Shear properties and stable wrinkle resistance in 2D Ti₃C₂T_x MXene monolayers

Two-dimensional (2D) transition metal carbides or nitrides (MXenes), represented by Ti₃C₂T_x, exhibit exceptional mechanical and electrical properties, making them ideal candidates in aerospace, structural membranes, and flexible electronics. Understanding the mechanical properties of 2D Ti₃C₂T_x under various load conditions is crucial for ensuring structural integrity and performance reliability. Here, we conduct direct in-situ shear test of monolayer Ti₃C₂T_x nanosheets using a push-to-shear strategy under the scanning electron microscope. Contrary to the expected ultra-low shear performance and wrinkle instability of 2D materials, we report a high in-plane shear modulus of 0.279 ± 0.007 TPa for single-crystal monolayer Ti₃C₂T_x, along with stable wrinkle resistance. Additionally, the monolayer Ti₃C₂T_x exhibits a shear strength as high as ~18.6 GPa and an average shear strain of ~8.6%. This work provides direct measurement of the intrinsic shear properties of monolayer Ti₃C₂T_x and highlights the promising potential of Ti₃C₂T_x in maintaining device performance and reliability.