Synthesis of Ti matrix composites reinforced with TiC particles: in situ synchrotron X-ray diffraction and modeling

Abstract

The reaction tending towards thermodynamic equilibrium during the synthesis of Ti/TiC MMC prepared by the powder metallurgy route was studied by in-situ synchrotron X-ray diffraction.The carbide composition was found to change rapidly from its initial stoichiometric value TiC 0.96 towards a sub-stoichiometric value (TiC 0.57 ) corresponding to thermodynamic equilibrium with the C-saturated Ti matrix. The reaction rate is very fast and the solid-state reaction is almost complete after only a few minutes at 1073K (800°C) for the smallest particles, whereas the ratelimiting step remains the particle size. In addition, modeling of the diffusion processes in MMCs, i.e. initial dissolution of particles and their trend towards equilibrium composition, was performed using three particles size classes and the calculations were performed using the ThermoCalc and Dictra package. First, dissolution of the smallest particles (10% of the initial TiC 0.96To cite this paper : J. Andrieux, B. Gardiola, O. Dezellus, Synthesis of Ti matrix composites reinforced with TiC particles: in-situ synchrotron X ray diffraction and modeling, Journal of Materials Science 2018, Accepted for publication, doi 10.1007/s10853-018-2258 particles) is expected to be achieved after only 1s at 800°C. Second, the change in TiC composition lead to an increase in the total amount of carbide in the composite from 16 mass% to 19 mass%. The consequences on the industrial process of Ti/TiC MMC synthesis have also been considered. A typical industrial heat treatment of a MMC billet, 1h at 900°C, was modeled and the results showing an increase of the total amount of carbide in the composite from 16 mass% to 22 mass% are in rather good agreement with the experimental value (21 mass%).This highlights the potential of thermodynamic and kinetic modeling to help understand and optimize industrial processes for MMC synthesis.

The effect of cetyltrimethylammonium bromide (CTAB) addition on green synthesis of porous N-doped TiO2 for photoreduction of heavy metal ion Cr(vi)

“…According to Andrieux et al (2018), smoothing success is indicated by obtaining an R -profile ( R p ) of less than 15%, an R -weight profile ( R wp ) of less than 20%, and a goodness of fit (X 2 ) of less than 5. 34 …”

“…According to Andrieux et al (2018), smoothing success is indicated by obtaining an R-prole (R p ) of less than 15%, an R-weight prole (R wp ) of less than 20%, and a goodness of t (X 2 ) of less than 5. 34 Table 2 demonstrates that undoped TiO 2 with N-doped TiO 2 does not change its structure, such as space group, crystal lattice, and asymmetry. The magnication of the peak with the highest intensity indicates that the peak shi occurs due to the lattice tension on the crystal size.…”

Fabrication of in-situ rod-like TiC particles dispersed Ti matrix composite using graphite power sheet

“…Therefore, a layer-like TiC x forms at the interface. When the holding time is increased to 3.6 ks, the sample is closer to thermodynamic equilibrium and most of the carbon atoms diffuse uniformly throughout the sample 16 , 17 . However, at the original position of graphite powder sheets, straight dotted lines formed by the arrangement of the short rod TiC can be still observed.…”

“…9b. This observation suggests that the applied load may have been transferred from the substrate to the TiC x particles, since strong interfacial adhesion can provide effective load transfer capability and thus increase the yield strength 17 . Moreover, there are many ununiform dimples could be observed, which indicating good plasticity.…”

Time-Resolved In Situ Neutron Diffraction Study of Cu22Fe8Ge4S32 Germanite: A Guide for the Synthesis of Complex Chalcogenides

“…Real-time in situ reaction monitoring is a powerful tool that allows us to develop rational synthesis schemes and to better understand the reactions kinetic and mechanism occurring during crystallization sequences. − Such experiments have been mainly limited to XRD analyses.…”