Atomistic studies are carried out to investigate the formation and evolution of defects during nanoindentation of a gold crystal. The results in this theoretical study complement the experimental investigations [J. D. Kiely and J. E. Houston, Phys. Rev. B, v57, 12588 (1998)] extremely well. The defects are produced by a three step mechanism involving nucleation, glide and reaction of Shockley partials on the {111} slip planes noncoplanar with the indented surface. We have observed that slip is in the directions along which the resolved shear stress has reached the critical value of approximately 2 GPa. The first yield occurs when the shear stresses reach this critical value on all the {111} planes involved in the formation of the defect. The phenomenon of strain hardening is observed due to the sessile stair-rods produced by the zipping of the partials. The dislocation locks produced during the second yield give rise to permanent deformation after retraction.
@article{arxiv.cond-mat/0201426,
title = {Atomistic Studies of Defect Nucleation during Nanoindentation of Au (001)},
author = {Anil Gannepalli and Surya K. Mallapragada},
journal= {arXiv preprint arXiv:cond-mat/0201426},
year = {2009}
}
Comments
11 pages, 13 figures, submitted to Physical Review B