Hard composite with deformable constituent and method of applying to earth-engaging tool

Abstract

A hardmetal composite used as wear-resistant surfaces and inlays in earth-engaging equipment includes more than one hardphase. At least one hardphase has a high average particle size, for example, from 100 μm to 2000 μm. The hardphases vary in terms of particle size, hardness, and binder content, and at least one hardphase includes a particulate constituent capable of plastic deformation that comprises at least 1% residual porosity.

1 - 19 . (canceled) 
     
     
         20 . A method forming a drill bit comprising teeth, each of the teeth having a crest and a tang, the method comprising:
 selecting one or more hardphases comprising a hardmetal;   encapsulating particles of the one or more hardphases in a malleable matrix material to form first and second hardmetal composites, a volume fraction of the one or more hardphases for the first hardmetal composite being smaller than a volume fraction of the one or more hardphases for the second hardmetal composite;   applying a desired amount of the encapsulated particles to an outer surface of the drill bit such that the first hardmetal composite is applied to the crest of the teeth and the second hardmetal composite is applied to the tang of the teeth; and   finishing the drill bit by forging.   
     
     
         21 . The method of  claim 20 , wherein the hardmetal is carbide, one of the one or more hardphases has a particle size of from 100 μm to 2000 μm, and a total of the volume fractions is greater than 50%. 
     
     
         22 . The method of  claim 20 , wherein the one or more hardphases display bi-modal or multi-modal particle size distribution. 
     
     
         23 . The method of  claim 20 , wherein the one or more hardphases comprise at least two hardphases, wherein the particulate constituent of the two hardphases comprises a particulate constituent capable of plastic deformation that comprises at least 1% residual porosity. 
     
     
         24 . The method of  claim 20 , wherein the volume fraction of the malleable matrix is from 5% to 60% of the encapsulated particles. 
     
     
         25 . A method of forming a solid state forged product, the solid state forged product comprising a drill bit, the drill bit comprising teeth, each of the teeth having a crest and a tang, comprising:
 selecting a primary hardphase and at least one secondary hardphase, at least one of the primary and at least one secondary hardphases having at least 15% residual porosity and which exhibit plastic deformation under pressure, wherein a particulate constituent of the at least one secondary hardphase has an average particle size smaller than an average particle size of the primary hardphase;   forming first and second hardmetal composites by encapsulating particles of the primary and at least one secondary hardphases in a steel matrix comprised of iron powder, a volume fraction of the primary and secondary hardphases for the first hardmetal composite being smaller than a volume fraction of the primary and secondary hardphases for the second hardmetal composite;   applying a desired amount of the encapsulated particles to an outer surface of the drill bit such that the first hardmetal composite is applied to the crest of the teeth and the second hardmetal composite is applied to the tang of the teeth; and   finishing the drill bit by forging.   
     
     
         26 . The method of  claim 25 , wherein the primary hardphase has an average particle size of from 100 μm to 2000 μm. 
     
     
         27 . The method of  claim 25 , wherein the particulate constituent of the at least one secondary hardphase further comprises an average particle size of from 50 μm to 300 μm. 
     
     
         28 . The method of  claim 28 , wherein the particulate constituent of the at least one secondary hardphase further comprises an average particle size of from 50 μm to 100 μm. 
     
     
         29 . The method of  claim 28 , wherein the particulate constituent of the at least one secondary hardphase further comprises a binder content greater than 10 wt %. 
     
     
         30 . The method of  claim 28 , wherein the at least one secondary hardphase further comprises a hardness less than 1500 VHN. 
     
     
         31 . The method of  claim 25 , wherein the primary hardphase comprises a Co binder and the at least one secondary hardphase further comprises a Ni binder. 
     
     
         32 . The method of  claim 25 , wherein the volume fraction of the primary hardphase plus the volume fraction of the at least one secondary hardphase is greater than 50 vol % of the solid state forged product. 
     
     
         33 . The method of  claim 25 , wherein the volume fraction of the primary hardphase plus the volume fraction of the at least one secondary hardphase is greater than 60 vol % of the solid state forged product. 
     
     
         34 . The method of  claim 25 , wherein the steel matrix is comprised of iron powder with an average particle size of less than 20 μm. 
     
     
         35 . The method of  claim 34 , wherein the steel matrix is in the form of a malleable shell of the encapsulated particles of the primary and at least one secondary hardphases to form the encapsulated particles. 
     
     
         36 . The method of  claim 35 , wherein a volume fraction of the malleable matrix is from 5% to 60% of each of the encapsulated particles. 
     
     
         37 . The method of  claim 25 , wherein the primary hardphase and the at least one secondary hardphase comprise a hardmetal chosen from the group consisting of carbide, diamond, cubic boron nitride, and ceramic. 
     
     
         38 . The method of  claim 25 , wherein the solid state forged product is an earth-engaging tools. 
     
     
         39 . The method of  claim 20 , wherein the volume fraction of the primary and the at least one secondary hardphases for the first hardmetal composite is about 65%, and the volume fraction of the primary and the at least one secondary hardphases for the second hardmetal composite is about 75%. 
     
     
         40 . The method of  claim 25 , wherein the volume fraction of the primary and the at least one secondary hardphases for the first hardmetal composite is about 65%, and the volume fraction of the primary and the at least one secondary hardphases for the second hardmetal composite is about 75%. 
     
     
         41 . A drill bit for drilling through earth, comprising:
 a bit body having teeth extending therefrom, the teeth having a crest along a leading surface and a gage along a heel surface thereof;   a first hardmetal composite applied to the crest;   a second hardmetal composite applied to the gage;   wherein each of the first and second hardmetal composites comprises a primary and at least one secondary hardphase encapsulated in a steel matrix comprised of iron powder, at least one of the primary and at least one secondary hardphases for each of the first and second hardmetal composites having at least 15% residual porosity and exhibiting plastic deformation under pressure, a volume fraction of the primary and the at least one secondary hardphases for the first hardmetal composite being smaller than a volume fraction of the primary and the at least one secondary hardphases for the at least one second hardmetal composite; and   wherein a particulate constituent of the at least one secondary hardphase has an average particle size smaller than an average particle size of the primary hardphase.