U.S. patent application number 14/019411 was filed with the patent office on 2014-03-13 for ultra-hard constructions with improved attachment strength.
This patent application is currently assigned to SMITH INTERNATIONAL, INC.. The applicant listed for this patent is SMITH INTERNATIONAL, INC.. Invention is credited to J. DANIEL BELNAP.
Application Number | 20140069727 14/019411 |
Document ID | / |
Family ID | 50232098 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140069727 |
Kind Code |
A1 |
BELNAP; J. DANIEL |
March 13, 2014 |
ULTRA-HARD CONSTRUCTIONS WITH IMPROVED ATTACHMENT STRENGTH
Abstract
Ultra-hard constructions comprise a sintered diamond-bonded body
comprising a matrix of bonded-together diamond grains and a
plurality of interstitial regions substantially free of a catalyst
material. A metal material comprising a carbide constituent is
disposed on a substrate interface surface of the diamond body. A
substrate is attached to the diamond-bonded body through a braze
joint interposed between the metal material and the substrate. The
braze joint is formed from a non-active braze material that reacts
with the substrate and metal material. The braze joint is formed at
the melting temperature of the non-active braze material in the
absence of high-pressure conditions. In an example embodiment, the
non-active braze material reacts with the carbide constituent in
the metal material. Example materials useful for forming the
non-active braze material include those selected from Cu, Ni, Mn,
Au, Pd, and combinations and alloys thereof.
Inventors: |
BELNAP; J. DANIEL; (LINDON,
UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SMITH INTERNATIONAL, INC. |
HOUSTON |
TX |
US |
|
|
Assignee: |
SMITH INTERNATIONAL, INC.
HOUSTON
TX
|
Family ID: |
50232098 |
Appl. No.: |
14/019411 |
Filed: |
September 5, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61698408 |
Sep 7, 2012 |
|
|
|
Current U.S.
Class: |
175/433 ; 51/297;
51/309 |
Current CPC
Class: |
C04B 37/025 20130101;
C04B 2235/5436 20130101; C04B 2237/55 20130101; C04B 35/645
20130101; C04B 2237/123 20130101; C04B 2237/401 20130101; B23K
2101/002 20180801; B24D 3/007 20130101; C04B 37/026 20130101; B24D
3/10 20130101; E21B 10/567 20130101; B24D 18/0009 20130101; C04B
2237/406 20130101; E21B 10/5735 20130101; C04B 2237/124 20130101;
C04B 2237/72 20130101; C04B 2237/60 20130101; E21B 10/55 20130101;
C04B 2237/125 20130101; C04B 2237/363 20130101; C04B 2237/708
20130101; C04B 2237/12 20130101; B23K 1/0008 20130101; C04B
2237/083 20130101 |
Class at
Publication: |
175/433 ; 51/309;
51/297 |
International
Class: |
B24D 3/00 20060101
B24D003/00; E21B 10/55 20060101 E21B010/55; E21B 10/567 20060101
E21B010/567 |
Claims
1. An ultra-hard construction comprising: a diamond-bonded body
comprising a matrix phase of bonded-together diamond grains,
wherein the body is thermally stable at temperatures above about
750.degree. C.; a metal material disposed on a substrate interface
surface of the diamond body, the metal material having a carbide
constituent; and a substrate connected with the diamond-bonded body
through a braze joint interposed between the metal material and the
substrate.
2. The construction as recited in claim 1, wherein the
diamond-bonded body further comprises a plurality of interstitial
regions interposed between the bonded-together diamond grains,
wherein the interstitial regions are substantially free of a
catalyst material used to sinter the diamond-bonded body at
high-pressure/high-temperature conditions.
3. The construction as recited in claim 1, wherein the
diamond-bonded body comprises a material synthesized under high
pressure and high temperature conditions using a carbonate
material.
4. The construction as recited in claim 1, wherein the metal
material comprises a carbide constituent, and wherein the substrate
comprises a carbide constituent.
5. The construction as recited in claim 1, wherein the braze joint
is formed from a non-active braze material that reacts with the
substrate and metal material.
6. The construction as recited in claim 1, wherein the metal
material has a layer thickness in the range of from about 0.1 to 10
microns.
7. The construction as recited in claim 5, wherein the non-active
braze material is selected from the group consisting of Cu, Ni, Mn,
Au, Pd and combinations and alloys thereof.
8. A cutting element for use in drilling subterranean formations,
the cutting element comprising the ultra-hard construction as
recited in claim 1.
9. A bit for drilling subterranean formations comprising a body and
a number of the cutting elements recited in claim 8 operatively
attached thereto.
10. An ultra-hard construction prepared by the process of: forming
a diamond-bonded body at high-pressure/high-temperature conditions
comprising a matrix phase of bonded-together diamond grains, the
body being thermally stable at temperatures above about 750.degree.
