JPS61274803A - Reinforced ceramic cutting tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to cutting tools, and more particularly to improved ceramic cutting tools.

BACKGROUND OF THE INVENTION Metal cutting is recognized as one of the most important and widely used methods of manufacturing. Typical machining includes shaping, milling, milling, face milling, broaching, grinding, sawing, circular milling, boring, @9 milling, and reaming.

Some of these methods, for example, work on both the external and internal surfaces of the workpiece, while others act on the internal surface of the workpiece (e.g., reaming and sawing), while others act on the internal surface of the workpiece (e.g., reaming and sawing). For these various methods, please refer to Degarmo (D6 Garmo).
Author: Mater-ials and Grosses in Mani 7
Processes in Manufacturer
ing)% 3rd edition (1969)% Especially the 16th table metal cutting 1'jtlK has a detailed explanation.

The productivity of one machining method is determined by the total amount of metal removed from the workpiece in a given time. For this purpose, a number of materials have been proposed for use as cutting tools. These materials usually have 5
Classified into tool steels, high-speed steels, cast nonferrous alloys, sintered carbides, and milled ceramics. (1 sentence, there are limited uses for cypress, which is similar to diamond.) Parameters commonly measured regarding the performance of cutting tools include cutting speed, depth of cut,
Determined by feed rate and machining tool life. None of the cutting tool materials in the prior art are sufficient in one or more of these parameters. tool steel.

High-speed steel and cast non-ferrous alloys all have critical temperature limits! ll, its cutting speed (e.g.

Feet 7 minutes (fpm)'! 7'c / minute (double /
) can be kept to a relatively small value. Generally, when cutting high-speed steel, 30 to 70 + 1/
minute (100-225 fpm) and for cutting non-ferrous materials, 75-90 a/min (250-3001 p
m) is limited to. Approximately 2 of these speeds for cast non-ferrous alloys
Can be used up to twice the value. With carbide 1!2y materials such as tungsten carbide, the cutting speed of steel is improved by a factor of 2 to 5, especially with carbide 4I! This is noticeable when performing L-over. However, 9J carbide does not have the toughness of steel and is prone to impact fracture. In order to improve the efficiency of carbide, use 1 where impact is one of the factors, for example, stair cutting 1 fls (inter
The machining of hard cut cuts is subject to severe limitations.

It has become clear that ceramic materials, such as alumina, can be used to produce cutting tools that can be used at a faster rate than conventional steel and carbide cutting tools. For example, for steel cutting, 150-430 s/min (500-
Cutting speeds as high as 140 fpm have been reported.

However, there are serious problems with ceramic tool life.

This is because ceramics are more brittle and smaller than carbides. In particular, it should be considered that
Ceramic materials have a tendency to suddenly disintegrate and break down when subjected to impact. Therefore, it can only be used at very small feed rates, which are high in cutting speeds for ceramic materials, but much lower than the feed rates used in steel and carbide cutting tools.

From the foregoing it can be seen that the productivity, which is a function of cutting speed and feed rate, is relatively small for all prior art types of cutting tools. Carbide tools for steel machining require large feed rates.

The cutting speed is relatively small. On the contrary, to ceramic.

Although it has a high cutting speed, it cannot be used because it has a small feed rate. Therefore, metal 1 removed in a given time
Productivity, determined as a quantity, remains relatively small regardless of the type of cutting tool used.

Documents related to the use of 6-dan ceramics as cutting tools include U.S. Pat. No. 4,543,343, which includes alumina, zirconia, 'S?
The use of ceramics consisting of engineered titanium carbide as well as titanium boride is mentioned. Another example is U.S. Patent No. 4.3.
66.254g spec.
This is about Lamic.

