Laser shock peening is a modernized surface enhancement performed methodically to improve fatigue life, enhance the hardness of the material and make coarse grains flat under the superficial layer. In this current stu...Laser shock peening is a modernized surface enhancement performed methodically to improve fatigue life, enhance the hardness of the material and make coarse grains flat under the superficial layer. In this current study, the effect of varying optimized multiple laser shock peening (LSP) is studied on the surface integrity, microhardness, and mechanical properties. The results show that the LSP-treated specimens have visible signs of valleys, wavy and varying height distribution as well as dimples. However, the presence of non-uniformity and sharp protrusions was detected from the superficiality of the as-received specimen and this was so because of the SiC abrasive material used to polish the superficial layer of the specimen before the test experiment. Prior to LSP, the surface roughness was 2 μm, however, after LSP the roughness increased to 4 μm, 6 μm and 17 μm for 1, 2, and 4 impacts, respectively. High-density dislocation can also be observed close to the grain boundary because the grain boundary prevents the migration of dislocation which could lead to dislocation walls and dislocation tangles. The increase in impacts decrease the average grain size, nevertheless, the micro-strain increased after multiple impacts. Furthermore, coarse grains after LSP were transformed into finer grains. The increase in the number of impacts increases the micro-strain likewise the full-width half maximum (FWHM). Finally, the increase in microhardness increases as the LSP impacts increase.展开更多
Ionic liquids have attracted a lot of research attention for their applications in novel optoelectronic structures and devices as an optical means of regulating electricity. Although the electro-optic effect of ionic ...Ionic liquids have attracted a lot of research attention for their applications in novel optoelectronic structures and devices as an optical means of regulating electricity. Although the electro-optic effect of ionic liquids is mentioned in some literature, quantitative testing and analysis are hardly found in light absorption coefficients of ionic liquids under an electric field. In the present study, an experimental apparatus is designed to measure the absorption coefficients of ionic liquids under different electric fields. Five groups of imidazole ionic liquids are experimentally investigated and an inversion is performed to determine the spectral absorption coefficients of the imidazole ionic liquids under the electric fields. Different intensities with multiple interface refractions and reflections are also considered, and the various measurement errors are analyzed through uncertainties propagation analysis. Spectral absorptions of ionic liquids from 300 nm to 2500 nm are obtained and the absorption coefficients are retrieved. It is found that the absorption behavior of ionic liquids changes in some frequency bands under an applied electric field. The experimental results show that the absorption coefficient of the ionic liquid increases with the voltage increasing at 1520 nm and 1920 nm. The change rate is affected by the types of anions and cations in the ionic liquid and the diffusion rate of the ions therein. This study provides illustrations for the ionic liquid-based electro-optical regulation in terms of physical property parameters and the testing technique.展开更多
文摘Laser shock peening is a modernized surface enhancement performed methodically to improve fatigue life, enhance the hardness of the material and make coarse grains flat under the superficial layer. In this current study, the effect of varying optimized multiple laser shock peening (LSP) is studied on the surface integrity, microhardness, and mechanical properties. The results show that the LSP-treated specimens have visible signs of valleys, wavy and varying height distribution as well as dimples. However, the presence of non-uniformity and sharp protrusions was detected from the superficiality of the as-received specimen and this was so because of the SiC abrasive material used to polish the superficial layer of the specimen before the test experiment. Prior to LSP, the surface roughness was 2 μm, however, after LSP the roughness increased to 4 μm, 6 μm and 17 μm for 1, 2, and 4 impacts, respectively. High-density dislocation can also be observed close to the grain boundary because the grain boundary prevents the migration of dislocation which could lead to dislocation walls and dislocation tangles. The increase in impacts decrease the average grain size, nevertheless, the micro-strain increased after multiple impacts. Furthermore, coarse grains after LSP were transformed into finer grains. The increase in the number of impacts increases the micro-strain likewise the full-width half maximum (FWHM). Finally, the increase in microhardness increases as the LSP impacts increase.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51576054 and 51705210)
文摘Ionic liquids have attracted a lot of research attention for their applications in novel optoelectronic structures and devices as an optical means of regulating electricity. Although the electro-optic effect of ionic liquids is mentioned in some literature, quantitative testing and analysis are hardly found in light absorption coefficients of ionic liquids under an electric field. In the present study, an experimental apparatus is designed to measure the absorption coefficients of ionic liquids under different electric fields. Five groups of imidazole ionic liquids are experimentally investigated and an inversion is performed to determine the spectral absorption coefficients of the imidazole ionic liquids under the electric fields. Different intensities with multiple interface refractions and reflections are also considered, and the various measurement errors are analyzed through uncertainties propagation analysis. Spectral absorptions of ionic liquids from 300 nm to 2500 nm are obtained and the absorption coefficients are retrieved. It is found that the absorption behavior of ionic liquids changes in some frequency bands under an applied electric field. The experimental results show that the absorption coefficient of the ionic liquid increases with the voltage increasing at 1520 nm and 1920 nm. The change rate is affected by the types of anions and cations in the ionic liquid and the diffusion rate of the ions therein. This study provides illustrations for the ionic liquid-based electro-optical regulation in terms of physical property parameters and the testing technique.
