X". To form a moving magnetic field.

Screw flights 7, 8 restrict the slurry in the space 6 from moving in the longitudinal direction without being disturbed, and instead the flights 7, 8, the wall 5 and the body 4. The slurry is moved in a helical path along the two passages 11, 12 formed by it. Arrow “Y” in FIG. 3 indicates the general direction of this helical flow. Such a flow has elements of axial and centrifugal (combined, helical) under magnetic influence.

Inside each of the passages 11, 12, an impressed field is placed between the axial directions, which tend to move the metal or slurry in a generally helical path constrained by the metal or slurry to follow. There is a difference. The effect of this is thought to be to add a circulating flow (arrow "Y") that generally traverses the main flow in each passage, without being limited to any particular theory regarding the behavior of the device 2, and thus the above It inhibits dendritic growth while enhancing mixing and heat transfer between the slurry and the walls of the duct. Arrow “Z” in FIG. 3 represents this flow added to passage 11. As a result, the slurry is moved or pumped from the inlet end 13 of the duct 1 toward the outlet end 14.

      Thus, the apparatus 2 shown in FIGS. 3 and 4 can be used to pump the slurry and to provide the following:

(a) the flow shear required to limit the formation of dendritic shaped particles of the material such that the dendritic shaped particles become (or maintained) spheroidal degenerate dendritic particles and a thixotropic slurry is formed. And stirring,

(b) mixing the slurry with solid additives (eg fly ash), preferably when a slurry of metal matrix composite material is desired.

Moreover, the non-rotationality of the screw flights 7, 8 is believed to limit the wear they suffer. Also note that in the device 2 the paths followed by the metal or slurry between the inlet 13 and the outlet 14 are generally longer than in the case of pure axial flow devices and are therefore used for mixing and stirring. The length of the possible flow paths is longer than for axial flow ducts of the same length, on the one hand the coil 10 and the coolant jacket 9 can be relatively short.

Alternative Examples  And process steps

Many modifications are possible to enhance and / or modify these effects to suit particular conditions and particular applications. Some are described in paragraphs (a) to (j) below.

As disclosed in the above-mentioned patents and as known in the prior art, different coil arrangements have been developed which can be used with the present invention. For example, at least the following alternative configurations of (a) to (e) may be applied individually or in a suitable combination.

(a) Instead of the set of solenoid coils 10 shown in FIGS. 3 and 4, a stator ring arrangement (not shown) similar to a polyphase induction motor may be provided, The duct 1 passes through the stator ring. The rotating magnetic field so applied to the slurry tends to rotate the slurry about the duct shaft 3. However, the effect of the screw flights 7, 8 is that such movement leads to axial movement. Further flows can also occur in the apparatus 2 shown in FIGS. 3 and 4.

   (b) Another coil device (not shown) that may be used is a device that provides a helically traveling field. Such coil arrangements are disclosed, for example, in US Pat. No. 2,786,416. If the helix angle and direction of the screw flights 7 and 8 are the same as the torsion angle and direction of the energized moving magnetic field, the effect is along the flow passages 11 and 12 between the flights. The idea is to move the metal or slurry with relatively low levels of added circulating flow and mixing. However, if the torsion angle of the screw flight and the torsion angle of the magnetic field do not coincide, then the relative ratio of the flows along the spiral flow passages 11, 12 and secondly the added flows in those paths is different. It is believed to increase turbulence. An appropriate degree of mismatch can be chosen.

(c) Different types of coils may be used in combination. For example, using a "stack" of solenoid coils arranged in the longitudinal direction (such as coil 10 in FIG. 3) in combination with one or more stator-ring devices (not shown) described in (a) above It is possible. In this way, it is possible to enable a range of levels and forms of mixing, stirring and pumping along the longitudinal direction of the device 2.

(d) The coils are excited in various ways. For example, by changing the line frequency, the rate of movement of the slurry and the degree of penetration of the magnetic field (e.g., rotation or solenoid) into the slurry can be changed, resulting in a change in the flow pattern and thus pumping. It is thought that a change is caused even in a mixture. Another possibility is to use pulsed direct current, not constant alternating current.

   (e) Coils inside the central body 4 of the device shown in FIGS. 3 and 4 in some arrangements, either in place of or in addition to external coils such as coils 7, 8. It may be possible to provide (not shown). For example, US Pat. No. 3,885,890 discloses a device of coils that can provide a spiral moving field and can be mounted to a body within an annular flow space. By combining different types of coils, for example by helically combining an outer solenoid in the central body, a wide range of shear strengths and induced flow paths can be produced and thus influence the mixing process.

