JPH04297544A - Ceramic-metal article and manufacture - Google Patents

Abstract

PURPOSE: To develop a cutting tool provided with the wear resistance and impact resistance.

CONSTITUTION: The highly dense ceramic-metal article contains 80-95 vol.% granular hard phase and 5-20 vol.% metallic phase, the hard phase consists of carbide, nitride, carbonitride, oxy-carbide, oxy-nitride, and carboxyl-nitride which are hard and high in melting point, of the cubic solid solution of W-Ti, W-Hf, W-Nb, W-Ta, Zr-Ti, Hf-Zr, V-Ti, Nb-Ti, Ta-Ti, and Mo-Ti, while the metallic phase consists of Ni and Al combined with each other of the Ni body Al of 90:10-70:30, and arbitrarily up to 5 wt.% Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Co, B and C. The article is pre-sintered at the temperature of 1475-1675°C, and its density is increased with the pressure of 34-207MPa at approximately 1575-1675°C by a hot isostatic press. The gradient hardness product can be manufactured by dropping the sintering temperature by at least 50°C below the temperature of the high density stage. The hard phase contains carbide, nitride, carbonitride, oxy-carbide, oxy-nitride, carboxyl-nitride, and boride which are hard and high in melting point, of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and B.

COPYRIGHT: (C)1992,JPO

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION This invention relates to metal-bonded ceramics, such as carbides, nitrides, and carbonitride articles, for use as cutting tools, wear-resistant parts, etc., and more particularly to metal-bonded ceramics, such as carbides, nitrides, and carbonitrides articles containing both nickel and aluminum. The present invention relates to such articles bonded with binders containing the present invention and methods of manufacturing such articles.

0002

BACKGROUND OF THE INVENTION The development and implementation of cobalt-bonded tungsten carbide (WC-Co) as a tool material for metal cutting has greatly expanded its range of applications beyond that of previous tool steels. Over the past 50 years, process and compositional improvements to WC-Co materials have yielded additional benefits in wear resistance, but the potential capabilities of these materials are inherently limited by the physical properties of the cobalt binder phase. ing. This becomes noticeable when the cutting speed is increased to a level that generates enough heat to soften the metal binder. High speed finishing of steel rolls is an example of a metal cutting application where the tool insert must maintain its cutting edge configuration at high temperatures and resist both wear and deformation.

0003

[Problem to be solved by the invention] Unfortunately, in general, “
WC-Co-based metal-bonded carbide sintered alloys, referred to as ``cemented carbide'', are also adversely affected by chemical interactions at high temperatures at the interface between the iron-based alloy workpiece and the cemented carbide tool surface. Cubic carbide (i.e. TiC) to WC-Co system
) addition led to certain improvements in tool performance during steel machining, partially as a result of the consequent increase in hardness as well as increased resistance to chemical interactions. However, the performance of such TiC-enriched WC-Co alloys is
Affected by the low fracture toughness of the phase, this created a tendency to fracture during machining operations involving spaced cuts, such as milling.

It would therefore be of great benefit if a cemented carbide material suitable for cutting tools could be developed that could withstand the demands of hard steel turning (wear resistance) and steel milling demands (impact resistance). becomes valuable. The object of the present invention is to develop a ceramic-metal article that meets these needs.

[0005]

According to one aspect of the invention, about 80-95% by volume of a granular hard phase and about 5-20% by volume of a granular hard phase.
a ceramic-metal article comprising a metal phase of zirconium-titanium, hafnium-titanium, hafnium-zirconium, vanadium-titanium, niobium-titanium, tantalum-titanium, molybdenum-titanium, tungsten. - cubic solid solution hard high-melting carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides and mixtures thereof selected from the group consisting of titanium, tungsten-hafnium, tungsten-niobium and tungsten-tantalum; while the metallic phase comprises a combination of nickel and aluminum having a nickel to aluminum ratio of about 90:10 to 70:30 by weight, and 0 to 5% by weight of titanium, zirconium, hafnium, vanadium, niobium, tantalum,
Chromium, molybdenum, tungsten, cobalt, boron,
and an additive selected from the group consisting of carbon and combinations thereof, and having a density of at least about 95% of the theoretical density.

