Selection of Composition and Structure of Coatings for Cutting Tools Based On Quantum Mechanical Calculations

On the basis of quantum mechanical calculations, the authors simulated the formation of interatomic bonding of a wear-resistant coating with the cemented carbide substrate, which determines the adhesion strength of the coating to the substrate. The article describes the method and results of the optimization of the composition and structure of the coating to increase its durability. The most efficient coating compositions for machining of various materials are determined. The quantum mechanical calculations to alter the structure of the simplest compositions of the coatings (TiN, TiC) through the introduction of transition metal atoms have shown their effectiveness, especially for tantalum Ta and niobium Nb. It is shown that the compatibility of the friction pairs (tool material and machined material) can be predicted by calculating the total energy of the systems. The calculations have revealed that cobalt is the most active element in the structure of hard alloys. In this regard, during the coating deposition, the nucleation of refractory metal grains occurs in the cobalt compound binder. Titanium is more active than iron in a cobalt binder as well as in carbide phases, due to which titanium alloys are characterized by lower machinability than iron steel.

References

[1] Kabaldin Iu.G. Struktura, prochnost’ i iznosostoikost’ kompozitsionnykh instrumental’nykh materialov [Structure, the strength and durability of composite tool materials]. Vladivostok, Dal’nauka publ., 1996. 183 p.

[2] Kabaldin Iu.G., Seryi S.V., Kretinin O.V., Laptev I.L., Vlasov E.E., Kuz’mishina A.M. Komp’iuternoe modelirovanie i issledovanie nanostruktur v protsessakh obrabotki rezaniem na osnove kvantovo-mekhanicheskikh raschetov [Computer modeling and study of nanostructuresin machining processes on the basis of quantum mechanical calculations]. N.Novgorod, NNSTU n.a. R.E. Alekseev publ., 2014. 119 p.

[3] Vereshchaka A.S., Tret’iakov I.P. Rezhushchie instrumenty s iznosostoikimi pokrytiiami [Cutting tools with wear-resistant coatings]. Moscow, Mashinostroenie publ., 1986. 192 p.

[4] Grigorovich V.K. Metallicheskaia sviaz’ i struktura metallov [Metallic bond and structure of metals.]. Moscow, Nauka publ., 1988. 296 p.

[5] Kabaldin Y.G., Seryi S.V., Murav’ev S.N., Prosolovich A.A., Simagina E.V. Improving cutter performance by the application of nanostructural coatings. Russian Engineering Research, 2010, vol. 30, no. 3, pp. 235–242.

[6] Kabaldin Y.G., Seryi S.V. Optimizing the composition and properties of nanostructural coatings for cutting tools on the basis of the electron-density functional. Russian Engineering Research, 2011, vol. 31, no. 5, pp. 458–464.