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US 2006/0189474 A1Published application
Alumina-boron carbide ceramics and methods of making and using the same
OwnerRussell Yeckley, Shanghua Wuinventors
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Abstract
A ceramic body that contains between about 15 volume percent and about 35 volume percent of a boron carbide irregular-shaped phase and at least about 50 volume percent of alumina. The substrate has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5.
Claims23
A ceramic metalcutting insert for chip forming machining made from a starting powder mixture, the ceramic insert body comprising:
- a substrate having a rake surface and a flank surface wherein the rake surface and the flank surface intersect to form a cutting edge;
- the substrate comprising between about 15 volume percent and about 35 volume percent of a boron carbide irregular-shaped phase and at least about 50 volume percent alumina;
- and
- the substrate having a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5.
1 more element
A process for making a ceramic body comprising the steps of:
- providing a starting powder mixture,
- the starting powder mixture comprises between about 15 volume percent and about 35 volume percent boron carbide powder and at least about 50 volume percent alumina powder and no more than about 5 volume percent of a sintering aid;
- and
- consolidating the powder mixture at a temperature equal to between about 1400 degrees Centigrade and 1850 degrees Centigrade to achieve a ceramic with a density equal to greater than 99 percent of theoretical density.
1 more element
A ceramic body comprising:
- between about 15 volume percent and about 35 volume percent of a boron carbide irregular-shaped phase, and at least about 50 volume percent alumina, and
- the ceramic body has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5.
A method of machining a workpiece comprising the steps of:
- providing a workpiece;
- providing a ceramic cutting insert having a rake surface and a flank surface wherein the rake surface and the flank surface intersect to form a cutting edge and the ceramic cutting insert having a substrate that comprises between about 15 volume percent and about 35 volume percent of a boron carbide phase and at least about 50 volume percent alumina and has a fracture toughness (KIC, 18.5 Kg Load E&C) greater than or equal to about 4.5 MPa·m0.5;
- causing relative rotational movement between the workpiece and the ceramic cutting insert wherein the surface speed of the relative rotational movement is equal to or greater than about 457 surface meters per minute;
- and
- bringing the ceramic cutting insert and the workpiece into contact with each other so as to remove material from the workpiece.
2 more elements
Dependencies are inferred from the claim text.