A cutting tool comprising a substrate and a coating film disposed on the substrate, wherein the coating film comprises a first layer; the first layer has a thickness of 0.2 μm or more and 9 μm or less; the first layer is composed of Ti.sub.(1-x-y)Al.sub.xM.sub.yN, wherein M is at least one element such as zirconium; in the first layer, x and y change along the thickness direction of the first layer; a maximum value of x, x.sub.max, is 0.20 or more and 0.70 or less; a minimum value of x, x.sub.min, is 0 or more and 0.6 or less; x.sub.max and x.sub.min satisfy 0.01≤x.sub.max−x.sub.min≤0.7; a maximum value of y, y.sub.max, is 0.01 or more and 0.20 or less; a minimum value of y, y.sub.min, is 0 or more and 0.19 or less; and y.sub.max and y.sub.min satisfy 0.01≤y.sub.max−y.sub.min≤0.2.

A cutting tool includes a substrate and a coated film arranged on the substrate. The coated film includes a first layer. The first layer includes a plurality of crystal grains. The crystal grains are composed of Al.sub.xTi.sub.1-xC.sub.yN.sub.1-y, wherein x is more than 0.65 and less than 0.95, and y is not less than 0 and less than 0.1. In a first region, the crystal grains have an average aspect ratio of not more than 3.0. In a second region, the crystal grains have an average aspect ratio of more than 3.0 and not more than 10.0. The crystal grains include crystal grains having a cubic crystal structure. The first layer has a ratio of an area occupied by the crystal grains having a cubic crystal structure of not less than 90%. The first layer has a thickness of not less than 2 μm and not more than 20 μm.

A cutting tool comprising a base material and a coating arranged on the base material; wherein: the coating comprises an α-Al.sub.2O.sub.3 layer composed of a plurality of α-Al.sub.2O.sub.3 particles; the average particle diameter a of the α-Al.sub.2O.sub.3 particles in a first region of the α-Al.sub.2O.sub.3 layer is 0.10 μm or more and 0.30 μm or less; the average particle diameter b of the α-Al.sub.2O.sub.3 particles in a second region of the α-Al.sub.2O.sub.3 layer is 0.30 μm or more and 0.50 μm or less; the average particle diameter c of the α-Al.sub.2O.sub.3 particles in a third region of the α-Al.sub.2O.sub.3 layer is 0.10 μm or more and 0.30 μm or less; and the ratio b/a is 1.5 or more and 5.0 or less.

A coated cutting tool includes a rake face, a flank face, and a cutting edge region between and adjoining the flank face and the rake face in a nose area of a cutting tool insert. The cutting edge region is intersected by an edge line and defines a cutting edge sector that defines an cutting edge radius, r.sub.e. The coated cutting tool includes a substrate with a coating having a thickness between 1 μm and 40 μm, where the coating includes an α-Al.sub.2O.sub.3 layer and an MTCVD TiCN layer located between the substrate and the α-Al.sub.2O.sub.3 layer. The α-Al.sub.2O.sub.3 layer exhibits a texture coefficient TC(hkl), as measured by X-ray diffraction using CuKa radiation and θ-2θ scan, defined according to Harris formula

[00001]$TC\left(hkl\right)={\frac{I\left(\mathrm{hkl}\right)}{I_0\left(hkl\right)}\left[\frac{1}{n}\underset{n=1}{\overset{n}{.Math.}}\frac{I\left(\mathrm{hkl}\right)}{I_0\left(hkl\right)}\right]}^{-1}$

where I(hkl) is the measured integrated area intensity of the (hkl) reflection with corresponding reference intensity I.sub.0(hkl), and n is the number of reflections used in the calculation.

A cutting tool comprises a coating on a substrate. The coating comprises a first layer element having an overall composition comprising the metal or metalloid elements aluminum, chromium, titanium, and silicon. The first layer element comprises at least 2 N.sub.lay first layer element layers. Each of the first layer element layers comprises a nitride layer comprising the metal or metalloid elements aluminum, chromium, titanium and silicon. The N.sub.lay first layer element layers comprise at least two different types of layers that at least differ in a silicon content. A first type of the layers has a highest silicon content C.sub.Si,H, (in at. %) and a second type of the layers has a lowest silicon content C.sub.Si,L (in at. %), both relative to a total of the metal and metalloid elements, and with a ratio of the lowest silicon content C.sub.Si,L to the highest silicon content C.sub.Si,H in the range of 0.25≤C.sub.Si,L/C.sub.Si,H≤0.9.