It is known that ceramics reinforced with silicon carbide fibers can be used in a variety of mechanical parts. For example, heat exchanger, mold, nozzle, turbine, nozzle,
Can be used for machined gears, etc. Japanese Patent No. 59-546
80 Okobi No. 59-102681 Specification '4It-Please refer to it. However, the disclosed content is not closely related to the cutting tool invention described in detail. This is because these parts are not subject to impact stress as part of a normal use environment. The above specification does not mention any improvement in impact resistance other than toughness, and is not interested in its mechanical properties.

[It has also been shown that the fracture toughness of L ceramics can be improved by incorporating silicon carbide whiskers into the ceramics. Two papers by Becher and WeiK describe the mechanism of increase in toughness due to whisker content and orientation. 'Toughening Behavior in SiO Whisker Reinforced Alumina J
r in 8i0 Whisker Re1nforc
ed Alu -mina' entered Oomm, Am, Oa
r, 8oc, (8ept-, 1984)
Reinforced Ceramics J (%Trans
formation Toughened and
Whis-ker Re1nforced C3e
ramics&), Soc, Auto, Engrs
,.

Proc, 21st Auto, Tech, De
y, Mtg, , 201 205 (Mar, 19
84) t-referenced. Also, U.S. special liver No. 4,54
3.345g'Also refer to the AIa oath. However, these articles and specifications only address high temperature and bending applications and do not give any attention to machining processes. Therefore, it would be very advantageous to have a tool that works at high cutting speeds on ceramics, but also allows high feed rates on steels and carbides. Any cutting tool according to the prior art would provide significantly greater productivity.

SUMMARY OF THE INVENTION In its broadest form, the invention relates to a cutting tool consisting of a composite material consisting of a ceramic matrix, the matrix having nine reinforcements dispersed within the matrix consisting of ceramic whiskers. Deroru.

In a preferred embodiment, the ceramic matrix consists of pure 17'c alumina with modified material impurities. Silicon nitride is an alternative ceramic matrix that can also be enriched by 9%.

The most preferred reinforcing ceramic whiskers are silicon carbide whiskers. Other suitable whiskers include alumina, aluminum nitride, beryllia, boron carbide, graphite, and engineered silicon nitride. In each tool, of course, whisker reinforcement.

It must be made of a material that is compatible with and forms a suitable reinforcing bond with the ceramic matrix.

Whisker content within the ceramic matrix varies from 2 to
40 volume Sagi% whisker. Compounded with an alumina matrix and a 25% silicon carbide voice car, it becomes a very difficult ceramic cutting tool.
Togawakatsu Rin.

Preferred Embodiments Cutting tools are of a unique and highly specialized type of industrial equipment. The shape of the cutting tool is such that significant cutting stress is concentrated at the cutting edge of the tool. Transform the processing w, chip? 9. Necessary work to create 41 operations, work to prevent friction between the machining tip and the cutting SIJ tool surface.9. Significant heat is generated within the cutting tool. Properties of the workpiece e.g. ductility′! ! f
It is also said that the stress and working temperature to which the cutting tool is exposed to become extremely dry due to the decrease in hardness. The cutting tool is subjected to shocks of various sizes. especially,
The size of the %'IIfi forces changes not only when performing interrupted cutting, but also when machining flaws tend to form continuous or discontinuous chips. A detailed discussion of these types of working conditions and a description of various tool geometries can be found in the aforementioned DeGarmo book. Due to the critical and unique combination of working stresses, temperatures, and shocks, the determination of materials suitable for use as cutting tools and the determination of materials for other industrial products, such as gears, It will be very different.

By incorporating a certain amount of ceramic reinforcing whiskers into the ceramic matrix, the present invention not only preserves the large cutting speeds of prior art unreinforced ceramics, but also, surprisingly, reduces the cutting speed ti! This led to the discovery that only by making the material smaller and paying attention to its properties, a cutting tool structure could be created that made it possible to use ceramics at a feed rate that was conventionally achievable with only steel and carbide. It is based on

The matrix body of the cutting tool may be any ceramic material that has heretofore been found to be useful as a cutting tool in its unreinforced state. The most important of these is alumina.

