Composite material formed of cubic boron nitride without Ti-based ceramic compounds and method for making same

Abstract

About 30-65% by volume of cBN, about 3-30% by volume of zirconium (Zr)-containing compounds, about 0-10% by volume of cobalt-tungsten-borides (Co x W y B z ), a cubic boron nitride (cBN)-based composite containing about 2-30 volume percent aluminum oxide (Al2O3), about 0.5-10 volume percent tungsten boride, and up to about 5 volume percent aluminum nitride (AlN).

Description

[Technical field]

[0001] Technical Field and Industrial Applicability FIELD OF THE DISCLOSURE This disclosure relates generally to composite materials formed with cubic boron nitride and methods of making and using them. In particular, this disclosure relates to composite materials useful in machining difficult-to-cut materials. [Background technology]

[0002] In the discussion of the background art that follows, reference is made to certain structures and / or methods. However, the reference below should not be construed as an admission that these structures and / or methods constitute prior art. Applicants expressly reserve the right to demonstrate that such structures and / or methods do not qualify as prior art.

[0003] Cubic boron nitride (cBN) is a superhard material that is often used to form cBN-based composites for cutting and / or machining applications. To improve resistance to chemical wear, it is often mixed with, for example, alumina (Al 2 O 3 Certain ceramic materials, such as CrN, titanium nitride (TiN), silicon nitride (SiN), etc., may be blended with cBN. However, such ceramic materials may not have sufficient hardness and / or heat resistance to perform optimally when machining hard materials. For example, existing cBN-based composites may still exhibit rapid wear, fracture, and / or failure, especially when cutting or machining difficult-to-cut materials such as heat-resistant superalloys. Thus, there is a need for better cBN-based composites with improved properties for cutting or machining difficult-to-cut materials. Summary of the Invention

[0004] A cubic boron nitride (cBN) based composite is provided. The composite comprises about 30-65% by volume of cBN, about 3-30% by volume of a zirconium (Zr)-containing compound, about 0-10% by volume of a cobalt-tungsten-boride (CoxWyBz), about 2-30% by volume of an aluminum oxide (Al 2 O 3 ), about 0.5-10 volume percent tungsten boride, and up to about 5 volume percent aluminum nitride (AlN).

[0005] A method of forming a cubic boron nitride (cBN) based composite is also provided. The method includes blending powders of a cBN based formulation for forming a cBN based composite to form a first mixture. The cBN based composite has about 30-65% by volume cBN, about 3-30% by volume zirconium (Zr) containing compound, about 0-10% by volume cobalt-tungsten-boride (CoBN) containing compound, and about 0-10% by volume cobalt-tungsten-boride (CoBN) containing compound. x W y B z ), about 2 to 30 volume percent aluminum oxide (Al 2 O 3 %, about 0.5-10 volume percent tungsten boride, and about 5 volume percent or less aluminum nitride (AlN). The method includes drying the first mixture to form a second mixture, and filling the second mixture into one or more heat-resistant molds. The method also includes sintering the second mixture under high pressure and high temperature conditions.

[0006] Further provided is a cutting tool comprising a sintered cubic boron nitride (cBN)-based compact, the cBN-based compact comprising about 30-65 volume % cBN, about 3-30 volume % zirconium (Zr)-containing compound, about 0-10 volume % cobalt-tungsten-boride (CoBN ... x W y B z ), about 2 to 30 volume percent aluminum oxide (Al 2 O 3%, about 0.5-10 volume percent tungsten boride, and about 5 volume percent or less aluminum nitride (AlN). The sintered compact is formed by mixing powders of a cBN-based formulation for forming a sintered cBN-based compact to form a first mixture, drying the first mixture to form a second mixture, filling the second mixture into one or more heat-resistant molds, and sintering the second mixture under high pressure and high temperature conditions to form the sintered compact.

