The Key Role of Tin (Sn) in Microstructure and Mechanical Properties of Ti 2 SnC (M 2 AX) Thin Nanocrystalline Films and Powdered Polycrystalline Samples.

Layered ternary Ti 2 SnC carbides have attracted significant attention because of their advantage as a M2AX phase to bridge the gap between properties of metals and ceramics. In this study, Ti 2 SnC materials were synthesized by two different methods-an unconventional low-energy ion facility (LEIF) based on Ar + ion beam sputtering of the Ti, Sn, and C targets and sintering of a compressed mixture consisting of Ti, Sn, and C elemental powders up to 1250 °C. The Ti 2 SnC nanocrystalline thin films obtained by LEIF were irradiated by Ar + ions with an energy of 30 keV to the fluence of 1.10 15 cm -2 in order to examine their irradiation-induced resistivity. Quantitative structural analysis obtained by Cs-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) confirmed transition from ternary Ti 2 SnC to binary Ti 0.98 C carbide due to irradiation-induced β-Sn surface segregation. The nanoindentation of Ti 2 SnC thin nanocrystalline films and Ti 2 SnC polycrystalline powders shows that irradiation did not affect significantly their mechanical properties when concerning their hardness (H) and Young's modulus (E). We highlighted the importance of the HAADF-STEM techniques to track atomic pathways clarifying the behavior of Sn atoms at the proximity of irradiation-induced nanoscale defects in Ti 2 SnC thin films.