Nanoindentation of a nickel surface with twin boundaries using molecular dynamics simulations

In this work, nanoindentation on a (110) crystal plane with a spherical indenter and (111) twin boundaries at different distances was simulated using molecular dynamics. In addition, the load-displacement curves and mechanical properties were calculated, and the deformation mechanism of the nickel matrix was analysed using a dislocation extraction algorithm (DXA). The results showed that the load decreased in the load-displacement curve, which was caused by the initial nucleation of the dislocations, and the twinning boundary hindered dislocation propagation. Furthermore, Young's modulus values near the twin boundary were lower than those farther away, and the maximum shear stress near the twin boundary was lower. Therefore, dislocation activity in the nickel matrix during indentation was mainly in the form of Shockley partial dislocations.