[0007] The foregoing summary, as well as the following detailed description of the embodiments, may be better understood when read in conjunction with the accompanying drawings, in which: It is to be understood that the depicted embodiments are not limited to the precise arrangements and instrumentalities shown. [Brief description of the drawings]

[0008] [Figure 1] 1 illustrates an exemplary method for forming a cBN-based sintered compact or composite. [Diagram 2] 1 shows an XRD spectrum illustrating the phases present in an exemplary cBN-based sintered compact or composite. [Diagram 3] 1 shows an XRD spectrum illustrating the phases present in another exemplary cBN-based sintered compact or composite. [Figure 4] 1 shows an XRD spectrum illustrating the phases present in another exemplary cBN-based sintered compact or composite. [Diagram 5] 1 shows an XRD spectrum illustrating the phases present in another exemplary cBN-based sintered compact or composite. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present disclosure relates to composites or sintered compacts formed with cubic boron nitride (cBN), and methods of making and using the same. In particular, the present disclosure relates to improved cBN-based composites useful in cutting and machining difficult-to-cut materials, such as superalloys for applications requiring high strength at high temperatures. For example, the cBN-based composites (e.g., sintered compacts) disclosed herein can be used to cut and / or machine nickel-based superalloys (e.g., Inconel 718, Inconel 625), cobalt-based superalloys (e.g., Alloy 188, Haynes 25, Alloy L605), iron-based superalloys (e.g., A286), or any material with mechanical properties comparable to, inferior to, or superior to these superalloys.

[0010] The cBN-based composite materials disclosed herein may include, among other improvements, greater wear resistance, toughness, chemical resistance, hardness, and / or high temperature hardness. These improvements may be achieved by using the cBN, cobalt-tungsten-boride (CoBN) alloy in the proportions disclosed herein. x W y B z ), tungsten boride (WB, W 2 B,W 2 B 5 or a combination thereof), alumina (Al 2 O 3 ) and zirconium (Zr)-containing compounds (zirconium dioxide, zirconium nitride, zirconium carbide, zirconium carbonitride, zirconium diboride or combinations thereof). The present disclosure also describes methods for forming cBN-based formulations into sintered compacts that can be used for cutting or machining difficult-to-cut materials.

[0011] With the above in mind, Tables 1 and 2 list exemplary cBN-based composite (e.g., sintered compact) compositions. An exemplary method for forming a cBN-based composite is depicted in the flow diagram of FIG. 1. In Tables 1 and 2, all volume percents (vol.%) listed are based on the total volume percent of the cBN-based composite. TIFF0007682184000001.tif70170TIFF0007682184000002.tif70170

[0012] The cBN-based composite material (e.g., sintered compact) may contain about 30-65% by volume cBN, about 40-60% by volume cBN, about 45-55% by volume cBN, about 50% by volume cBN, or about 60% by volume cBN. Additionally, the cBN-based composite material may contain about 0-15% by volume (e.g., about 0.1-15% by volume) Co. x W y B z , about 0 to 10% by volume (e.g., about 0.1 to 10% by volume) of Co x W y B z , about 3 to 15 volume percent Co x W y B z , about 3 to 12 volume percent Co x W y B z , or about 3 to 8 volume percent Co x W y B z Additionally, the cBN-based composite may include about 0.5-10 volume percent tungsten boride, about 0.5-6 volume percent tungsten boride, about 3-8 volume percent tungsten boride, or about 1-3 volume percent tungsten boride. As provided, the cBN-based composite may include about 2-30 volume percent Al. 2 O 3 , about 5 to 25 volume percent Al 2 O 3 , about 2 to 15 volume percent Al 2 O 3 , about 10 to 20 volume percent Al 2 O 3 , or about 5-10% by volume of Al 2 O 3The cBN-based composite may also include about 2-30 volume percent of a zirconium-containing compound, about 5-25 volume percent of a zirconium-containing compound, about 8-15 volume percent of a zirconium-containing compound, or about 3-15 volume percent of a zirconium-containing compound. Additionally, the cBN-based composite may include about 5 volume percent or less of aluminum nitride (AlN) (e.g., about 0.01-1 volume percent AlN, about 0.01-4 volume percent AlN, about 0.01-3 volume percent AlN, or about 0.01-1 volume percent AlN). Tungsten boride as disclosed herein includes WB, W 2 B,W 2 B 5 or a combination thereof. The zirconium-containing compound disclosed herein may include zirconium dioxide (ZrO 2 ), zirconium nitride (ZrN), zirconium carbide (ZrC), zirconium carbonitride (ZrCN), zirconium diboride (ZrB 2 ), or a combination thereof. Zirconium dioxide may include a cubic phase (c-ZrO 2 ), monoclinic phase (m-ZrO 2 ), and / or the tetragonal phase.

