Using TEM, SEM and XRD, the surface microstructures of nanocomposite ceramics
prepared by heterocoagulation was studied in two-dimensional ultraprecision grinding with
ultrasonic assistance. This research was focused on the structure of ground surface degenerating
layer, surface generation mechanism and characteristics of nanocomposite ceramic parts. The
experimental results showed that the microscopic deformation mechanism of the ordinary Al2O3
parts was grain- boundary twinning and grain-boundary sliding while microscopic deformation
mechanism of nanophase ceramic parts was the inner crystal dislocation of strengthened phase with
intragranular structure. And its deformation coordination mechanisms were the grain-boundary
sliding and coordination deformation of intercrystalline second-phase.
The observation on the fracture surfaces of nanocomposite materials with different microscopic
structures by TEM and SEM showed that ZrO2 particles had an important effect on the generation
and expansion of crack in ceramic parts. The introduction of ZrO2 particles strengthened the
interface intensity of grain boundary. If there were rich ZrO2 particles on the grain boundary, the
cracks generated during the grinding process would be prevented. Smooth and plastic deformation
processing surface was obtained. It was proved further that the nanophase materials behaved
transcrystalline fracture due to the nano particles, dispersed in the grain boundary and prevented the
expansion of crack. This material’s fracture behavior made favorable surface possible. In the
precise grinding of nano materials, the plastic removal mechanism dominated the process. The
dislocated depth of the nanocomposite ceramics after grinding was bigger than that of common
ceramics, which meant that dislocation increased.
Publisher's Note: “Non-monotonic dependence of the conductivity of carbon nanotube-filled elastomers subjected to uniaxial compression/decompression” [J. Appl. Phys. 113, 103706 (2013)]
