Experimental Study Of Micro And Nano Scale Contact Mechanical Behavior

Micro and nano scale contact surface is apt to cause adhesion and abrasion; it is resulting in micro-electromechanical systems produce severe adhesion, friction and abrasion problems. It is the main factor to lead a micro-mechanical system failure in the manufacture and use; it is also an important issue to be solved in micro and nano-mechanica.This topic is selected from the National Natural Science Foundation of China:"Study on methods of multiscale coupling analysis on contact mechanical behavior of Micromechine friction pair". First analyze the micro-and nano-scale theory of contact mechanics, and use the nano-indentation and atomic force microscopy, spherical plane type of micro-mechanical friction pair formed between the cantilever and the specimen. Then experimental through the probes with different crystal orientation of the specimen samples surface contact between the mechanical behaviors and experimental of contact slip dynamic behavior, then use the last use of atomic force microscope scanning pressure, scratches, observation of the specimen surface morphology. Finally, we use Matlab software to analyze experimental data, draw displacement-load curve and sliding distance-friction curve, calculated hardness, modulus and other mechanical properties, analyze the experimental data and surface topography after atomic force microscopy scanning then draw the relevant law:(1) By analyzing the displacement-load curve and found that the more obvious drang and creep in contact mechanical behavior during the experiment, mainly due to the material internal structure changes, such as lattice deformation, lattice reconstruction, and so on. Moreover, in the course of the experiment, the hardness values and the elastic modulus is different in the type of grain to the specimen.(2) Observed the indentation pictures of three crystals to single-crystal silicon specimens, it can be found the elastic-plastic deformation under the specimen in the indentation depth is less than1000nm; crack around the indentation under the pressure deep1000nm; there is a clear brittle fracture under the pressure deep2000nm. Observed the indentation pictures of three crystals to single-crystal silicon specimens, it can be found, and there is no crack or brittle fracture around the indentation in contact mechanics behavior during the experiment. It is found that due to the good ductility of copper, less elastic recovery after disengagement.(3) It can be found the friction not constant during the sliding contact experiment after compare the curve of the three crystal to a single crystal silicon specimen in case of the sliding distance of the type of load and the type of speed and the sliding distance of the three crystal orientations of the single crystal copper specimen. With the case of the same load, the faster of the speed, the smaller of the relative volatility; the type of grain to the specimen curve is different and not a smooth one when the load and speed are the same; in case of the larger of the load and the faster of the speed, the smaller of the fluctuations of the friction between the probe and the specimen, the smaller of the adhesion role.