| With the rapid development of micro and nano technology, mechanical testing study on micro-nanoscale materials is getting more and more attention now. In all kinds of materials testing methods, Indentation/scratch test technology is extensively concerned to the domestic and foreign academic circles because of the advantages of its simple method, easy to do the sample preparation, high precision, can obtain rich material performance information. In recent years, with the development of science and technology, especially the continuously increasing requirement of the level of performance test for the materials, in situ nano-indentation testing technology arises at the historic moment. Currently, there are foreign commercialized in situ micro/nano-indentation/scratch equipment for sale, but difficulties are huge for the long period of importing, high prices, the core technology embargoes, also the limit for instrument structure, which lead to the commercial instrument is difficult to realize function extension. In view of this kind of problem, this paper designs an in situ nano-indentation/scratch test platform on the basis of a study to in situ nano indentation/scratch test technology, which can be applied to the material’s indentation/scratch performance tests. This device not only can obtain the load-depth curve during indentation, but also it could achieve the real-time normal force and tangential force during scratching process. The platform is integrated with precision scratch drive unit and large stroke scratch motion components in order to realize the drive of scratch test, with piezoelectric actuators as the indentation test precision drive loading unit. It detects the force in the process of indentation and the ruling force in the process of scratch through the precision three-axis force sensor.In the review of this paper, basing on analysis of the in situ nano-indentation/scratch test technology researches home and abroad, the current basic theory and data analysis methods of indentation and scratch testing are studied, and the factors which influence the indentation/scratch test are analyzed briefly. In combination with the work above, this paper carries out the design to the in situ nano-indentation/scratch test equipment, designs the structure of the precise scratching unit and the large stroke scratch motion components. And conducts finite element analysis to the key components. The results of the test of the key components show that the precision Scratch unit output a displacement of 12μm at the driving voltage of 100 V. Also, the results of the large stroke scratch motion components show that the speed of the moving components can reach 28.15μm/s while the driving situation is 5Hz and 60 V.This paper also conducts calibration analysis to each sensor in the device, as well as debugging and calibration of the developed in situ nano-indentation/scratch test device. Though the performance test of the testing devices after calibration, the paper concludes: indentation test load noise is less than 80μN, the noise of displacement is about 1nm. Output characteristic testing results of the motor movement adjusting unit turn out: When the motor speed is 3 pulses/s, the output of motor adjusting unit is about 4nm/s. And when the former rate is 20,000 pulses/s, the later output rate is about 26.1μm/s. Though The error analysis and correction of the testing device, the flexibility measurement results of the force sensor is 3.9nm/m N, while machine frame flexibility is measured to be 6.14nm/m N. The test of the standard fused silica sample shows that the test system has good performance in repeatability, resolution and precision.This paper uses the test device do indentation/scratch test on single crystal silicon and single crystal copper respectively, after which the indentations load-depth curve and scratch normal-tangential force curve are achieved. Then analysis the results according to the curves and the residual indentation/scratch morphology. Indentation test results show that the(100) crystal plane of single crystal silicon suffers more damage and the crack propagation is more serious under the same load. What’s more, indentation test results show that single crystal copper’s deformation has a certain direction and discontinuous loading will cause banding lines at the indentation position. Scratch test results show that single crystal silicon has the ductile-brittle transition during the whole process. When the normal force on single crystal silicon is low, ductility is the main removal mode. With the increase of the normal force, collapse broken is the main way of removing while the scratch force has a lager fluctuation. When it comes to single crystal copper scratch test, ductility is the main removal mode, the trench is smooth while the cutting swarf accumulate on both sides, and it produces a lateral flow phenomenon. |
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