(f) In FIGS. 3 and 4, the device 2 has only two screw flights 7, 8 of constant pitch and of a specific twist angle. However, it is possible to change the shape of the flights. For example, the number and twist angle of the flights may vary and the pitch may vary along the duct length direction. This affects, for example, the turbulence characteristic that can be generated. It may also be desirable to intentionally mismatch the pitch of the screw flights and the longitudinal spacing of the coils in order to increase the flow change and promote mixing along the longitudinal direction of the duct. (This is not shown in FIG. 3, where the number of coils per flight pitch length is an integer.)

It is also possible to provide interruption to the screw flights. One embodiment is shown in FIGS. 5 and 6. 5, which is provided for reference, is an exploded view of the inner surface of the wall in which the inner surface 15 of the wall 5 is fixed to the screw flights 7, 8. To understand FIG. 5, consider that the wall 5 is cut in the longitudinal direction and then flattened at a point on the circumference indicated by "Q" in FIG. 4. In FIG. 5, screw flights 7, 8 fixed to the surface 15 are shown. The front edges 16, 17 of the screw flights 7, 8 are shown in FIGS. 3 and 5. FIG. 6 is written in the same manner as FIG. 5 and is intended to allow direct contrast. In the flight arrangement of FIG. 6, four screw flights 18, 19, 20, 21 are shown. The flights 18, 19 are shorter than the flights 7, 8 and extend only in the longitudinal direction in the segment 22 of the duct 1, the flights 18, 19 are shown in FIGS. Same as the flights 7, 8 of FIGS. 4 and 5. After the short longitudinal clearance 23, the flights 20, 21 start and extend along the segment 24 of the duct 1. The torsion angles "T" of the flights are shown to be the same in magnitude as the torsion angles of the flights 18, 19, but the flights 20, 21 are in opposite directions to the flights 18, 19 and the flights 20, The leading edges 25, 26 of 21 are circumferentially moved from the trailing edges 27, 28 of the flights 18, 19.

The effect of this arrangement is a set of solenoid type coils (such as a jaw of coils 10) arranged to move the contained metal or slurry in the axial direction of the duct (shown by arrow “P” in FIG. 6). When used together, there is an axial force component within the flight groups 18/19, 20/21. The metal or slurry moves along the duct 1 but generally improved shear agitation and mixing is present in the region, in particular firstly between the flights 18, 19 and secondly between the flights 20, 21. Must exist or exist.

It will be appreciated that other flight devices may be designed to enhance mixing and shearing / stirring of the contained metal or slurry. For example, the duct may have a larger number of flights of several pairs arranged axially than the two pairs 18/19, 20/21 shown in FIG.

(g) In Figures 3 and 4 there are shown flights 7, 8 which extend completely between the duct wall and the central body. Yet another possibility is to provide flights (not shown) that are secured to the central body and leave a gap while only partially extending outwardly towards the wall, or which are fixed to the wall and partially extend inwardly towards the central parent. It is. In each case, the gap is expected to enhance shear / stirring of the contained metal or slurry. More generally, the openings (holes, slots, etc.) of the flights or shaped free edges (where the flight is not fixed to the central body or wall) are mixed and sheared / stirred of the contained slurry. Can be provided to enhance.

Since the movement of the metal or slurry in the duct is caused by an externally applied moving magnetic field, the gap between the flights and the boundaries of the duct (or central body) is such that the flights are mechanically provided to provide such movement. Note that it does not have to be kept as small as in the case of rotation. It is therefore believed that wear can be reduced. It is also possible to modify the casing and / or flight shape to change the cross sectional shape of the flow conduits.

(h) In alternative embodiments, in any of the conduits through which the received material passes, it is possible to fix means for turbulating, such as non-flight bodies or structures, wherein the body or structure It introduces itself into turbulent or shear or other disturbing actions in the flow through the body or structure to enhance mixing and / or agitation.

(i) Optionally, the central body 4 can be made of a different diameter or its diameter can be varied in the longitudinal direction. The central body can accommodate a ferromagnetic (or other) material or component suitable for changing the magnetic flux pattern in the annular space 6 between the central body 4 and the duct wall 5. Means for cooling (or heating) the outer surface of the central body may be provided on the central body 4. The central body 4 may be omitted entirely as shown in FIG. 7 shows in a longitudinal cross section a duct 30 with spiral flights 31 extending inwardly from the inner surface 32 of the duct wall but leaving the central space 33. If there is no flow in the duct 30 (eg, if the duct is a duct that leads the slurry into the casting machine and the casting machine is between the shots) then the stirring and circulation of the slurry in the duct 30 is indicated by arrows 34. It can be maintained by movement through the flights 31 with recirculation through the space 33 as shown by. Shear / stirring and mixing occur at the cylindrical surface that divides the space 33 between the flights and from the edges 35 of the flights. Coils necessary to apply a voltage to the magnetic field are omitted in FIG.

