Nanomechanic Characterizations with High Pressure Techniques

Bin Chen^1,*, Xiaoling Zhou ¹, Jianing Xu¹, Hongliang Dong¹, Yanju Wang¹, Zongqiang Feng², Xiaoxu Huang²

¹Center for High Pressure Science and Technology Advanced Research, Pudong, Shanghai 201203, China

²International Joint Laboratory for Light Alloys (MOE), College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China

ABSTRACT: High pressure techniques have been introduced to nanomaterials research for about three decades. Most of the studies, especially in the earlier time, were mainly about the structural transition and equation of state with XRD, Raman and IR spectroscopy characterizations. In recent years, we extended the explorations for the plastic deformation of nanomaterials by employing radial diamond-anvil cell XRD and TEM. We have successfully probed the lower grain size limit of dislocation activities, but also seen that partial dislocations and deformation twinning dominate the plastic deformation below 20 nm. Our high-pressure studies reveal that dislocations are operative in nanoceramics. We have observed the reversal in the grain size dependence of grain rotation in nickel. It is detected that the strengthening of nickel nanocrystals can be extended down to 3 nm. Excitingly, we found that nanometals in a certain range of grain size exhibit both superplasticity and high strength. Compared with the traditional techniques, high pressure techniques are more advantageous in applying mechanical load to nanosized samples and characterizing the structural and mechanical properties in situ or ex situ, which could help unveil the mysteries of mechanics at the nanoscale and bridge the knowledge on the material mechanics at the multiscale. With these knowledge, more advanced materials could be fabricated for wider and specialized applications.