Alumina can be used alone (i.e., with the exception of recognized impurities of gold and other materials ``4+'') or in small amounts (i.e., up to about 30% of reinforcing components such as zirconia, ittria, etc.). Hefea, Magnesia.

Silicon nitride, and titanium carbide, as well as mixtures thereof, can be combined to form a "dawg". In the SAE abuse by Becher et al. cited earlier, 3
Contains zirconia at 0%l, zirconia is 3 m
Typical compositions containing up to 1% ittria are shown. Other ceramics commonly used as cutting tool matrices include silicon nitride, which can also be considered a modifying component.

Silicon carbide whiskers are also effectively used as reinforcing water whiskers. Both alpha and beta type silicon carbide whiskers are commercially available and can be used for one use. The whisker used in the invention has a single crystal structure. A particularly preferred market supply includes AROO Chemical Co.
mpany) Advanced Materials (Adva
Ruru is a silicon carbide voice car manufactured and sold by nced Materials J Group.

This whisker is made from rice husks and is generally o, 6μW.
It has an average diameter of about L and an aspect ratio of about 15 to 150. Generally 1 strength rx,% 70.000kf/
At around cIi (1,000,000psi), the tensile modulus is (4~7) x 10' kf/d ((
Approximately 60 to 100]×10@psi). Silicon carbide whiskers are thermally stable up to 1760°C (3200°C). Other suitable whiskers include:
Examples include alumina, aluminum nitride, aluminum alloy, boron carbide, graphite, and silicon nitride. Mixtures of whiskers can also be used. For more detailed information on single crystal whiskers, see H.
Nis Katta (H, 8, Katz), J.V., Milewski (J, V, Milewski J arrival,
Handbook of Fillers and Reinforcements for Plastics
k of Fill-ers and Reinfor
cements for plastics)%pp
446~46'f (0,25) (Von No5t
rand Refnhold Co.

See N, Y. (1978) i.

A distinction should be made between polycrystalline type short-stole materials and monocrystalline whiskers used in the invention. The polycrystalline filament Taka9 is shredded and the fiber has a much larger diameter, e.g.
I'm in the μ genus and above. U.S. Pat. No. 4,543,345, cited above.
In the process shown in the title, polycrystalline fibers undergo considerable deterioration due to crystal grain growth at temperatures of approximately 1,250°C or higher, and the manufacturing process is at a high temperature.

For example, its utility in hot presses for producing near-theoretical density ceramic composites is severely limited. Furthermore, high pressure load jt? In this case, the loading area during hot pressing is destroyed by the cutting edge and polycrystalline fibers, thereby impairing the reinforcing properties of the fibers in the ceramic composite material. Also.

These polycrystalline fibers provide insufficient resistance to cracking in ceramic composites. This is because crack @ mam is a fiber that crosses the fracture surface.

This is because there is not enough tensile strength to prevent crack growth within the composite. This is especially true when composite cupware is manufactured by exposing it to high pressure and temperature in a hot press. ” i-Friend, G.V. Milesky “Short Smooth Fiber〇Reinforcement; Where the 7/Shore I, e J, j'
9 Styx Connosounding (J, V, Mi
lewski%8hort-Fiber 几ein-fo
rcemeats: Where The Actio
n Is #, Plastics Compound
ing,) November/December 1979. pp17-37
See also gold. On pages 17-19 of this Kaburabun.

A clear distinction is made between single-crystalline whiskers I and polycrystalline a′ microfibrils I.

Ceramic whiskers and ceramics are placed in the surrounding areas.
The composition must be compatible with the matrix composition. Since most of these materials are sufficiently compatible with each other, those skilled in the art will have no problem avoiding some instances of non-compatible assemblies.