[0013] 1 depicts an exemplary method 100 of forming a cBN-based composite material (e.g., a sintered compact). The exemplary method 100 includes mixing powders of a cBN-based composition to form a first mixture (step 102). The cBN-based composition can be one or more powdered compositions, such as a powder that includes or consists of cBN, zirconium oxide (which can be in the cubic, monoclinic, and / or tetragonal phases), ZrN, ZrC, ZrCN, and / or ZrB. 2 Powders containing or consisting of zirconium, such as powders containing Al 2 O 3and / or a powder formulation including aluminum-containing or aluminum-based powders, such as AlN-containing powders, tungsten (W)-containing or W-containing powders, cobalt (Co)-containing or Co-containing powders, boron (B)-containing or B-containing powders, and combinations thereof. Step 102 includes providing a powder that can be used to form the cBN-based composite material disclosed herein (e.g., the compositions shown in Tables 1 or 2). The powder can be a nano- and / or micron-sized powder, e.g., the powder of the cBN-based compound can have an average particle size in the nanometer (nm) or micrometer (μm) range, i.e., about 100 nm to 6 μm. Step 102 includes mixing the powders to form a mixture or slurry. The powders can be mixed using any suitable milling or blending technique, such as, for example, an attribution mill or a ball mill. The powders may be milled or blended in any suitable solvent, such as, for example, ethanol, isopropanol, acetone, methanol, hexane, heptane, or combinations thereof, to form a first mixture. The milling conditions (e.g., time, revolutions per minute, type of media or solvent, etc.) may be adjusted or regulated depending on the size and / or type of mill used to achieve the desired mixing effect (e.g., powder distribution, uniformity, etc.).

[0014] Step 100 may include drying the first mixture to form a second mixture, step 104. The first mixture or slurry formed in step 102 may be dried using any suitable technique to substantially remove the solvent and / or binder in the first mixture, such as, for example, vacuum drying, air drying, etc.

[0015] Step 100 may include filling the second mixture into a refractory mold (step 106). The refractory mold may be made of any suitable material, including any suitable refractory metal, such as titanium, niobium, molybdenum, etc. Step 106 may include filling the second mixture into the refractory mold and capping with a cemented carbide (WC-Co) disk that fits within the mold opening. Step 106 may also include sealing the refractory mold containing the second mixture and / or the WC-Co substrate / disk.

[0016] Step 100 may include sintering the second mixture at high pressure, high temperature conditions (step 108). The sealed, refractory mold containing the second mixture may be placed in a high pressure, high temperature (HPHT) cell, and HPHT sintering conditions are applied to form a cBN-based composite material (e.g., a sintered compact) disclosed herein. Step 108 may include sintering the second mixture at a pressure of about 5 gigapascals (GPa) to 8 GPa and a temperature of about 1300 to 1600°C. Step 108 may include sintering the second mixture at a pressure of at least about 4 GPa and a temperature of at least about 1100°C. The cBN-based composite material (e.g., sintered compact) can have cBN grain sizes in the nanometer or submicron range, such as, for example, about 0.1-10 μm, about 0.1-8 μm, about 0.1-6 μm, about 0.1-4 μm, about 0.1-2 μm, about 2-4 μm, about 0.1-1 μm, about 0.8-1.2 μm, or about 1 μm.

