Deformation mechanisms of hierarchically structured 2D single-crystal materials revealed by real-time high-resolution in-situ nanomechanical testing

Conference Dates

October 2 – 7, 2022


Hierarchically structured materials such as two-dimensional (2D) single-crystal transition metal dichalcogenides (TMDs) are being increasingly explored for their electronic and piezoelectric properties for applications in devices and sensors. These materials exhibit complex deformation mechanisms that can only be revealed by real-time, nanomechanical investigations. This study investigated the plastic delamination response of 2D, single-crystal TMDs with varying lattice parameters by an integrated in-situ nano scratch, visualization, and analytical modeling approach. Nanowear at systematically progressing depths from 15 – 45 nm delaminates 50 – 80 layers with an increasing lateral force of resistance from 3.5 – 8.0 mN, thereby consuming 80 – 154 nJ of energy. Based on in-situ visualizations, the evolution of lateral force over delamination distance is modeled on linear debonding and sinusoidal pile-up forces. These novel insights on the multi-scale, hierarchical mechanical and tribological responses and failure mechanisms constitute a significant advancement in the understanding of the processing-property correlations in these architecture materials.

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