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激光感应复合熔覆的稀释率分析模型及实验研究 总被引:1,自引:0,他引:1
在分析计算感应加热温度模型和激光感应复合熔覆能量作用的基础上,推导出了激光感应复合熔覆稀释率的表达式,定量反映了稀释率与激光、感应能量、材料特性和工艺参数之间的关系,并且通过实验进行了验证。研究结果表明:复合熔覆的稀释率随激光功率的增加而增大,随送粉率的增加而减小,随扫描速度的增大而减小;在其他参数恒定,感应能量增加时,稀释率显著增大。该稀释率分析模型有助于复合熔覆加工中稀释率的控制,为复合熔覆工艺参数的优化设计和熔覆层的质量控制提供了理论基础。 相似文献
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飞秒激光微加工Au膜 总被引:2,自引:0,他引:2
飞秒激光微加工薄膜对于MEMS设备的制造是一个急需的技术。文章使用波长为775 nm的Ti: sapphire飞秒激光器(脉宽约为130 fs, 频率为1 000 Hz)研究厚度为4 μm的Au薄膜,在不同加工参数下的结构特性,发现单脉冲消融时消融直径随着脉冲能量的增大而增大。当单脉冲能量一定时,消融直径随着脉冲的个数变化不大。计算得到Au膜的单脉冲消融阈值为Fth=0.7 J·cm-2,使用脉冲能量略大于阈值时,在薄膜上所划出的线为凸起状;当超过阈值时所得直线为凹起状。同时发现在脉冲能量一定时所得线宽随着加工速度的增加而减小;当加工速度一定时线宽随着能量的增加而增大。 相似文献
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主要研究面曝光选区激光熔化单层成形时,激光光斑搭接率和电流对形状精度的影响。实验通过控制变量法研究搭接率、曝光时间、电流等工艺参数对激光光斑、熔道、圆环、尖角等成形形状精度的影响。实验结果表明:一定范围内,电流越大,激光光斑更均匀,成形一致性更好;搭接率38.4%能够获得最低的形状误差的熔道;搭接率一定,圆环成形误差随电流的增加而增加;尖角成形误差随着电流增加,呈现先增后减的趋势;搭接率为46.1%、38.4%时,零级衍射带来的形状误差降低。 相似文献
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采用环形再生腔结构的啁啾脉冲放大技术方案, 在重复频率100 Hz,单脉冲能量33.1 mJ的532 nm激光抽运下, 从钛宝石激光中获得了单脉冲能量9.84 mJ的放大输出, 对应的斜效率达33.1%.在重复频率10 Hz的情况下, 同样获得了单脉冲能量为9.64 mJ, 对应斜效率达36.8%的高效率放大结果. 通过色散补偿压缩该啁啾激光脉冲后的单脉冲能量为6.36 mJ, 脉冲宽度为59.7 fs. 测量结果表明典型的能量不稳定度为1.85%.
关键词:
啁啾脉冲放大
再生放大
飞秒激光
环形腔 相似文献
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《光学学报》2010,(9)
热效应是限制高能激光输出性能的重要因素之一,液体激光体系在此方面具有特殊的优势。开展了二极管抽运无机液体激光器的流动出光实验,实现了流动状态下较长时间高重复频率的激光脉冲输出。测量了激光光谱、激光脉冲波形和单脉冲激光能量等参数,其中激光中心波长为1052.7nm,脉宽约为170μs,最大单脉冲能量约为5mJ。在抽运频率400Hz时可连续工作10min以上。但随着抽运频率上升,激光脉冲能量相应下降。结果表明,二极管抽运的无机液体激光体系在流动状态下能有效地避免热沉积,从而实现较长时间、高重复频率的激光脉冲输出,有望发展成为新型高功率、高光束质量激光体系,值得开展深入的实验研究。 相似文献
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研制了大能量高光束质量短脉冲激光器,系统采用主振荡+预放大器+主放大器2级主振荡功率放大器(MOPA)结构。采用双棒热效应补偿改善光束质量的措施,在重复频率400 Hz时实现单脉冲能量40 mJ、光束质量因子约为1.2的激光输出。激光器放大后实现单路脉冲能量712.5 mJ、脉宽12.4 ns的激光输出,采用球差补偿的方法提高了激光器的光束质量,在最大输出功率下实现了光束质量因子小于2.3,光光效率27.7%。偏振合束后,激光器输出能量大于1.4 J。 相似文献
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This paper presents a pulsed Nd: YAG laser-robot system for spot and seam welding of mild steel sheets. The study evaluates the laser beams behaviour for welding, and then investigates pulsed Nd: YAG laser spot and seam welding processes. High pulse power intensity is needed to initiate the key-hole welding process and a threshold pulse energy to reach full penetration. In seam welding, a weld consists of successive overlapping spots. Both high pulse energy and high average power are needed to keep the key-hole welding going. A 70% overlap is used to define overlapping spot welding as seam welding and to optimize process parameters because a high tensile strength joint compatible with the strength of the base material can be obtained when the overlap is ≥70%; at the same time a smooth seam with full penetration is obtained. In these cases, the joints in pulsed Nd: YAG laser welding are comparable in strength to those obtained with CO2 laser welding. Robot positioning and motion accuracies can meet the demands of Nd: YAG laser sheet metal welding, but its cornering accuracy affects the welding processes. The purpose of the study is to evaluate the YAG laser-robot system for production in the automotive industry. 相似文献
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Y. Matsuoka K. Wake T. Nagashima N. Iehisa 《Applied Physics A: Materials Science & Processing》2007,87(1):81-85
Ablation processing of borosilicate glass was carried out using the fourth harmonic of the Q-switch Nd:YAG laser. The dependency
of the ablation depth on irradiation pulse energy density and the dependency of the ablation depth on irradiation spot size
were investigated. The average ablation depth increased with an increase in irradiation pulse energy density. When the irradiation
pulse energy density was the same, the ablation depth of the focused beam with a large spot diameter was deeper than that
of the focused beam with a small spot diameter. To shorten the processing time, an increase in the irradiation pulse energy
density and use of a large spot size focused beam are effective. Using area scanning together with line scanning, a rectangular
through hole (sub-mm size) without cracks or chips was formed in borosilicate glass of 140 μm in thickness.
