Coated cutting tool
A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer including at least one α-type aluminum oxide layer, wherein: in the α-type aluminum oxide layer, a texture coefficient TC (0,0,12) of a (0,0,12) plane falls within a predetermined range; a residual stress value in a (1,1,6) plane of the α-type aluminum oxide layer falls, at least in part thereof, within a predetermined range; and a residual stress value in a (4,0,10) plane of the α-type aluminum oxide layer falls, at least in part thereof, within a predetermined range.
1. A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, the coating layer comprising at least one α-type aluminum oxide layer, wherein:
in the α-type aluminum oxide layer, a texture coefficient TC (0,0,12) of a (0,0,12) plane represented by formula (1) below is from 4.0 or more to 8.4 or less;
a residual stress value in a (1,1,6) plane of the α-type aluminum oxide layer is from −600 MPa or higher to −300 MPa or lower;
the coating layer comprises a titanium carbonitride layer between the substrate and the α-type aluminum oxide layer;
a residual stress value in a (4,2,2) plane of the titanium carbonitride layer is from 0 MPa or higher to 400 MPa or lower; and
a residual stress value in a (4,0,10) plane of the α-type aluminum oxide layer is from 0 MPa or higher to 300 MPa or lower
TC
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(In formula (1), I (h,k,l) denotes a peak intensity for an (h,k,l) plane in X-ray diffraction of the α-type aluminum oxide layer, I 0 (h,k,l) denotes a standard diffraction intensity for an (h,k,l) plane which is indicated on a JCPDS Card No. 10-0173 for α-type aluminum oxide, and (h,k,l) refers to nine crystal planes of (0,1,2), (1,0,4), (1,1,0), (1,1,3), (1,1,6), (0,1,8), (2,1,4), (3,0,0) and (0,0,12).
2. The coated cutting tool according to claim 1 , wherein the coating layer satisfies a condition represented by formula (A) below
0 ≤|S 1 −S 2|≤400 (A)
(In formula (A), S1 denotes a residual stress value (unit: MPa) in a (4,0,10) plane of the α-type aluminum oxide layer, and S2 denotes a residual stress value (unit: MPa) in a (4,2,2) of the titanium carbonitride layer.
3. The coated cutting tool according to claim 1 , wherein an average thickness of the titanium carbonitride layer is from 1.0 μm or more to 20.0 μm or less.
4. The coated cutting tool according to claim 1 , wherein the coating layer comprises, between the titanium carbonitride layer and the α-type aluminum oxide layer, an intermediate layer comprising a compound of at least one kind selected from the group consisting of a Ti carboxide, a Ti oxynitride and a Ti carboxynitride.
5. The coated cutting tool according to claim 4 , wherein an average thickness of the intermediate layer is from 0.1 μm or more to 1.5 μm or less.
6. The coated cutting tool according to claim 1 , wherein, in the α-type aluminum oxide layer, the texture coefficient TC (0,0,12) is from 5.0 or more to 8.2 or less.
7. The coated cutting tool according to claim 1 , wherein a residual stress value in a (4,0,10) plane of the α-type aluminum oxide layer is, in at least part thereof, from 0 MPa or higher to 200 MPa or lower.
8. The coated cutting tool according to claim 1 , wherein an average thickness of the α-type aluminum oxide layer is from 1.0 μm or more to 15.0 μm or less.
9. The coated cutting tool according to claim 1 , wherein an average thickness of the coating layer is from 3.0 μm or more to 30.0 μm or less.
10. The coated cutting tool according to claim 1 , wherein the coating layer comprises a TiN layer as an outermost layer on the α-type aluminum oxide layer.
11. The coated cutting tool according to claim 1 , wherein the substrate is comprised of any of a cemented carbide, cermet, ceramics and a sintered body containing cubic boron nitride.
12. The coated cutting tool according to claim 2 , wherein an average thickness of the titanium carbonitride layer is from 1.0 μm or more to 20.0 μm or less.
13. The coated cutting tool according to claim 2 , wherein the coating layer comprises, between the titanium carbonitride layer and the α-type aluminum oxide layer, an intermediate layer comprising a compound of at least one kind selected from the group consisting of a Ti carboxide, a Ti oxynitride and a Ti carboxynitride.
14. The coated cutting tool according to claim 3 , wherein the coating layer comprises, between the titanium carbonitride layer and the α-type aluminum oxide layer, an intermediate layer comprising a compound of at least one kind selected from the group consisting of a Ti carboxide, a Ti oxynitride and a Ti carboxynitride.