Abstract: The invention is directed to a method of making liquid metal compositions containing a large number of solid particles per unit volume, without external heat removal, which solid particles act as nuclei for grains when the metal is solidified. A method of forming a metal solid includes the step of partially removing a solute of a liquid metallic solution which is at its liquidus temperature to partially solidify a metal solvent component, thereby forming a solid fraction, wherein there is essentially no reduction in temperature of the liquid metallic solution and solid fraction. The method further includes the step of subsequently lowering the temperature of the liquid metallic solution and solid fraction to solidify the remaining liquid metallic solution and thereby form a solid that includes the solid fraction formed during the step of partial solute removal. In an embodiment, the method further includes turbulence from gas evolution which aids in solid particle formation and grain refinement.

Abstract: The invention is directed to a method of making liquid metal compositions containing a large number of solid particles per unit volume, without external heat removal, which solid particles act as nuclei for grains when the metal is solidified. A method of forming a metal solid includes the step of partially removing a solute of a liquid metallic solution which is at its liquidus temperature to partially solidify a metal solvent component, thereby forming a solid fraction, wherein there is essentially no reduction in temperature of the liquid metallic solution and solid fraction. The method further includes the step of subsequently lowering the temperature of the liquid metallic solution and solid fraction to solidify the remaining liquid metallic solution and thereby form a solid that includes the solid fraction formed during the step of partial solute removal. In an embodiment, the method further includes turbulence from gas evolution which aids in solid particle formation and grain refinement.

Abstract: A system and method for centrifugal casting of composites, especially metal-matrix composites. According to the system and method, a porous preform is infiltrated with matrix material using a centrifugal force to pressurize the matrix material against the preform. The pressure head of the matrix material is maintained at an approximately constant level throughout infiltration.

Abstract: A method and apparatus for producing a metal component from a non-dendritic, semi-solid metal alloy slurry involves the use of a graphite agitator that is functionally equivalent to conventional metal rod agitators, and has the additional advantage of having a very low surface wettability, whereby labor and expenses associated with removing a metal alloy skin formed after withdrawal of the agitator from a metal slurry is eliminated or at least substantially reduced. The invention also provides an improved process and apparatus for producing a metal component from a non-dendritic semi-solid metal slurry by transferring the slurry to a cooling vessel for subsequent cooling and raising of the solids content without agitation after the slurry has been formed with agitation in a first vessel, whereby more rapid cooling of the slurry and increased production rates are achievable.

Abstract: A method and apparatus for producing a metal component from a non-dendritic, semi-solid metal alloy slurry involves the use of a graphite agitator that is functionally equivalent to conventional metal rod agitators, and has the additional advantage of having a very low surface wettability, whereby labor and expenses associated with removing a metal alloy skin formed after withdrawal of the agitator from a metal slurry is eliminated or at least substantially reduced. The invention also provides an improved process and apparatus for producing a metal component from a non-dendritic semi-solid metal slurry by transferring the slurry to a cooling vessel for subsequent cooling and raising of the solids content without agitation after the slurry has been formed with agitation in a first vessel, whereby more rapid cooling of the slurry and increased production rates are achievable.

Abstract: A system and method for centrifugal casting of composites, especially metal-matrix composites. According to the system and method, a porous preform is infiltrated with matrix material using a centrifugal force to pressurize the matrix material against the preform. The pressure head of the matrix material is maintained at an approximately constant level throughout infiltration.

Abstract: A skinless metal alloy composition free of entrapped gas and comprising primary solid discrete degenerate dendrites homogeneously dispersed within a secondary phase is formed by a process wherein the metal alloy is heated in a vessel to render it a liquid. The liquid is then rapidly cooled while vigorously agitating it under conditions to avoid entrapment of gas while forming solid nuclei homogeneously distributed in the liquid. Agitation then is ceased when the liquid contains a small fraction solid or the liquid-solid alloy is removed from the source of agitation while cooling is continued to form the primary solid discrete degenerate dendrites in liquid secondary phase. The solid-liquid mixture then can be formed such as by casting.

Abstract: A hot chamber method of die casting material in a semisolid state. The semisolid material has a high viscosity, which can be controlled by controlling the fraction of solid phase and the morphology of the solid phase. By controlling the viscosity of the melt, turbulence and consequent gas entrapment can be minimized or eliminated. Further, shrinkage is substantially reduced, thereby reducing porosity and hot tearing to form stronger, more reliable castings.

Abstract: A skinless metal alloy composition free of entrapped gas and comprising primary solid discrete degenerate dendrites homogeneously dispersed within a secondary phase is formed by a process wherein the metal alloy is heated in a vessel to render it a liquid. The liquid is then rapidly cooled while vigorously agitating it under conditions to avoid entrapment of gas while forming solid nuclei homogeneously distributed in the liquid. Agitation then is ceased when the liquid contains a small fraction solid or the liquid-solid alloy is removed from the source of agitation while cooling is continued to form the primary solid discrete degenerate dendrites in liquid secondary phase. The solid-liquid mixture then can be formed such as by casting.

