Composite article with coolant channels and tool fabrication method

Abstract

Embodiments of the present invention include composite articles comprising at least a first region and a second region and methods of making such articles. The first region may comprise a first composite material, wherein the first region comprises less than 5 wt. % cubic carbides by weight, and the second region may comprise a second composite material, wherein the second composite material differs from the first composite material in at least one characteristic. The composite article may additionally comprise at least one coolant channel. In certain embodiments, the first and second composite material may individually comprise hard particles in a binder, wherein the hard particles independently comprise at least one of a carbide, a nitride, a boride, a silicide, an oxide, and solid solutions thereof and the binder comprises at least one metal selected from cobalt, nickel, iron and alloys thereof. In specific embodiments, the first composite material and the second composite material may individually comprise metal carbides in a binder, such as a cemented carbide.

We claim: 
     
         1 . A method of forming an article, comprising:
 coextruding at least two composite materials comprising metal carbides to form a green compact.   
     
     
         2 . The method of forming an article of  claim 1 , wherein the coextruding at least two composite materials is performed through a die. 
     
     
         3 . The method of  claim 2 , wherein the die comprises means for making internal channels in the green compact. 
     
     
         4 . The method of  claim 2 , wherein the die comprises at least one wire. 
     
     
         5 . The method of  claim 4 , wherein the at least one wire forms an internal channel within the green compact. 
     
     
         6 . The method of  claim 4 , wherein the die comprises at least two wires. 
     
     
         7 . The method of  claim 6 , wherein the die comprises three wires. 
     
     
         8 . The method of  claim 4 , wherein at least one wire is a flexible wire. 
     
     
         9 . The method of  claim 8 , wherein the flexible wire comprises at least one of nylon, a polymer coated metal wire, polyethylene, high density polyethylene, polyester, polyvinyl chloride, polypropylene, an aramid, Kevlar, polyetheretherketone, cotton, animal gut, hemp and jute. 
     
     
         10 . The method of  claim 4 , wherein the wire is an inflexible. 
     
     
         11 . The method of  claim 10 , wherein the wire comprises a metal. 
     
     
         12 . The method of  claim 1 , further comprising:
 loading a feed chamber with at least two cemented carbide grades.   
     
     
         13 . The method of  claim 12 , wherein at least one cemented carbide grade is in extruded form. 
     
     
         14 . The method of  claim 13 , wherein the extruded form is at least one of a rod, bar, and a tube. 
     
     
         15 . The method of  claim 12 , wherein loading the feed chamber comprises loading at least one cemented carbide grade in a rod shape and at least one cemented carbide in a tube shape. 
     
     
         16 . The method of  claim 13 , wherein a plurality of cemented carbide grades are loaded into the feed chamber in the shape of a tube. 
     
     
         17 . The method of  claim 12 , further comprising:
 extruding a first cemented carbide grade in the form of a tube.   
     
     
         18 . The method of  claim 17 , further comprising:
 extruding a second cemented carbide in the form of a rod.   
     
     
         19 . The method of  claim 18 , wherein the cemented carbide in the form of a rod is extruded directly into a feed chamber of a coextruder. 
     
     
         20 . The method of  claim 1 , wherein composite materials are cemented carbides. 
     
     
         21 . The method of  claim 1 , wherein the green compact comprises two cemented carbide grades and the cemented carbide grades are coaxially disposed. 
     
     
         22 . The method of  claim 1 , wherein at the die includes a channel die. 
     
     
         23 . The method of  claim 22 , wherein the at least two cemented carbide grades are coextruded through a die comprising internal spiral serrations. 
     
     
         24 . The method of  claim 22 , wherein the at least two cemented carbides are coextruded through a rotating die. 
     
     
         25 . The method of  claim 2 , wherein the green compact comprises at least one channel. 
     
     
         26 . The method of  claim 2 , wherein the green compact comprises two helical channels. 
     
     
         27 . A method of producing a rotary tool having a composite structure, the method comprising:
 placing extruded first powder metal into a first region of a void of a mold;   placing a second metallurgical powder metal into a second region of the void, the extruded first powder metal differing from the second metallurgical powder; compressing the mold to consolidate the extruded first powder metal and the second powder metal to form a green compact;   and over-pressure sintering the green compact.   
     
     
         28 . The method of  claim 27 , further comprising:
 removing material from the green compact to provide at least one cutting edge.   
     
     
         29 . The method of  claim 28 , wherein the mold is a dry-bag rubber mold, and further wherein compressing the mold comprises isostatically compressing the dry-bag rubber mold to form the green compact. 
     
     
         30 . The method of  claim 28 , wherein removing material from the green compact comprises machining the compact to form at least one helically oriented flute defining at least one helically oriented cutting edge. 
     
     
         31 . The method of  claim 27 , wherein the extruded first compost powder comprises at least one channel. 
     
     
         32 . The method of  claim 31 , wherein the extruded first powder metal comprises at least two channels. 
     
     
         33 . The method of  claim 27 , wherein both the first powder metal and the second powder metal comprise a powdered binder and particles of at least one carbide of an element selected from the group consisting of group IVB, group VB and group VIB elements. 
     
     
         34 . The method of  claim 33 , wherein the binders of the first powder metal and the second powder metal each individually comprise at least one metal selected from the group consisting of cobalt, cobalt alloy, nickel, nickel alloy, iron and iron alloy. 
     
     
         35 . The method of  claim 27 , wherein the first powder metal and the second powder metal each individually comprise 2 to 40 weight percent of the powdered binder and 60 to 98 weight percent of the carbide particles. 
     
     
         36 . The method of  claim 27 , wherein at least one of the first powder metal and the second powder metal comprises tungsten carbide particles having an average particle size of 0.3 to 10 μm. 
     
     
         37 . The method of  claim 27 , wherein over pressure sintering the compact comprises heating the compact at a temperature of 1350° C. to 1500° C. under a pressure of 300-2000 psi. 
     
     
         38 . The method of  claim 27 , wherein compressing the mold comprises isostatically compressing the mold at a pressure of 5,000 to 50,000 psi. 
     
     
         39 . The method of  claim 27 , wherein the green compact formed by compressing the mold comprises:
 a first region comprising a first cemented carbide material provided by consolidation of the first metallurgical powder; and   a second region comprising a second cemented carbide material provided by consolidation of the second metallurgical powder, the first region and the second region differing with respect to at least one characteristic.   
     
     
         40 . The method of  claim 39 , wherein the characteristic is at least one selected from the group consisting of modulus of elasticity, hardness, wear resistance, fracture toughness, tensile strength, corrosion resistance, coefficient of thermal expansion, and coefficient of thermal conductivity.