Loading Rate Effect on Nanoscale Plasticity in MgO Doped Alumina

Abstract

Abstract: Here we report for the very first time the effect of loading rate on nanoscale plasticity in 1-5 wt.% MgO doped Alumina (MA) ceramics. All samples are characterized by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Nanoindentation (NI) techniques. The experimentally measured load versus depth plots confirm the profuse signature of nanoscale plasticity through ‘micro-pop-in’s. The results show both critical load and critical depth are sensitive functions of the loading rates and the amount of sintering aids. Further, the nanoscale hardness is also found to be strongly affected by the loading rates. The occurrence of nanoscale plasticity or micro-pop-in is explained by the generated maximum shear stress inside the nanoindentation cavity.