CN117222776A

CN117222776A - Coated cutting tool

Info

Publication number: CN117222776A
Application number: CN202280031536.2A
Authority: CN
Inventors: 扬·菲利普·莱比格; 沃尔夫冈·恩格哈特; 法伊特·席尔
Original assignee: Walter AG
Current assignee: Walter AG
Priority date: 2021-04-30
Filing date: 2022-04-29
Publication date: 2023-12-12
Also published as: CN117222775A

Abstract

The present invention relates to a coated cutting tool having at least one rake face and at least one relief face and a cutting edge therebetween, the coated cutting tool comprising a substrate and a coating, the coating comprising (Ti, al) N layers having a total atomic ratio Al/(ti+al) >0.67 but +.0.85, wherein the (Ti, al) N layers exhibit a distribution of 111 orientation difference angles, the 111 orientation difference angles being the angle between the normal vector of the (Ti, al) N layer surface and the <111> direction of the normal vector closest to the (Ti, al) N layer surface, the cumulative frequency distribution of 111 orientation difference angles being such that ≡60% of the 111 orientation difference angles is less than 10 degrees.

Description

Coated cutting tool

Technical Field

The invention relates to a coated cutting tool having a coating comprising a (Ti, al) N layer with a 111 crystallographic texture.

Background

There is a continuing desire to improve cutting tools for metal machining to have longer service lives, withstand higher cutting speeds and/or other increasingly demanding cutting operations. Typically, cutting tools for metal machining comprise a hard matrix material, such as cemented carbide, with a thin hard wear coating.

When depositing wear resistant coatings, a common method is Chemical Vapor Deposition (CVD) or Physical Vapor Deposition (PVD). There are limitations to the coating properties that can be provided by either method. Even when coatings of the same chemical composition are deposited using either method, their properties vary in terms of, for example, internal residual stress, density, crystallinity, and crystal size. Thus, their characteristics and properties in end use metal cutting applications will be different.

The wear resistant coating typically comprises one layer, or a combination of layers, of a metal nitride, a metal carbonitride or a metal oxide. The source of metallic elements in the coating deposited by PVD is the so-called "target" in a PVD reactor. There are various PVD methods, the main categories of which are cathodic arc evaporation and magnetron sputtering. Within the generic term "magnetron sputtering" there are also different methods from each other, such as Dual Magnetron Sputtering (DMS) and high power pulsed magnetron sputtering (HIPIMS).

Titanium aluminum nitride (Ti, al) N coatings deposited by PVD methods and their use as wear resistant coatings in cutting tools are well known. One type of (Ti, al) N coating is a single layer, wherein the (Ti, al) N composition of the entire layer is substantially the same. When more than one target used in the deposition process has the same Ti to Al ratio, a single layer coating is provided. Another type of (Ti, al) N coating is a multilayer, wherein there are (Ti, al) N sublayers of different composition in the layer. When at least two of the targets used in the deposition process have different Ti to Al ratios, such multiple layers may be provided such that sub-layers of different compositions are alternately deposited as the substrate rotates in the chamber. One particular type of multilayer is a nanomultilayer, where the thickness of the individual layers can be as low as only a few nanometers.

The crystal structure of (Ti, al) N in the PVD coating may be cubic or hexagonal. In prior art studies, lower Al content in (Ti, al) N like < 60 at% of al+ti generally gives a single-phase cubic structure, whereas a large number of hexagonal structures are seen when the Al content in (Ti, al) N > 67 at% of al+ti, in particular the Al content > 70 at% of al+ti. Specific limitations for the Al content level for giving a single-phase cubic structure, or a mixed structure comprising cubic and hexagonal structures, have been reported and vary to some extent depending on, for example, deposition conditions.

It is known that the (Ti, al) N of the cubic phase has good properties in terms of hardness and elastic modulus. These properties are beneficial for the coating of the cutting tool. On the other hand, the mechanical properties of the hexagonal phase (Ti, al) N are poor, with negative effects on the wear resistance of the coating in metal cutting.

Disclosure of Invention

Object of the Invention

It is an object of the present invention to provide a coated cutting tool display that shows excellent wear resistance, in particular excellent flank wear resistance, during milling operations.

Disclosure of Invention

There is now provided a coated cutting tool meeting the above-mentioned objects. The coated cutting tool has at least one rake face and at least one flank face with a cutting edge in between, the coated cutting tool comprising a substrate and a coating, the coating comprising (Ti, al) N layers being a single monolithic layer or multiple layers of alternating (Ti, al) N sub-layer types differing in composition, the total atomic ratio Al/(ti+al) >0.67 but +.0.85 of the (Ti, al) N layers, wherein the (Ti, al) N layers exhibit a distribution of 111 orientation difference angles (misorientation angle), the 111 orientation difference angles being the angles between the normal vector of the (Ti, al) N layer surfaces and the <111> direction closest to the normal vector of the (Ti, al) N layer surfaces, the cumulative frequency distribution of the 111 orientation difference angles being such that ∈60% of the 111 orientation difference angles is less than 10 degrees.

