Simulation And Experiment Research On Nano Ceramic Machining Property

Nano ceramic not only possesses so many excellent properties, such as wear-resistance,corrosion resistance,retention at elevated temperature,high hardness and chemical stability, but also has more potential properties, such as ductile property and super-plasticity at a low temperature. The coming out of nano ceramics provides a new idea for the solution to the brittleness of ceramics. However, the research in nano ceramics has just been started and many parameters of material mechanical property are unknown. In this paper, elastic-plasticity and brittleness-ductility transition of the nano ZrO₂ ceramics are studied, in which the influencing factors of the finished surface quality are analyzed.Firstly, the sorts of hardness and the theory of nano indention are expatiated in detail, and several groups of nano indentation experiments are operated to the nano ZrO₂ ceramics and the elastic modulus, rigidity and load-displacement curve of nano ZrO₂ ceramics are obtained.Secondly, via the finite element simulation, the nano indention mathematic model is built which can simulate the stress variation of nano indentation experiments in loading and unloading process. Through fitting the load-displacement curves of the experiments and finite element simulation, if the results keep conformity, material plastic property is obtained.Thirdly, the removal mechanism and process of the nano ZrO₂ ceramics are analyzed. The grinding surface appearance is observed by the AFM when the semi-grinding experiments are operated, and when the cutting depth is 0.02mm, the chips are removed by the shape of brittleness-ductility, which can supply the experimental references for the cutting simulation.Finally, based on the obtained material parameters, the precise cutting simulation model of the nano ceramics is built up by the plane strain element. During the brittleness-ductility transition, the influencing factors of finished surface quality are simulated in the variable tool orthogonal rakes, rounded cutting edge radius, cutting depth, material defect and rate of cutting. The...