In particular, the metallic phase is substantially Ni3Al
A ceramic-metallic article is provided which consists essentially of an ordered crystal structure or a Ni3Al ordered crystal structure coexisting with or modified by said additives.

[0007] According to another aspect of the invention, a ceramic-metal hardness graded article is provided in which the surface has a higher hardness than the core, wherein the hard phase is titanium, zirconium,
hafnium, vanadium, niobium, tantalum, chromium,
It may also be a hard high melting point carbide, nitride, carbonitride, oxycarbide, oxynitride, carbonitride, boride and mixtures thereof of elements selected from the group consisting of molybdenum, tungsten, cobalt and boron.

According to yet another aspect of the invention, (a) a hard high melting point element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt and boron; carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides, borides and mixtures thereof, and (b) zirconium-titanium, hafnium-titanium, hafnium-zirconium, vanadium-titanium, niobium-titanium, Tantalum - titanium, molybdenum - titanium, tungsten -
from cubic solid solution hard high melting point carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides and mixtures thereof selected from the group consisting of titanium, tungsten-hafnium, tungsten-niobium and tungsten-tantalum; about 80-95% by volume of a granular hard phase consisting essentially of a ceramic material selected from the group consisting of: about 85:1 by weight;
Nickel and aluminum with a nickel to aluminum ratio of 5 to 88:12 and 0 to 5% by weight of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, boron, carbon and combinations thereof. Pre-sintering a mixture of metal phase components substantially consisting of an additive selected from the group consisting of a sintering step, and densifying the pre-sintered mixture by hot isostatic pressing at a temperature of about 1575-1675° C. in an inert atmosphere and at a pressure of 34-207 MPa to at least about 95% of the theoretical value. a densification step to produce an article having a density of .

More particularly, said pre-sintering step is about 1
A method is provided which is carried out at a temperature of 475-1575°C, where the sintering temperature is at least 50°C lower than the temperature of the densification stage.

More specifically, the ratio of nickel to aluminum is such that during the densification stage the metallic phase component is Ni3A
1 ordered crystal structure or a Ni3 Al ordered crystal structure coexisting with or modified by said additives is provided.

[0011]

By providing a ceramic-metallic article in which the metal phase consists essentially of a Ni3Al ordered crystal structure or a Ni3Al ordered crystal structure coexisting with or modified by the additive, A cutting tool having both wear resistance and impact resistance is provided.

0012

[Example] Here, as an example of a ceramic material, one or more hard high melting point carbides, nitrides, oxides of tungsten-titanium solid solution bonded by an intermetallic compound combining nickel and aluminum or a binder containing the same. Examples include carbides, oxynitrides, carbonitrides, carbonitrides and borides, and one or more hard high-melting point carbides, nitrides, oxycarbides, oxynitrides, carbonitrides and carbonitrides of tungsten. These exemplary materials are considered representative of the ceramic family of the present invention, and the following description is not intended to limit the invention.

A typical densified, metal-bonded, hard ceramic body or article is a combination of a cubic solid solution powder as the hard phase component and both Ni and Al powders in an amount of about 5-20% by volume as the binder component. It is prepared from a powder mixture containing. A typical solid solution powder is (Wx, Ti1-x
)C, (Wx, Ti1-x)N, (Wx, Ti1-x
) (C, N), (Wx, Ti1-x ) (O, C),
(Wx, Ti1-x) (O, N), (Wx, Ti1-
x ) (O, C, N) and combinations thereof. Most preferably, x is in the weight fraction range of about 0.3 to 0.7. The optimum combination of properties (hardness and fracture toughness) is obtained when the total amount of metal binder addition is in the range of about 7-15% by volume. For best results during sintering and in the balance of both physical and chemical properties, the weight ratio of tungsten to titanium in the solid solution hard phase is about 0.3 to 3.0, more preferably about 0. It should be in the range of 6 to 1.5. Materials with a W:Ti ratio of less than about 0.3 suffer from reduced fracture toughness and impact resistance, which can be important in some applications, such as when used as a cutting tool for milling steel. shows. Ratios greater than about 3.0 do not improve wear resistance, which is also important in some applications, such as when used as a cutting tool for turning steel.

