Method and apparatus for producing semisolid method slurries and shaped components
AssigneeBrunel University
InventorsZhongyun Fan, Michael John Bevis, Shouxun Ji
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Abstract
A method and apparatus for converting liquid alloy into its thixotropic state and for fabricating high integrity components by injecting subsequently the thixotropic alloy into a die cavity. The apparatus includes a liquid metal feeder, a high shear twin-screw extruder, a shot assembly and a central control system. The apparatus and method can offer net-shaped components characterized by close to zero porosity, fine and equiaxed particles with a uniform distribution in the eutectic matrix, and a large range of solid volume fractions.
Claims24
A method for forming a shaped component from liquid metal alloy, comprising the steps of:
- a. cooling the alloy to a temperature below its liquidus temperature while applying shear at a sufficiently high shear rate and intensity of turbulence to convert the alloy into its thixotropic state, and
- b. subsequently transferring the alloy into a mold to form a shaped component,
- wherein shear is applied to the alloy by means of an extruder having at least two screws which are at least partially intermeshed.
Apparatus for forming a shaped component from liquid metal alloy, comprising:
- a. a temperature-controlled extruder able to impart sufficient shear and intensity of turbulence to a liquid metal alloy to convert it into its thixotropic state,
- b. a shot assembly in fluid communication with the extruder, and
- c. a mold in fluid communication with the shot assembly,
- wherein the extruder has at least two screws which are at least partially intermeshed.
Apparatus as claimed in 7, wherein the extruder barrel has an inner layer is mechanically bonded to an outer layer of said barrel by shrink fitting.
A method of forming a semisolid slurry from a liquid metal alloy, comprising the steps of cooling the alloy below its liquidus temperature while applying shear at a sufficiently high shear rate and intensity of turbulence to convert the alloy into its thixotropic state, wherein shear is applied to the alloy by means of an extruder having at least two screws which are at least partially intermeshed.
Dependencies are inferred from the claim text.