C.; treating the diamond-bonded body to include a metal material on
a substrate interface surface, wherein the metal material is
selected from the group consisting of carbide-including materials
and carbide-forming materials; and attaching a metallic substrate
to the diamond-bonded body, wherein a braze joint is used to attach
the metallic substrate to the diamond-bonded body at elevated
temperature in the absence of high-pressure conditions.
11. The construction as recited in claim 10, wherein the
diamond-bonded body comprises a plurality of interstitial regions
interposed between the bonded-together diamond grains.
12. The construction as recited in claim 10, wherein during the
step of forming, a carbonate material is used.
13. The construction as recited in claim 11, wherein the
diamond-bonded body is treated to render the interstitial regions
substantially free of a catalyst material used to form the
diamond-bonded body at the high-pressure/high-temperature
conditions.
14. The construction as recited in claim 10, wherein the metal
material is a carbide-forming material, and the process further
comprises a step of carburizing the metal material to provide a
carbide constituent.
15. The construction as recited in claim 14, wherein the step of
carburizing takes place at a temperature of greater than about
900.degree. C.
16. The construction as recited in claim 10, wherein the braze
joint is formed from a non-active braze material that reacts with
carbide in the substrate and body substrate interface surface to
form a strong bond therebetween, and wherein the elevated
temperature is approximately the melting temperature of the
non-active braze material.
17. A method for making an ultra-hard construction comprising the
steps of: forming a diamond-bonded body at
high-pressure/high-temperature conditions comprising a matrix phase
of bonded-together diamond grains, the body being thermally stable
at temperatures above about 750.degree. C.; treating a substrate
interface surface of the diamond-bonded body to include a metal
material layer thereon; and attaching a metallic substrate to the
diamond-bonded body, wherein prior to the step of attaching the
metal material comprises a carbide constituent, and wherein during
the step of attaching a braze material is melted and forms a braze
joint in the absence of high-pressure conditions.
18. The method as recited in claim 17, wherein the substrate
includes a carbide constituent, and wherein the braze material is a
non-active braze material.
19. The method as recited in claim 17, wherein during the step of
forming a carbonate material is used.
20. The method as recited in claim 17, wherein the body comprises a
plurality of interstitial regions interposed between the
bonded-together diamond grains, wherein the interstitial regions
are substantially free of a catalyst material used to form the
diamond-bonded body at the high-pressure/high-temperature
conditions.
21. The method as recited in claim 17, wherein during the step of
treating, the metal material is a carbide-forming material, and
where the method further comprises the step of carburizing the
metal material at a temperature greater than about 900.degree. C.
to provide a carbide constituent.
22. The method as recited in claim 21, wherein the step of
carburizing is carried out separately from the step of
attaching.
23. The method as recited in claim 17, wherein the step of
attaching is performed at a temperature between about 900 and
1,200.degree. C. in a vacuum environment.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of co-pending U.S.
Provisional Patent Application Ser. No. 61/698,408 filed on Sep. 7,
2012, which is incorporated herein by reference in its
entirety.
BACKGROUND
[0002] The use of constructions comprising ultra-hard and metallic
components that are joined together is well known in the art. An
example of such may be found in the form of cutting elements
comprising an ultra-hard component that is joined to a metallic
component. In such cutting element embodiment, the wear or cutting
portion is formed from the ultra-hard component and the metallic
portion of the cutting element is attached to the wear and/or
cutting device. In such known constructions, the ultra-hard
component may be formed from a polycrystalline material such as
polycrystalline diamond (PCD), polycrystalline cubic boron nitride
(PcBN), or the like, that has a degree of wear and/or abrasion
resistance that is greater than that of the metallic component.
[0003] In particular examples, the ultra-hard component may be PCD
that has been treated so that it is substantially free of a
catalyst material, e.g., a Group VIII metal from the Periodic
table, that was used to form/sinter the same at
high-pressure/high-temperature conditions, and that comprises
bonded-together diamond crystals. PCD that has been rendered
substantially free of the catalyst material is referred to as
thermally stable polycrystalline diamond (TSP), as removal of the
catalyst material has been found to improve the thermal stability
of the resulting diamond body by eliminating unwanted degradation
and thermal expansion mismatches that with increasing temperature
may adversely impact the effective service life of the diamond
body.
[0004] While TSP provides desired improvements in thermal
stability, a problem known to exist with TSP is that its lack of
catalyst material within the body operates to preclude subsequent
attachment of the TSP body to a metallic substrate by solvent
catalyst infiltration. Further, such TSP bodies have a coefficient
of thermal expansion that is sufficiently different from that of
conventional substrate materials (such as cermets like WC--Co and
the like) that are typically infiltrated or otherwise attached to a
PCD body. Attaching such substrates to the TSP body is highly
desired to provide a TSP compact that may be readily adapted for
use in many desirable applications. However, the difference in
thermal expansion between the TSP body and the substrate, and the
poor wettability of the TSP body due to the substantial absence of
the catalyst material, makes it very difficult to bond the TSP body
to conventionally used substrates. Thus, some TSP bodies are
attached or mounted directly to the desired end-use device without
the presence of an adjoining substrate.
