A cBN sintered body contains cBN particles whose proportion is 85-97% by volume, and a binding phase whose proportion is 3-15% by volume. The cBN sintered body contains Al whose ratio to the entirety of the cBN sintered body is 0.1-5% by mass, and Co whose mass ratio to the Al is 3 to 40, and includes Al.sub.3B.sub.6Co.sub.20.

A sintered friction material is formed by pressure sintering mixed powder at 800 C. or above, the mixed powder consisting of, in mass %, Cu and/or Cu alloy: 40.0 to 80.0%, Ni: 0% or more and less than 5.0%, Sn: 0 to 10.0%, Zn: 0 to 10.0%, VC: 0.5 to 5.0%, Fe and/or Fe alloy: 2.0 to 40.0%, lubricant: 5.0 to 30.0%, metal oxide and/or metal nitride: 1.5 to 30.0%, and the balance being impurity.

A cubic boron nitride sintered body including cubic boron nitride and a binder phase, wherein: a content ratio of the cubic boron nitride is 85 volume % or more and 95 volume % or less, a content ratio of the binder phase is 5 volume % or more and 15 volume % or less, the binder phase contains Co.sub.3W.sub.3C, W.sub.2Co.sub.21B.sub.6, and an Al compound, and I.sub.B/I.sub.A is 0.02 or more and 0.15 or less, I.sub.C/I.sub.A is 0.02 or more and 1.00 or less, and I.sub.C?I.sub.D, where I.sub.A denotes an X-ray diffraction peak intensity of a (111) plane of the cubic boron nitride, I.sub.B denotes an X-ray diffraction peak intensity of a (400) plane of the Co.sub.3W.sub.3C, I.sub.C denotes an X-ray diffraction peak intensity of a (420) plane of the W.sub.2Co.sub.21B.sub.6, and I.sub.D denotes an X-ray diffraction peak intensity of a (001) plane of WC.

Methods for large-scale additive manufacturing of high-strength boron nitride nanotubes (BNNT)/aluminum (Al) (e.g., reinforced Al alloy) metal matrix composites (MMCs) (BNNT/Al MMCs), as well as the BNNT/Al MMCs produced by the large-scale additive manufacturing methods, are provided. A combination of ultrasonication and spray drying techniques can produce good BNNT/Al alloy feedstock powders, which can be used in a cold spraying process.

A cubic boron nitride sintered material comprises cubic boron nitride particles and a bonding material, wherein the bonding material comprises at least one first metallic element selected from the group consisting of titanium, zirconium, vanadium, niobium, hafnium, tantalum, chromium, rhenium, molybdenum, and tungsten; cobalt; and aluminum; the cubic boron nitride sintered material has a first interface region sandwiched between an interface between the cubic boron nitride particles and the bonding material, and a first virtual line passing through a point 10 nm apart from the interface to the bonding material side; and when an element that is present at the highest concentration among the first metallic elements in the first interface region is defined as a first element, an atomic concentration of the first element in the first interface region is higher than an atomic concentration of the first element in the bonding material excluding the first interface region.

Methods for large-scale additive manufacturing of high-strength boron nitride nanotubes (BNNT)/aluminum (Al) (e.g., reinforced Al alloy) metal matrix composites (MMCs) (BNNT/Al MMCs), as well as the BNNT/Al MMCs produced by the large-scale additive manufacturing methods, are provided. A combination of ultrasonication and spray drying techniques can produce good BNNT/Al alloy feedstock powders, which can be used in a cold spraying process.

The present application is a new improvement in the fine-grained cubic boron nitride sintered compact which may be employed to manufacture a cutting tool. The compact contains at least 80 vol % cBN with a metallic binder system and is sintered under HPHT conditions. The improvement incorporates alloys of aluminum in the metallic binder system.

Methods for large-scale additive manufacturing of high-strength boron nitride nanotubes (BNNT)/aluminum (Al) (e.g., reinforced Al alloy) metal matrix composites (MMCs) (BNNT/Al MMCs), as well as the BNNT/Al MMCs produced by the large-scale additive manufacturing methods, are provided. A combination of ultrasonication and spray drying techniques can produce good BNNT/Al alloy feedstock powders, which can be used in a cold spraying process.

The present application is a new improvement in the fine-grained cubic boron nitride sintered compact which may be employed to manufacture a cutting tool. The compact contains at least 80 vol % cBN with a metallic binder system and is sintered under HPHT conditions. The improvement incorporates alloys of aluminum in the metallic binder system. The invention has proved beneficial in the machining of cast iron.

A sintered material contains hard particles composed of one or more selected from the group consisting of cubic boron nitride, Al.sub.2O.sub.3, AlON, SiAlON, TiC, TiCN, TiN, WC, and diamond, a metallic binder phase mainly composed of Co or Ni and containing at least one element selected from the group consisting of Co, Ni, Al, W, V, and Ti, and Al.sub.2O.sub.3 dispersed in the metallic binder phase.