It should also be understood that the whiskers may be placed in the matrix circle to provide matrix reinforcement. The detailed nature of bond strengthening is not fully covered. It has been demonstrated by several researchers to give general knowledge about excellent reinforcement. One simple description is the Handbook of Fillers and Reinforcement for Glasses by Katz et al.
lers and inforceme-nts
for Plasticm), 454-457 (
1978). The ceramic whisker content is about 2-40 v of the whisker/matrix composite.
oL% range, the bond rX is satisfactory and provides sufficient reinforcement for the uninvented cutting tool. Whisker additions with a whisker content of more than about 40% are detrimental to toughness (results when the matrix material accounts for 60-98%). In addition, if the whisker content is too large, the toughness of the whisker-rich region itself will be limited, or if the whisker content is too large, areas with low matrix cohesion will develop in the ceramic matrix. Seem. Below about 2%, there is insufficient whisker content to provide adequate reinforcement.

The preferred range of whisker content depends on the type of cutting operation for which the tool is intended. relatively small inclusion [t
(approximately 2% to 12%), the tool is generally used for types of cutting (e.g., rounding) in which cutting forces are applied relatively continuously and heat is accumulated in the tool mark. If F is suitable.

However, if a ceramic sword has many slits or is seen in an intermittent manner, the wealth is relatively large! (e.g., 20-35%) is preferable. Cutting tools containing about 25% by volume silicon carbide whisker in an alumina matrix circle exhibit excellent performance. It goes without saying that a routine Eiken test for I/C children is required to determine the I/C level, but such an experiment would be readily available to those skilled in the art.

Typical examples of the tool of the present invention are shown in Table 1.

First of all, my data is from Alco Addicted Chemical Company.
OOOchemical Company'! Fracture toughness (KC) vi - measured results for a sample consisting of an alumina matrix containing silicon carbide whiskers of R
It is derived from IL.

@Table 1 Whisker content Fracture toughness o4.15 18 6.9 24 8.9 30 8.7 35 7.6 A similar improvement in toughness can be expected in the case of other ceramic matrices. For example, a ceramic matrix made of silicon nitride added with titanium carbide or alumina both has an a-fracture toughness that is about 01.25 times the fracture toughness of an alumina matrix. A similar degree of fracture toughness improvement due to whisker reinforcement as shown for alumina in Table 1 is expected to occur for the silicon nitride milled alumina/titanium carbide matrix.

The ceramic cutting tool of the present invention is manufactured by first blending a powdered ceramic matrix material with a ceramic whisker in an appropriate ratio. Various methods have been proposed for mixing particulate solids. A typical example is the Chemical Engineers Handbook by Ferry et al.
2l from iners' Handbook 21-30
-36 (5th edition, 1973)
However, the formulation must be so vigorous that the whiskers are thoroughly dispersed throughout the granular ceramic matrix material, but must not be so aggressive as to seriously damage the whiskers. It won't happen. Non-inventive and preferred @ is US Ij#1FF-No. 40463.0
No. 58 Ming? Please include what is shown in the FA letter.

Once the ceramic matrix material and ceramic whiskers are fully blended, the manufacturing of the composite cutting tool begins in step 1.
It is carried out in the same way as for the production of conventional non-reinforced ceramic tools.

Generally, tool II, 200-4200 kg/d
(31,000 to 60,000 ps.t.), and at the same time,
Sinter at a temperature of ~1750°C (1500~3200?). Of course, in the particular shape given by molding.

Depends on the intended roughness of the cutting tool.

Uninvented improved ceramic tool with great toughness and wear resistance. In a particularly preferred embodiment, the cutting tool is provided with standard shapes used in the cutting industry for use as milling, facing, milling, boring and cutting tool inserts. This is a convertible insert. A machine processing method using the cutting tool of the present invention is as follows.

chining Pr1nciples for
8hop Application#) Metcut Research Allied, Inc.
es.

Inc., 3980 Roslyn Drive, Bae 981,
Cincinnati, Ohio (Rosslyn Drive
, 0incinna-ti, 0hio 45209, for a general discussion, please refer to.