[0005] It is known that TSP bodies may be attached to a desired
metallic substrate through the use of active braze materials, which
are known to have relatively low melting temperature and low yield
strengths. Combining the known limitations of active braze
materials with the inherently poor wettability of the TSP body, the
braze joint attachment that is formed between the TSP body and the
substrate is one that is not as strong as the attachment bond
formed between conventional PCD and a metallic substrate by
infiltration. The resulting construction is one having a diminished
service life due to the low yield strength of the braze material,
which leads to delamination between the TSP body and the substrate
during service.
SUMMARY
[0006] Ultra-hard construction disclosed herein comprise a
diamond-bonded body comprising a matrix phase of bonded-together
diamond grains and a plurality of interstitial regions interposed
between the bonded-together diamond grains. The interstitial
regions are substantially free of a catalyst material used to
sinter the diamond-bonded body at high-pressure/high-temperature
conditions. A metal material is disposed on a substrate interface
surface of the diamond body. In an example embodiment, the metal
material has a carbide constituent. In an example embodiment, the
metal material has a layer thickness in the range of from about 0.1
to 10 microns. The construction further includes a substrate
connected with the diamond-bonded body. The substrate may comprise
a carbide constituent. The substrate is attached to the
diamond-bonded body through a braze joint interposed between the
metal material and the substrate. The braze joint is formed from a
non-active braze material that reacts with the substrate and metal
material. In an example embodiment, the braze joint is formed at
the melting temperature of the non-active braze material in the
absence of high-pressure conditions. The diamond-bonded body of
such ultra-hard constructions is made at
high-pressure/high-temperature conditions. A substrate interface
surface of the so-formed body is treated to include the metal
material layer thereon. A metallic substrate is attached to the
diamond-bonded body by the braze joint comprising the non-active
braze material at approximately the melting temperature of the
braze material in the absence of high-pressure conditions. If
desired, a carburizing treatment can be performed prior attaching
the substrate. This summary is provided to introduce a selection of
concepts that are further described below in the detailed
description. This summary is not intended to identify key or
essential features of the claimed subject matter, nor is it
intended to be used as an aid in limiting the scope of the claimed
subject matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of ultra-hard constructions are described with
reference to the following figures:
[0008] FIG. 1 is view taken from a section of a diamond-bonded body
after it has been treated to remove a catalyst material used to
form the same therefrom;
[0009] FIG. 2 is a perspective view of the diamond-bonded body
after it has been treated to remove the catalyst material used to
form the same therefrom;
[0010] FIG. 3 is a cross-sectional side view of a diamond-bonded
body comprising a metal material disposed on to a body substrate
interface surface;
[0011] FIG. 4 is a cross-sectional side view of an ultra-hard
construction as disclosed herein comprising a diamond-bonded body
comprising a metal material disposed on to a body substrate
interface surface, and further comprising a braze material forming
a braze joint interposed between and bonding a substrate to the
body;
[0012] FIG. 5 is a side view of an ultra-hard construction as
disclosed herein embodied in the form of an insert;
[0013] FIG. 6 is a perspective side view of a rotary cone drill bit
comprising a number of the inserts illustrated in FIG. 5;
[0014] FIG. 7 is a perspective side view of percussion or hammer
bit comprising a number of inserts illustrated in FIG. 5;
[0015] FIG. 8 is a perspective view of an ultra-hard construction
as disclosed herein embodied in the form of a shear cutter; and
[0016] FIG. 9 is a perspective side view of a drag bit comprising a
number of the shear cutters illustrated in FIG. 8.
DETAILED DESCRIPTION
[0017] Ultra-hard and metallic constructions as disclosed herein
comprise a thermally stable polycrystalline diamond (TSP) bonded
body that is substantially free of a catalyst material initially
used to sinter the body, and that is specially engineered to
accommodate attachment with a substrate or end-use device by a
braze joint in a manner that provides an enhanced degree of
attachment strength therewith when compared to conventional TSP
constructions.
[0018] As used herein, the term "ultra-hard" is understood to refer
to those materials known in the art to have a grain hardness of
about 4,000 HV or greater. Such ultra-hard materials may include
those capable of demonstrating physical stability at temperatures
above about 750.degree. C., and for certain applications above
about 1,000.degree. C., that are formed from consolidated
materials. Such ultra-hard materials may include but are not
limited to diamond, cubic boron nitride (cBN), diamond-like carbon,
boron suboxide, aluminum manganese boride, and other materials in
the boron-nitrogen-carbon phase diagram which have shown hardness
values similar to cBN and other ceramic materials.
