| With the development of science and technology,brittle materials are used in the national defense industry,aerospace industry and electronic information industry.But fragility,thermal ablation,recast layers and other quality problems are arising in processing the brittle materials for its inherent characteristics,affecting further application and development.In this dissertation,Drilling of alumina ceramic without recast-layer and direct-welding of glass by the ultrafast laser micro-processing system is studied.A study adopted by picosecond pulsed laser with 1064 nm wavelength as the light source.Different methods were set up such as laser drilling in air and water separately,and series experiments of laser drilling alumina ceramic were carried out in this dissertation.The effects of single pulse energy,scanning times and other laser parameters on the size of hole diameter,taper angle and recast layer were investigated systematically,and the mechanism of two methods abovementioned were discussed and analyzed.The way of melt expel from hole,the change of water quality parameters and the intense impact effect of bubbles generated by liquid cavitation were discussed as well.High quality holes were realized successful with no recast layer and small taper in water assisted laser drilling.Next a series of experimental studies on micro-welding of soda-lime glass were carried out by using picosecond laser and galvanometers scanning technique.The effect of single pulse energy,pulse repetition frequency,scanning times and o verlap rates on welding quality of glass was studied on shear strength,sealing property and water resistance.And the relationship between the primary and secondary factors and the significant degree of different laser processing parameters were calculated and obtained by orthogonal experimental.In view of the interdependence of the influence of each laser parameters on weld quality,the average fluence Favg was put forward as a useful integrated measurement.It was found that the Favg in the range of 0.199J/mm2 to 0.269J/mm2,the welding seam had high shear strength,excellent sealing and water resistance,and the maximum shear strength can reach 19.4MPa.In the focal area at the glass interface,the surrounding ellipse-shape extended along the optical axis was observed and in the bottom was a teardrop-shaped region.In the weld profile,a significant thermal melting zone and micro-void structure were found. |
