A surface-coated cutting tool has a hard coating layer including an upper layer α, an adhesion layer β, and a lower layer γ. The upper layer α is formed of an α-Al.sub.2O.sub.3 layer formed under low temperature conditions. The adhesion layer β includes a TiCN layer having a thickness of 0.5 μm or more in an outermost layer and contains 0.5 to 3 μm to a maximum depth of 0.5 μm toward the inside in a layer thickness direction of the TiCN layer from the interface between the TiCN layer and the upper layer α. The lower layer γ is formed of (Ti.sub.1-XAl.sub.X)(C.sub.YN.sub.1-Y) of a single phase of a NaCl type face-centered cubic structure, in which an average content ratio X.sub.avg of Al and an average content ratio Y.sub.avg of C in this composition formula satisfy 0.60≤X.sub.avg≤0.95 and 0≤Y.sub.avg≤0.005.

A coated tool may include a base member including a first surface, and a coating layer. The coating layer may include a plurality of voids located side by side in a first layer in a direction along an interface, which is a boundary between the first layer and a second layer. The second layer may include a lower layer part and an upper layer part, and an angle formed by a normal line of (001) surface of the constituent particles with respect to a cross section of the second layer is an orientation difference, the lower layer part of the second layer includes a ratio of the particles whose orientation difference is 10° or more of 50% or more, and the upper layer part of the second layer includes a ratio of the particles whose orientation difference is 10° or less of 80% or more.

The present disclosure relates to a cutting tool including a cemented carbide substrate having WC, gamma phase and a binder phase. The substrate is provided with a binder phase enriched surface zone, which is depleted of gamma phase, wherein no graphite and no ETA phase is present in the microstructure and wherein the binder phase is a high entropy alloy.

A cutting tool made of a cemented carbide substrate of WC, a metallic binder phase and gamma phase is provided. The cemented carbide has a well distributed gamma phase and a reduced amount of abnormal WC grains. The cutting tool has a more predicted tool life and an increased resistance against plastic deformation.

A coated cutting tool of a cemented carbide substrate made of WC, a metallic binder phase and a gamma phase has a well distributed gamma phase and a reduced amount of abnormal WC grains. Further, the coated cutting tool is provided with a CVD coating of TiCN and an α-Al.sub.2O.sub.3 layer, wherein the α-Al.sub.2O.sub.3 layer exhibits a texture coefficient TC(0 0 12)≥7.2 and wherein in the ratio I(0 0 12)/I(0 1 14)≥1. The coated cutting tool has an increased resistance against plastic deformation. whilst maintaining toughness.

In the surface-coated cutting tool, a Ti compound layer containing at least nitrogen and carbon is formed on a surface of cutting tool substrate, a nitrogen concentration in the Ti compound layer, in a case of being measured in a direction perpendicular to the surface of the cutting tool substrate in a vicinity of a cutting edge, gradually increases as a distance from cutting tool substrate increases within a range of 0.20 μm from the surface of the cutting tool substrate toward the Ti compound layer, an average concentration gradient of the nitrogen concentration is 20 at %/μm or more and 300 at %/μm or less, and an average nitrogen concentration in the Ti compound layer in the vicinity of the cutting edge is lower than an average nitrogen concentration in the Ti compound layer at a position of a flank face away from the cutting edge by 3 at % or more.

A coated cutting tool according to the present invention is a coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer, an intermediate layer formed on a surface of the lower layer, and an upper layer formed on a surface of the intermediate layer; the lower layer is a predetermined Ti compound layer with a predetermined average thickness; the intermediate layer is an α-type aluminum oxide layer with a predetermined average thickness; the upper layer is a Ti carbonitride layer with a predetermined average thickness; and a texture coefficient of a predetermined plane of each of the α-type aluminum oxide layer and the Ti carbonitride layer falls within a predetermined range.

A surface-coated cutting tool comprises a hard coating layer that includes a TiAlN layer and is provided on a surface of a cutting tool body. In case the composition of the TiAlN layer is expressed by a formula: (Ti.sub.xAl.sub.1-x)N, 0.10≤x≤0.35 (here, x is in atomic ratio) is satisfied. In the TiAlN layer, a high Ti band-like region is present in a direction at 30 degrees or less with respect to a line normal to the surface of the cutting tool body. An average composition X of the Ti component in the high Ti band-like region satisfies (x+0.01)≤X≤(x+0.05), an average width W of the high Ti band-like region is 30 to 500 nm, and an average area ratio St of the high Ti band-like region is 3 to 50 area %.

A coated cutting tool comprising a substrate and a coating layer formed on a surface of the substrate, wherein: the coating layer comprises a lower layer including at least one Ti compound layer containing a specific Ti compound, an intermediate layer including an α-type Al.sub.2O.sub.3 layer containing α-type Al.sub.2O.sub.3, and an upper layer including a TiCN layer containing TiCN; the respective layers are laminated in this order from the substrate side toward a surface side of the coating layer; an average thickness of the coating layer is from 5.0 μm or more to 30.0 μm or less; and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the intermediate layer and is parallel to the surface of the substrate and a normal to a (001) plane of a particle of an α-type Al.sub.2O.sub.3 layer, and an angle formed by a normal to a cross-sectional surface which is located within a predetermined range below a surface of the upper layer and is parallel to the surface of the substrate and a normal to a (111) plane of a particle of a TiCN layer, respectively satisfy predetermined conditions.

A cutting tool comprises a substrate and a coating that coats the substrate, the coating including an -alumina layer, the -alumina layer including crystal grains of -alumina, the -alumina layer including a lower portion and an upper portion, the upper portion being occupied in area at a ratio of 50% or more by crystal grains of -alumina having (006) plane with a normal thereto having a direction within 15 with respect to a direction of a normal to the second interface, the lower portion being occupied in area at a ratio of 5% or more and less than 50% by crystal grains of -alumina having (012) plane, (104) plane, (110) plane, (113) plane, (116) plane, (300) plane, (214) plane and (006) plane each with a normal thereto having a direction within 15 with respect to the direction of the normal to the second interface.