Alternatively, ceramic materials typically include compounds of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, boron, and mixtures thereof. Typical examples of these hard phase components are TiC, HfC, VC, TaC, Mo2C,
WC, B4 C, TiN, Ti(C,N), TiB2
Or it includes WB. The powder mixture comprises the hard components mentioned above, such as tungsten carbide, and a combination of both Ni and Al powders in an amount of about 5-20% by volume as the metal component. The optimum combination of properties (hardness and fracture toughness) is obtained when the total amount of metallic phase addition is in the range of about 7-15% by volume. In this exemplary material, the tungsten carbide ceramic component provides excellent wear resistance, which is important in applications such as cutting tools for steel turning. The metallic phase gives the material higher fracture toughness than the sintered ceramic material alone, and the metallic phase combined with aluminum and nickel in the above ratios provides improved high temperature properties such as creep resistance over cobalt or other single metals. give.

In any of these materials, as mentioned above, the metal powder component represents about 5-20% by volume of the starting formulation, preferably about 7-15% by volume. The binder metal powder contains nickel in an amount of about 85-88% by weight and 12-88% by weight.
It contains aluminum in an amount of 15% by weight (both relative to the total weight of binder metal powder). Minor amounts of titanium, zirconium, hafnium, vanadium, niobium, tantalum, in amounts not exceeding about 5% by weight of the total binder metal;
Chromium, molybdenum, tungsten, cobalt, boron and/or carbon may also be included. A preferred composition is 12-14% by weight Al and balance Ni. In the most preferred binder composition, the Ni:Al ratio is N
Substantially Ni3A with i3Al ordered crystal structure
1 resulting in the formation of a binder. The amount of Ni3Al also depends on the processing conditions, e.g. processing temperature, and can be selected to achieve various properties as a cermet, e.g. 100%, 40-80%, less than 50% of the metallic phase, etc. N required to achieve the desired amount of Ni3Al
The ratio of i:Al powder can be easily determined empirically. Alternatively, prereacted Ni3Al can be used in the starting formulation.

[0016] In some compositions, this ordered crystal structure can coexist with or be modified by the additives mentioned above. The preferred average grain size of the hard phase in a densified body of this material for use as a cutting tool is about 0.
．． It is 5 to 5.0 μm. For other types of articles for applications with lower requirements for deformation resistance, such as sandblasting nozzles, a larger range of grain sizes, e.g.
will be satisfactory.

The material can be densified by known methods such as sintering, continuous cycle sintering, two-stage sintering + HIP, or hot pressing. These are all known in the industry.

Another densified metal-bonded hard ceramic body or article has the same overall composition as described above, but in that it exhibits a graded hardness, most preferably in the central portion. The difference is that the hardness is low and gradually increases toward the surface. To obtain ceramic bodies with these properties, the densification process includes a presintering step in which the starting powder mixture is heated in a vacuum (e.g., about 0.1 torr) or in an inert atmosphere (e.g., about 1 atm). ) at a temperature of about 1475-1575°C, preferably 1475-1550°C, for a time sufficient to develop a microstructure with closed pores, for example about 0.5-2 hours. The term "microstructure with closed pores" as used herein is intended to mean a microstructure in which the remaining pores are no longer interconnected. Subsequently, the ceramic body is heated under an overpressure of an inert atmosphere of about 34-207 MPa and at 1575-1675°C, preferably 16
Sufficient densification is carried out at a temperature of 0.000 to 1675° C. for a sufficient time to achieve full density, such as from 0.5 to 2 hours. The pre-sintering temperature is at least 5% lower than the final densification temperature.
0℃ lower. These graded hardness ceramic bodies exhibit outstanding impact resistance and are particularly useful as milling tool inserts and as tools for space cutting of steel.

The depth at which the hardness gradient is produced depends on the presintering temperature. Thus, if fully graded hardness is not important, a similar process can be used with a wider range of presintering temperatures, about 1475-1675°C, and between presintering and hot pressing temperatures of 50°C. °C temperature difference requirements are not required.