[0019] Polycrystalline diamond (PCD) is a useful material for
forming the ultra-hard component once it has been treated to remove
a catalyst material, such as the Group VIII materials noted above,
used to initially sinter or form the same at
high-pressure/high-temperature (HPHT) conditions. As used herein,
the term "catalyst material" refers to the material that was
initially used to facilitate diamond-to-diamond bonding or
sintering at the initial HPHT process conditions used to form the
PCD.
[0020] TSP has a material microstructure characterized by a
polycrystalline matrix phase comprising bonded-together diamond
grains or crystals, and a plurality of voids or empty pores that
exist within interstitial regions within the matrix disposed
between the bonded-together diamond grains. The TSP material is
initially formed by bonding together adjacent diamond grains or
crystals at HPHT process conditions. The bonding together of the
diamond grains at HPHT conditions is facilitated by the use of an
appropriate catalyst material, such as a metal solvent catalyst
selected from Group VIII of the Periodic table, thereby forming
conventional PCD comprising the catalyst material disposed within
the plurality of voids or pores.
[0021] Diamond grains useful for forming the TSP component or body
may include natural and/or synthetic diamond powders having an
average diameter grain size in the range of from submicrometer in
size to 100 micrometers, and in the range of from about 1 to 80
micrometers. The diamond powder may contain grains having a mono or
multi-modal size distribution. In an example embodiment, the
diamond powder has an average particle grain size of approximately
20 micrometers. In the event that diamond powders are used having
differently sized grains, the diamond grains are mixed together by
conventional process, such as by ball or attritor milling for as
much time as necessary to ensure good uniform distribution.
[0022] The diamond grain powder is cleaned, to enhance the
sinterability of the powder by treatment at high temperature, in a
vacuum or reducing atmosphere. The diamond powder mixture is loaded
into a desired container for placement within a suitable HPHT
consolidation and sintering device.
[0023] The diamond powder may be combined with a desired catalyst
material, e.g., a solvent metal catalyst, in the form of a powder
to facilitate diamond bonding during the HPHT process and/or the
catalyst material may be provided by infiltration from a substrate
positioned adjacent the diamond powder and that includes the
catalyst material. Suitable substrates useful as a source for
infiltrating the catalyst material may include those used to form
conventional PCD materials, and may be provided in powder, green
state, and/or already sintered form. A feature of such substrate is
that it includes a metal solvent catalyst that is capable of
melting and infiltrating into the adjacent volume of diamond powder
to facilitate bonding the diamond grains together during the HPHT
process. In an example embodiment, the catalyst material is cobalt
(Co), and a substrate useful for providing the same is a Co
containing cermet material, such as WC--Co.
[0024] The diamond powder mixture may be provided in the form of a
green-state part or mixture comprising diamond powder that is
combined with a binding agent to provide a conformable material
product, e.g., in the form of diamond tape or other
formable/conformable diamond mixture product to facilitate the
manufacturing process. In the event that the diamond powder is
provided in the form of such a green-state part, it is desirable
that a preheating step take place before HPHT consolidation and
sintering to drive off the binder material. In an example
embodiment, the PCD material resulting from the above-described
HPHT process may have diamond volume content in the range of from
about 85 to 95 percent.
[0025] The diamond powder mixture or green-state part is loaded
into a desired container for placement within a suitable HPHT
consolidation and sintering device. The HPHT device is activated to
subject the container to a desired HPHT condition to effect
consolidation and sintering of the diamond powder. In an example
embodiment, the device is controlled so that the container is
subjected to a HPHT process having a pressure of 5,000 MPa or
greater, and a temperature of from about 1,350.degree. C. to
1,500.degree. C. for a predetermined period of time. At this
pressure and temperature, the catalyst material melts and
infiltrates into the diamond powder mixture, thereby sintering the
diamond grains to form PCD. After the HPHT process is completed,
the container is removed from the HPHT device, and the so-formed
PCD material is removed from the container.
[0026] In the event that a substrate is used during the HPHT
process, e.g., as a source of the catalyst material, the substrate
is removed prior to treating the PCD material to remove the
catalyst material therefrom to form TSP. The substrate may be
removed during or after the treatment to form TSP. In an
embodiment, any substrate is removed prior to treatment to expedite
the process of removing the catalyst material from the PCD
body.
[0027] The term, "removed," as used with reference to the catalyst
material after the treatment process for forming TSP, is understood
to mean that a substantial portion of the catalyst material no
longer resides within the remaining diamond bonded body. However,
it is to be understood that some small amount of catalyst material
may still remain in the resulting diamond bonded body, e.g., within
the interstitial regions and/or adhered to the surface of the
diamond crystals. Additionally, the term, "substantially free," as
used herein to refer to the catalyst material in the diamond bonded
body after the treatment process, is understood to mean that there
may still be some small/trace amount of catalyst material remaining
within the TSP material as noted above. Rather than removing the
catalyst material from the PCD, the PCD may be rendered TSP by
treating the catalyst material used to form the PCD in such a
manner so as to render the catalyst material nonreactive or
noncatalytic at construction operating temperatures.
