Abstract: A surface-coated cutting tool includes a substrate and a coating film that coats the substrate, wherein the coating film includes a hard coating layer constituted of a domain region and a matrix region, the domain region is a region having a plurality of portions divided and distributed in the matrix region, the domain region has a structure in which a first layer composed of a first Alx1Ti(1-x1) compound and a second layer composed of a second Alx2Ti(1-x2) compound are layered on each other, the matrix region has a structure in which a third layer composed of a third Alx3Ti(1-x3) compound and a fourth layer composed of a fourth Alx4Ti(1-x4) compound are layered on each other, the first AlTi compound and the third AlTi compound have a hexagonal crystal structure, the second AlTi compound and the fourth AlTi compound have a cubic crystal structure.

Abstract: A surface-coated cutting tool includes a substrate and a coating film that coats the substrate, wherein the coating film includes a hard coating layer constituted of a domain region and a matrix region, the domain region is a region having a plurality of portions divided and distributed in the matrix region, the domain region has a structure in which a first layer composed of a first Alx1Ti(1-x1) compound and a second layer composed of a second Alx2Ti(1-x2) compound are layered on each other, the matrix region has a structure in which a third layer composed of a third Alx3Ti(1-x3) compound and a fourth layer composed of a fourth Alx4Ti(1-x4) compound are layered on each other.

Abstract: A surface-coated cutting tool includes a substrate and a coating film that coats the substrate, wherein the coating film includes a hard coating layer constituted of a domain region and a matrix region, the domain region is a region having a plurality of portions divided and distributed in the matrix region, the domain region has a structure in which a first layer composed of a first Alx1Ti(1-x1) compound and a second layer composed of a second Alx2Ti(1-x2) compound are layered on each other, the matrix region has a structure in which a third layer composed of a third Alx3Ti(1-x3) compound and a fourth layer composed of a fourth Alx4Ti(1-x4) compound are layered on each other, the first AlTi compound, the second AlTi compound and the fourth AlTi compound have a cubic crystal structure, the third AlTi compound has a hexagonal crystal structure.

Abstract: A surface-coated cutting tool includes a substrate and a coating film that coats the substrate, wherein the coating film includes a hard coating layer constituted of a domain region and a matrix region, the domain region is a region having a plurality of portions divided and distributed in the matrix region, the domain region has a structure in which a first layer composed of a first Alx1Ti(1?x1) compound and a second layer composed of a second Alx2Ti(1?x2) compound are layered on each other, the matrix region has a structure in which a third layer composed of a third Alx3Ti(1?x3) compound and a fourth layer composed of a fourth Alx4Ti(1?x4) compound are layered on each other, the first AlTi compound and the second AlTi compound have a cubic crystal structure, the third AlTi compound and the fourth AlTi compound have a cubic crystal structure.

Abstract: A cemented carbide includes second hard phase grains, wherein the second hard phase grains includes a core portion, and in a case where a total of 70 unit regions that are each constituted of a square having each side of 8?m are provided by successively arranging 7 unit regions in a longitudinal direction and 10 unit regions in a lateral direction in an electron microscope image of any cross section of the cemented carbide captured at a magnification of 1500×, where the total number of core portions in the total of 70 unit regions is calculated, and where a percentage of the number of core portions in each of the unit regions with respect to the total number of core portions is calculated, the number of unit regions in which the percentage is less than 0.43% or more than 2.43% is less than or equal to 10.

Abstract: A cemented carbide comprising a first hard phase composed of tungsten carbide particles and a binder phase including Co, the cemented carbide having a ratio Nt/Na of 0.9 or more, where, in any surface or any cross section of the cemented carbide, a region in which there is a distance X of 5 nm or less between surfaces respectively of tungsten carbide particles adjacent to each other, the surfaces facing each other along a length L of 100 nm or more, is referred to as a WC/WC interface, and Na represents a total number of WC/WC interfaces and Nt represents a number of WC/WC interfaces having distance X of 1 nm or more and 5 nm or less and having therein an atomic percentage of Co higher than an average value of atomic percentages of Co in the tungsten carbide particles.