If antiparallel directions/facets are excluded (e.g., -1-1-1 and 111 antiparallel), there are 4 unique sets of {111} type facets ((111), (1-1-1), (-11-1) and (-1-11)) in the cubic crystal structure. They are at an angle of 70.5 deg. to each other. If one of these faces is parallel to the (Ti, al) N surface, i.e. ideally 111 oriented, the 111 orientation difference angle should be 0, but there is still an angle of the normal vector of the other {111} type faces to the surface greater than the 0 orientation difference angle. The 111 orientation difference angle herein refers to the minimum angle, i.e., the angle between the normal vector of the (Ti, al) N layer and the <111> direction closest to the normal vector of the (Ti, al) N layer.

The distribution of 111 orientation difference angles can be determined in electron back scattering analysis (EBSD). However, columnar grain width generally increases with increasing thickness of the (Ti, al) N layer, especially for the first few microns of the (Ti, al) N layer, EBSD analysis may not be appropriate if the grain width is too small. Therefore, in the case where the thickness of the (Ti, al) N layer is 2 μm or less, if the grain size is considered to be too small for EBSD analysis, it is preferable to measure the distribution of the 111 orientation difference angle in Transmission Electron Microscope (TEM) analysis. EBSD or TEM analysis was performed within a distance of 0.7mm from the cutting edge.

The cumulative frequency distribution of the 111 orientation difference angles is such that suitably not less than 75%, preferably not less than 90% of the 111 orientation difference angles are less than 10 degrees.

The cumulative frequency distribution of the 111 orientation difference angles is such that suitably 75% to 97%, preferably 90% to 95%, of the 111 orientation difference angles are less than 10 degrees.

In one embodiment, the cumulative frequency distribution of the 111 orientation difference angles is such that no less than 20%, preferably no less than 35%, of the 111 orientation difference angles are less than 5 degrees.

In one embodiment, the cumulative frequency distribution of the 111 orientation difference angles is such that 20% to 90%, preferably 30% to 75%, most preferably 35% to 65% of the 111 orientation difference angles are less than 5 degrees.

In one embodiment, the (Ti, al) N layer has a thickness of 0.1-15 μm, preferably 0.5-12 μm, most preferably 1-8 μm.

In one embodiment, the (Ti, al) N layer has a Vickers hardness of 3000HV (15 mN load), preferably 3500-4200HV (15 mN load).

In one embodiment, the (Ti, al) N layer has a plane strain modulus of 450GPa or more, preferably 475GPa or more. The plane strain modulus of the (Ti, al) N layer is preferably 450-540GPa, more preferably 475-530GPa.

The total atomic ratio Al/(Ti+Al) of the (Ti, al) N layer is suitably 0.70 to 0.85, preferably 0.70 to 0.80, most preferably 0.72 to 0.76.

In one embodiment, the (Ti, al) N layer is a single monolithic layer.

In one embodiment, the (Ti, al) N layer is a multilayer of two or more alternating (Ti, al) N sub-layer types differing in composition, wherein the atomic ratio Al/(ti+al) of at least one (Ti, al) N sub-layer type is 0.50-0.67, preferably 0.55-0.67, most preferably 0.60-0.67, and the atomic ratio Al/(ti+al) of at least one (Ti, al) N sub-layer type is 0.70-0.90, preferably 0.75-0.90, most preferably 0.75-0.85.

In one embodiment, the (Ti, al) N layer is a multilayer of alternating (Ti, al) N sub-layer types having one or two atomic ratios Al/(ti+al) of 0.50-0.67, preferably 0.55-0.67, most preferably 0.60-0.67, with one or two (Ti, al) N sub-layer types having an atomic ratio Al/(ti+al) of 0.70-0.90, preferably 0.75-0.90, most preferably 0.75-0.85.

In a preferred embodiment, the (Ti, al) N layer is a multilayer of alternating one (Ti, al) N sub-layer type with an atomic ratio Al/(ti+al) of 0.50-0.67, preferably 0.55-0.67, most preferably 0.60-0.67, and one (Ti, al) N sub-layer type with an atomic ratio Al/(ti+al) of 0.70-0.90, preferably 0.75-0.90, most preferably 0.75-0.85.

The average thickness of the (Ti, al) N sub-layer type in the multilayer is suitably 1-100nm, preferably 1.5-50nm, most preferably 2-20nm.

In one embodiment, the ratio of the average thicknesses of the different (Ti, al) N sub-layer types is 0.5 to 2, preferably 0.75 to 1.5.

The (Ti, al) N layer comprises a cubic crystal structure.

In one embodiment, the (Ti, al) N layer has a single-phase cubic B1 crystal structure on the rake face and/or the relief face at a distance of at least 0.5mm, preferably at least 1mm, from a point at the cutting edge in a direction perpendicular to the cutting edge.

The determination of the crystal structure or structures present in the (Ti, al) N layer is suitably performed by X-ray diffraction analysis or TEM analysis.