[0017] The cBN-based composites (e.g., sintered compacts) formed by method 100 may be used to cut or machine difficult-to-cut materials. For example, the cBN-based composites formed by method 100 may be formed into cutting tools for cutting and / or machining high strength superalloys, including nickel-based superalloys (e.g., Inconel 718, Inconel 625), cobalt-based superalloys (e.g., Alloy 188, Haynes 25, Alloy L605), iron-based superalloys (e.g., A286), or any materials with mechanical properties comparable, inferior, or superior to these superalloys.

[0018] Without being bound to a particular theory, the composition and phases of the cBN-based composites (e.g., sintered compacts) disclosed herein may contribute to improving wear resistance, toughness, chemical resistance, hardness, hot hardness, or a combination thereof, thereby improving cutting and machining capabilities. Table 3 shows exemplary cutting performance when using cutting tools made with the cBN-based composites (e.g., sintered compacts) disclosed herein. TIFF0007682184000003.tif114170

[0019] In the examples shown, Samples 1-5 represent cutting tools made with cBN-based composites (e.g., sintered compacts) formed according to the compositions shown in Tables 1 and 2 and method 100 described in FIG. 1. Cutting tests were performed against Inconel 718 at a speed of 350 meters per minute (m / min) and a feed rate of 0.15 millimeters per revolution (mm / revolution) with coolant continuously applied to the cutting interface. Cutting tests were performed for Samples 1-5 to a predetermined flank wear of 0.25 mm. The cutting distance in kilometers (km) at the end of tool life is shown in the right-most column in Table 3.

[0020] Both Sample 1 and Sample 2 consisted of approximately 60% by volume of cBN, an Al-containing phase or compound (Al 2 O 3 and / or AlN), Zr-containing phases or compounds (ZrCN and / or ZrB 2 ) and W-containing phases or compounds (WB, W 2 B,W 2 B 5 , CoW 2 B 2 , and / or CoWB), and neither contains titanium (Ti)-containing phases or compounds. The difference between sample 1 and sample 2 is that sample 2 contains W 2 B 5 and Co x W y B z (CoW 2 B 2, CoW 3 B 3 , and / or CoWB), whereas sample 1 does not, and sample 2 has a slightly smaller sintered grain size. The cutting distances are 0.8 km for sample 1 and 1.0 km for sample 2. Both sample 3 and sample 4 contain about 50 vol. % cBN, Al-containing phases or compounds (Al 2 O 3 ), Zr-containing phases or compounds (ZrCN and / or ZrB 2 ) and W-containing phases or compounds (WB, WC, CoW 2 B 2 , CoW 3 B 3 and / or CoWB), and neither contains any titanium (Ti)-containing phase or compound. The difference between sample 3 and sample 4 is that sample 3 contains ZrB 2 The cutting distances are 1.3 km for sample 3 and 1.0 km for sample 4. Sample 5 also contains about 50 vol.% cBN, but sample 5 contains Ti-containing phases or compounds (titanium carbonitride (TiCN) and / or titanium nitride (TiN)) and Zr-containing phases or compounds, and Co. x W y B z Sample 5 differs from samples 1 to 4 in that it does not contain any of the above. The cutting distance of sample 5 is 0.7 km.

[0021] Without being bound by any particular theory, 2 O 3 The presence of Co x W y B z It is believed that the presence of Al, tungsten boride, and Zr-containing compounds may contribute to the improved cutting ability. It is also believed that cBN-based composites with relatively low cBN content (e.g., about 50 volume %, about 45-55 volume %) may have better cutting ability than those with relatively high cBN content (e.g., about 60 volume %, about 65 volume %). In some embodiments, Al 2 O 3 , Co x W y Bz A cBN-based composite material having a titanium (Ti)-containing binder but containing tungsten boride and / or Co, tungsten boride, and Zr-containing compounds, and free or substantially free of Ti-containing compounds (e.g., titanium nitride (TiN), titanium carbonitride (TiCN), titanium carbide (TiC), titanium carbonitride (TiCON), titanium oxynitride (TiNO), or combinations thereof) is also disclosed. x W y B z It is believed that the cutting ability of the carbide-containing carbide may be better than that of the carbide-containing ...

