Surface microstructure of nano-composite ceramics prepared by mixed coherence system
and machined by two-dimensional ultrasonic precision grinding was researched using TEM, SEM,
XRD detector and other equipments. Structure, formation mechanism and characteristic of
metamorphic layer of ground surface of nano-composite ceramics were researched. The experiment
shows micro deformation mechanism of ceramic material in two-dimensional ultrasound grinding is
twin grain boundary and grain-boundary sliding for Al2O3, and it is crystal dislocation of enhanced
phase, matrix grain boundary sliding, coordination deformation of intergranular second phase as well
as its deformation mechanism for nano-composite ceramics. The fracture surfaces of nano-composite
materials with different microscopic structure were observed using TEM and SEM. Research shows
that ZrO2 plays an important influence on the generation and expansion of crack, and enhances the
strength of grain boundaries. When grain boundaries is rich in the ZrO2 particles, the crack produced
in grinding process will be prevented, and the surface with plastic deformation will be smooth. The
results shows nanoparticles dispersed in grain boundary prevents crack propagation and makes
materials fracture transgranularly which makes the processed surface fine.
Shrinkage mechanisms of grain boundary loops in two-dimensional colloidal crystals