In one embodiment, the (Ti, al) N layer shows only cubic (Ti, al) N reflection in X-ray diffraction analysis or TEM analysis within 0.5mm, preferably within 1mm, from the cutting edge.

In X-ray diffraction analysis or TEM analysis, suitably only cubic (Ti, al) N reflection is visible, at least when measured within 1mm from the cutting edge.

In one embodiment, the (Ti, al) N layer has an average columnar grain width measured at a distance of up to 2 μm from the lower interface of the (Ti, al) N layer of less than 175nm, preferably less than 150nm.

In one embodiment, the (Ti, al) N layer has an average columnar grain width of 80-175nm, preferably 100-150nm, measured at a distance of up to 2 μm from the lower interface of the (Ti, al) N layer.

In one embodiment, there is an innermost layer of the coating directly on the substrate below the (Ti, al) N layer, the innermost layer being a nitride of one or more elements belonging to groups 4, 5 or 6 of the periodic table or a nitride of Al and one or more elements belonging to groups 4, 5 or 6 of the periodic table. The innermost layer may serve at least in part as a bond to the substrate that increases the adhesion of the entire coating to the substrateA layer. Such tie layers are common in the art and one skilled in the art should select an appropriate one. Preferred alternatives to the innermost layer are TiN and (Ti _1-x Al _x ) N, x is suitably>0 but less than or equal to 0.67. The thickness of the innermost layer is suitably less than 3 μm. In one embodiment, the innermost layer has a thickness of 0.1 to 3 μm, preferably 0.2 to 1 μm.

In one embodiment, there is one or more other layers commonly used in the coating for cutting tools in combination with the (Ti, al) N layer of the present invention. For example, a nitride of one or more elements belonging to groups 4, 5 or 6 of the periodic table, or a nitride of Al and one or more elements belonging to groups 4, 5 or 6 of the periodic table. For example, (Ti) _1-y Al _y ) N layer, y is suitably>0 but less than or equal to 0.67.

In one embodiment, the coating comprises (Ti) having a thickness of 0.5-3 μm _1-y Al _y ) N (0.25.ltoreq.y.ltoreq.0.67) followed by a layer of (Ti, al) N according to the invention having a thickness of 0.5-5. Mu.m.

The (Ti, al) N layer according to the invention is deposited by PVD, i.e. the (Ti, al) N layer is a PVD layer. Suitably, the (Ti, al) N layer is a PVD layer deposited by a sputtering process, preferably a high power pulsed magnetron sputtering (HIPIMS) deposited layer.

The substrate of the coated cutting tool may be of any kind commonly found in the field of cutting tools for metal machining. The substrate is suitably selected from cemented carbides, cermets, cubic boron nitride (cBN), ceramics, polycrystalline diamond (PCD) and High Speed Steel (HSS).

In a preferred embodiment, the substrate is cemented carbide.

The coated cutting tool is suitably in the form of a blade, a drill or an end mill.

Drawings

Fig. 1 shows a schematic view of an embodiment of a cutting tool as a milling insert.

FIG. 2 shows a schematic representation of a cross-section of one embodiment of a coated cutting tool of the present invention, wherein a substrate and a coating are shown.

Fig. 3 shows a frequency distribution curve of 111 orientation difference angles from Electron Back Scattering Diffraction (EBSD) analysis of one embodiment of the "sample 2a (invention)" of the present invention.

Fig. 4 shows a frequency distribution curve of 111 orientation difference angles from Electron Back Scattering Diffraction (EBSD) analysis of one embodiment of the "sample 5 (invention)" of the present invention.

Fig. 5 shows the frequency distribution curve of the 111 orientation difference angle from the Electron Back Scattering Diffraction (EBSD) analysis of "sample 6 (comparative)".

Fig. 6 shows a Transmission Electron Microscope (TEM) electron diffraction pattern for the (Ti, al) N layer of one embodiment of the "sample 2a (invention)" of the present invention.

Detailed Description

Fig. 1 shows a schematic view of an embodiment of a cutting tool (1) having a rake face (2), a relief face (3) and a cutting edge (4). The cutting tool (1) is in this embodiment a milling insert. Fig. 2 shows a schematic view of a cross section of one embodiment of a coated cutting tool of the present invention having a substrate body (5) and a (Ti, al) N coating (6).

Method

Electron Back Scattering Diffraction (EBSD):

EBSD measurements were made on the flank face of the cutting tool sample at a distance of 50 μm from the cutting edge.

Prior to EBSD scanning, each sample surface was carefully polished using a colloidal silica suspension with a nominal grain size of 40nm (Struers OPS 0.04 μm). This step serves to remove any roughness present on the surface of the deposited coating. No more than 100nm of the top coating is removed by this process.

If the (Ti, al) N layer is not the uppermost layer of the coating, a suitable method such as polishing is used to remove the layer located over the (Ti, al) N layer to ultimately provide a polished (Ti, al) N surface for the EBSD scan.