[0022] Without being bound to any particular theory, it is believed that the particular combination and / or exclusion of certain crystalline phases may contribute to the enhanced cutting capabilities of the cBN-based composites (e.g., sintered compacts) disclosed herein. For example, Co x W y B z exists as a crystalline phase in cBN-based composites (e.g., sintered compacts), thereby contributing to improved cutting ability. x W y B z is one or more of crystalline CoWB, crystalline CoW 2 B 2 , and / or crystalline CoW 3 B 3 For example, the Zr-containing compound may be present as ZrB 2 and / or ZrCN in cBN-based composites (e.g., sintered compacts), thereby contributing to improved cutting capabilities. 2 B and W 2 B 5 ) are present in cBN-based composites (e.g., sintered compacts) and thereby contribute to improved cutting capabilities.

[0023] In some embodiments, the cBN-based composite materials (e.g., sintered compacts) disclosed herein may contain aluminum nitride (AlN) and / or aluminum diboride (AlB 2) may be substantially free of or may be excluded. In some embodiments, the cBN-based composites (e.g., sintered compacts) disclosed herein may be substantially free of or may be excluded of titanium (Ti)-containing compounds or phases (e.g., TiCN, TiN). In some embodiments, the cBN-based composites (e.g., sintered compacts) disclosed herein may contain very small or negligible amounts of AlN, e.g., less than 1% AlN by volume. In some embodiments, the cBN-based composites (e.g., sintered compacts) disclosed herein may contain Al 2 O 3 In some embodiments, the cBN-based composites (e.g., sintered compacts) disclosed herein may contain W, Zr-containing compounds. 2 C 21 B 6 may be substantially free of or may be excluded.

[0024] X-ray diffraction (XRD) can be performed on the cBN-based composite materials (e.g., sintered compacts) disclosed herein to identify the phases present. Figures 2, 3, 4, and 5 show the XRD spectra of Sample 1, Sample 2, Sample 3, and Sample 4, respectively. The XRD spectrum in Figure 2 shows that Sample 1 contains a cBN phase and an Al 2 O 3 , AlN, ZrB 2 , W.B., and W. 2 The XRD spectrum in FIG. 3 demonstrates that sample 2 contains the cBN phase and other major phases including Al. 2 O 3 , ZrCN, W 2 B,W 2 B 5 , CoWB, and CoW 2 B 2 As shown in the XRD spectrum of Figure 3, the crystalline structure of the crystalline structure contains CoW, 3 B 3 The XRD spectrum in Figure 4 shows that sample 3 is composed of cBN phase and Al 2 O 3 , ZrB2, ZrCN, WB, CoW 2 B2 The XRD spectrum of FIG. 5 demonstrates that Sample 4 contains the cBN phase and the Al phase. 2 O 3 , ZrCN, WB, WC, CoW 2 B 2 As shown in the XRD spectrum of FIG. 5, the CoW phase is 3 B 3 exists.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the subject matter described herein pertains.

[0026] When a range of values ​​is provided, such as, for example, a concentration range, a percentage range, or a ratio range, it is understood that each intervening value between the upper and lower limits of that range, to one-tenth of the unit of the lower limit, and any other specified or intervening value within that stated range, is included in the described subject matter, unless the context clearly dictates otherwise. The upper and lower limits of these smaller ranges may be independently included in the smaller ranges, and such embodiments are also included in the described subject matter, subject to any limit specifically excluded from that stated range. When a stated range includes one or both limits, ranges excluding either or both of those included limits are also included in the described subject matter.

[0027] The terms "a" and "an," as used above and elsewhere in this disclosure, should be understood to refer to "one or more" of the listed components. It will be apparent to one of ordinary skill in the art that the use of the singular includes the plural unless specifically specified otherwise. Thus, the terms "a," "an," and "at least one" are used interchangeably in this application.