Abstract: A hot chamber method of die casting material in a semisolid state. The semisolid material has a high viscosity, which can be controlled by controlling the fraction of solid phase and the morphology of the solid phase. By controlling the viscosity of the melt, turbulence and consequent gas entrapment can be minimized or eliminated. Further, shrinkage is substantially reduced, thereby reducing porosity and hot tearing to form stronger, more reliable castings.

Abstract: Apparatus and methods of die casting which reduce waste, by providing heated channels to feed solidification shrinkage. The channels are heated to a temperature which prevents solidification in the channels, thus allowing the channels to be substantially smaller than conventional risers. An insulating layer in the mold prevents excessive heat loss from the channels to the mold cavity area.

Abstract: Method for producing metal matrix composites. The method includes the steps of placing a substantially liquid metal in the vicinity of a reinforcement material and in the vicinity of the source of a transient magnetic field sufficient to produce an electromagnetic body force within the metal. The magnetic field is activated thereby propelling the substantially liquid metal into the reinforcement material thereby producing metal matrix composites.

Abstract: Composites of materials in which the matrix material does not spontaneously or readily wet the disperse phase and in which the volume fraction of the disperse phase is less than that formed in a packed bed of dispersate particles can be made effectively by an indirect method of infiltrating a packed bed of dispersate particles, using pressure or other mechanical force as needed to overcome poor wetting and form an intermediate concentrated composite. The concentrated composite is then mixed with additional matrix-forming material to produce the finally desired composite. The technique is particularly valuable for composites with ceramic dispersates and metal or alloy matrixes.

Abstract: The present invention involves a method and apparatus for making an intermetallic casting (e.g. a titanium, nickel, iron, etc. aluminide casting) wherein a charge of a solid first metal protected from air as required is disposed in a vessel, and a charge of a second metal that reacts exothermically with the first metal is melted in another vessel. The molten second metal is introduced to the vessel containing the charge of the first metal so as to contact the first metal. The first and second metals are heated in the vessel to exothermically react them and form a melt for gravity or countergravity casting into a mold. The exothermic reaction between the first and second metals releases substantial heat that reduces the time needed to obtain a melt ready for casting into a mold. In particular, the exothermic reaction between the first and second metals, in effect, reduces the residence time of the intermetallic melt in the vessel.

Abstract: A novel process for rapid solidification of ceramic melts combines certain features of cooling by atomization and by contact with chilling surfaces. The material to be solidified is divided into fine liquid droplets that are propelled by a rapid flow of gas toward a rapidly moving chill surface, striking the surface with sufficient velocity to flatten each drop into a flat flake like shape. Apparatus for the process is also disclosed. The process is particularly applicable to making very fine grained, or even amorphous, ceramic materials that can be powdered and then sintered into strong, tough ceramic structures.

Abstract: The casting apparatus and method include a magnetically responsive valve disposed in the molten metal inlet passage of the mold for movement between an open position during mold filling and a closed position after mold filling and during removal of the mold from the underlying molten metal pool to prevent run-out of molten metal from the metal-filled mold cavity. The valve is moved to the closed position by a magnetic force exerted thereon by permanent magnets or an electromagnet disposed around the inlet passage below the valve.

Abstract: The continuous manufacture of a composite in which dispersates are mixed within a matrix material is set forth. Molten metal alloy and concentrated dispersion containing a particulate ceramic dispersate in a precurser dispersion material are continuously fed into a chamber where the mixture is first blended, then agitated to shear both the particulate and matrix. Well dispersed slurry is then fed into a crucible for solidification processing, or is continuously cast into a billet.

Abstract: A novel process for rapid solidification of ceramic melts combines certain features of cooling by atomization and by contact with chilling surfaces. The material to be solidified is divided into fine liquid dropletes that are propelled by a rapid flow of gas toward a rapidly moving chill surface, striking the surface with sufficient velocity to flatten each drop into a flat flake like shape. Apparatus for the process is also disclosed. The process is particularly applicable to making very fine grained, or even amorphous, ceramic materials that can be powdered and then sintered into strong, tough ceramic structures.

Abstract: Purified metal compositions and metal compositions free of secondary phase material are produced by heating a metal alloy from the nonequilibrium solidus temperature while subjecting the liquid-solid mixture to high pressure and forcing the liquid through a filter. Compositions obtained by the process of this invention have a nondendritic structure which can be substantially free of secondary phase material.

Abstract: A homogeneous mixture of liquid-solid metal is shaped by passing the composition from an agitation zone onto a surface moving relative to the exit of the agitation zone. A portion of the composition contacting the moving surface is solidified and the entire composition then is formed.