Shaped bodies containing short inorganic fibers or whiskers within a metal matrix

• US 5,153,057 A
• Filed: 04/24/1991
• Issued: 10/06/1992
• Est. Priority Date: 02/15/1989
• Status: Expired due to Fees

• Current Assignee: Technical Ceramics Laboratories, Inc. (Carpenter Technology Corporation)
• Original Assignee: Technical Ceramics Laboratories, Inc. (Carpenter Technology Corporation)
• Inventors: Corbett, William J., Lunde, Marvin C., Shaffer, Peter T. B.
• Primary Examiner(s): Lesmes, George F.
• Assistant Examiner(s): WITHERS, JAMES
• Application Number:
  US07/690,347
• Time in Patent Office: 531 Days
• Field of Search: 428/283, 428/296, 428/367, 428/408, 428/902, 428/288, 428/289, 428/302, 428/364, 428/457, 428/539.5, 428/903, 428/939, 501/89, 501/32, 501/95, 264/59, 264/63, 264/109, 264/125
• US Class Current: 428/293.1
• CPC Class Codes: B22F 2998/00 Supplementary information concerning processes or compositions relating to powder metallurgy
• CPC Class Codes: B22F 3/225 by injection molding
• CPC Class Codes: C04B 2235/522 Oxidic
• CPC Class Codes: C04B 2235/5224 Alumina or aluminates
• CPC Class Codes: C04B 2235/5228 Silica and alumina, including aluminosilicates, e.g. mullite
• CPC Class Codes: C04B 2235/5232 Silica or silicates other than aluminosilicates, e.g. quartz
• CPC Class Codes: C04B 2235/524 Non-oxidic, e.g. borides, carbides, silicides or nitrides
• CPC Class Codes: C04B 2235/5244 Silicon carbide
• CPC Class Codes: C04B 2235/5248 Carbon, e.g. graphite
• CPC Class Codes: C04B 2235/526 characterised by the length of the fibers
• CPC Class Codes: C04B 2235/5264 characterised by the diameter of the fibers
• CPC Class Codes: C04B 2235/5276 Whiskers, spindles, needles or pins
• CPC Class Codes: C04B 2235/5296 with a defined aspect ratio, e.g. indicating sphericity spherical constituents C04B2235/528
• CPC Class Codes: C04B 2235/6022 Injection moulding
• CPC Class Codes: C04B 2235/95 Products characterised by their size, e.g. microceramics
• CPC Class Codes: C04B 30/02 containing fibrous materials
• CPC Class Codes: C04B 35/6316 Binders based on silicon compounds
• CPC Class Codes: C04B 35/632 Organic additives
• CPC Class Codes: C04B 35/80 Fibres, filaments, whiskers, platelets, or the like
• CPC Class Codes: C04B 41/53 involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete C04B41/0036 - C04B41/0054 take precedence
• CPC Class Codes: C04B 41/72 : involving the removal of part of the materials of the treated articles, e.g. etching
• CPC Class Codes: C08K 7/02 : Fibres or whiskers
• CPC Class Codes: C22C 47/025 : Aligning or orienting the fibres
• CPC Class Codes: C22C 47/06 : by forming the fibres or filaments into a preformed structure, e.g. using a temporary binder to form a mat-like element
• CPC Class Codes: C22C 47/08 : by contacting the fibres or filaments with molten metal, e.g. by infiltrating the fibres or filaments placed in a mould C22C47/16 takes precedence
• CPC Class Codes: C22C 49/00 : Alloys containing metallic or non-metallic fibres or filaments
• CPC Class Codes: C22C 49/06 : Aluminium
• CPC Class Codes: Y10S 428/902 : High modulus filament or fiber
• CPC Class Codes: Y10S 428/903 : Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10S 428/939 : Molten or fused coating
• CPC Class Codes: Y10T 428/249927 : Fiber embedded in a metal matrix
• CPC Class Codes: Y10T 428/2913 : Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 : including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer
• CPC Class Codes: Y10T 428/31678 : Of metal

Abstract

A fiber-organic composition includes from about 5% to 50% by volume of uniformly dispersed, non-planar or three dimensionally random oriented inorganic fibers or whiskers, and a thermoplastic material such as paraffin wax. The composition also includes surfactants to promote wetting and dispersion of the inorganic fibers or whiskers. These materials are subjected to high shear mixing to form a uniform randomly oriented three-dimensional dispersion of the inorganic fibers or whiskers. After molding the mixture in such a manner so as not to disrupt the uniform, three-dimensional orientation of the fibers or whiskers, a majority of the thermoplastic material is removed leaving a shaped body or preform having sufficient strength for handling. The shaped body or preform can then be infiltrated with molten metal or the like to form a metal matrix composite.

Claims

1. A metal matrix composite comprising a mass of short inorganic fibers dispersed throughout the composite with a high degree of three-dimensional orientation, said inorganic fibers comprising at least 5% by volume of the composite and forming a shaped body or preform, and a metallic mass infiltrating and surrounding said fibers to thereby form the metal matrix composite and wherein the average angular deviation of said inorganic fibers within the composite is between 30°

and 60°

.

2. A metal matrix composite according to claim 1 wherein said fibers are selected from the group consisting of alumina, aluminum nitride, aluminum silicate, boron carbide, carbon, magnesium oxide, mullite, silicon carbide, silicon dioxide, silicon nitride, titanium nitride, zirconium, dioxide, iron, titanium and tungsten fibers, and wherein the fibers amount to at least about 10% to about 40% by volume of the composite.

3. A metal matrix composite according to claim 2 in which said fibers are bonded together at their points of contact by a ceramic bond.

4. A metal matrix composite according to claim 1 in which said metallic mass infiltrates and surrounds said mass of fibers to thereby provide a substantially void free composite and in which said metal and said fibers amount to about 100% by volume of said composite.

5. A metal matrix composite according to claim 4 wherein said fibers amount to between about 10% to 40% by volume of the composite and in which the metal amounts to between about 60% to 90% by volume.

6. A metal matrix composite according to claim 5 wherein said fibers are silicon carbide whiskers.

7. A metal matrix composite according to claim 6 wherein the silicon carbide whiskers are bonded together at their points of contact by oxidation.

8. A metal matrix composite according to claim 5 wherein said inorganic fibers are silicon nitride and wherein said inorganic fibers are bonded together at their points of contact by oxidation.

9. A metal matrix composite according to claim 1 wherein said metallic mass is selected from the group consisting of aluminum, aluminum alloys, magnesium and magnesium alloys, beryllium and beryllium alloys.

10. A metal matrix composite according to claim 9 in which said metallic mass is an aluminum alloy.

11. A metal matrix composite according to claim 1 which includes additional inorganic particles sufficient to raise the total volume fraction of inorganic particles and inorganic fibers to as much as about 0.80.

12. A metal matrix composite according to claim 11 wherein said inorganic fibers and said inorganic particles are bonded together at their points of contact by a ceramic bond.

13. A metal matrix composite according to claim 11 wherein said ceramic whiskers and said inorganic particles are silicon carbide.