Significantly improved companion products of the present invention are shown in Table 2.

In these examples, various types of ceramic cutting tool i1600 surface wind/min (2,000 surface feet/min) speed, 1.0 m (0,040 in. Convenient friend for sharpening.

Table 1. Tool life 1 shows the number of inches of metal cut until the tool becomes unusable due to damage.

Table 2 Alumina/TiO56 (22) Silicon nitride/Tie 10? (42,) Silicon nitride (8iA1ON) 112 (44) Alumina/25%5tc-h Iscar 1280 (50
4) (a) The test was completed without any tool damage.' Even though the test for the reinforced tool was completed before the end of the tool life, it was found that the tool life of the reinforced tool was more than one order of magnitude longer than the test. Therefore, there is also a significant improvement in formability. Longer tool life is obtained with certain steel and carbide cutting tools, some of which can be used at the higher cutting speeds available with ceramics. On the other hand, as is clear from the data in Table 2, it becomes a non-reinforced ceramic.

When used at high cutting speeds, tool life is unacceptably short. However, the reinforced cutting tool of the present invention has the best properties of the one-car type prior art tool.

It is clear that the combination does not have the disadvantages of either.

In a detailed description of the invention, we show that RZ fabricates cutting tool inserts consisting of an alumina matrix containing varying amounts of silicon carbide whiskers and conducts surface milling tests. For comparison, we also manufactured and tested a conventional insert.

Inventive inserts of finely powdered alumina were used in the previous examples of seven suitable powders, nine charcoal and one silicon whisker, and this formulation'k 280 ks+/cd, 185
Hot press at 0℃ for 1 hour to achieve theoretical density r of 99% or more
It was manufactured by molding an insert blank. This blank? Grind and 8NG-432
A ceramic cutting insert in the shape of a 'finishing friend'.

The surface milling test was carried out using a Fi311 11trL, Oin-cinnati m5 vertical milling machine.

This milling machine has a 40 horsepower DOi for the spindle.
The speed drive motor is equipped with a 10 horsepower AO variable speed drive motor for table feeding.

Class 30 gray cast iron is used as processing material. 9 The shape of the machined workpiece has an outer diameter of 30.5 mm (12 inches/inch x inner diameter of 20 mm)
The hardness of these tubes is 179°B.

Convenient for single blade price 6u9 test, fcw is 5 m (2 inches) x 10 cm (4 inches) x 30.5
m (12 indeno. The surface scale must be removed from all specimens before any test is performed. Tool insert) At-removed @, 0.15 ■ for all tool beveling.
(0,006 inches) x 30°. Beveling the tool insert jl'1.0.15m ((1,006 inches) x 20'.

All tool tests are 9 (side cut) to 1g 1 part cutting.
When the tool has uniform wear of 0.25 m (0,010 inch), when the tool has localized wear of 0.51 mm (0,020 inch), or when the tool breaks,
I finished it.

The conditions for milling are as follows.

Depth of cut 1.27 cod (o, o so o
Inch depth of cut 10.20 (4.0 inch) setting Center cutting fluid Dry processing material Class 30 gray cast iron, 179BHN
Tool, w class 8NG-432 Insert shape Axial rake angle -da, End cutting hex angle 15° Radial rake angle -5°, Radial relief angle 5° Corner angle
15°, cutting edge radius 0.76 mm (α030 inch radial depth of cut 10.2 cm (4.0 inch axial depth of cut 1.27 mm (0,
Table 3 shows the results of the single tool face milling test. .

Also shown in Figure 1 and Figure 2. These tests are intended to evaluate the toughness of cutting tools. 60 to cutting speed
It is kept constant at 0 tn1 minute (2000 feet/minute).

Initial cutting load (chip 1 oadJ to 1.0 mm/tooth (
0,040 inches/tooth). Depth of cut and width of cut respectively 1-27 wm (0,050 inch)
10.2 nanometers (4.0 nanometers). Under this condition setting, h 8 x 3 N 4 / 30%Ti
0.8i3 N4/alumina, milled alumina/30%
For TiO insert.