[0028] In an example embodiment, the PCD body is treated to render
the entire body substantially free of the catalyst material. This
may be done, by subjecting the PCD body to chemical treatment such
as by acid leaching or aqua regia bath, electrochemical treatment
such as by electrolytic process, by liquid metal solubility, or by
liquid metal infiltration that sweeps the existing catalyst
material away and replaces it with another noncatalyst material
during a liquid phase sintering process, or by combinations
thereof. This process may be conducted under conditions of elevated
temperature, elevated pressure, high-frequency vibration and
combinations thereof. In an example embodiment, the catalyst
material is removed from the PCD body by an acid leaching
technique, such as that disclosed for example in U.S. Pat. No.
4,224,380.
[0029] The TSP may be formed using thermally stable catalyst
systems such as carbonates, sulfites or pyrites. In such cases
temperatures above 2000.degree. C. and pressures over 7.0 GPa may
be required to form the TSP body. In an additional embodiment, the
TSP may be formed from graphitic or non-diamond carbon sources
which will require temperatures greater than 2000.degree. C.
pressures above 10.0 GPa.
[0030] FIG. 1 illustrates a section of the diamond-bonded TSP body
10 resulting from the removal of the catalyst material therefrom.
The TSP body has a material microstructure comprising a
polycrystalline diamond matrix phase made up of a plurality of
diamond grains or crystals 12 that are bonded together, and a
plurality of interstitial regions 14 that are disposed within the
matrix between the bonded together diamond grains, and that exist
as empty pores or voids within the material microstructure, as a
result of the catalyst material being removed therefrom.
[0031] FIG. 2 illustrates an example embodiment of the TSP body 16
wherein the TSP body includes a top surface 22 extending along the
diamond table, and a side surface 24 that extends along a wall
portion of the body. The TSP body comprises a working surface that
may include all or a portion of the top and/or side surfaces,
depending on the particular end-use application. While the TSP body
illustrated in FIG. 2 is in the form of a wafer or disc that has a
generally cylindrical side surface and flat top and bottom
surfaces, it is to be understood that TSP bodies that are
configured differently are intended to be within the scope of the
ultra-hard construction as disclosed herein. Additionally, the TSP
body 16 may include one or more surface features provided to
facilitate use of the construction in its end-use application. For
example, the TSP body may at this stage of processing include a
chamfer or a beveled surface section between the top and side
surfaces, e.g., extending circumferentially around an edge of the
top surface, and such surface may be a working surface.
[0032] The so-formed TSP body is treated prior to being attached to
a substrate by use of a braze joint, which substrate may be
provided in the form of part that is separate from the end-use
device, such as a substrate that is conventionally used for making
PCD compacts, or may be in the form of the end-use device itself.
The treatment comprises applying a layer of metal material to a
surface of the TSP body positioned to interface with the substrate,
i.e., a substrate interface surface. The metal material is provided
for the purpose of enhancing the strength of the attachment that is
formed with the substrate through the braze joint, to thereby
provide an improved service life by avoiding substrate
delamination.
[0033] In an example embodiment, the TSP body is treated by
depositing the metal material thereon by any suitable deposition
process, e.g., by dipping, by spray, CVD process, sputtering
process, or the like. In an example embodiment, it is desired that
a metal material be one that includes carbide and/or that is a
carbide former, e.g., that forms carbide upon subsequent treatment.
It is desired that the metal material be applied in sufficient
amount and/or thickness to provide a desired amount of carbide at
the substrate interface for the purpose of permitting the use of a
non-active braze to join the substrate and TSP body together. In
some instances, more than one layer of the metal material may be
applied to achieve the desired amount or content of carbide on the
TSP body surface.
[0034] In an example embodiment, the thickness of the metal layer
may be in the range of from about 0.1 to 10 microns, in the range
of from about 0.5 to 5 microns, and in the range of from about 1 to
3 microns. It is understood that the exact thickness of the metal
layer that is used will depend on the type of metal material being
applied as well as the type of braze material being used. The
treatment may be one that provides a surface coating of the metal
material onto the substrate interface surface and/or that
introduces the metal material into a region of the TSP body that
extends a partial depth from the substrate interface surface.
[0035] Metal materials useful for this treatment may include
metallic materials, metals, metal alloys, and the like that either
include carbide or that are produce carbide, e.g., are carbide
formers, upon further treatment. As noted above, the metal material
is used to provide a desired amount of carbide on the TSP body to
permit the use of non-active braze materials in joining the TSP
body to the substrate. The use of such non-active braze materials
is desired because they provide a strong attachment bond with the
metallic substrate and have a relatively higher yield strength and
melting temperature than active braze materials conventionally used
in the process of joining diamond-bonded bodies (PCD and TSP) to a
cermet substrate. As used herein, the term "active braze" means a
braze material that reacts the polycrystalline ultra-hard material
(untreated). The term "non-active braze" means a braze material
that does not react with the polycrystalline ultra-hard material
(untreated).