Electron diffraction patterns were collected in a Zeiss cross beam 540 FIB-SEM (Carl Zeiss group, supra, henry, germany) and an EDAX DigiView 5 EBSD camera (EDAX corporation, mo Washi, new jersey, usa) at a standard sample tilt of 70 ° and a working distance of 5 mm. An electron beam acceleration voltage of 10 to 13kV was used for acquisition. The mapping step size was 20nm. The mapping area was 15.00×11.25 μm.

The measured crystal orientation data was further evaluated using EDAX OIM analysis software, indexed by EDAX TEAM software.

The cumulative frequency distribution of the orientation difference angle is calculated 111 as follows: the crystallographic direction perpendicular to the surface plane of the (Ti, al) N layer was derived from the measured absolute crystallographic orientation (i.e., the orientation data of the euler angles) measured for each point of the total EBSD scan (representing the incremental surface area of the entire analysis surface area).

Subsequently, the vector angle between the crystallographic direction and the nearest <111> type direction is calculated. Where "closest" refers to the <111> type direction (among all four crystallographic equivalent possibilities) that includes the smallest possible angle with the surface normal. The angle is defined as the 111 orientation difference angle. Since the measurement points constitute equal parts of the analysis area, the relative frequency distribution of these angular misalignment values characterizes the overall extent of the 111 surface texture.

Electron diffraction in Transmission Electron Microscopy (TEM):

in the electron diffraction analysis performed herein, these are using a transmission electron microscope: TEM measurements at 200kV were performed with a JEOL ARM 200F microscope. Only the coating will contribute to the diffraction pattern by using the field stop. TEM operates using parallel illumination diffraction during Selective Area Electron Diffraction (SAED).

The sample is subjected to cross-sectional analysis, i.e. the incident electron beam is parallel to the membrane surface. In order to eliminate amorphization during sample preparation, different methods can be used, i) classical preparation including mechanical cutting, bonding, grinding and ion polishing, and ii) cutting the sample using FIB and extracting for final polishing. The analysis site was near the substrate, about 200nm from the substrate. Further, the analysis position is at a distance within 1mm from the cutting edge.

SAED data for the samples were obtained. The diffraction intensity profile along the 111 ring centered at the angular position corresponding to the coating normal is provided from the SAED data. Then normalized integration was performed at the 111 diffraction spots and the-1-1-1 diffraction spots, respectively, to reach a 45-degree orientation difference angle. The two integrals are combined to form an intensity distribution curve. Intensity distribution data from the 111 diffraction spots and the-1-1-1 diffraction spots are used to increase the number of data points, thereby reducing the signal-to-noise ratio as much as possible.

The intensity at a particular orientation difference angle is proportional to the sample volume exhibiting this misorientation. Thus, the intensity distribution curve corresponds to the distribution of the 111 orientation difference angle. Then, correspondingly, the cumulative intensity profile obtained from the intensity profile corresponds to the cumulative frequency profile of the 111 orientation difference angle.

X-ray diffraction:

x-ray diffraction patterns were acquired by tangential incidence mode (GID) on a diffractometer (PTS 3003) from Seifert/GE. Cu-ka radiation and a multi-capillary lens (for generating parallel beams) were applied for analysis (high voltage 40kV, current 40 mA). The incident beam is defined by a pinhole of 0.5 mm. For the diffracted beam path, an energy dispersive detector (meter 0D) was used. The measurement is performed in tangential incidence mode (ω=4°). 2 theta ranges from about 20 deg. -80 deg., step size is 0.03 deg., and counting time is 6s. XRD measurements were performed at a distance on the flank of the cutting tool sample within 1mm from the cutting edge.

Vickers hardness:

vickers hardness was measured by nanoindentation (load depth map) using the picodentr HM500 of Helmut Fischer, inc. For measurement and calculation, oliver and Pharr evaluation algorithms were applied, in which diamond test bodies according to Vickers were pressed into the layers and force-path curves were recorded during the measurement. The maximum load used was 15mN (HV 0.0015), and the load increase and load decrease periods were 20 seconds each. From this curve, hardness was calculated.

Modulus of plane strain:

by the Oliver and Pharr method, by the so-called in-plane strain modulus E derived from nanoindentation _ps Characterization of the coating samplesElastic properties of the product. Nano-indentation data was obtained from the indentations described above for vickers hardness.

Grain width:

average (Ti, al) N grain width was determined by evaluating SEM cross sections by the stereo line intersection method: the wire mesh grid was overlaid onto the SEM micrograph and the intersection points of the wires and the grain boundary network were marked. Statistics of the distance between adjacent intersections reflect the size of the three-dimensional grains (see, e.g., B.Ilschner, R.F.Singer, werkstoffwissenschaften and Fertigungstechnik, springer Berlin Heidelberg,2016, ISBN: 978-3-642-53891-9). SEM micrographs were taken at a distance of about 0.7 μm from the cutting edge on the flank surface.

