Ion implantation was used to form high densities (~1019
/cm3) of small oxide precipitates in Ni in order to
investigate the strength mechanism produced by such highly refined
structures. Nanometer-size precipitates of Al2O3 and
NiO are found to block dislocation motion in the Ni matrix, producing yield
strengths up to 4.6 GPa, more than twice that of hardened bearing steel.
Dispersion strengthening theory, developed for micrometer-size precipitates
and spacings, was found to account quantitatively for the yield strengths
produced by nanometer-size oxides as well. Nanoindentation plus
finite-element modeling was used to quantify the mechanical properties of
implanted metal layers, and was extended to examination of amorphous Si
layers formed by self-ion implantation. The amorphous phase was found to
have a yield strength of 4.45 ± 0.20 GPa, Young's modulus of 144 ± 7 GPa,
and hardness of 10.3 ± 0.4 GPa. The modulus and hardness are reduced by 10%
and 15%, respectively, from those of crystalline Si.