Conferences

First-principles quantum molecular calculations of structural and mechanical properties of TiN/SiNx heterostructures, and the achievable hardness of the nc-TiN/SiNx nanocomposites

 
S.Veprek,
 
A.S.Argon,
 
P.E.A.Turchi,
 
L.Gorb,
 
F.Hill,
 
J.Leszczynski
 

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Thin Solid Films, 2015, #578
http://www.materials.kiev.ua/article/1630

Abstract

TiN/SiNx heterostructures with one monolayer of the interfacial SiNx have been investigated in the framework of first-principles molecular dynamics calculations in the temperature range of 0 to 1400 K with subsequent static relaxation. The atomic configurations, thermal stability and stress–strain relations have been calculated. Among he heterostructures studied, only the TiN(111)/SiN/TiN(111) and TiN(111)/Si2N3/TiN(111) ones are thermally stable. Upon tensile load, decohesion occurs between the TiN bonds adjacent to the SiNx interfacial layer for TiN(001)/SiN/TiN(001) and TiN(111)/Si2N3/TiN(111) heterostructures, and inside the TiN slab for TiN(001)/ Si3N4/TiN(001) and TiN(110)/SiN/TiN(110) ones. Upon shear, failure occurs in TiN near the interfaces in all the heterostructures, except for the TiN(001)/Si3N4/TiN(001) one, for which the plastic flow occurs inside the TiN slab. Based on these results we estimate the maximum achievable hardness of nc-TiN/Si3N4 nanocomposites free of impurities to be about 170 GPa.