Examples:

example 1:

using a composition of Ti _0.33 Al _0.67 Is composed of Ti _0.20 Al _0.80 The target arrangement of the target of (Ti, al) N layer is deposited onto the WC-Co based substrate. The WC-Co based matrix is a flat geometry blade for easier analysis of the coating. The composition of the matrix was 8 wt% Co and the balance WC.

HIPIMS mode was used in Hauzer Flexicoat 1000 equipment. The total pressure was varied during three separate deposition processes while maintaining all other conditions the same. Three different total pressures, 0.505Pa, 0.219Pa, and 0.167Pa, were tested.

The following process parameters were used:

temperature: 300 DEG C

Average power: 40kW (20 kW per target)

Pulse duration: 80 mu s

Setting a peak current: target 1:800A, target 2:800A

Dc pulse voltage: 1800V

Ar flow rate: 500 sccm.sub.180sccm.sub.130 sccm

Total pressure (N) ₂ +Ar)：0.505Pa|0.219Pa|0.167Pa

(～167sccm N ₂ )|(～115sccm N ₂ )|(～108sccm N ₂ )

Bias potential: -100V

A layer of (Ti, al) N was deposited to a thickness of about 1.75 μm. The average thickness of the (Ti, al) N sub-layer calculated from the substrate rotation speed was about 3nm.

The supplied coated cutting tools were referred to as "sample 1 (comparative)", "sample 2 (invention)", and "sample 3 (invention)".

An additional sample having a higher thickness (7.3 μm) corresponding to "sample 2 (invention)" was prepared. The technological parameters are as follows:

temperature: 300 DEG C

Average power: 40kW (20 kW per target)

Pulse duration: 80 mu s

Setting a peak current: target 1:800A, target 2:800A

Dc pulse voltage: 1800V

Ar flow rate: 180sccm

Total pressure (N) ₂ +Ar)：0.22Pa

(～115sccm N ₂ )

Bias potential: -110V

The supplied coated cutting tool was referred to as "sample 2a (invention)".

Additional samples were made according to the present invention intended for metal cutting testing. 1.3 μm conventional Ti was deposited by cathodic arc evaporation _0.40 Al _0.60 The N first layer is provided on a WC-Co based substrate followed by a 1.25 μm (Ti, al) N layer very similar to the (Ti, al) N layer of "sample 2 (invention)". The WC-Co type of substrate has two different milling insert geometries, SPMW12 and ADMT160608R-F56. The composition of the matrix was 8 wt% Co and the balance WC. The primary purpose of the innermost layer of arc evaporation deposition is to improve adhesion to the substrate so that tool life is not limited by flaking. The two layers were made as follows:

_0.40 _0.60 TiAlN innermost layer:

the composition is Ti _0.40 Al _0.60 Will be 1.3 μm Ti _0.40 Al _0.60 N layer deposited on WC-CoAnd (3) on the similar matrix.

The arc mode was used in a Hauzer Flexicoat 1000 device. The deposition was carried out at a total pressure of 5Pa, a DC bias of-40V and a temperature of 580 ℃.

(Ti, al) N layer:

using a composition of Ti _0.33 Al _0.67 Is composed of Ti _0.20 Al _0.80 Target setting of target(s) 1.25 μm (Ti, al) N layer was deposited to arc deposited Ti _0.40 Al _0.60 On the N layer. HIPIMS mode was used in Hauzer Flexicoat 1000 equipment.

The following process parameters were used:

temperature: 300 DEG C

Average power: 40kW (20 kW per target)

Pulse duration: 80 mu s

Setting a peak current: target 1:800A, target 2:800A

Dc pulse voltage: 1800V

Ar flow rate: 180sccm

Total pressure (N) ₂ +Ar)：0.22Pa

(～115sccm N ₂ )

Bias potential: -100V

The average thickness of the (Ti, al) N sub-layer calculated from the substrate rotation speed was about 3nm.

The resulting coated cutting tool was referred to as "sample 4 (invention)".

Example 2:

using a composition of Ti _0.20 Al _0.80 The target arrangement of the target of (c) deposits a single monolithic layer, i.e., (Ti, al) N layer, onto a WC-Co based substrate. The WC-Co based matrix is a flat geometry blade for easier analysis of the coating. The composition of the matrix was 8 wt% Co and the balance WC.

HIPIMS mode was used in Hauzer Flexicoat 1000 equipment.

The following process parameters were used:

temperature: 200 DEG C

Average power: 20kW

Pulse duration: 80 mu s

Setting a peak current: 800A

Dc pulse voltage: 1800V

Ar flow rate: 150sccm

Total pressure (N) ₂ +Ar)：0.190Pa

(～88sccm N ₂ )

Bias potential: -150V

A layer of (Ti, al) N was deposited on the blade to a thickness of about 1.7 μm.

The provided coated cutting tool was referred to as "sample 5 (invention)".

