To provide a surface-coated cutting tool exhibiting excellent wear resistance in a high-speed cutting process and having prolonged service life. The surface-coated cutting tool includes a tool substrate containing WC crystal grains and insulating grains, and a coating layer composed of a multiple nitride of Ti, Al, and V and disposed on the surface of the tool substrate. The multiple nitride is represented by a compositional formula: Ti.sub.aAl.sub.bV.sub.cN satisfying the following relations:

0.25≤a≤0.35,

0.64≤b≤0.74,

0<c≤0.06, and

a+b+c=1

(wherein each of a, b, and c represents an atomic proportion). The coating layer is characterized by exhibiting a peak attributed to a hexagonal crystal phase and a peak attributed to a cubic crystal phase as observed through X-ray diffractometry.

A cutting tool including a rake face, a flank face, and a cutting edge portion, comprising a substrate and an AlTiN layer, the AlTiN layer including cubic Al.sub.xTi.sub.1-xN crystal grains, Al having an atomic ratio x of 0.7 or more and 0.95 or less, the AlTiN layer including a central portion, the central portion at the rake face being occupied in area by (200) oriented crystal grains at a ratio of 80% or more, the central portion at the flank face being occupied in area by (200) oriented crystal grains at a ratio of 80% or more, the central portion at the cutting edge portion being occupied in area by (200) oriented crystal grains at a ratio of 80% or more.

A surface-coated cutting tool includes a substrate and a coating film. The coating film includes an alternate layer. The alternate layer includes a first layer having a first composition and a second layer having a second composition. The alternate layer is formed by alternately stacking at least one first layer and at least one second layer. The first layer and the second layer each have a thickness not smaller than 2 nm and not greater than 100 nm. The first composition is expressed as Ti.sub.aAl.sub.bSi.sub.cN (0.25≤a≤0.45, 0.55≤b≤0.75, 0≤c≤0.1, a+b+c=1). The second composition is expressed as Ti.sub.dAl.sub.eSi.sub.fN (0.35≤d≤0.55, 0.45≤e≤0.65, 0≤f≤0.1, d+e+f=1). The first composition and the second composition satisfy a condition of 0.05≤d−a≤0.2 and 0.05≤b−e≤0.2.

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 coated cutting tool includes a substrate and a coating of one of more layers. The coating includes a layer of α-Al.sub.2O.sub.3 of a thickness of 1-20 μm deposited by chemical vapour deposition (CVD). The α-Al.sub.2O.sub.3 layer exhibits an X-ray diffraction pattern and wherein the texture coefficient TC(h k 1) is defined according to the Harris formula, wherein 1<TC(0 2 4)<4 and 3<TC(0 0 12)<6.

A hard material includes a first hard phase containing titanium carbonitride as a major constituent and a binder phase containing an iron group element as a major constituent. In any surface or cross-section of the hard material, the grain size D50 at a cumulative percentage of 50% of a grain size distribution by area of the first hard phase is 1.0 μm or more, and the average aspect ratio of first hard phase particles having grain sizes larger than or equal to D50 is 2.0 or less.

A surface-coated cutting tool includes a base material and a coating covering the base material. The base material includes a rake face and a flank face. The coating includes a TiCN layer. The TiCN layer has a (311) orientation in a region d1 in the rake face. The TiCN layer has a (422) orientation in a region d2 in the flank face.

A cutting tool includes a substrate and a coating film, wherein the coating film has a first layer formed from a plurality of hard grains, the hard grains are made of TiSiCN having a cubic crystal structure, the hard grains have a lamellar structure in which a layer having a relatively high silicon concentration and a layer having a relatively low silicon concentration are alternately stacked, and a maximum value of percentage of number A.sub.Si of silicon atoms to a sum of the number A.sub.Si of silicon atoms and number A.sub.Ti of titanium atoms in a grain boundary region between the hard grains, {A.sub.Si/(A.sub.Si+A.sub.Ti)}×100, is larger than an average value of percentage of number B.sub.Si of silicon atoms to a sum of the number B.sub.Si of silicon atoms and number B.sub.Ti of titanium atoms in the first layer, {B.sub.Si/(B.sub.Si+B.sub.Ti)}×100.

A coated tool may include a base member including a first surface, and a coating layer located at least on the first surface of the base member. The coating layer may include a first layer located on the first surface and including a titanium compound, and a second layer contactedly located on the first layer and including aluminum oxide. The second layer may include an orientation coefficient Tc(0012) of 3.0 or more by X-ray diffraction analysis. The coating layer may include a plurality of voids located in a direction along an interface between the first layer and the second layer, and an average value of widths of the voids in a direction along the interface is smaller than an average value of distances between the voids adjacent to each other in a cross section orthogonal to the first surface.

The present disclosure relates to a cutting tool of a cemented carbide substrate including WC and a binder phase having one or more of Co, Fe and Ni, wherein the cemented carbide also includes a finely dispersed eta phase of Me12C and/or Me6C carbides, where Me is one or more metals selected from W, Mo and the binder phase metals, wherein the substoichiometric carbon content in the cemented carbide is between −0.30 to −0.16 wt %. The disclosed cutting tool will achieve an improved resistance against comb cracks.