Abstract: A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of AlxTi1?x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of AlyTi1?y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

Abstract: A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of AlxTi1-x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of AlyTi1-y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

Abstract: A surface-coated cutting tool includes a substrate and a coating formed on a surface of the substrate, the coating including one or two or more layers, at least one of the layers being an Al-rich layer including hard particles, the hard particle having a sodium chloride type crystal structure, and including a first unit phase in a form of a plurality of lumps and a second unit phase interposed between the lumps of the first unit phase, the first unit phase being composed of a nitride or carbonitride of AlxTi1-x, the first unit phase having an atomic ratio x of Al of 0.7 or more and 0.96 or less, the second unit phase being composed of a nitride or carbonitride of AlyTi1-y, the second unit phase having an atomic ratio y of Al exceeding 0.5 and less than 0.7.

Abstract: A cemented carbide including a hard phase, a binding phase, and inevitable impurities. The hard phase satisfies a first hard phase composed mainly of tungsten carbide, and a second hard phase composed mainly of a compound. The compound contains multiple types of metallic elements including tungsten and at least one element selected from carbon, nitrogen, oxygen, and boron. The second hard phase satisfies D10/D90<0.4, wherein D10 denotes a cumulative 10% grain size in an area-based grain size distribution on a surface or cross section of the cemented carbide, and D90 denotes a cumulative 90% grain size in the area-based grain size distribution, and satisfies ?2<5.0, wherein ?2 denotes the variance of the distance between the centroids of the nearest two of the second hard phases. The average grain size DW of the first hard phase ranges from 0.8 to 4.0 ?m and satisfies DM/DW<1.0, wherein DM denotes the average grain size of the second hard phase.

Abstract: A cemented carbide comprising a first hard phase composed of tungsten carbide particles and a binder phase including Co, the cemented carbide having a ratio Nt/Na of 0.9 or more, where, in any surface or any cross section of the cemented carbide, a region in which there is a distance X of 5 nm or less between surfaces respectively of tungsten carbide particles adjacent to each other, the surfaces facing each other along a length L of 100 nm or more, is referred to as a WC/WC interface, and Na represents a total number of WC/WC interfaces and Nt represents a number of WC/WC interfaces having distance X of 1 nm or more and 5 nm or less and having therein an atomic percentage of Co higher than an average value of atomic percentages of Co in the tungsten carbide particles.

Abstract: A cemented carbide including a hard phase, a binding phase, and inevitable impurities. The hard phase satisfies a first hard phase composed mainly of tungsten carbide, and a second hard phase composed mainly of a compound. The compound contains multiple types of metallic elements including tungsten and at least one element selected from carbon, nitrogen, oxygen, and boron. The second hard phase satisfies D10/D90<0.4, wherein D10 denotes a cumulative 10% grain size in an area-based grain size distribution on a surface or cross section of the cemented carbide, and D90 denotes a cumulative 90% grain size in the area-based grain size distribution, and satisfies ?2<5.0, wherein ?2 denotes the variance of the distance between the centroids of the nearest two of the second hard phases. The average grain size DW of the first hard phase ranges from 0.8 to 4.0 ?m and satisfies DM/DW<1.0, wherein DM denotes the average grain size of the second hard phase.

Abstract: Provided are a cemented carbide having excellent plastic deformation resistance and a cutting tool in which the cemented carbide is used as a substrate. A cemented carbide includes a hard phase containing tungsten carbide particles and a binder phase containing, as a main component, an iron-group element, wherein the formula B/A?0.05 is satisfied, where A represents the number of the tungsten carbide particles, and B represents the number of tungsten carbide particles whose number of contact points with other tungsten carbide particles is 1 or less. Preferably, the iron-group element includes cobalt, and the cobalt content in the cemented carbide is 8% by mass or more. Preferably, the tungsten carbide particles have an average particle diameter of 3 ?m or more.