(j) The specific chemistry of the slurry or metal contained in the duct is not essential to the present invention if it comprises a material that is susceptible to magnetic influence. However preferably the metal or metal matrix material which at least partially forms the slurry comprises aluminum or magnesium or alloys thereof.

8 shows a closed vessel 40 in which screw flights 41 are provided on the wall 42 to promote circulating flow and agitation as shown by arrows 43. The flow is thought to be similar to that derived by different means in US Pat. No. 6,637,927. Coils for energizing the magnetic field are omitted in FIG. 8 for clarity.

Other embodiments and methods

9 shows diagrammatically in a simplified schematic manner how the device of the invention may be used. The duct 52 formed at least in part by the apparatus 53 according to the invention (as shown for example in FIGS. 3 and 4) is a thixotropic slurry 51 (or just a fully molten metal or metal). From the reservoir 50 containing the alloy) to the outlet 54. The outlet 54 directs the metal or slurry to the shot sleeve 55 of the casting machine 56, from which the metal or slurry can be injected in a known manner into the die 58 by the plunger 57. Can be. Here, the apparatus 53 acts as a pump and is operated as needed once per casting cycle to transfer metal or slurry 51 to the casting machine 56. Although no flow control valve, heating jacket or other equipment is shown in FIG. 9, it is understood that these or other components may be provided as needed in a known manner.

A similar application (not shown) is to use a device similar to device 53 to pump semi-solid metal into position between the bisected dies of a thixofoaming machine.

10 shows yet another possible use example of the device 60 according to the invention in a simplified schematic manner. The duct 63 at least partially formed by the device 60 leads from the reservoir 61 to the nozzle 64 containing the thixotropic slurry (or simply completely molten metal) 62. The slurry 62 passes through the die 65 directly from the nozzle 64. Compared to the application shown in FIG. 9, in this case the pressure generated by the device needs to be higher and this is reflected in the design in many ways. As before, other components that may be required in accordance with the details of this application are not shown in this simplified diagram.

In an application similar to that shown in FIG. 10 (not shown), the slurry may be directed towards the upward flow portion of the extrusion die, the apparatus being continuous or half with the pressure required to extrude the material. Provide a continuous volume flow.

Another application of the device according to the invention is to mix the molten metal with the particulate additive and to condition the mixture to form a slurry and to keep the slurry in proper condition for continuous casting. For example, FIG. 11 shows various devices 71, 72, 73, a container 75 of molten metal 76 and a particulate additive 78 (in any of the appropriate forms described above) according to the present invention. Shown schematically is a device 69 having a duct 70, including an inlet end 74 in communication with a container 77. The molten metal 76 and additive 78 may each be (eg) an aluminum matrix alloy or a magnesium matrix alloy, and a fly ash (or other additive material), and may be a constituent of the metal matrix composite material.

In this application, the devices 71-73 perform three functions: combining the metal 76 and the additive 78; Providing a stirring process during cooling of the mixture required for the formation of a non-resin thixotropic slurry; And conveying the mixture to an outlet end 79 of the duct 70, from which the slurry can be directed to another processing point (e.g., a casting or thixofoaming machine) as needed.

  Along the longitudinal direction of the duct, three devices 71 to 73 are shown to emphasize the fact that different operating characteristics can be found to be desirable at different points. However, this does not mean that three devices are required or that each device performs one limited function-each device can contribute several different degrees of conveying, mixing and stirring functions. Each application determines the number of devices in question and all the parameters.

Apparatus 69 is capable of exiting the outlet in that it passes through the metal and additives once and the slurry of the specific properties is ready to be used "on the fly" or ready for further processing. once through) "device. The device 69 may be, for example, a substitute for augers and barrels of machines of the type shown in US Pat. Nos. 5,501,266 and 6,065,526.

Although not shown, it is possible to make changes to devices such as reference numerals 53, 60 and 69 in order to electromagnetically induce melt the metal or alloy itself in a known manner. This means that solid metal is added to one inlet and an additive for mixing with the metal is added to another inlet (if a metal matrix is created) and the thixotropic slurry is continuously or semi-continuously transported out of the outlet. Provide other possible forms.