A hard coating includes a three kinds of layers that are alternately laminated. The three kinds of layers consist of a single composition layer and two kinds of nanolayer-alternated layers. The single composition layer is constituted by one of an A composition (nitride of AlCrSiα), a B composition (nitride of CrBSiβ) and a C composition (nitride of AlCr(SiC)γ). The two kinds of nanolayer-alternated layers include nanolayers which are alternately laminated and which are constituted by two of three combinations consisting of a combination of the A composition and B composition, a combination of the A composition and C composition and a combination of the B composition and C composition. The single composition layer has a thickness of 0.5-1000 nm. Each of the nanolayers constituting the two kinds of nanolayer-alternated layers has a thickness of 0.5-500 nm, and each of the two kinds of nanolayer-alternated layers has a thickness of 1-1000 nm.

A coated tool in the present disclosure includes a base and a coating layer located on a surface of the base. The coating layer includes an intermediate layer including Ti, and an Al.sub.2O.sub.3 layer. The Al.sub.2O.sub.3 layer is located in contact with the intermediate layer at a position further away from the base than the intermediate layer. The intermediate layer includes a plurality of first protrusions protruding toward the Al.sub.2O.sub.3 layer. An average distance between the plurality of first protrusions is 70-120 nm. A cutting tool in the present disclosure includes a holder which is extended from a first end toward a second end and includes a pocket on a side of the first end, and the coated tool located in the pocket.

A cutting tool comprises a substrate and an AlTiN layer, the AlTiN layer including cubic Al.sub.xTi.sub.(1-x)N crystal grains, an atomic ratio x of Al in the Al.sub.xTi.sub.(1-x)N being 0.7 or more and 0.95 or less, the AlTiN layer including a first major surface on a side of a surface of the cutting tool and a second major surface on a side of the substrate, the AlTiN layer including a first region having a distance of 0 nm or more and 100 nm or less from the first major surface, and a second region having a distance of more than 100 nm and 150 nm or less from the first major surface, the first region having a maximum oxygen content ratio of 5 atomic % or more and 30 atomic % or less, the second region having a maximum oxygen content ratio of less than 5 atomic %.

A cutting tool comprising a base material and a coating arranged on the base material; wherein: the coating comprises an α-Al.sub.2O.sub.3 layer composed of a plurality of α-Al.sub.2O.sub.3 particles; the average particle diameter a of the α-Al.sub.2O.sub.3 particles in a first region of the α-Al.sub.2O.sub.3 layer is 0.10 μm or more and 0.30 μm or less; the average particle diameter b of the α-Al.sub.2O.sub.3 particles in a second region of the α-Al.sub.2O.sub.3 layer is 0.30 μm or more and 0.50 μm or less; the average particle diameter c of the α-Al.sub.2O.sub.3 particles in a third region of the α-Al.sub.2O.sub.3 layer is 0.50 μm or more and 1.50 μm or less; and the ratio b/a is 1.5 or more and 5.0 or less.

A coated cutting tool comprising a substrate containing a cubic boron nitride-containing sintered body, and a coating layer formed on the substrate, wherein the coating layer comprises a lowermost layer and an alternating laminate structure in this order, the lowermost layer comprises (Al.sub.1-xCr.sub.x)N, an average thickness of the lowermost layer is 0.01 μm or more and 0.2 μm or less, the alternating laminate structure includes mutually different two kinds of compound layers of a first compound layer containing (Al.sub.1-y1Cr.sub.y1)N and a second compound layer containing (Al.sub.1-y2Cr.sub.y2)N alternately laminated repeatedly twice or more, an average thickness of the entire alternating laminate structure is 0.1 μm or more and 1.2 μm or less, an average thickness of the entire coating layer is 0.2 μm or more and 1.3 μm or less, and a compressive residual stress at the cubic crystal (111) plane is 3.0 GPa or less.