For certain applications, such as cutting tools, the articles described herein may be coated with high melting point materials to provide certain desired surface properties. Preferred coatings are refractory metal carbides, nitrides and/or carbonitrides of, for example, titanium, tantalum or hafnium, or oxides of, for example aluminum or zirconium, or one of the combinations of these materials as different layers and/or solid solutions. having two or more cohesive, compositionally distinct layers. Such coatings may be deposited by methods such as chemical vapor deposition (CVD) or physical vapor deposition (PVD) and preferably to a total thickness of about 0.5-10 μm. C, which is known in the art as being suitable for cemented carbide coatings.
VD or PVD techniques are preferred for coating the articles described herein.

Alumina, titanium carbide, titanium nitride, titanium carbonitride, hafnium carbide, hafnium nitride or hafnium carbonitride coatings are typically applied by CVD. The other coatings listed above can be applied either by CVD or by PVD, if applicable. Examples of suitable CVD techniques include direct evaporation and sputtering. Alternatively, a refractory metal or precursor can be deposited on the ceramic body by chemical or physical deposition techniques and subsequently carbonized and/or nitrided to form a refractory metal carbide, carbonitride or nitride coating. It is also possible to generate one. Useful properties of the preferred CVD method include the purity of the deposited coating as well as the layer adhesion often caused by diffusion interactions between the deposited layer and the substrate and between interlayers during the early stages of the deposition process. It's an improvement.

For certain applications, such as cutting tools, combinations of the various coatings described above may be devised to improve overall performance; and depends on the workpiece material. This is achieved, for example, through the selection of coating combinations that improve coating-to-substrate and coating-to-coating adhesion, and through improvement of microstructurally influenced properties of the substrate. An example of such a property is
Mention may be made of the hardness, fracture toughness, impact resistance, and chemical inertness of the substrate.

The following examples are presented to enable those skilled in the art to more clearly understand and practice the invention. It should be noted that these examples do not limit the scope of the invention, but are merely illustrative of the invention.

(Example) 10% by volume of metal binder (86.
7 wt% Ni and 13.3 wt% Al, which is Ni3
A powder mixture of 90% by volume of hard phase (either carbide or boride as a non-solid solution or (W,Ti)C in a solid solution W:Ti in a 50:50 weight ratio) A cutting tool was prepared from.

(Example 1) 111.52 g of (W,Ti)C
and metal powder, 0.0315 g carbon, 4.13 g paraffin and 150 cc heptane.
Milling was performed in a 00 cc capacity tungsten carbide attritor mill using 2000 g of 3.2 mm sintered tungsten carbide ball media at 120 rpm for 2-1/2 hours. After milling, the powder was separated from the milling media by washing through a stainless steel screen with additional heptane. Excess heptane was slowly evaporated. To prevent the binder (wax) from becoming uneven,
This thick slurry was mixed continuously during the evaporation operation and the cake-forming powder was ground into small dry particles with a plastic spatula. The dried particles were then sieved in two stages using 40 mesh and 80 mesh screens. The sieved powder was then pressed at 138 MPa to form a 16×16×6
．． A green compact was produced having dimensions of 6 mm and a solids loading of 50-60% by volume.

The pressed compacts were placed in a graphite boat, covered with alumina sand and placed in a hydrogen furnace at room temperature. Thereafter, the temperature was increased by 100° C. every hour and maintained at 300° C. for 2 hours to complete the removal of the organic binder. The dewaxed sample was removed from the hot zone of the furnace, cooled to room temperature, and removed from the hydrogen furnace.

The dewaxed samples were then densified in two steps: pre-sintering and hot isostatic pressing (HIP). The dewaxed samples were presintered at 1650° C. for 1 hour at about 0.1 Torr in a cold wall graphite vacuum furnace on graphite plates that had been dusted with coarse alumina sand. The initial temperature increase was rapid, at 15° C./min up to 800° C. Temperature increase rate from 800℃ to 4.5℃/
The sample was degassed. The chamber pressure was maintained at approximately 0.1 Torr throughout the pre-sintering cycle.

