Sang H Yoo

US Patent:

60013044, Dec 14, 1999

Filed:

Dec 31, 1998

Appl. No.:

9/223964

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

B22F 312

US Classification:

419 10

Abstract:

A method of bonding a particle material to near theoretical density, includes placing a particle material in a die. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps, is applied. The method can be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material. The method may also be applied to perform combustion synthesis of a reactive material, followed by consolidation or joining to near-net shaped articles or parts. The method may further be applied to repair a damaged or worn substrate or part, coat a particle onto a substrate, and grow single crystals of a particle material.

US Patent:

59894873, Nov 23, 1999

Filed:

Mar 23, 1999

Appl. No.:

9/274878

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

B22F 312

US Classification:

266249

Abstract:

An apparatus for bonding a particle material to near theoretical density, includes a chamber, a punch and die assembly for supporting a particle material, plungers for applying shear and/or axial pressures, and a power supply for applying a current. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps. is applied. The apparatus may be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material.

US Patent:

63095912, Oct 30, 2001

Filed:

Oct 5, 1999

Appl. No.:

9/412518

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

B22F 314
B22F 704

US Classification:

266249

Abstract:

An apparatus for bonding a particle material to near theoretical density, includes a chamber, a punch and die assembly for supporting a particle material, plungers for applying shear and/or axial pressures, and a power supply for applying a current. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps. is applied. The apparatus may be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material.

US Patent:

61836907, Feb 6, 2001

Filed:

Oct 5, 1999

Appl. No.:

9/412519

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

B22F 312

US Classification:

419 52

Abstract:

A method of bonding a particle material to near theoretical density, includes placing a particle material in a die. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps. is applied. The method can be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material. The method may also be applied to perform combustion synthesis of a reactive material, followed by consolidation or joining to near-net shaped articles or parts. The method may further be applied to repair a damaged or worn substrate or part, coat a particle onto a substrate, and grow single crystals of a particle material.

US Patent:

62707183, Aug 7, 2001

Filed:

Oct 5, 1999

Appl. No.:

9/412520

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

B22F 700

US Classification:

419 8

Abstract:

A method of bonding a particle material to near theoretical density, includes placing a particle material in a die. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps. is applied. The method can be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material. The method may also be applied to perform combustion synthesis of a reactive material, followed by consolidation or joining to near-net shaped articles or parts. The method may further be applied to repair a damaged or worn substrate or part, coat a particle onto a substrate, and grow single crystals of a particle material.

US Patent:

61870870, Feb 13, 2001

Filed:

Oct 5, 1999

Appl. No.:

9/412521

Inventors:

Sang H. Yoo - Fairfax VA
Tirumalai S. Sudarshan - Vienna VA

Assignee:

Materials Modification, Inc. - Fairfax VA

International Classification:

C30B 102
C30B 112

US Classification:

117 7

Abstract:

A method of bonding a particle material to near theoretical density, includes placing a particle material in a die. In the first stage, a pulsed current of about 1 to 20,000 amps. , is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a shear force of about 5-50 MPa is applied. In the second stage, an axial pressure of about less than 1 to 2,000 MPa is applied to the particle material for a predetermined time period, and substantially simultaneously therewith, a steady current of about 1 to 20,000 amps. is applied. The method can be used to bond metallic, ceramic, intermetallic and composite materials to near-net shape, directly from precursors or elemental particle material without the need for synthesizing the material. The method may also be applied to perform combustion synthesis of a reactive material, followed by consolidation or joining to near-net shaped articles or parts. The method may further be applied to repair a damaged or worn substrate or part, coat a particle onto a substrate, and grow single crystals of a particle material.