We investigate the elastic and plastic behavior of the monolayer when tensile strain is applied to the larger value. The strain energy increases while increasing the strain within the harmonic region (Fig. ). The harmonic region indicates that even though the applied strain is removed the system relaxes back to its equilibrium state commonly known as the elastic region. Further, after reaching the maximum value (critical strain ) the strain energy decreases beyond that the system transits from elastic to the plastic region (Fig. ). The system in the plastic region will be in a metastable state. In this region, the removal of applied strain doesn't make it possible to relax back to its equilibrium geometry (irreversible structural change). Here, calculations show that the biaxial is significantly lower than that of the uniaxial (Table ). The higher of these materials suggest that they are ductile materials similar to MoS 2 .