[0036] Suitable carbide containing metal materials useful for this
treatment include B, Si, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W, and
combinations and alloys thereof. Example carbide-containing metal
materials include and are not limited to B.sub.4C, SiC, TiC, ZrC,
HfC, VC, NbC, TaC, Cr.sub.2C.sub.3, CrC.sub.2, Mo.sub.2C, MoC,
W.sub.2C and WC.
[0037] Suitable carbide-forming metal materials useful for this
treatment include those that are capable of forming a carbide when
subjected to a carburizing process, which carburizing process may
be conducted as a step separate from brazing or during the brazing
process. Suitable carbide-forming materials include refractory
metals such as those selected from Groups IV through VII of the
Periodic table. In an example embodiment, the metal material is
tungsten (W), and the layer of tungsten is carburized such that the
primary constituent on the substrate interface surface is tungsten
carbide (WC). The metal material is titanium and the carbide is
titanium carbide (TiC).
[0038] It is desired that the metal material used for this
treatment be one that produces a desired level or content of
carbide on the substrate interface surface to facilitate use of a
non-active braze material to join the substrate and TSP body
together. Non-active braze materials are ones uniquely suited to
form a strong bond with a carbide containing surface. Thus,
treating the TSP body substrate interface surface in this matter
provides such a carbide surface on the TSP body to match the
carbide already present on the surface of the substrate, thereby
ensuring that a strong brazed attachment is formed therebetween.
Additionally, because non-active braze materials have a relatively
higher yield strength and melting temperature than active braze
materials (that are conventionally used to join polycrystalline
bodies to metallic substrate), the braze joint formed by the
non-active braze material is less apt to delaminate and fail during
service, thereby enhancing the service life of ultra-hard
constructions that are formed therefrom.
[0039] The metal material used to facilitate brazed attachment
between the TSP body and substrate may also serve as a barrier to
prevent any unwanted migration or infiltration of material into the
TSP body during the braze operation. Additionally, the metal
material may help to accommodate any mismatch in mechanical
properties that exist between the TSP body, the braze material, and
the substrate, e.g., differences in thermal expansion
characteristics, that may create high residual stresses in the
construction during the attachment process. The residual stress
mismatch may be helped by having a tungsten or titanium layer that
contains a gradient composition with respect to carbide content,
for example containing approximately 90% or higher carbide near the
ultra-hard material interface, and 50% or lower carbide content at
the interface to be joined with a non-active braze.
[0040] FIG. 3 illustrates an example embodiment of the ultra-hard
construction as disclosed herein at a stage of processing where a
layer of the metal material 30 has been applied or deposited onto a
substrate interfacing surface 32 of the TSP body 34 for purpose of
subsequent substrate attachment. In an example embodiment, the
metal material 30 is tungsten and is provided by CVD, PVD, or
sputtering process. The amount of metal material 30 that is applied
will depend on whether a surface coating along the substrate
interface surface 32 is desired, or whether it is desired to form
an infiltrated region in the TSP body extending a partial depth
from the substrate interface surface. Whether a surface layer or
infiltrated region is desired will depend on a number of factors
such as the type of substrate and braze material that is used, as
well as the end-use application.
[0041] A treatment providing a coated surface may be desired in
instances where maximum thermal protection of the TSP cutting edge
or working surface is required. An additional barrier layer coating
may optimize the thermal gradient into the TSP body and thereby
prolong cutting life. In an example embodiment where a coated
surface is provided, the coating may extend a thickness measured
from the substrate interface surface of the TSP body of from about
1 to 5 microns, from about 5 to 20 microns, and more than about 20
microns.
[0042] A treatment providing an infiltrated region within the TSP
body may be desired in instances where an enhanced attachment
strength between the substrate and TSP body is desired and provided
by the bonding of the braze material, in addition to the surface of
the TSP body, to the region within the TSP body comprising the
metal material. In an example embodiment, where infiltration of the
metal material is desired, the infiltration depth may be in the
range of from about 1 to 20 microns.
[0043] In an embodiment where the metal material is additionally
selected to act as a barrier material, its presence operates to
prevent unwanted migration of constituents from the braze joint
and/or substrate into the TSP body. Additionally, the presence of
such a barrier metal material may operate to block unwanted
infiltration of the any materials from the from the TSP body into
the adjacent braze joint or substrate.
