Establishing Of Single Crystal Silicon Dynamic Indentation Experimental System And Research

Single crystal silicon is the semiconductor material which is used mostly in the present electronic industry, it play a very important role in the field of aviation-astronavigation, optics, electron and micro-electronics. The single crystal silicon is brittle material at the room temperature, its fracture toughness is very low and would have cracks and go to fracture, and thereby it is difficult to machine the single crystal silicon. With the technology advancing, the technique of the super-precision machining and super-precision grinding are developed so quickly. The indentation experiment is often used in studying the mechanics properties of the single crystal silicon material and analyzing its elastic-plastic transition and the mechanism of the cracks forming by static indentation experiment because it is similar with super-precision machining. The single crystal silicon bears very high strain rate during the super-precision machining process and bears very low stain rate during the static indentation experiment, so it is improper to use the conclusion which is obtained in the static indentation experiment to analyze the single crystal silicon machining.A suit of dynamic indentation experimental system is design and establish firstly in the country which is based on static indentation experimental theory and SHPB theory. It includes dynamic indentation experimental equipment, strain measuring circuit, data acquisition system. This system can be used to implement dynamic indentation experiment on the material surface. It can obtain the material's dynamic mechanics parameters and also obtain the plot of the material's dynamic stress-strain to analyze the material's dynamic plastic properties. It is concluded that the single crystal silicon's hardness under the dynamic indentation experiment is less than under static indentation experiment and the hardness obtained on the coarse surface is less than on the smooth surface. It is found that the great cracks on the coarse surface are initiated easily than on the smooth surface by the SEM observation and the crack size obtained at the dynamic indentation experiment is bigger than at the static indentation experiment under the same load. It is showed the single crystal silicon is easier to initiate the crack and fracture under dynamic load, the single crystal silicon's...