The Development And Implementation Of In Situ Micro Indentation Instrument

With the development of science and technology,the micro scale indentation test has gradually become the standard test to study the mechanical properties of different materials,and is widely used in the fields of material surface engineering,the cermet testing,microelectronic devices,bioengineering and medical materials,semiconductor research and development.Compared with the traditional mechanical property testing methods,micro indentation experiment has the characteristics of simple operation,simple sample preparation,rich testing content and micro damage.It has been widely used to test the hardness,modulus,stress-strain curve,fracture toughness and creep relaxation of materials.According to the characteristics of nano indentation instrument produced in the market and the nano indentation technology applied,a micron scale indentation text instrument is designed and developed.The structure design of indentation instrument and the design of measurement and control software are completed.The components and the whole of indentation instrument are analyzed,and the reliability analysis of typical material indentation test is completed.The main contents are as follows:(1)According to indentation test method,the Oliver-Pharr theory for obtaining the mechanical property parameters of materials and the theoretical method for the obtaining the fracture toughness of material surface and interface are expounded.The factors influencing the determination of material mechanical property parameters are systematically analyzed.Based on the finite element software,the influence of the instrument tilt angle on the measured material mechanical parameters under different indenter is explored.(2)The structure design of micro indentation equipment is carried out,and the selection of each part is carried out.Then,the applicability of each part is tested and analyzed.The modal analysis of the core components and the whole structure of the indentation instrument is carried out to determine its stability.The test results show that all parts of the instrument meet the test requirements,and the overall structure of the instrument is stable and reasonable.(3)According to the structure property and test function of the indentation text instrument,the sensor and other core components of the indentation instrument are calibrated and debugged,and the closed-loop control,the repeatability and calibration of test results are completed.The reliability of different material was analyzed based on the calibrated indentation instrument.The indentation test was carried out with aluminum,copper and tungsten with different hardness gradients,and the fracture toughness of zirconia ceramic material was tested.