112.107. Okubi 69α (44, 42, Okubi 2
It was damaged after the Finchino work process. All other tools were tested to a minimum of 274 vices (108 inches) without failure.

Next, the cutting load k 2.0 wm/if (0,0
80 inches/tooth) and five tools of 1A were tested. Results [shown in Figure 1].

Uninvented 25% 8i (85 in 3 whisker inserts)
3 cm (336 inches) damage-free working distance v11''
have I gave a follow-up test to a friend to confirm this result.

This second test rX, 302 on (119 inches), was completed with no damage. Next, this tool t
Tested with a cutting load of 2.5 cm/tooth (o, io o inch/tooth). At this cutting load, %518. α(204
The test was completed with no damage. For all other tools f(2, Owax/tooth (0,080 inches/IR) cutting load, failure is 9. These tools C1800m 7 minutes (6000 feet/min) and 0.13m/tooth (0,005ia f/
111) Length 0.25m/tooth (0,010 inch/1
M) was also tested at the feed speed.

The results of these tests are shown in Table 3, and Figure 2 shows the stile,
Shown as a tool life-feed rate curve. The advantages of the cutting tool of the present invention over similar commercially available tools are clear.

To further demonstrate the effects achieved with the inventive cutting tool compared to conventional cutting tools, further trial SRs were carried out. The results are shown below. In the following, 25X Sto inserts were prepared using the method shown in the previous example.
It consists of a 25% VoA silicon carbide whisker and an alumina matrix material.

Insert EU conventional alumina (4% silconian insert, insert G, AIN, human tco 03. Add Y2O3 sintering aid to conventional 8i3N4 insert. These inserts t-, some It was conveniently compared for different cutting processes.

Processing W'Ipr Cast iron Meehanite Go, hardness 1851 (V insert type 8NGN 1204
16 T tool life standard 7 rank wear of up to 1m or 7'
Early failure cutting data on c Feed rate 0.2m/rotation Depth of cut 2fi Cutting speed If 700ml/min and 450m/min Result 7001ml/min 450 wind/planting type
38 R8 25%8i0 1.69 42 1.52 54g
1.07 104 0.080 113
G 1.00 97 1.00 57 =
9 Life Ranking for Cutting S - 9 Life Variation for Cutting = Maximum - Minimum Life Average Life 4rr % of One Inventive 25% S 50 For this interrupted cutting operation on an alumina insert reinforced with 50 whiskers. Compared to manufactured silicon nitride ceramic G, alumina ceramic E has a longer life and less variation in life.

Processing material Spheroidal graphite-iron 880737-00. Hardness 27
0HB insert type 8NGN 120416T Tool life standard Bulk failure cutting data feed rate 0.38mm/rotation Depth of cut 3mm cutting speed 500mm/- Result type Relative tool life 25% SiO1,24 G 1.00 E Test For the uninvented insert, which has extremely strict conditions, the Insert G is also made of a material with high toughness for interrupted cutting of cast iron.

In this test, the workpiece material was used to cause a very large thermal cycle of the cutting edge and the tool light layer. Alumina ceramics and silicon nitride ceramics also have poor toughness. Consequently, in the 8i0 whisker-reinforced ceramic, the silicon nitride alloy is also reinforced to exhibit excellent toughness behavior and preserve the wear resistance of -10,000 alumina.

Hardened steel rounding material Hardened steel 882310. Hardness 648RO
Insert type 8NGN 120461T Tool life standard Damaged cutting data Feed rate 0.23■/rotational depth of cut 0.5■ Cutting speed 60 wet/min Result type Relative tool life 25%8i0 1.60 G 1.00 Standard failure Inserts reinforced with the SiO whiskers of the invention also show excellent performance in continuous machining of hardened steel.

