Characteristics Hardness About Layered Thick Al Film Based On Nanoindentation Technology

This paper has made further research to the hardness test and its influencing factors about layered thick Al film with echelle grating.Because echelle grating has a lot of advantages,like high diffraction orders,wide spectral range,high dispersion,so,echelle grating is widely used in spectroscopy detection.Because of the structural characteristics of echelle grating,such as deeper groove depth and Wider groove width,the echelle grating must be prepared by mechanical ruling.The preparation process is using tool successive ruling thick Al film.The thick Al film will produe periodic structure.In order to obtain high quality aluminum film,the process of step-by-step evaporation makes the inner layer of Al film appear.Preliminary theoretical and technological research results show that: If the hardness of Al film is too hard,tool will be severe wear in the process;If the hardness of Al film is too soft,the groove shape is imperfect.Especially for the preparation of large area echelle grating,the hardness is not only an important index to evaluate the quality of evaporation Al film,but also an important factor to influence the ruling process.Therefore,obtaining the true hardness of the layered thick Al film is helpful to the optimization of evaporation process and ruling process.At the same time,it is of great significance for the crystal structure design of the ruling tool to obtain the internal hardness variation characteristics of the layered thick Al film.The research object is thick layered Al film that is used in producting 79g/mm echelle grating.The hardness of Al film prepared by different evaporation process parameters was determined,for the first time,the calculation method of the hardness of layered thick Al film is revised,The hardness characteristics and test influencing factors of layered thick Al film were studied systematically.Based on nanoindentation theory and experimental technology,The characteristics and applicability of the hardness calculation methods(O&P and indentation work)in the hardness testing of layered thick Al film are analyzed and summarized.According to the characteristics of pile-up phenomenon during testing,the calculation method of projected contact area in O&P method is revised.This work make O&P method is more accurate.Based on the principle of volume invariance,the calculation method of plastic deformation volume in indentation work is corrected;the advantage of numerical integrals is used in processing large amounts of data,this work have improved the accuracy of the plastic work calculation,and made the indentation work more accurate characterization of the hardness of layered thick Al film.These works provide an accurate hardness testing method for practical engineering applications.During the test,due to the size effect and substrate effect,the test results will deviate from the real value.For the impact of both,this paper made clear the law of their influence on the hardness testing.In this paper,the accurate characterization model and the pressure interval to avoid the influence are obtained,and analyzes the reasons for the influence bytest and finite element simulation.In this paper,the influence of microstructure(grain size and layer number)on the thickness of Al film is discussed.The results of this paper provide an accurate hardness calculation method for the hardness test of the layered thick aluminum film with echelle grating.The hardness of layered thick aluminum film was tested.The reason and rule of size effect and base effect on the test results are clarified.The influence of microstructures on the representation of size effect and base effect and the rule of avoidance interval are studied.The results of this paper can also be used for reference for the crystal structure design of cutting tools and for reference for the optimization of ruling technology and evaporation technology.