Multilayered coated cutting tool

Abstract

A cutting tool includes a body of a hard alloy of cemented carbide, cermet, ceramics, cubic boron nitride based material or high speed steel and on which at least one of the functioning parts of the surface thereof, a hard and wear resistant coating is applied. The coating includes a polycrystalline laminar, multilayered structure of metal nitride compounds, in a repetitive form . . . MeN/(Ti1-xAlx)N/MeN/(Ti1-xAlx)N/MeN/(Ti1-xAlx)N/MeN/(Ti1-xAlx)N . . . of cubic structured (Ti1-xAlx)N layers where 0.3<x<0.95 and cubic structured MeN layers where Me is one or more of the metal element Ti, Zr, Hf, V, Nb, Ta, Mo and Al. The laminated structure has a repeat period, λ, of 5 nm≦λ<20 nm, a layer thickness relation of 1/10<(dMeN/d(Ti,Al)N)<1/3 and a thickness dMeN≧1 nm that is essentially constant throughout its total thickness up to 20 μm. The coating hardens as a nanocomposite, adapting its strength during spinodal decomposition of (Ti1-xAlx)N in cubic TiN and cubic AlN domains where the additional cubic structured MeN layers provides elements for locking a predominantly overall cubic coating structure thus suppressing the hexagonal AlN phase formation leading to improved high temperature metal cutting properties.

Dependencies are inferred from the claim text.