Example 3 (comparative):

in an Olerlikon Balzers device using S3p technology, ti is entered using HIPIMS mode _0.40 Al _0.60 The N layer was deposited onto WC-Co based substrates as cutting tools with SPMW12 and ADMT160608R-F56 type milling inserts as well as flat inserts (for easier analysis of the coating). The HIPIMS deposited coating is known to give very good results in machining steel (ISO-P) materials.

The composition of the matrix was 8 wt% Co and the balance WC.

The deposition process was carried out in HIPIMS mode using the following process parameters

And (3) target material: ti (Ti) _0.40 Al _0.60

Target size: 6, circular, diameter 15cm

Average power per target: 9kW

Peak pulse power: 55kW

Pulse duration: 4ms of

Temperature: 430 DEG C

Total pressure: 0.61Pa

Argon pressure: 0.43Pa

Bias potential: -40V

A layer thickness of about 7.2 μm was deposited.

The provided coated cutting tool was referred to as "sample 6 (comparative)".

Example 4 (comparison))：

Ti is mixed with _0.10 Al _0.90 A single layer is deposited onto a WC-Co based substrate, which is a flat cutting insert for easy analysis of the coating. Using two Ti facing each other _0.10 Al _0.90 And (3) a target. Using HIPIMS mode, deposition was performed with the following process parameters:

and (3) target material: (2) Ti _0.10 Al _0.90

Temperature: 300 DEG C

Average power: 40kW (20 kW per target)

Pulse duration: 80 mu s

Setting a peak current: target 1:800A, target 2:800A

Dc pulse voltage: 1800V

Ar flow rate: 150sccm

Total pressure (N) ₂ +Ar)：0.19Pa

(～125sccm N ₂ )

Bias potential: -110V

A layer thickness of about 1.4 μm was deposited.

The provided coated cutting tool was referred to as "sample 7 (comparative)".

Example 5 (analysis):

XRD：

XRD analysis was performed on "sample 1 (comparative)", "sample 2 (invention)", "sample 3 (invention)", and "sample 5 (invention)".

All four samples showed peaks from the faces of cubes (111), (200) and (220). However, "sample 1 (comparative)" also showed distinct peaks at about 57 degrees and 70 degrees 2θ, which are one or both of hexagonal (110) (hexagonal AlN 57.29 °) and (112) (hexagonal AlN 68.85 °) and (201) (hexagonal AlN 69.98 °).

XRD analysis was also performed on "sample 7 (comparative)".

Significant hexagonal peaks were seen.

EBSD：

An Electron Back Scattering Diffraction (EBSD) analysis was performed on "sample 2a (invention)", "sample 5 (invention)", and "sample 6 (comparison)". The grain size was large enough to enable EBSD analysis even if the layer thickness of "sample 5 (invention)" was only 1.7. Mu.m. The cumulative frequency distribution of the orientation difference angles is calculated 111 as described in the method section. Fig. 3 shows the frequency distribution curve of the 111 orientation difference angle from the EBSD analysis of "sample 2a (invention)". Fig. 4 shows a frequency distribution curve of the 111 orientation difference angle from the EBSD analysis of "sample 5 (invention)". Fig. 5 shows the frequency distribution curve of the 111 orientation difference angle from the EBSD analysis of "sample 6 (comparative)".

For "sample 2a (invention)", (Ti, al) N layers showed cumulative frequency distribution of 111 orientation difference angles such that about 94% of the 111 orientation difference angles were less than 10 degrees and about 55% of the 111 orientation difference angles were less than 5 degrees.

For "sample 5 (invention)", (Ti, al) N layers showed cumulative frequency distribution of 111 orientation difference angles such that about 77% of the 111 orientation difference angles were less than 10 degrees and about 37% of the 111 orientation difference angles were less than 5 degrees.

For "sample 6 (comparative)", ti _0.40 Al _0.60 The N layers exhibit a cumulative frequency distribution of 111 orientation difference angles such that about 14% of the 111 orientation difference angles are less than 10 degrees and about 4% of the 111 orientation difference angles are less than 5 degrees.

TEM：

A Transmission Electron Microscope (TEM) analysis was performed on "sample 2a" (invention). Fig. 6 shows a TEM electron diffraction pattern of the (Ti, al) N layer of "sample 2a (invention)".

The diffraction pattern of "sample 2a (invention)" showed significant specks, which means a high crystallographic texture. The diffraction pattern shows a 111 structured layer.

TEM analysis of "sample 2a (invention)" also showed that the average thickness of each (Ti, al) N sub-layer type was about the same, about 3nm.

EDX：

By energy dispersive X-ray spectroscopy (EDX) analysis, it was demonstrated that the average composition of the (Ti, al) N layer of "sample 2a (invention)" corresponds to the expected value of the target composition.The average composition is Ti _0.27 Al _0.73 The total atomic ratio Al/(ti+al) of N, i.e., the (Ti, al) N layer was 0.73.

Mechanical properties:

hardness measurements (load 15 mN) were performed on the flank face of the coated cutting tool listed in table 1 to determine vickers hardness and in-plane strain modulus (E _ps )。

Table 1.