Final condensation is carried out in the HIP unit at 165
It was carried out at 0° C. and using a heating rate of about 10° C./min for 1 hour in an argon atmosphere of 207 MPa. Maximum temperature (1650° C.) and pressure (207 MPa) were reached simultaneously and maintained for about 1 hour, after which time the furnace was cooled to room temperature.

The cutting tool prepared by this process is
As shown in Figure 1, it showed improved performance over commercially available cutting tools in machining steel. The tool is 104
600 ft (180 m)/min in dry turning of 5 steel;
0.016in (0.041cm)/rotation, 0.050
in (0.13cm) D. O. C. (depth o
fcut cutting depth). The wear values shown in FIG. 1 are the average values of the wear occurring at the three corners. 29.1 in3 (477 cm3) of metal was removed. As seen in FIG. 1, the tool of this example exhibits significantly better notch wear in turning performance compared to commercial tool #1 and has significantly better performance than commercial tool #2. Table 1 shows a comparison of the composition and hardness at room temperature of the commercially available tool in FIG. 1 and the tool of this example.

Example 2 The cutting tool of this example was prepared in the same manner as in Example 1, except that the dewaxed compact was heated at 0.1 Torr in the same wall-cooled graphite vacuum furnace.
Preliminary sintering was performed at 500°C for 1 hour. The temperature increase rate was the same as in Example 1. That is, the heating rate was initially rapidly increased to 800°C at 15°C/min, and from 800°C, the heating rate was reduced to 4.5°C/min to vent gas.

The metal-bonded carbide cutting tool of this example is shown in Table 1.
As shown in Figure 1, the hardness gradient and fracture toughness are characterized by a specific microstructure that develops from the surface of the densified article to its core. The performance of this graded hardness cutting tool was measured by machining tests, and the results are shown in FIG. The impact resistance of the tool of this example, the tool of Example 1, and two commercially available tools was determined by a dry fly cutter milling test on a steel workpiece (Rockwell hardness Rc = 24) at 750 ft.
(225 m)/min, 4.2 in (10.7 cm)/rev, 0.125 in (0.32 cm) D. O. C. standard milling cutter (US GTE Va.
(commercially available from Lenite Corporation). The wear values shown in Figure 2 are average values for 4 corners at 341 impacts/corner. The cutting tools used in the machining tests are shown in Table 1 along with their composition and room temperature hardness.

As shown in FIG. 2, the tool of this example outperforms both commercially available tools in milling performance. Furthermore, although the tool of Example 2 is most suitable for this application, the tool of Example 1 has also been found to be of commercial value for such high impact applications.

[0033]

[Table 1]

Examples 3-6 Cutting tools were prepared using the same hard phase/metallic phase powders as described for Examples 1 and 2, but presintered at the temperatures and times shown in Table 2. Then some of them were pressed with equal pressure. The heating rate was the same as in Example 1, initially rapidly at 15°C/min up to 800°C, and from 800°C the heating rate was reduced to 4.5°C/min. Characterization by X-ray diffraction confirmed that the compacts evidenced the formation of varying amounts of γ' crystal structure Ni3Al in their metallic phase.

[0035]

[Table 2]

Examples 7-10 Ceramic-metal cutting tools having nickel and aluminum metallic phases were prepared as described for Example 1, except that the compositions were as shown in Table 3.
It was made as shown in. Cubic solid solution (W,Ti)C
Performance of base ceramic-metal cutting tools, 1045 steel, 4
75ft (142.5m)/min, 0.012in (0.
03cm)/rotation, 0.050in (0.13cm) D. O. C. The performance of a similar tool without solid solution carbide was compared in dry turning under conditions of .

[0037]

[Table 3]

The wear values shown in Table 3 are the average of the wear values that occurred at the three corners during the extended cutting test. The WC-based cermet tool failed before the extension test was completed. For the remaining tests, approximately 65-70 in3
(1064-1147 cm3) of metal was removed. As shown in Table 3, the titanium carbide-based cermet tool outperformed a similar tungsten carbide tool (which failed before completing the extended cutting test) in extended wear performance and that of a similar tool based on a mixture of tungsten carbide and titanium carbide. Outperformed crater wear performance.

