Elastic constants of single-crystalTiNx(001)(0.67⩽x⩽1.0)

Abstract

The elastic constants c 11 and c 44 of single-crystal NaCl-structure ␦-TiN x ͑001͒ layers, with x ranging from 0.67 to 1.0, were determined using sound velocity measurements. Picosecond ultrasonic optical pump/probe techniques were employed to generate and detect longitudinal sound waves and surface acoustic waves ͑SAW͒ in order to obtain c 11 ͑x͒ and c 44 ͑x͒, respectively. SAW generation was achieved by depositing a periodic series of Al bars on the TiN x ͑001͒ layers to spatially modulate the surface reflectivity. c 11 and c 44 were found to decrease continuously from 626 and 156 GPa with x = 1 to 439 and 92 GPa with x = 0.67. The Voit-Reuss-Hill average aggregate elastic moduli E VRH ͑x͒ obtained from our measured c 11 ͑x͒ and c 44 ͑x͒ values are in good agreement with previous TiN x ͑001͒ nanoindentation results.

Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction experiments

“…In particular, time-resolved reflectivity experiments, performed on gratings of metallic nanometric stripes (2-D confined) on transparent (SiO 2 ) or semitransparent (Si) substrates, evidenced oscillations in the GHz range [1,2,3,4], however their origin of these oscillations is still matter of debate [3,4]. The reason resides in the difficulty to model the strong mechanical coupling [5,6] between the nano-objects and the substrate and to calculate the mechanical eigenfrequencies of the coupled system.…”

Ab Initio Molecular Dynamics Simulations of Nitrogen/VN(001) Surface Reactions: Vacancy-Catalyzed N2 Dissociative Chemisorption, N Adatom Migration, and N2 Desorption

“…13(d)). Experimental results for epitaxial growth of TiNx(001) [33,88], as well as TaNx(001) [34,124] and HfNx, 95 indicate that plasma activation producing gas-phase atomic N is essential for forming stoichiometric layers. Our simulation results are consistent with the experimental reports and show that N2 is much less reactive than atomic N since the molecular species require interaction with surface anion vacancies (see Sec.…”

“…[82][83][84][85][86][87] For N adatoms on TiN(001), electronic-structure analyses show that associative Nad/Nad recombination and desorption is considerably less likely than Nad/Nsurf desorption due to the high activation energy (~2 eV) required to overcome long-range Nad/Nad repulsive interactions. 62 NaCl-structure TM nitride systems have wide single-phase compound fields and varying the stoichiometry ratio (N/TM) during synthesis has been used to tune electrical, 34, 88, 89 optical, [90][91][92] structural, [93][94][95][96] catalytic, 97,98 and mechanical 33,35,89,99 properties. Thus, elucidation of the mechanisms leading to anion-vacancy formation and N2 desorption during synthesis may provide guidance for adjusting experimental conditions to tailor the material's characteristics to meet specific requirements.…”

“…[24][25][26][27] The properties of TM nitrides ultimately depend on their nanostructure [28][29][30][31][32] and stoichiometry. [33][34][35] Growth and surface morphological evolution of titanium nitride (TiN), one of the first hard-coating materials, 36,37 have been extensively studied experimentally. [38][39][40][41][42][43][44][45] Vanadium nitride (VN), another important TM nitride, although not as well characterized as TiN, is of interest for low-friction, hard coatings.…”

Microstructure of TiN coatings synthesized by direct pulsed Nd:YAG laser nitriding of titanium: Development of grain size, microstrain, and grain orientation

“…TiN x is cubic (Fm3m, 225) and has a lattice constant of a = 4.24 Å [36] for x = 1. The virgin titanium is hexagonal (P63/mmc, 194) and has lattice constants of a = 2.950 Å and c = 4.682 Å [37].…”