Direct metal fabrication (DMF) using a carbon precursor to bind the "green form" part and catalyze a eutectic reducing element in a supersolidus liquid phase sintering (SLPS) process
First Claim
Patent Images
1. A method of direct metal fabrication (DMF) of metal parts, comprising:
- using a carbon precursor to wet a metal powder alloy (X) whose particles are mixed with a eutectic reducing element (A) and bind the particles into a green form part with a specified shape, said particles each having a plurality of grains that are bound together along grain boundaries;
partially reducing the carbon precursor such that a thin carbon (C) film remains whose C═
C bonds maintain the part'"'"'s specified shape and acts as a catalyst causing the eutectic reducing element to become diffusely mobile;
diffusing the eutectic reducing element along the particles'"'"' grain boundaries such that the reducing element interacts with the carbon film at the interface between the particles to form organo-metallic bonds C═
A that are much stronger than the film'"'"'s C═
C bonds; and
initiating supersolidus liquid phase sintering (SLPS) to form a liquid film along the particles'"'"' grain boundaries so that the grains slide relative to each other and densify in response to surface tension and capillary pressure to form a final part whose organo-metallic C═
A bonds maintain the specified shape.
7 Assignments
0 Petitions
Accused Products
Abstract
Direct Metal Fabrication of metal parts is accomplished with a continuous thermal process in which partial reduction of the "green form" part leaves a thin carbon film that maintains the part'"'"'s structural integrity. The remaining carbon catalyzes a eutectic reducing element to diffuse throughout the part forming organo-metallic bonds that bind the homogenized metal alloy. Supersolidus liquid phase sintering (SLPS) densities the alloy to provide a final part of parent material quality. The DMF process can be used in magnetographic printing to imprint an image.
-
Citations
36 Claims
-
1. A method of direct metal fabrication (DMF) of metal parts, comprising:
-
using a carbon precursor to wet a metal powder alloy (X) whose particles are mixed with a eutectic reducing element (A) and bind the particles into a green form part with a specified shape, said particles each having a plurality of grains that are bound together along grain boundaries; partially reducing the carbon precursor such that a thin carbon (C) film remains whose C═
C bonds maintain the part'"'"'s specified shape and acts as a catalyst causing the eutectic reducing element to become diffusely mobile;diffusing the eutectic reducing element along the particles'"'"' grain boundaries such that the reducing element interacts with the carbon film at the interface between the particles to form organo-metallic bonds C═
A that are much stronger than the film'"'"'s C═
C bonds; andinitiating supersolidus liquid phase sintering (SLPS) to form a liquid film along the particles'"'"' grain boundaries so that the grains slide relative to each other and densify in response to surface tension and capillary pressure to form a final part whose organo-metallic C═
A bonds maintain the specified shape. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method of direct metal fabrication (DMF) of metal parts, comprising:
-
providing a mixture of a polymer (P) having a concentration of carbon (C) and metal powder alloys (X) and (Y) having substantially the same elemental compositions except that alloy Y includes a eutectic reducing element A at a concentration higher than any concentration of said eutectic reducing element A present in alloy X, said X and Y alloys'"'"' particles each having a plurality of grains that are bounded together along grain boundaries; using the polymer to wet and bind the X and Y alloy particles into a green form part with a specified shape; and in a single thermal cycle, heating the green form part to partially reduce the polymer so that a thin carbon film remains whose C═
C bonds maintain the part'"'"'s specified shape and acts as a catalyst causing the eutectic reducing element to become diffusely mobile;increasing the temperature to accelerate the diffusion of the eutectic reducing element along the grain boundaries of the alloy Y particles, through the carbon film, and along the grain boundaries of the adjacent alloy X particles until equilibrium of element A in the mixture is achieved so that the mixture is a fully homogenized metal powder alloy Z that is held together by the organo-metallic bonds C═
A formed when said element A interacts with the carbon film;increasing the temperature above a solidus temperature for alloy Z to initiate supersolidus liquid phase sintering (SLPS) where a liquid film forms along the particles'"'"' grain boundaries so that the grains slide relative to each other and densify in response to surface tension and capillary pressure to form a final part whose organo-metallic C═
A bonds maintain the specified shape, said carbon and eutectic reducing elements constituting such a small portion of said final part that it exhibits the properties of the parent alloy X; andcooling the final part to complete densification. - View Dependent Claims (16, 17, 18, 19, 20)
-
-
21. A method of direct metal fabrication (DMF) of metal parts, comprising:
-
a) mixing powders of a parent metal, a eutectic reducing element A, and a polymer to form a mixture; b) spreading a layer of said mixture on a platform; c) directing a beam of energy onto selected areas of said layer to cause localized melting of said polymer, said polymer resolidifying to bind said metal powders in said selected areas; d) repeating steps b and c to build up a green form part; and e) placing said green form part in a furnace where it is subjected to a thermal cycle that f) partially reduces the polymer leaving a thin carbon film whose C═
C bonds maintain the part'"'"'s specified shape and act as a catalyst causing the eutectic reducing element to become diffusely mobile, g) accelerates the diffusion of the eutectic reducing element along the grain boundaries of the adjacent parent metal particles to form organo-metallic bonds C═
A, h) initiates supersolidus liquid phase sintering (SLPS) to densify the powder into a final part whose organo-metallic C═
A bonds maintain the specified shape, and i)cools the final part to complete densification. - View Dependent Claims (22, 23, 24)
-
-
25. A method of direct metal fabrication of metal parts, comprising:
-
a) mixing powders of a parent metal, a eutectic reducing element A, and a polymer to form a mixture; b) feeding the mixture to a magnetographic printer that sequentially prints latent images formed from said mixture onto respective sheets of a thermally activated substrate carrier as it moves through the printer; c) cutting the next sheet off said substrate carrier; d) registering and laminating each successive sheet on top of the previous sheet to buildup a green form part layer-by-layer; and e) placing said green form part in a furnace where it is subjected to a thermal cycle that f) partially reduces the polymer leaving a thin carbon film whose C═
C bonds maintain the part'"'"'s specified shape and act as a catalyst causing the eutectic reducing element to become diffusely mobile, g) accelerates the diffusion of the eutectic reducing element along the grain boundaries of the adjacent parent metal particles to form organo-metallic bonds C═
A, h) initiates supersolidus liquid phase sintering (SLPS) to densify the powder into a final part whose organo-metallic C═
A bonds maintain the specified shape, and i)cools the final part to complete densification. - View Dependent Claims (26, 27, 28, 29, 30)
-
-
31. A method of direct metal fabrication (DMF) of metal parts, comprising:
-
a) providing a master mold for a green form part; b) mixing a metal powder alloy comprising alloy X particles and a eutectic reducing element with a polymer resin that wets and binds the particles in said mold to form the green form part; c) placing said mold in a furnace where it is subjected to a thermal cycle that f) partially reduces the polymer resin leaving a thin carbon film whose C═
C bonds maintain the part'"'"'s specified shape and acts as a catalyst causing the eutectic reducing element to become diffusely mobile, g) accelerates the diffusion of the eutectic reducing element along the grain boundaries of the adjacent alloy X particles to form organo-metallic bonds C═
A, h) initiates supersolidus liquid phase sintering (SLPS) to densify the powder into a final part whose organo-metallic C═
A bonds maintain the specified shape, and i)cools the final part to complete densification; andj) removing the final part from the mold. - View Dependent Claims (32, 33, 34, 35, 36)
-
Specification