The tool of Example 10 was similar in all respects except that it included cubic solid solution carbides of tungsten and titanium. The tools of Examples 9 and 10 were of virtually identical chemical composition, containing a 50:50 weight ratio of tungsten and titanium. However, surprisingly, this solid solution carbide-containing tool outperformed WC-based tools and even (TiC+WC)-based tools in machining tests. The solid solution carbide-based tool was also found to exhibit better flank wear performance and equal crater wear performance than the supposedly harder TiC-based tool of Example 8.

The surprising superiority of cubic solid solution carbide-based tools is illustrated in Figures 3-6, which are micrographs of the wear that occurred after 20 in3 (328 cm3) of metal removal in one corner of each of the tools listed in Table 3. Can be seen clearly. As illustrated in FIG. 3, tungsten carbide-based tools exhibit severe cratering that ultimately leads to tool failure. FIG. 4 illustrates severe nose deformation of a titanium carbide-based tool, which exhibits virtually no cratering. In FIG. 5, (W
This example illustrates the effect of combining titanium carbide's resistance to cratering and tungsten carbide's resistance to nose deformation in a C+TiC)-based tool. The superiority of a tool according to one aspect of the present invention, the solid solution carbide-based tool of Example 10, is illustrated in FIG. Here, the tool is virtually crater-free and exhibits significantly less deformation and wear than any similar tool.

(Examples 11 to 16) 10% by volume metallic phase (86
．． 7 wt% Ni and 13.3 wt% Al, Ni3Al
A ceramic-metal tool was prepared from a powder mixture of stoichiometric equivalent) and 90% by volume ceramic hard phase.

A charge consisting of 221.28 g of tungsten carbide and metal powder, 0.0315 g of carbon, 4.13 g of paraffin and 150 cc of heptane was
Milling was performed in a cc capacity tungsten carbide attritor mill using 2000 g of 3.2 mm sintered tungsten carbide ball media at 120 rpm for 2-1/2 hours. This milling process was repeated using such weights of hard phase as to produce equal volume percentages.

After milling, the powder was separated from the milling media by washing each powder batch through a stainless steel screen with additional heptane. Excess heptane was slowly evaporated. To prevent binder (wax) non-uniformity, this thick slurry was mixed continuously during the evaporation operation and the cake-forming powder was ground into small dry particles with a plastic spatula. The dried particles were then sieved in two stages using 40 mesh and 80 mesh screens. The sieved powder was then pressed at 138 MPa to have dimensions of 16 x 16 x 6.6 mm and 50-60
A green compact was produced having a solids loading of % by volume.

The pressed compacts were placed in a graphite boat, covered with alumina sand and placed in a hydrogen furnace at room temperature. Thereafter, the temperature was increased by 100° C. every hour and maintained at 300° C. for 2 hours to complete the removal of the organic binder. The dewaxed sample was removed from the hot zone of the furnace, cooled to room temperature, and removed from the hydrogen furnace.

The dewaxed samples were then densified in two steps: pre-sintering and hot isostatic pressing (HIP). The dewaxed samples were presintered at 1650° C. for 1 hour at about 0.1 Torr in a cold wall graphite vacuum furnace on graphite plates that had been dusted with coarse alumina sand. The initial temperature was raised rapidly to 800°C at a rate of 15°C per minute. From 800°C, the heating rate was reduced to 4.5°C/min. The chamber pressure was maintained at approximately 0.1 Torr throughout the pre-sintering cycle.

Final condensation is carried out in the HIP unit at 165
It was carried out at 0° C. and using a heating rate of about 10° C./min for 1 hour in an argon atmosphere of 207 MPa. Maximum temperature (1650° C.) and pressure (207 MPa) were reached simultaneously and maintained for about 1 hour, after which time the furnace was cooled to room temperature. Table 4 shows the Knoop hardness of the surface of each densified compact.