Coating layer	Hardness HV Vickers]	Modulus of plane strain E _ps [GPa]
			"sample 1 (comparative)".	2612	386
"sample 2 (invention)".	3301	485
			"sample 3 (invention)",	3474	513
"sample 5 (invention)",	3760	516
			"sample 6 (comparative)".	3051	492
"sample 7 (comparative)".	2261	357

Samples 1, 2 and 5 within the present invention all show high hardness and high in-plane strain modulus values.

The conclusion is that if too high total pressure is used as in "sample 1 (comparative)", the hardness becomes low, and the plane strain modulus becomes also low. This means that the amount of cubic crystal structure in the coating is insufficient. XRD results also showed that hexagonal peaks were present in addition to the cubic peaks.

"sample 6 (comparative)" is full cubic Ti _0.40 Al _0.60 The Al content of the N sample is well below the limit at which hexagonal phase formation is possible. Thus, good mechanical properties are expected.

It was further concluded that if the Al content in the (Ti, al) N layer is too high as in "sample 7 (comparative)", the hardness becomes low, and the plane strain modulus becomes also low. This means that the amount of cubic crystal structure in the coating is insufficient. XRD analysis also showed that hexagonal peaks were evident in addition to the rather weak cubic peaks.

Grain width:

the grain width of "sample 2a (invention)" was measured. The grain widths at distances of 2, 4 and 6 μm from the lower interface of the substrate were measured.

The average grain width values were 127, 165 and 247nm, respectively.

Example 5:

cutting test, ISO-P milling:

"sample 4 (invention)" was further tested in the ISO-P milling test and flank wear was measured. In this test, the "sample 4 (invention)" was compared with a cutting insert which was almost identical to the "sample 6 (comparative)" and known to be good in ISO-P milling.

The comparative samples were commercial production samples. In addition to the substances present in "sample 6 (comparative)", they also had an upper thin ZrN layer of 0.2 μm deposited for the purpose of color and easier wear detection. However, this further layer does not have any substantial effect on the wear resistance.

The comparative coating tool was made by the following steps: a milling insert cemented carbide substrate of geometry SPMW12 was provided, consisting of 8 wt% Co and balance WC, and a coating was deposited according to the following conditions:

_0.40 _0.60 innermost TiAlN layer:

and (3) target material: ti (Ti) _0.40 Al _0.60

Target size: 6, circular, diameter 15cm

Average power per target: 9kW

Peak pulse power: 55kW

Pulse duration: 4ms of

Temperature: 430 DEG C

Total pressure: 0.61Pa

Argon pressure: 0.43Pa

Bias potential: -40V

A layer of 2.1 μm was deposited.

Outermost ZrN layer:

and (3) target material: zr (Zr)

Target size: 3, circular, diameter 15cm

Average power per target: 9kW

Peak pulse power: 27kW

Pulse duration: 26ms

Temperature: 430 DEG C

Total pressure: 0.55Pa

Argon pressure: 0.43Pa

Bias potential: -40V

A layer of 0.2 μm was deposited.

The test conditions and test data are summarized below. Steel (ISO-P) was used as the work piece material.

Test conditions:

milling tests were performed at a cutting speed of 240 m/min. Other test conditions were as follows:

tool geometry:

blade geometry: SPMW12

Tool diameter D _c ：125mm

Setting an angle kappa: 45 degree

Cutting data:

contact width a _e ：100mm

Depth of cut a _p ：3mm

Cutting speed: 240 m/min

Feed per tooth: 0.2mm

Work piece:

material ISO-P steel, 42CrMoV4 type

Tensile strength 785MPa

Cutting fluid: none, i.e. dry

In this test, the greatest wear was observed at the cutting edge on the flank side. Three cutting edges were tested for each sample and the average of each cutting length is shown in table 2.

TABLE 2

The comparative samples have coatings known to give very good results in milling of ISO-P steels. Nevertheless, it was concluded that "sample 4 (invention)" performed much better than the comparative sample.

The comparative sample is essentially "sample 6 (comparative)", and "sample 4 (invention)" can be regarded as the upper half of the coating of "sample 6 (comparative)" being exchanged for the (Ti, al) N layer of the invention of "sample 2 (invention)".

As can be seen in table 1, "sample 6 (comparative)" and "sample 2 (invention)" have similar mechanical properties (hardness and in-plane strain modulus). Nonetheless, "sample 6 (comparative)" performed much worse than the inventive sample in this cutting test.

Example 6:

cutting test, ISO-M milling:

"sample 4 (invention)" was further tested in the ISO-M milling test and flank wear was measured. In this test, "sample 4 (invention)" was compared with cutting inserts known to be good in ISO-M milling with arc deposited coatings.

The comparative coating tool was made by the following steps: a milling insert cemented carbide substrate of composition 8 wt% Co and the rest WC was provided and a coating was deposited according to the following conditions:

_0.50 _0.50 _0.33 _0.67 innermost multilayer TiAlN/TiAlN layer:

and (3) target material: 1 Ti _0.50 Al _0.50 1/1 Ti _0.33 Al _0.67

Temperature: 550 DEG C

Total pressure: 10Pa

Bias potential: -60V

A layer of 1.3 μm was deposited.

