Selective laser sintering using nanocomposite materials

• US 5,431,967 A
• Filed: 04/08/1993
• Issued: 07/11/1995
• Est. Priority Date: 09/05/1989
• Status: Expired due to Fees

• Current Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Original Assignee: Board of Regents of the University of Texas System (University of Texas System)
• Inventors: Marcus, Harris L., Manthiram, Arumugam, Bourell, David L.
• Primary Examiner(s): BELL, JANYCE A
• Application Number:
  US08/044,971
• Time in Patent Office: 824 Days
• Field of Search: 127/555, 127/556, 127/197, 127/226, 127/376.2, 127/376.3, 127/266, 127/265
• US Class Current: 427/555
• CPC Class Codes: B22F 10/28 Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM]
• CPC Class Codes: B22F 10/64 by thermal means control of energy beam parameters for post heating B22F10/364
• CPC Class Codes: B22F 2003/1052 assisted by energy absorption enhanced by the coating or powder
• CPC Class Codes: B22F 3/004 Filling molds with powder feeding material to presses in general B30B15/302
• CPC Class Codes: B23K 26/34 Laser welding for purposes other than joining
• CPC Class Codes: B23K 35/0244 Powders, particles or spheres; Preforms made therefrom
• CPC Class Codes: B29C 64/153 using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 40/20 Post-treatment, e.g. curing, coating or polishing
• CPC Class Codes: B33Y 70/00 Materials specially adapted for additive manufacturing
• CPC Class Codes: B33Y 70/10 Composites of different types of material, e.g. mixtures of ceramics and polymers or mixtures of metals and biomaterials
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: C04B 35/622 Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
• CPC Class Codes: C04B 35/64 Burning or sintering processes C04B33/32 takes precedence ; powder metallurgy B22F
• CPC Class Codes: G05B 2219/49013 Deposit layers, cured by scanning laser, stereo lithography SLA, prototyping
• CPC Class Codes: Y02P 10/25 Process efficiency

Abstract

A method of fabricating three-dimensional objects in a layerwise fashion, and having high structural strength and high density, is disclosed. Methods are disclosed by which nanocomposite powders of ceramic-ceramic systems, ceramic-metal systems, ceramic-polymer systems, and metal-polymer systems are produced. Disclosed examples utilize solution chemistry approaches, such as sol-gel processing, by way of which a gel is produced which is then fired and milled to form a powder suitable for selective laser sintering, where a laser fuses selected portions of layers of the powders according to a computer-aided-design data base. The ultraheterogeneity of the powder results in larger surface area and grain boundaries of the constituents, which enhances the solid state diffusion mechanism, and thus reduces the time and temperature required for sintering to occur. In addition, the higher stored metastable energy of the nanocomposite powder is believed to enhance densification during solid-phase sintering. Objects of high density of complex shape may thus be obtained directly from CAD data base design representations.

Claims

1. A method of producing a three-dimensional object, comprising the steps of:

applying a layer of a nanocomposite powder at a target surface, said nanocomposite powder comprising at least first and second constituent materials, said first constituent material having a lower melting temperature than said second constituent material;

directing energy at selected locations of said layer corresponding to the cross-section of the object to be formed in said layer, to fuse particles of said first constituent material thereat;

repeating said applying and directing steps to form the object in layerwise fashion; and

removing unfused nanocomposite powder from said object.

2. The method of claim 1, further comprising:

placing precursors for said first and second constituent materials in solution;

forming a nanocomposite gel phase from said solution, said nanocomposite gel phase comprising said first and second constituent materials;

firing said nanocomposite gel phase; and

milling the fired nanocomposite gel phase to produce the nanocomposite powder comprising said first and second constituent materials.

3. The method of claim 1, wherein said first constituent material is the matrix phase of the object.

4. The method of claim 1, wherein said second constituent material is the matrix phase of the object.

5. The method of claim 1, further comprising:

heating the object after the step of removing the unfused nanocomposite powder.

6. The method of claim 5, wherein said first constituent material is a polymer;

and wherein said heating step removes the polymer from the object and fuses particles of said second constituent material to one another.

7. The method of claim 5, wherein said first constituent material is a polymer;

and wherein said heating step decomposes the polymer to provide a product phase remaining in the object.

8. The method of claim 2, further comprising:

wherein said first and second constituent materials are each a ceramic.

9. The method of claim 8, further comprising:

heating said nanocomposite powder during said directing energy step.

10. The method of claim 8, wherein said directing energy step also forms a spinel oxide.

11. The method of claim 2, wherein said first constituent material is a metal and said second constituent material is a ceramic.

12. The method of claim 11, further comprising:

after said step of removing the unfused nanocomposite powder, infiltrating the object with a fusing material.

13. The method of claim 2, wherein said first constituent material is a metal and said second constituent material comprises boron.