[0047]

[Table 4]

As shown in Table 4, the carbide compacts prepared as described above exhibited improved hardness over commercially available cutting tools. Titanium and tungsten-titanium tools prepared as described above were 1045
475 ft (143 m)/min, 0 in steel dry turning
．． 012in (0.03cm)/rotation, 0.050in
(0.13cm) D. O. C. It showed good performance under these conditions.

Example 17 Compacts were prepared using the same powder and the same process in the starting formulation as described for Examples 11-16. However, the dewaxed compacts were presintered in the same wall-cooled graphite vacuum furnace at 1500° C. for 1 hour at 0.1 Torr. The temperature increase rate was the same as in Example 1. That is, initially rapidly 8
The heating rate was 15°C/min up to 00°C, and from 800°C the heating rate was reduced to 4.5°C/min.

The metal-bonded carbide cutting tool of Example 17 is characterized by a particular microstructure that develops a high degree of gradient from the surface of the densified article to its core.

[0051]

The present invention provides an improved cutting tool that can withstand the demands of hard steel turning, which requires a high degree of wear resistance, as well as steel milling, which requires a high degree of impact resistance. provide. The present invention also provides wear parts and other structural parts requiring high strength and wear resistance.

Although preferred embodiments of the invention have been described, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a graph comparing the machining performance of a cutting tool according to one embodiment of the present invention and a commercially available tool.

FIG. 2 is a graph comparing the milling performance of a cutting tool according to two embodiments of the present invention and a commercially available tool.

FIG. 3 is a micrograph showing the metallographic structure of wear that occurred after metal removal of the tungsten carbide-based tool in Table 3;
Shows severe cratering that ultimately leads to tool failure.

FIG. 4 is a micrograph showing the metallographic structure of the abrasion that occurred after metal removal of the titanium carbide-based tool in Table 3, showing severe nose deformation but virtually no cratering.

FIG. 5 is a micrograph showing the metallographic structure of wear that occurred after metal removal of the (WC+TiC)-based tool in Table 3, showing the resistance of titanium carbide to cratering and the nose deformation of tungsten carbide in the (WC+TiC)-based tool. It exhibits a combined effect with resistance, and virtually no cratering occurs.

FIG. 6 is a photomicrograph showing the metallographic structure of the wear that occurred after metal removal in the solid solution carbide-based tool of Example 10, showing that the tool was substantially free of cratering and showed more deformation and wear than any similar tool. There are far fewer.

Claims (15)