[0028] Unless otherwise indicated, all numbers used in the specification and claims expressing amounts of ingredients or properties such as size, weight, reaction conditions, etc., are understood to be all modified by the word "about". Throughout this application, the word "about" may mean a numerical value of plus or minus 10% of the numerical value being used. Thus, about 50% may mean a range of 45% to 55%. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximations that may vary depending on the desired properties sought to be obtained by the invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0029] Throughout this application, descriptions of various embodiments use the language "comprising," but it will be understood by those of ordinary skill in the art that some embodiments could alternatively be described using the language "consisting essentially of" or "consisting of."

[0030] Although reference has been made to specific embodiments, it will be apparent that other embodiments and variations can be devised by others skilled in the art without departing from the spirit and scope thereof, and it is intended that the appended claims be construed to include all such embodiments and equivalent variations.

Claims

1. 45-55 volume percent cubic boron nitride (cBN); 8 to 15 volume percent of at least zirconium carbonitride (ZrCN) or zirconium diboride (ZrB ２ ). 3-8 vol. % crystalline CoWB, crystalline CoW 2 B 2 , crystalline CoW 3 B 3 , or combinations thereof; 5 to 25% by volume of aluminum oxide (Al ２ O ３ ). 3-8 volume percent tungsten boride; and Less than 1% by volume of Aluminum Nitride (AlN) 1. A sintered cBN-based composite comprising: Excluding Ti-containing compounds, Sintered cBN based composite.

2. Tungsten boride is WB, W ２ B.W. ２ B ５ 10. The sintered cBN-based composite of claim 1, comprising:

3. Aluminum nitride (AlN), aluminum diboride (AlB ２ 10. The sintered cBN-based composite of claim 1 , excluding:

4. 45 to 55 volume percent cubic boron nitride (cBN); 8 to 30 volume percent of zirconium carbonitride (ZrCN), zirconium diboride (ZrB 2 ), zirconium nitride (ZrN), zirconium carbide (ZrC), zirconium dioxide (ZrO ２ ), or a combination thereof; 3-8 vol. % crystalline CoWB, crystalline CoW 2 B 2 , crystalline CoW 3 B 3 , or combinations thereof; 5-25% by volume of aluminum oxide (Al 2 O 3 ); 3-8 volume percent tungsten boride; and Less than 1% by volume of Aluminum Nitride (AlN) 1. A sintered cBN-based composite comprising: Excluding Ti-containing compounds, Sintered cBN based composite.

5. 13. A cutting tool for cutting superalloys including Inconel 718, Inconel 625, Alloy 188, Haynes 25, Alloy L605, and / or A286, the cutting tool comprising the sintered cBN-based composite of claim 1.

6. 1. A method for forming a cubic boron nitride (cBN) based composite material comprising: mixing powders of a cBN-based formulation for forming a cBN-based composite; sintering the cBN-based formulation at a pressure of at least 4 gigapascals (GPa) and a temperature of at least 1100° C. to form a (cBN)-based composite; and forming the cBN-based composite upon sintering: 45-55 vol.% cBN; 8 to 15 volume percent of at least zirconium carbonitride (ZrCN) or zirconium diboride (ZrB ２ ). 3-8 vol. % crystalline CoWB, crystalline CoW 2 B 2 , crystalline CoW 3 B 3 , or combinations thereof; 5 to 25% by volume of aluminum oxide (Al ２ O ３ ). 3-8 volume percent tungsten boride; and Less than 1% by volume of Aluminum Nitride (AlN) Including, Excluding Ti-containing compounds, method.

7. 7. The method of claim 6, comprising mixing a powder of the cBN-based compound with one or more solvents comprising ethanol, isopropanol, acetone, methanol, hexane, heptane, or combinations thereof to form a first mixture.

8. The method of claim 6, wherein the cBN-based formulation is sintered onto a cemented carbide (WC-Co) substrate or disk.

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