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

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.

1 . An apparatus for mixing, agitating and transporting a slurry of one or more molten or semi-solid metals or metal-containing alloys or metal-matrix composite materials including:
 a casing for containing the slurry;   at least one electrical conductor means in magnetic communication with the casing and arranged for applying to the slurry a magnetic field to induce slurry flow in the casing; and   at least one component secured and located within the casing that modifies flow of the slurry induced by the magnetic field.   
   
   
       2 . The apparatus of  claim 1  wherein the casing includes an inlet and an outlet, the slurry flowing from the inlet to the outlet under the influence of the magnetic field. 
   
   
       3 . The apparatus of  claim 1  wherein the at least one electrical conductor means comprises one or more sets of windings that are connectable to an alternating current. 
   
   
       4 . The apparatus of  claim 1  further including:
 one or more fluid coolant jackets that at least partially lie in thermal communication with the casing so that a fluid coolant can pass therewithin to transfer heat between the slurry and the fluid coolant.   
   
   
       5 . The apparatus of  claim 1  wherein the at least one component comprises a pair of helical screw flights that define therebetween at least one conduit for guiding the flow of the slurry. 
   
   
       6 . The apparatus of  claim 5  wherein the at least one conduit includes at least one segment inclined to a direction of movement of the slurry for promoting turbulence. 
   
   
       7 . The apparatus of  claim 1  wherein the casing is formed at least in part of titanium or a titanium-containing material. 
   
   
       8 . The apparatus of  claim 1  wherein the at least one component is formed at least in part of titanium or a titanium-containing material. 
   
   
       9 . The apparatus of  claim 1  wherein the at least one electrical conductor means comprises one or more solenoidal coils. 
   
   
       10 . The apparatus of  claim 1  wherein the at least one electrical conductor means includes a stator ring through which the casing passes so that a rotating magnetic field is applied to the slurry, thereby urging it to rotate about a longitudinal axis of the casing. 
   
   
       11 . The apparatus of  claim 1  wherein the at least one electrical conductor means provides a helically traveling field whereby the slurry is urged along one or more passages defined between the at least one component. 
   
   
       12 . The apparatus of  claim 1  wherein the at least one electrical conductor means comprises one or more solenoidal coils in combination with one or more stator-ring arrangements in order to provide a range of degrees and forms of mixing, agitation and pumping along the length of the casing. 
   
   
       13 . The apparatus of  claim 1  further including:
 means for varying the manner in which the at least one electrical conductor means is excited so that by varying a line frequency, movement of the slurry within the casing and the depth of penetration of the magnetic field can be varied in order to produce changes in the flow pattern and so influence pumping and mixing characteristics.   
   
   
       14 . The apparatus of  claim 1  further including:
 a source of electrical energy connected to the at least one electrical conductor means, the source being selected from the group consisting of an AC current, a pulsed DC current, and combinations thereof.   
   
   
       15 . The apparatus of  claim 1  wherein the at least one component comprises two screw flights. 
   
   
       16 . The apparatus of  claim 15  wherein each of the two screw flights has a constant pitch and a common helix angle. 
   
   
       17 . The apparatus of  claim 1  wherein the at least one component comprises two screw flights, each flight having a helix angle and pitch that can be varied. 
   
   
       18 . The apparatus of  claim 1  wherein a gap is defined between the at least one component and an inner wall of the casing. 
   
   
       19 . The apparatus of  claim 1  further including means for turbulating extending from the at least one component which introduce turbulence or shearing or other disturbance to flow past the turbulating means so that mixing and/or agitation are enhanced. 
   
   
       20 . The apparatus of  claim 1  further including means for modifying a magnetic flux pattern in an annular space between the at least one component and an internal wall of the casing. 
   
   
       21 . The apparatus of  claim 1  wherein the at least one component extends inwardly from an internal wall of the casing, thereby leaving an axially extending space through which the slurry may flow. 
   
   
       22 . A method for casting a slurry, comprising the steps of:
 providing the apparatus of  claim 1 ; and   transporting 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.   
   
   
       23 . A method for transporting and controlling the state of a slurry including steps of:
 placing the slurry in a casing;   providing at least one electrical conductor means in magnetic communication with the slurry so that a moving magnetic field is applied to the slurry to induce flow thereof in the casing; and   providing at least one component secured to and located within the casing so as to modify the flow pattern of the slurry, thereby controlling, preventing or limiting the growth of dendritic particles.   
   
   
       24 . The method of  claim 23  further including the step of:
 passing a fluid coolant through a coolant jacket in thermal communication with the casing so that the temperature of the slurry can be controlled.   
   
   
       25 . A method for incorporating an additive material into a slurry of molten or semi-molten metal or metal alloy to produce a metal-matrix composite, including steps of:
 introducing the slurry into a casing that includes an internal containment space therefor;   introducing the additive material into the internal containment space for mixture with the slurry;   energizing at least one electrical conductor means in magnetic communication with the slurry, thereby applying to the slurry within the internal containment space a magnetic field to induce flow; and   providing at least one component secured to and located within the casing so as to modify the flow of the slurry induced by the magnetic field and thereby enhancing mixing thereof with the additive material.   
   
   
       26 . A method for controlling the growth of dendritic solid particles in a slurry of molten or semi-molten metal or metal alloy or metal-matrix composite material, including steps of:
 introducing the slurry into a casing;   energizing at least one electrical conductor means in magnetic communication with the casing so that the slurry is subjected to a moving magnetic field that induces flow; and   providing at least one component secured to and located within the casing to modify the flow of the slurry and thereby retarding dendritic nucleation and growth.