[Claims] 1. About 80-95% by volume of a granular hard phase;
about 5-20% by volume of a metal phase, wherein the particulate hard phase is a zirconium-
Titanium, hafnium-titanium, hafnium-zirconium, vanadium-titanium, niobium-titanium, tantalum-
Titanium, molybdenum-titanium, tungsten-titanium,
Among cubic solid solution hard high melting point carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides and mixtures thereof selected from the group consisting of tungsten-hafnium, tungsten-niobium and tungsten-tantalum. selected ceramic materials, while the metallic phase comprises a combination of nickel and aluminum having a nickel to aluminum ratio of about 90:10 to 70:30 by weight, and 0 to 5% by weight of titanium, zirconium, hafnium, and an additive selected from the group consisting of vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, boron, carbon and combinations thereof, and wherein said article has a density of at least 95% of the theoretical density. Ceramic-metal article featuring features. 2. The ceramic-metallic article of claim 1, wherein the metallic phase consists essentially of a Ni3Al ordered crystal structure or a Ni3Al ordered crystal structure coexisting with or modified by said additive. 3. The article is coated with one or more coherent compositionally distinct layers, each layer comprising a titanium, tantalum or hafnium carbide, a nitride or carbonitride, an aluminum or zirconium oxide, or a mixture or solid solution thereof. 4. The ceramic-metal article of claim 1, wherein the hard phase comprises tungsten-titanium carbide which is a substantially cubic solid solution. 5. The ceramic-metal article of claim 4, wherein the weight ratio of tungsten to titanium in the hard phase is about 1:3 to 3:1. 6. About 80-95% by volume of a granular hard phase;
about 5-20% by volume of a metal phase, wherein the particulate hard phase comprises (a) titanium;
Hard high melting point carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides of elements selected from the group consisting of zirconium, hafnium, vanadium, niobium, tantalum, chromium, cobalt, molybdenum, tungsten and boron. , borides and mixtures thereof, and (b) zirconium-titanium, hafnium-titanium, hafnium-zirconium, vanadium-titanium, niobium-titanium, tantalum-titanium, molybdenum-titanium, tungsten-titanium, tungsten-hafnium, tungsten-niobium. and ceramic materials selected from the group consisting of cubic solid solution hard high melting point carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides and mixtures thereof selected from the group consisting of tungsten-tantalum. substantially consisting of a combination of nickel and aluminum having a nickel to aluminum ratio of about 90:10 to 70:30 by weight, and 0 to 5% by weight of titanium, zirconium, hafnium, vanadium, niobium, an additive selected from the group consisting of tantalum, chromium, molybdenum, tungsten, cobalt, boron, carbon and combinations thereof, and wherein said article is graded from greater hardness at the surface to decreasing hardness at the core. hardness and
A ceramic-metal article characterized in that it has a density of at least 95% of the theoretical density. 7. The metal phase comprises a Ni3Al ordered crystal structure or a Ni3Al ordered crystal structure coexisting with or modified by the additive in an amount of about 15 to 80% by volume of the volume of the metal phase. 7. The ceramic-metallic article of claim 6 comprising substantially the following. 8. The article is coated with one or more coherent compositionally distinct layers, each layer comprising a titanium, tantalum or hafnium carbide, nitride or carbonitride, an aluminum or zirconium oxide, The ceramic-metal article of claim 6 which is a mixture or solid solution thereof. 9. The ceramic-metal article of claim 6, wherein the hard phase comprises tungsten-titanium carbide which is a substantially cubic solid solution. 10. The ceramic-metal article of claim 9, wherein the weight ratio of tungsten to titanium in the hard phase is about 1:3 to 3:1. 11. A method of manufacturing a ceramic-metal article, comprising: (a) an element selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt and boron. Hard high melting point carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, carbonitrides, borides and mixtures thereof; and (b) zirconium-titanium, hafnium-titanium, hafnium-zirconium, vanadium-titanium,
cubic solid solution hard refractory carbides, nitrides, carbonitrides selected from the group consisting of niobium-titanium, tantalum-titanium, molybdenum-titanium, tungsten-titanium, tungsten-hafnium, tungsten-niobium and tungsten-tantalum; about 80-95% by volume of a particulate hard phase consisting essentially of a ceramic material selected from the group consisting of oxycarbides, oxynitrides, carbonitrides and mixtures thereof, and about 85:15-88:12 by weight nickel. nickel and aluminum having a ratio of 0 to aluminum;
~5% by weight of an additive selected from the group consisting of titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, cobalt, boron, carbon and combinations thereof. , about 1475 in vacuum or inert atmosphere
a pre-sintering step of pre-sintering at ~1675°C to develop a pore-sealed microstructure; and hot isopressing the pre-sintered mixture at a temperature of about 1575-1675°C in an inert atmosphere. and a densification step at a pressure of 34 to 207 MPa to produce an article having a density of at least about 95% of theoretical. 12. The pre-sintering step is about 1475-157.
12. The method of claim 11, wherein the process is carried out at 5[deg.]C and the sintering temperature is carried out at a temperature at least 50[deg.]C lower than the temperature of the densification step. 13. The ratio of nickel to aluminum during the densification step is such that the metal phase component substantially changes to a Ni3Al ordered crystal structure or a Ni3Al ordered crystal structure coexisting with or modified by the additive. 12. The method of claim 11, wherein the method is selected to be converted. 14. A claim in which the hard phase component consists essentially of a ceramic material selected from the group consisting of carbides, nitrides, carbonitrides, oxycarbides, oxynitrides, and carbonitrides of cubic solid solutions of tungsten and titanium. Method of Section 11. 15. The method of claim 14, wherein the weight ratio of tungsten to titanium in the hard phase is about 1:3 to 3:1.