[0044] Once the TSP body has been treated to include the metal
material, it may be subjected to further treatment prior to being
braze attached to the substrate. In the event that the metal
material applied to the TSP body already contains carbide, then the
TSP body may be brazed without further treatment. In the event that
the metal material applied to the TSP body was a carbide former and
does not already contain carbide, then further treatment will take
place to form the desired carbide constituent. In an example
embodiment, such further treatment may comprise carburizing the
metal material at an elevated temperature in the range of from
about 700 to 1,500.degree. C. In an example embodiment, the
carburizing process takes place at a temperature of about
900.degree. C. for an amount of time sufficient to create the
desired carbide. Temperatures and times may also be manipulated to
create a desired gradient condition in the metallic layer.
[0045] The step of forming the carbide constituent in the metal
material, e.g., by carburizing, may take place separately and
independent from the step of brazing the TSP body to the substrate.
The step of forming the carbide constituent may take place during
the step of brazing, e.g., immediately before joining together the
TSP body and the braze material.
[0046] Suitable non-active braze materials useful in forming
ultra-hard constructions as disclosed herein include those selected
from the group including Cu, Ni, Mn, Au, Pd and combinations and
alloys thereof. Example alloys include those having the following
composition and liquid temperature (LT) and solid temperature (ST),
where the composition amounts are provided in the form of weight
percentages: 40 Ni, 60 Pd, LT=ST=1,238.degree. C.; 70 Au, 22 Ni, 8
Pd, LT=1,037.degree. C., ST=1,005.degree. C.; 35 Au, 31.5 Cu, 14
Ni, 10 Pd, 9.5 Mn, LT=1,004.degree. C., ST=971.degree. C.; 52.5 Cu,
9.5 Ni, 38 Mn, LT=925.degree. C., ST=880.degree. C.; 31 Au, 43.5
Cu, 9.75 Ni, 9.75 Pd, 16 Mn, LT=949.degree. C., ST=927.degree. C.;
54 Ag, 21 Cu, 25 Pd, LT=950.degree. C., ST=900.degree. C.; 67.5 Cu,
9 Ni, 23.5 Mn, LT=955.degree. C., ST=925.degree. C.; 58.5 Cu, 10
Co, 31.5 Mn, LT=999.degree. C., ST=896.degree. C.; 35 Au, 31.5 Cu,
14 Ni, 10 Pd, 9.5 Mn, LT=1,004.degree. C., ST=971.degree. C.; 25
Su, 37 Cu, 10 Ni, 15 Pd, 13 Mn, LT=1,013.degree. C., ST=970.degree.
C.; and 35 Au, 62 Cu, 3 Ni, LT=1,030.degree. C., ST=1,000.degree.
C.
[0047] The TSP body (comprising the carbide-containing substrate
interface surface) is joined to the substrate through the braze
material under elevated temperature conditions sufficient to melt
the braze material. The braze joint may be formed by using
conventional braze techniques such as by vacuum brazing, induction
brazing, and the like. Thus, a further feature of ultra-hard
constructions disclosed herein is that the TSP body is attached to
the substrate by brazing at elevated temperature without elevated
pressure, i.e., without having to subject the TSP body to a second
HPHT process. Avoiding the need to rely on an HPHT process for
attaching the TSP body to the substrate is highly desired as it
improves manufacturing efficiency and reduces related manufacturing
costs, and avoids unwanted infiltration issues.
[0048] FIG. 4 illustrates an example embodiment TSP construction 40
comprising a TSP body 42 that is attached to a substrate 44 via a
braze joint 46. The TSP body includes a working surface that may
exist along a top surface 48, a side surface 50 and/or an edge
surface 52. The TSP body comprises a substrate interface surface 54
and a metal material 56 containing a carbide constituent disposed
thereon, that operates to provide an enhanced attachment with a
non-active braze material used to form the braze joint 46 when
compared to conventional TSP construction that does not include the
metal material.
[0049] Example braze materials useful for forming the braze joint
include materials that are capable of forming a strong chemical
bond between the TSP body and a desired substrate. It is desired
that the braze material includes one or more elements that are
capable of reacting with one or more elements in the TSP body to
form such strong chemical bond. For this reason, materials useful
for forming the braze material may be referred to as being "active"
braze materials or alloys.
[0050] As noted above, the substrate useful in forming ultra-hard
constructions as disclosed herein may be provided in the form of a
part that is separate from the end-use device, such as a cermet or
carbide part, or may be provided in the form a portion of the
end-use device itself. Accordingly, it is to be understood that TSP
bodies that have been treated in the manner described above may be
attached directly or indirectly to the end-use device by the
above-described braze joint.
[0051] Suitable substrates that are provided separate from the
end-use device may be selected from those materials conventionally
used as substrates for forming PCD compacts, and may include
metallic materials, ceramic material, cermet materials, and
combinations thereof. An example substrate is one that is a
carbide, such as one formed from WC--Co. The size and configuration
of the substrate may and will vary depending on the size and
configuration of the TSP body and the end-use application. Various
types of steels may be employed as substrates and may include or be
later machined to contain features such as threads or other
fastener devices to facilitate convenient mechanical attachment to
a drill bit. Wherein the types of steels useful as a substrate
include those having a Rockwell C hardness of 50 or more.
