Young's Modulus and Tensile Strength of TiC MXene Nanosheets As Revealed by TEM Probing, AFM Nanomechanical Mapping, and Theoretical Calculations.

Two-dimensional transition metal carbides, that is, MXenes and especially TiC, attract attention due to their excellent combination of properties. TiC 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 TiC, which is essential for their utilization. We have fabricated TiC nanosheets and studied their mechanical properties using direct 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 TiC basal plane was found to be 80-100 GPa. The tensile strength of TiC 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 TiC as a function of nanosheet geometrical parameters and structural defect concentration.