Relationship between pulsed laser energy and fracture mode in multiple-pulse laser shock bulging process

Author(s):  
Yan Li ◽  
Zheng Liu ◽  
Guoqun Zhao ◽  
Zhong Ji ◽  
Chao Zheng
2019 ◽  
Vol 46 (3) ◽  
pp. 0302004
Author(s):  
刘铮 Liu Zheng ◽  
郑超 Zheng Chao ◽  
宋立彬 Song Libin ◽  
季忠 Ji Zhong

RSC Advances ◽  
2017 ◽  
Vol 7 (59) ◽  
pp. 37296-37301 ◽  
Author(s):  
Xiaopeng Yang ◽  
Xiang Xu ◽  
Feng Liu ◽  
Liqiang Zhang ◽  
Ziwu Ji ◽  
...  

An ingenious method of preparation of ZnO homojunctions for on-chip integration purposes is proposed, by local multiple pulse laser irradiating (MPLI) ZnO:Na film (NZO).


2021 ◽  
Vol 11 (12) ◽  
pp. 5406
Author(s):  
Fei Yin ◽  
Xia Ye ◽  
Hongbing Yao ◽  
Pengyu Wei ◽  
Xumei Wang ◽  
...  

In order to study the spallation phenomenon of titanium alloy under the shock of nanosecond laser, the Neodymium-Yttrium-Aluminum Garnet laser was used to carry out laser shock experiments on the surface of titanium alloy. By observing and measuring the surface morphology of the target material, the forming factors and the changes of the surface morphology under different parameter settings, the forming criteria of the titanium alloy were obtained. The results show that under the single variable method, the change of laser energy can affect the target shape variable, and there is a positive correlation between them. When the thickness was greater than or equal to 0.08 mm, no obvious cracks were found in the targets. Moreover, the number of impact times was the key factor for the target deformation; with the growth of impact times, the target deformation gradually became larger until the crack appeared. The larger the diameter of the spot, the more likely the target was to undergo plastic deformation. The surface of titanium alloy with a thickness of 0.08 mm appeared to rebound under specific laser shock condition. The changes in the back of the target material were observed in real time through a high-speed camera, and the plasma induced by the laser was observed in the process. This study is based on the results of previous studies to obtain the titanium alloy forming criteria, which provides a basis for the setting of laser parameters and the thickness of the target when the nanosecond laser impacts the Ti-6AL-4V target.


1995 ◽  
Vol 395 ◽  
Author(s):  
R.D. Vispute ◽  
H. Wu ◽  
K. Jagannadham ◽  
J. Narayan

ABSTRACTAIN thin films have been grown epitaxially on Si(111) and Al2O3(0001) substrates by pulsed laser deposition. These films were characterized by FTIR and UV-Visible, x-ray diffraction, high resolution transmission electron and scanning electron microscopy, and electrical resistivity. The films deposited on silicon and sapphire at 750-800°C and laser energy density of ∼ 2 to 3J/cm2 are epitaxial with an orientational relationship of AIN[0001]║ Si[111], AIN[2 110]║Si[011] and AlN[0001]║Al2O3[0001], AIN[1 2 1 0]║ Al2O3[0110] and AIN[1010] ║ Al2O3[2110]. The both AIN/Si and AIN/Al2O3 interfaces were found to be quite sharp without any indication of interfacial reactions. The absorption edge measured by UV-Visible spectroscopy for the epitaxial AIN film grown on sapphire was sharp and the band gap was found to be 6.1eV. The electrical resistivity of the films was about 5-6×l013Ω-cm with a breakdown field of 5×106V/cm. We also found that the films deposited at higher laser energy densities ≥10J/cm2 and lower temperatures ≤650°C were nitrogen deficient and containing free metallic aluminum which degrade the microstructural, electrical and optical properties of the AIN films


1981 ◽  
Vol 4 ◽  
Author(s):  
Douglas H. Lowndes ◽  
Bernard J. Feldman

ABSTRACTIn an effort to understand the origin of defects earlier found to be present in p–n junctions formed by pulsed laser annealing (PLA) of ion implanted (II) semiconducting GaAs, photoluminescence (PL) studies have been carried out. PL spectra have been obtained at 4K, 77K and 300K, for both n–and p–type GaAs, for laser energy densities 0 ≤ El ≤ 0.6 J/cm2. It is found that PLA of crystalline (c−) GaAs alters the PL spectrum and decreases the PL intensity, corresponding to an increase in density of non-radiative recombination centers with increasing El. The variation of PL intensity with El is found to be different for n– and p–type material. No PL is observed from high dose (1 or 5×1015 ions/cm2 ) Sior Zn-implanted GaAs, either before or after laser annealing. The results suggest that the ion implantation step is primarily responsible for formation of defects associated with the loss of radiative recombination, with pulsed annealing contributing only secondarily.


Author(s):  
Shizhou Xiao ◽  
Rui Guo ◽  
Guanghua Cheng ◽  
Yalei Wu ◽  
Wenhao Huang ◽  
...  

In this paper, a novel PZT film patterning method by femtosecond laser is proposed. The method is different from traditional dry-etching and wet-etching technology. Femtosecond laser microfabrication technology has several advantages such as high resolution, no mask direct-writing and seldom-heating, etc. A two-layer (PZT thin film and substrate) heating and ablating threshold model is built and the relationship of PZT/Si two-layer system micro ablation morphology depending on laser pulse energy is constructed. From the model and experiment data, we obtain the suitable energy region to pattern PZT film freely without damage Si substrate. A 3μm resolution of PZT pattern is achieved in our experiment. In order to verify the fabrication available of this technology, several micro functional devices are successfully patterned by optimized femtosecond pulsed laser energy and their function are detected. The results prove that the PZT patterning quality is good.


Author(s):  
Guihua Lai ◽  
Siyuan Geng ◽  
Hanwen Zheng ◽  
Zhifeng Yao ◽  
Qiang Zhong ◽  
...  

Abstract The objective of this paper is to observe and investigate the early evolution of the shock wave, induced by a nanosecond pulsed laser in still water. A numerical method is performed to calculate the propagation of the shock wave within 1µs, after optical breakdown, based on the Gilmore model and the Kirkwood-Bethe hypothesis. The input parameters of the numerical method include the laser pulse duration, the size of the plasma and the maximally extended cavitation bubble, which are measured utilizing a high time-resolved shadowgraph system. The calculation results are verified by shock wave observation experiments at the cavitation bubble expansion stage. The relative errors of the radiuses and the velocity of the shock wave front, reach the maximum value of 45% at 5 ns after breakdown and decrease to less than 20% within 20 ns. The high attenuation characteristics of the shock wave after the optical breakdown, are predicted by the numerical method. The quick time and space evolution of the shock wave are carefully analyzed. The normalized shock wave width is found to be independent of the laser energy and duration, and the energy partitions ratio is around 2.0 using the nanosecond pulsed laser.


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