FIG. 12 schematically illustrates an apparatus 100 comprising an apparatus 102 and a storage vessel 101 for transferring and stirring a molten or semi-molten metal, metal alloy or metal matrix composite material. The device 102 may be of the type shown in FIG. 3, for example. The device 102 and the container 101 are connected by ducts 103, 104 so that the contents of the container 101 can be circulated through the device 102 (as shown by arrow “A”). have. Thus, the state of the contents of the container 101 can be maintained (or adjusted if necessary) by the device 102 over time. The container 101 may have separate outlets and inlets for its contents (not shown).

FIG. 13 shows a possible apparatus for the production of a metal matrix composite material and subsequently for retaining the metal matrix composite material in a state suitable for receiving the metal matrix composite material and for use in a casting process (eg die casting). 105 is shown. A device 107 and a storage container 106 are provided for mixing, conveying and stirring the material passing through the device. The device 107 may be of the type shown in FIG. 3, for example, and it is possible to change as shown in FIG. 6 to enhance mixing. The device 107 is connected to the container by ducts 109, 110, so that the contents of the container 106 can be circulated and conveyed through the device 107 as indicated by arrow B. Means 108 are provided for introducing an additive (eg fly ash) from the vessel 106 to the metal or metal alloy passing through the apparatus 107 through the duct 110. Apparatus 107 transfers, mixes and stirs the material passing through it. The vessel 106 can be adapted to its own heating and cooling means independently of the apparatus 107. After a suitable time has elapsed, the metal matrix composite material can be produced in this way and given a suitable state for use thereafter and can remain in such a suitable state as required.

Various possible modifications of the invention disclosed herein are apparent to those skilled in the art, and they do not depart from the spirit and scope of the invention. Although embodiments of the invention have been described and described, it is not meant that these embodiments describe and describe all possible forms of the invention. Rather, the terms used herein are exemplary terms rather than limiting, and it is understood that various changes may be made without departing from the spirit and scope of the present invention.

Claims (26)

