Atomistic studies were carried out in order to investigate the formation and evolution of defects during the nano-indentation of a Au crystal. The results of this theoretical study complemented the experimental investigations extremely well. The defects were produced via a 3-step mechanism which involved nucleation, glide and reaction of Shockley partials on {111} slip planes which were non-coplanar with the indented surface. It was observed that slip occurred in directions along which the resolved shear stress had reached a critical value of about 2GPa. The first yield occurred when the shear stresses reached this critical value on all of the {111} planes involved in the formation of

the defect. Strain hardening was observed due to sessile stair-rods which were produced by zipping of the partials. The dislocation locks produced during the second yield gave rise to a permanent deformation after retraction.

Atomistic Studies of Defect Nucleation during Nano-Indentation of Au(001). A.Gannepalli, S.K.Mallapragada: Physical Review B, 2002, 66[10], 104103 (9pp)