Surface Intergrity Of Acoustic Levitation Polishing Process

Nanomechanical is not only an important parameter to evaluate the properties of Nanomaterials, but also the key direction to research the Nano-technology. The USA puts forwards to the three development prospects for the Nanotechnology,which two has been the relationship to the Nanomechanicals. In this field, the Nanomechanical measurement technique is an important branch, especially the mechanical measurement,and the high-quality nano sample is the key point to the measurement.Hence,how to prepare for the ultra-smooth,with little or no damage surface is the key technical problems of the nanoindentation/scratch test.On the one hand, nanoindentation tests require the sample to calibrate the instrument, on the other hand, the sample with little or no damage surface is the basic guarantees of the high reliability, reproducibility by nanoindentation tests. This paper puts forwards to a new polishing method-acoustic levitation polishing.Through this polishing way, the surface could be produced super smooth and low residual stress,and the anti-elasticity and deformation capacity is enhanced. This research involves:(1) The material removal mechanism of acoustic levitation polishing has been revealed, the ultrasound radiation force of ultrasound and the ultrasound cavitation effect on the abrasive has been analyzed. At the same time, through abrasive kinetic which overcome the force between the workpiece to achieve material removal has been analyzed.(2) The single abrasive impacts on the surface of the specimen has been simulated by the software ABAQUS, the stress relaxation of the surface which is acted by acoustic levitation polishing has been elaborated. The impacts of different velocities and angles covering the whole surface has been further analysis, the stress relaxation process law which is acted by the impact load was revealed,and using the random impacts on the surface has been simulated to the stress relaxation process.at last, the surface stress which has been experienced by the acoustic levitation polishing has been measured by the XRD. The experiment has been showed that the acoustic levitation could meets the needs to the sample of nanoindentaton tests,which the stress of the surface is low.(3) The sample process of the smooth surface has been acted by mechanical chemical polishing, at last, the ultra-smooth surface with little or no damage has been acted by the acoustic levitation polishing, the elastic modulus and the hardness of the different process has been made uses of nanoindentation tests. The surface morphology and lattice distortion of subsurface of which t samples before and after process has been tested by TEM, and the acoustic levitation polishing which has the capacity to get atomic-level ultra-smooth surface and with little or no damage surface has been verified.