A casing containing a slurry of at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite material, At least one electrical conductor means arranged to apply a magnetic field to the slurry for directing slurry flow in the casing and in magnetic communication with the casing, and At least one component located within the casing and fixed to the casing and modifying the flow of the slurry induced by the magnetic field, wherein at least one of the molten metal or semi-solid metal or metal containing alloy or metal matrix composite material Apparatus for mixing, stirring and conveying the slurry. The method of claim 1, The casing comprises an inlet and an outlet, wherein the slurry mixes a slurry of one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material, characterized in that it flows from the inlet to the outlet under the influence of the magnetic field. , Apparatus for stirring and conveying. The method of claim 1, The at least one electrical conductor means mixing one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material slurry, characterized in that it comprises at least one set of windings which can be connected to an alternating current. , Apparatus for stirring and conveying. The method of claim 1, And further comprising at least one fluid coolant jacket in at least partially thermal communication with the casing to allow the fluid coolant to transfer heat between the slurry and the fluid coolant. 10. Apparatus for mixing, stirring and conveying a slurry of one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material, characterized by being capable of passing through the interior of the substrate. The method of claim 1, The at least one component comprises at least one molten metal, characterized in that it comprises a pair of helical screw flights forming between at least one conduit for guiding the flow of the slurry; Apparatus for mixing, stirring and conveying a slurry of semi-solid metal or metal containing alloy or metal matrix composite material. The method of claim 5, The at least one conduit comprises at least one molten metal or semisolid metal or metal containing alloy or metal, characterized in that it comprises at least one segment inclined in the direction of movement of the slurry to promote turbulence. Apparatus for mixing, stirring and conveying a slurry of a known composite material. The method of claim 1, Wherein the casing is formed at least in part from a titanium or titanium containing material. 20. An apparatus for mixing, stirring and conveying a slurry of at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite material. The method of claim 1, Said at least one component is at least partially formed of a titanium or titanium containing material, wherein said device is for mixing, stirring and conveying a slurry of one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material . The method of claim 1, The at least one electrical conductor means for mixing, stirring and conveying a slurry of at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite material, characterized in that it comprises at least one solenoidal coil. Device. The method of claim 1, The at least one electrical conductor means comprises a stator ring through which the casing passes so that a rotating magnetic field is applied to the slurry and thereby causes the slurry to rotate about the longitudinal axis of the casing. Apparatus for mixing, stirring and conveying a slurry of one or more molten metal or semi-solid metal or metal containing alloy or metal matrix composite material comprising a. The method of claim 1, The at least one electrical conductor means provides a helically traveling field and thereby causes the slurry to move along one or more passageways formed between the at least one component or Apparatus for mixing, stirring and conveying a slurry of semi-solid metal or metal containing alloy or metal matrix composite material. The method of claim 1, Wherein said at least one electrical conductor means comprises at least one solenoid coil in combination with at least one stator-ring device to provide a predetermined range of levels and forms of mixing, stirring and pumping along the longitudinal direction of the casing. Apparatus for mixing, stirring and conveying a slurry of one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material. The method of claim 1, In order to change the pattern of the flow and thus affect the pumping and mixing properties, by varying the line frequency, the movement of the slurry in the casing and the depth of penetration of the magnetic field can be altered, Mixing at least one slurry of molten metal or semi-solid metal or metal containing alloy or metal matrix composite material, characterized in that it also comprises means for changing the manner in which the at least one electrical conductor means is excited. A device for stirring and conveying. The method of claim 1, At least one molten metal or semi-solid metal or metal containing, further comprising an electrical energy source connected to said at least one electrical conductor means selected from the group consisting of alternating current, pulsed direct current, and combinations thereof Apparatus for mixing, stirring and conveying a slurry of alloy or metal matrix composite material. The method of claim 1, Wherein said at least one component comprises two screw flights. 1. A device for mixing, stirring and conveying a slurry of at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite material. The method of claim 15, Mix and stir a slurry of one or more molten or semisolid metals or metal containing alloys or metal matrix composite materials, each of the two screw flights having a constant pitch and a common helix angle. And an apparatus for conveying. The method of claim 1, The at least one component comprises two screw flights, each screw flight having a pitch and a torsion angle which can be varied, wherein at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite Apparatus for mixing, stirring and conveying slurry of material. The method of claim 1, Mixing, stirring and conveying a slurry of one or more molten metal or semisolid metal or metal containing alloy or metal matrix composite material, characterized in that a gap is formed between the inner wall of the casing and the at least one component. One device. The method of claim 1, And turbulating means extending from the at least one component, wherein the turbulent forming means exerts turbulent or shear or other disturbing action on the flow past the turbulent forming means to enhance mixing and / or agitation. Apparatus for mixing, stirring and conveying a slurry of at least one molten metal or semisolid metal or metal containing alloy or metal matrix composite material characterized by introducing. The method of claim 1, At least one molten metal or semi-solid metal or metal containing alloy or metal matrix, further comprising means for altering the magnetic flux pattern in the annular space between the inner wall of the casing and the at least one component. Apparatus for mixing, stirring and conveying the slurry of the composite material. The method of claim 1, The at least one component extends inwardly from the inner wall of the casing to leave a space extending in the axial direction through which the slurry can pass, or at least one molten metal or semisolid metal or metal containing alloy or Apparatus for mixing, stirring and conveying a slurry of metal matrix composite material. Providing the device of claim 1, and Transferring the slurry from an outlet of the casing to a destination selected from the group consisting of a die, a mold of a casting machine, a mold of a thixoforging machine, a shot sleeve of a die casting machine, and combinations thereof Casting method of the slurry comprising a. Placing the slurry into the casing, Providing at least one electrical conductor means for magnetically communicating with the slurry such that a moving magnetic field is applied to the slurry to direct a slurry flow in the casing, and Providing at least one fixed component located within the casing to alter the flow pattern of the slurry, thereby controlling, preventing or limiting the growth of dendritic particles. Method of conveying and controlling the state of slurry. The method of claim 23, wherein Passing a fluid coolant through a coolant jacket in thermal communication with the casing so that the temperature of the slurry can be controlled. Introducing the slurry into a casing comprising an internal storage space for a slurry of molten metal or semi-melt metal or metal alloy, Introducing an additive into the internal storage space for mixing with the slurry, Applying a current to at least one electrical conductor means in magnetic communication with the slurry, thereby applying a magnetic field to induce a flow to the slurry in the internal storage space, and Strengthening the mixing of the additive and the slurry by providing at least one component located in the casing and secured to the casing to alter the flow of the slurry induced by the magnetic field. A method of mixing an additive into a slurry of molten metal or semi-melt metal or metal alloy to produce a composite. Introducing a slurry of molten metal or semi-melt metal or metal alloy or metal matrix composite material into the casing, Supplying current to at least one electrical conductor means in magnetic communication with the casing such that the slurry is affected by a moving magnetic field that induces flow; and Providing at least one component located within the casing and secured to the casing to retard dendritic nucleation and growth by altering the flow of the slurry to retard dendritic nucleation and growth. Or a method of controlling the growth of dendritic solid particles in a slurry of a metal alloy or metal matrix composite material.

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