Round machining material for heat-resistant alloy Inconel 718
Inconel 718, @ Body treatment and aging insert type 8NGN 120412g Tool life standard Flank wear machining / 7 rake cutting data for rake surface? hriyjfill ml@f, 0.25 0,1
5 0.15 Depth of cut Cod 2 2 2 Cutting speed f m1 min 180 180 130 Use flow coolant in all tests Results to average 9 Average depth of cut Average trailing edge notch 25%8i0 1. 68 1.24 1.
09 2.00G 1.00 1.0
0 1.00 1.00 Standard 1 wear resistance = l
/Inner G on the insert reinforced with a wear rate of 8i0 whisker! Excellent hole performance? 1 indicates high reliability and wear resistance.

Processing material Incoloy 901 + Solution treatment and aging Indate type 8NGN 120412B Tool life standard Flank wear machining / machining and flaking on the cutting surface Cutting data Feed rate 1llllA rotation 0.15 0.25 0.1
5 Depth of cut wm 2 2 2 Cutting speed -/min 310 180 180 All tests used flow coolant Results to average 9 Average flank Average - to cut Average trailing edge notch 25% 810 1. Q4 1.04 0.7
8))1 (No wear) G 1.0
0 1.00 1.00 1.00 Standard 1)
Wear resistance = 1/wear rate 8i0 Whisker reinforced insert) tI Inc
- Suitable for rounding 9 of o1oy901, 9G!5
It has an excellent trailing edge lifespan. The major advantage is that there is no trailing edge notch wear, resulting in an excellent surface finish.
It means to do i.

The uninvented industrial application potential lies in the field of metal cutting.

The uninvented cutting tool is one heavy metal cutting tool! It can be conveniently used in virtually all industrial fields where it is a major factor. Typical types of beams for which these cutting tools are considered effective are the automobile, aircraft, structural metal, and general metal processing industries.

It goes without saying that many variations are possible in embodiments of the invention. Although it has been unnecessary to specifically mention each of them, it is clear that they fall within the scope of non-invention and fulfill the intent of the present invention.

Accordingly, the above-mentioned terms and conditions are merely intended to indicate a typical IP1r, and should be construed as being within the scope of the invention as defined by the claims.

[Brief explanation of the drawing]

Fig. 2 of the first machining process shows the result of cutting 1 g of surface 72 chairs obtained with the uninvented cutting tool and the conventional cutting tool in a t-graph for comparison. Agent: Patent attorney Masaaki Aki, Masaaki Sawa, and one other person.

Claims (10)

[Claims] (1) Reinforced ceramic cutting consisting of a composite material consisting of a ceramic matrix, characterized in that the matrix has reinforcement dispersed in the matrix circles consisting of ceramic whiskers in an amount of 2 to 40% by volume. tool. 2. The cutting tool of claim 1, wherein the composite material comprises 65-80% by volume matrix and 20-35% by volume whiskers. 3. The cutting tool of claim 1, wherein the composite material comprises 88-98% by volume matrix and 2-12% by volume whiskers. (4) The cutting tool according to claim 1, wherein the matrix is made of alumina. (5) The cutting tool according to claim 1, wherein the matrix is made of silicon nitride. (6) the matrix is made of alumina, and further
A cutting tool according to claim 1, which also contains small amounts of zirconia, yttoria, hafnia, magnesia, silicon nitride, titanium carbide, or mixtures thereof. 7. The cutting tool of claim 1, wherein the whiskers are silicon carbide, alumina, aluminum nitride, beryllia, boron carbide, graphite, or silicon nitride whiskers, or mixtures of these whiskers. (8) The cutting tool according to claim 1, wherein the whisker comprises a silicon carbide whisker. (9) A cutting tool comprising an alumina matrix having 2 to 40% by volume of silicon carbide whiskers dispersed within the matrix. (10) A cutting tool comprising an alumina matrix having 25% by volume silicon carbide whiskers dispersed within the matrix.