Elastic constants and thermal expansion coefficient of metastable C49 TiSi2

Abstract

The elastic constants and thermal expansion coefficient of C49 TiSi2 thin films have been investigated by in situ curvature measurement during heat treatment and ex situ x-ray diffraction measurements. The C49 TiSi2 compound was formed from Ti-Si multilayers deposited on monocrystalline silicon and sapphire substrates. The films were polycrystalline without any evident texture. Young’s modulus (142 GPa), Poisson’s ratio (0.27), and the thermal expansion coefficient (10.9×10−6 K−1) have been determined. Note that these values are averages over random crystal orientations. Directly after formation C49 TiSi2 films exhibit tensile stress. This stress relaxes considerably above 375 °C. Below this temperature the thermal expansion is found to be independent of the state of relaxation of the C49 TiSi2 film.

Ab initio-based prediction and TEM study of silicide precipitation in titanium

“…The difference between our results and experiment [34,35,17,[36][37][38][39][40] is less than 1% for lattice constants and 10% for elastic constants.…”

Mechanical properties of TiSi2 nanowires

“…There are some theoretical research works to predict the elastic moduli of the TiSi 2 , for example, E = 277.8 GPa for ideal polycrystalline TiSi 2 compounds [7], E = 255.6 GPa for polycrystal conglomerates [8] and bulk modulus 176.4 GPa for C54 TiSi 2 [17]. Jongste et al obtained the elastic modulus 142 GPa for C49 film by X-ray diffraction [5]. It is found that these results are quite comparable with most of our measurement results reported above.…”

“…Titanium disilicide is among the most popular ones, which exhibits high melting temperature, relatively low density, the lowest resistivity (for C54 phase) [1] and good oxidation resistance at a high temperature. The film and bulk materials of titanium disilicide have been extensively studied, such as formation and phase transformation [1][2][3], electrical characterization [4], thermal expansion coefficient [5] and so on. Mechanical analysis, e.g., Young modulus and Poisson ratio of C49 polycrystalline film [5], the in situ stress of titanium silicide films during sintering [6], elastic constants of transition-metal-disilicide single crystals [7], and elastic properties, yield stress for sintered compound of TiSi 2 [8], was also more or less reported experimentally and theoretically.…”

Enhanced thermoelectric properties of Mg2Si by addition of TiO2 nanoparticles

“…In addition, in the magnified diffractograms shown in Fig. 1(b), two TiSi 2 phases (PDF #04-007-1144 and #04-002-1352, the latter being a metastable phase formed prior to the stable orthorhombic phase 36 ) were observed and possibly minute amounts of a high temperature Ti phase (PDF #00-044-1288). These observations are consistent with a scenario in which the TiO 2 reacts with Mg 2 Si or elemental Si present in the sample to form MgO, TiSi 2 and possibly Ti.…”