[0052] While particular example embodiment ultra-hard constructions
have been disclosed above and illustrated, it is understood that
variations of these example embodiment are understood to be within
the scope of what is being disclosed herein.
[0053] A feature of ultra-hard constructions as disclosed herein is
that the TSP body included therein has been treated to include a
metal material prior to brazed attachment with a substrate, wherein
such metal material either includes or is treated to include a
carbide constituent. A further feature of such ultra-hard
constructions as disclosed herein is that the braze material used
to form the braze joint is a non-active braze material that is well
suited to form an improved degree of bond strength between carbide
containing surfaces, as they currently exist on both the TSP body
and the substrate. A further feature of such ultra-hard
constructions is that the non-active braze material has a
relatively higher yield stress and melting temperature as compared
to active braze materials conventionally used to form the braze
joint between the TSP body and the substrate, thereby improving
service life by minimizing unwanted delamination while in service.
A still further feature of such ultra-hard constructions is the
avoidance of having to undergo HPHT processing to attach the TSP
body to the substrate, wherein the braze joint is formed at the
braze material melting temperature without the need for elevated
pressure, thereby improving manufacturing efficiency and reducing
related manufacturing costs.
[0054] Ultra-hard constructions as disclosed herein may be used in
a number of different applications, such as tools for mining,
cutting, machining, milling and construction applications, wherein
properties of shear strength, thermal stability, wear and abrasion
resistance, mechanical strength, and/or reduced thermal residual
stress are highly desired. Ultra-hard constructions as disclosed
herein are particularly well suited for forming working, wear
and/or cutting elements in machine tools and drill and mining bits
such as roller cone rock bits, percussion or hammer bits, diamond
bits, and shear cutters used in subterranean drilling
applications.
[0055] FIG. 5 illustrates an embodiment of an ultra-hard
construction as disclosed herein provided in the form of a cutting
element embodied as an insert 60 used in a wear or cutting
application in a roller cone drill bit or percussion or hammer
drill bit. For example, such inserts 60 may be formed from blanks
comprising a substrate portion 62 formed from one or more of the
substrate materials 64 disclosed above, and an ultra-hard material
body 66 having a working surface 68 formed from the thermally
stable region of the ultra-hard body. The blanks are pressed or
machined to the desired shape of a roller cone rock bit insert.
[0056] FIG. 6 illustrates a rotary or roller cone drill bit in the
form of a rock bit 70 comprising a number of the wear or cutting
inserts 60 disclosed above and illustrated in FIG. 5. The rock bit
70 comprises a body 72 having three legs 74, and a roller cutter
cone 76 mounted on a lower end of each leg. The inserts 60 may be
fabricated according to the method described above. The inserts 60
are provided in the surfaces of each cutter cone 76 for bearing on
a rock formation being drilled.
[0057] FIG. 7 illustrates the inserts 60 described above as used
with a percussion or hammer bit 80. The hammer bit comprises a
hollow steel body 82 having a threaded pin 84 on an end of the body
for assembling the bit onto a drill string (not shown) for drilling
oil wells and the like. A plurality of the inserts 76 (illustrated
in FIG. 7) are provided in the surface of a head 100 of the body 96
for bearing on the subterranean formation being drilled.
[0058] FIG. 8 illustrates an ultra-hard construction as disclosed
herein as embodied in the form of a shear cutter 90 used, for
example, with a drag bit for drilling subterranean formations. The
shear cutter 90 comprises a thermally stable ultra-hard body 92
that is sintered or otherwise attached/joined to a cutter substrate
94. The thermally stable ultra-hard material body includes a
working or cutting surface 96.
[0059] FIG. 9 illustrates a drag bit 100 comprising a plurality of
the shear cutters 90 described above and illustrated in FIG. 8. The
shear cutters are each attached to blades 102 that extend from a
head 104 of the drag bit for cutting against the subterranean
formation being drilled.
[0060] Although only a few example embodiments have been described
in detail above, those skilled in the art will readily appreciate
that many modifications are possible in the example embodiments
without materially departing from this invention. Accordingly, all
such modifications are intended to be included within the scope of
this disclosure as defined in the following claims. In the claims,
means-plus-function clauses are intended to cover the structures
described herein as performing the recited function and not only
structural equivalents, but also equivalent structures. Thus,
although a nail and a screw may not be structural equivalents in
that a nail employs a cylindrical surface to secure wooden parts
together, whereas a screw employs a helical surface, in the
environment of fastening wooden parts, a nail and a screw may be
equivalent structures. It is the express intention of the applicant
not to invoke 35 U.S.C. .sctn.112, paragraph 6 for any limitations
of any of the claims herein, except for those in which the claim
expressly uses the words `means for` together with an associated
function.
* * * * *