_0.50 _0.50 _0.33 _0.67 Outermost multilayer TiAlN/TiAlN layer:

and (3) target material: 1 Ti _0.50 Al _0.50 2 Ti _0.33 Al _0.67

Temperature: 550 DEG C

Total pressure: 10Pa

Bias potential: -50V

A layer of 1.2 μm was deposited.

The test conditions and test data are summarized below. Stainless steel (ISO-M) was used as the work piece material.

Test conditions:

tool geometry:

blade geometry: ADMT160608R-F56

Tool diameter D _c ：63mm

Setting an angle kappa: 90 degree (degree)

Tooth/number of blades mounted: 3

Cutting data:

contact width a _e ：50mm

Depth of cut a _p ：3mm

Cutting speed: 240 m/min

Feed per tooth: 0.15mm

Work piece:

material 1.4571/V4A-stainless steel

Tensile strength 720MPa

Cutting fluid: none, i.e. dry

In this test, the greatest wear was observed at the cutting edge on the flank side. Three cutting edges were tested for each coating and the average of each cutting length is shown in table 3.

TABLE 3 Table 3

The comparative samples have coatings known to give very good results in milling of stainless steel (ISO-M). Nevertheless, it was concluded that "sample 4 (invention)" performed much better than the comparative sample.

Claims

1. A coated cutting tool having at least one rake face and at least one relief face and a cutting edge therebetween, the coated cutting tool comprising a substrate and a coating comprising (Ti, al) N layers being a single monolithic layer or multiple layers of two or more alternating (Ti, al) N sub-layer types differing in composition, the total atomic ratio of the (Ti, al) N layers Al/(Ti+Al) >0.67 but +.0.85,

it is characterized in that

The (Ti, al) N layer shows a distribution of 111 orientation difference angles, the 111 orientation difference angles being angles between normal vectors of the (Ti, al) N layer surfaces and <111> directions closest to the normal vectors of the (Ti, al) N layer surfaces,

the cumulative frequency distribution of the 111 orientation difference angles is such that more than or equal to 60% of the 111 orientation difference angles are less than 10 degrees.

2. The coated cutting tool of claim 1, wherein the cumulative frequency distribution of 111 orientation difference angles is such that 75% to 97% of the 111 orientation difference angles are less than 10 degrees.

3. The coated cutting tool according to any one of claims 1 to 2, wherein the cumulative frequency distribution of the 111 orientation difference angles is such that ≡20%, preferably ≡35%, of the 111 orientation difference angles is less than 5 degrees.

4. A coated cutting tool according to any one of claims 1 to 3, wherein the cumulative frequency distribution of the 111 orientation difference angles is such that 20% to 90%, preferably 30% to 75%, most preferably 35% to 65% of the 111 orientation difference angles are less than 5 degrees.

5. The coated cutting tool according to any one of claims 1 to 4, wherein the (Ti, al) N layer has a thickness of 0.1 to 15 μm.

6. The coated cutting tool according to any one of claims 1 to 5, wherein the (Ti, al) N layer has a vickers hardness of ≡3000HV (15 mN load).

7. The coated cutting tool of any one of claims 1-6, wherein the (Ti, al) N layer has an in-plane strain modulus ≡450GPa.

8. The coated cutting tool according to any one of claims 1 to 7, wherein the total atomic ratio Al/(ti+al) of the (Ti, al) N layer is 0.70-0.80.

9. The coated cutting tool of any one of claims 1-8, wherein the (Ti, al) N layer is a single monolithic layer.

10. The coated cutting tool according to any one of claims 1 to 8, wherein the (Ti, al) N layer is a multilayer of two or more alternating (Ti, al) N sub-layer types differing in composition, wherein the atomic ratio Al/(ti+al) of at least one (Ti, al) N sub-layer type is 0.50-0.67 and the atomic ratio Al/(ti+al) of at least one (Ti, al) N sub-layer type is 0.70-0.90.

11. The coated cutting tool of claim 10, wherein the (Ti, al) N layer is a multilayer of alternating one (Ti, al) N sub-layer type having an atomic ratio Al/(ti+al) of 0.50-0.67 and one (Ti, al) N sub-layer type having an atomic ratio Al/(ti+al) of 0.70-0.90.

12. The coated cutting tool according to any one of claims 10 to 11, wherein the average thickness of the (Ti, al) N sub-layer type in the multilayer is 1-100nm.

13. The coated cutting tool according to any one of claims 1 to 12, wherein the substrate is selected from cemented carbides, cermets, cubic boron nitride (cBN), ceramics, polycrystalline diamond (PCD) and High Speed Steel (HSS).

14. The coated cutting tool according to any one of claims 1 to 13 in the form of a blade, a drill bit or an end mill.