Slide 13 of 29
Notes:
- Atom-by-atom physical vapor deposition of different metals into alternating nanometer scale layers is being used by our team to synthesize and explore new concepts in the physics of strengthening nanoscale materials. A transmission electron microscope image of a copper-niobium nanolayered composite with individual copper and niobium layers 1-nm thick is shown. The total sample thickness for the self-support tensile test sample shown is about 15 micrometers.
- Nanoscale design shows promise of synthesizing the strongest metals ever known to humankind. The strengths of typical fine-grain pure metals such as Cu are on the order of 0.01ñ0.1 gigapascals (GPa), whereas the super-strong nano-composites have strengths over 2 GPa. An estimate of the theoretical limit of strength of Cu is ~4 GPa. Hence, these materials approach the theoretical limit of strength.
- Such mechanical response is not predicted by scaling laws developed for bulk, conventional metals. We are using atomistic simulations (molecular dynamics) to complement the experiments and gain insight on the new deformation physics. Defects such as dislocations are shown at the Cu-Ni interface.
