Young's Modulus and Tensile Strength of Ti<sub>3</sub>C<sub>2</sub> MXene Nanosheets As Revealed by <i>In Situ</i> TEM Probing, AFM Nanomechanical Mapping, and Theoretical Calculations.

Firestein, Konstantin L; von Treifeldt, Joel E; Kvashnin, Dmitry G; Fernando, Joseph F S; Zhang, Chao; Kvashnin, Alexander G; Podryabinkin, Evgeny V; Shapeev, Alexander V et al. · Nano Lett · 2020

basic_science · Level V

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Abstract

Two-dimensional transition metal carbides, that is, MXenes and especially Ti<sub>3</sub>C<sub>2</sub>, attract attention due to their excellent combination of properties. Ti<sub>3</sub>C<sub>2</sub> nanosheets could be the material of choice for future flexible electronics, energy storage, and electromechanical nanodevices. There has been limited information available on the mechanical properties of Ti<sub>3</sub>C<sub>2</sub>, which is essential for their utilization. We have fabricated Ti<sub>3</sub>C<sub>2</sub> nanosheets and studied their mechanical properties using direct <i>in situ</i> tensile tests inside a transmission electron microscope, quantitative nanomechanical mapping, and theoretical calculations employing machine-learning derived potentials. Young's modulus in the direction perpendicular to the Ti<sub>3</sub>C<sub>2</sub> basal plane was found to be 80-100 GPa. The tensile strength of Ti<sub>3</sub>C<sub>2</sub> nanosheets reached up to 670 MPa for ∼40 nm thin nanoflakes, while a strong dependence of tensile strength on nanosheet thickness was demonstrated. Theoretical calculations allowed us to study mechanical characteristics of Ti<sub>3</sub>C<sub>2</sub> as a function of nanosheet geometrical parameters and structural defect concentration.