Methods of forming a metallic or ceramic article having a novel composition of functionally graded material and articles containing the same
There is disclosed a method of making a metallic or ceramic component, such as a cutting or forming tool, from at least two distinct powder precursors. In one embodiment, the method comprising forming a first mixture comprised of a plurality of coated particles, such as Tough-Coated Hard Powder (TCHP) composite particles created by encapsulating extremely hard core particles with very tough binder and structural materials, and at least one support powder, such as a carbide, typically WC—Co. The mixture is formed into a green body and sintered to form a functionally graded or multicomponent article. Non-limiting examples of the articles made from the disclosed methods are also disclosed and include drills, mills, cutting tools, forming tools, wires dies and mechanical components.
1. A method of making a metallic or ceramic component, said method comprising:
a) providing at least one first powder, said first powder comprising a plurality of composite particles, made of a core particle material, an intermediate layer on said core particle material, and an outer layer, wherein said core particle material has a hardness higher than both the intermediate layer and the outer layer, and said intermediate layer has a fracture toughness greater than both the core particle material and the outer layer;
b) providing at least one second powder comprising a carbide material;
c) forming a green body comprised of said first and second powder mixtures such that the first powder mixture forms a first portion of said green body with the second powder mixture forming a second portion of said green body;
d) molding, pressing or shaping said green body to form a compact; and
e) sintering said compact to form an article having portions of different juxtaposed properties, said first portion of said green body forming hard wear-resistant portion of said article and said second portion of said green body forming a tough, strong load bearing portion of said article.
2. The method of claim 1 , wherein said at least one first powder comprises a core particle comprising a compound selected from the group consisting of: TiN, Ti(C,N), TiC, TiB 2 , ZrC, ZrN, ZrB 2 , VC, VN, cBN, Al 2 O 3 , Si 3 N 4 , SiB 6 , SiAlCB, W 2 B 5 , AlN, AlMgB 14 , MoFeB (iron molybdenum boride), MoS 2 , MoSi 2 , Mo 2 B 5 , Mo 2 B, and diamond.
3. The method of claim 1 , wherein said at least one first powder comprises an intermediate layer on said core particles, said intermediate layer comprising at least one compound selected from WC, W 2 C, tool steel, glassy and devitrified nanosteel alloys, silicon nitride, tantalum carbide, or combinations thereof.
4. The method of claim 1 , wherein said outer layer comprises Co, Fe, Ni, or combinations thereof.
5. The method of claim 4 , wherein said at least one first powder comprises 9-10% by weight Co.
6. The method of claim 1 , wherein said at least one second powder comprising a carbide material comprises WC—Co.
7. The method of claim 4 , wherein said WC—Co has a particle size ranging from 0.5 to 5.0 micrometers.
8. The method of claim 1 , wherein the first and second powder mixtures of the green body are assembled under pressure ranging from 20,000-40,000 psi.
9. The method of claim 1 , wherein said molding, pressing or shaping comprises at least one method chosen from injection molding, extrusion, calendering, tape-casting, powder layering, or at least one additive manufacturing process.
10. The method of claim 1 , wherein the first and second powder mixtures form layers of the green body which are assembled into continuous rods, concentric cylinders or flat laminations, or more complex shapes.
11. The method of claim 1 , wherein the first and second powder mixtures of the green body are assembled at a temperature ranging from 30-200° C.
12. The method of claim 1 , wherein the green body assembly is sintered after compaction by a method selected from liquid phase sintering, hot pressing, hot isostatic pressing, sinter-HIP, spark plasma sintering, sinter forging, microwave, or rapid omnidirectional consolidation.
13. The method of claim 1 , wherein the green body assembly is sintered in an inert, carburizing, decarburizing or reducing, nitrogen, pressure or vacuum atmosphere.
14. The method of claim 1 , wherein the diameters of the first powder core particles and second powder particles comprising said green body assembly are in the range of about 0.5 to about 30 micrometers.
15. The method of claim 1 , wherein at least one of said first powder or said second powder are mixed with at least one additive chosen from paraffin waxes, stearic acid, ethylene bis-stearamide (EBS), polyvinyl alcohol, polyethylene glycol, and co-polymers with a plurality of said component particles prior to or simultaneous with said shaping.
16. The method of claim 1 , wherein said metallic or ceramic component comprises a functionally graded material, or a multi-component material.
17. A method of making a metallic or ceramic component, said method comprising:
a) providing at least one first formed green article, said formed green article comprising:
a plurality of composite particles, made of a core particle material, an intermediate layer on said core particle material, and an outer layer, wherein said core particle material has a hardness higher than both the intermediate layer and the outer layer, and said intermediate layer has a fracture toughness greater than both the core particle material and the outer layer;
b) providing at least one support powder comprising a carbide material;
c) forming a second green body comprised of said first green article and said at least one support powder;
d) compacting said first green article and said support powder to form a compact; and
e) sintering said compact to form an article having portions of different juxtaposed properties.
18. A sintered article comprising at least two distinct and adjacent compositional regions, comprising:
a first composition comprising:
a plurality of core particles comprising a compound selected from the group consisting of: TiN, Ti(C,N), TiC, TiB 2 , ZrC, ZrN, ZrB 2 , VC, VN, cBN, Al 2 O 3 , Si 3 N 4 , SiB 6 , SiAlCB, W 2 B 6 , AlN, AlMgB 14 , MoS 2 , MoSi 2 , Mo 2 B 5 , Mo 2 B, MoFeB (iron molybdenum boride), and diamond;
an intermediate layer on said core particles, said intermediate layer comprising at least one compound selected from WC, W 2 C, tool steel, glassy and devitrified nanosteel alloys, silicon nitride, tantalum carbide, or combinations thereof; and
an outer layer located on said intermediate layer which comprises Co, Fe, Ni, or combinations thereof; and
a second composition comprising a carbide material.
19. The article of claim 18 , wherein said second composition comprises WC—Co.
20. The article of claim 18 , wherein said first composition comprises 9-10% by weight Co.
21. The article of claim 18 , wherein said article comprising:
drills, mills, cutting or forming tools, drawing dies, extrusion dies, forging dies, cutting and stamping dies, forms, forming rollers, injection molds, shears, saws, hobs, breaches, reamers, taps;
individual mechanical parts chosen from gears, cams, journals, nozzles, seals, valve seats, pump impellers, capstans, sheaves, bearings, and wear surfaces;
integrated co-sintered components to replace mating parts, internal combustion engine rods, bearings, camshafts, transmission parts; and
electromechanical components such as memory drive reading heads and specialized magnets.
22. The article of claim 18 , wherein said article comprises a working region that is comprised substantially of said first composition, and a support region that is comprised substantially of said second composition.
23. The article of claim 18 , wherein said at least two distinct and adjacent compositional regions comprises a functionally graded material, or a multi-component material.