PACS 52.38.Mf; 42.70.Ce; 42.62.Cf 相似文献
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A.H. Wang W.Y. Wang Z.K. Bai C.S. Xie D.W. Zeng W.L. Song 《Optics & Laser Technology》2007,39(4):840-845
An Au-coated Fe–Ni alloy thin plate was laser drilled by a pulsed Nd:YAG laser. The influences of laser parameters on the diameter of perforation, the outer diameter of crater and the roundness of the perforation have been investigated by employing scanning electron microscopy. The diameter of perforation increases gradually with an increase in pulse width from 0.3 to 8 ms at the fixed average laser power and frequency, and increases with an increase in average laser power from 10 to 25 W at the fixed pulse width and frequency. Some craters are found around the perforations because of the heat affecting of laser beam to the non-irradiated zone. The diametric difference of the perforation between the incident and the effluent sides is very small under the shortest pulse width of 0.3 ms. Good roundness of the perforation can be achieved at either the lowest pulse width or the lowest laser power. 相似文献
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报道了一种腔内六棒串接的脉冲Nd:YAG激光器。采用44矩阵对晶体棒失调角度对谐振腔光轴的影响进行了理论分析,给出了六棒串接脉冲激光器中晶体棒失调角度的允许范围。在串接实验中,谐振腔采用对称平平腔结构,通过调整每根晶体棒的失调角度到允许范围内,实现了六棒串接脉冲Nd:YAG激光器。在输入电功率86 kW,占空比17%时,获得了平均功率3 018 W的脉冲激光输出,峰值功率17.75 kW,最高单脉冲能量为66 J,光束参数乘积为26.3 mmmrad,电光转换效率3.5%,长时间工作不稳定性小于2%。 相似文献
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A laser diode (LD) pumped Nd:YAG red pulse laser at 660 nm was presented by V:YAG passively Qswitching and LBO intracavity frequency doubling. With 1.6-W incident pump power, average output power of 46-mW, pulse duration (FWHM) of 23.3 ns, pulse repetition rate of 21.6 kHz, peak power of 91.4 W, and single pulse energy of 2.13μJ were obtained. The beam quality factor M2 was less than 1.2. The fluctuations of pulse energy and repetition rate were less than 3% in 4 hours. The pulsed laser at 660 nm is expected to be used as the pump source of Cr3+:doped crystal to obtain the gain-switched tunable laser. 相似文献
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对激光二极管端面泵浦Cr4+∶YAG被动调Q Nd∶YAG激光器输出特性进行了实验研究.实验研究发现,激光器输出功率及脉冲重复频率随谐振腔长度增大而增大.为解释这一实验现象,测量了泵浦光斑在激光晶体内尺寸,同时计算了激光晶体及Cr4+∶YAG晶体内的基模激光光斑半径随谐振腔长度变化.分析结果表明:激光晶体内泵浦光斑尺寸远小于激光晶体内基模光斑半径,腔模间交叠效率较低;当腔长增加时,激光晶体内的基模激光光斑减小,腔模间交叠效率增加,从而导致输出功率及脉冲重复频率随腔长增加而增加;另外,Cr4+∶YAG晶体内光斑半径也随谐振腔长度减小,引起Cr4+∶YAG晶体漂白时间缩短,导致脉冲重复频率随腔长增加而增加. 相似文献
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采用YLSS-M60U型高能Nd:YAG激光器,对发动机高压涡轮叶片材料K403/K3铸造高温合金试片进行激光冲击强化处理,强化工艺参数为:激光能量3J,光斑直径2.6mm,脉宽20ns,波长1064nm,吸收保护层为铝箔,约束层为水,搭接率50%,冲击3次。强化后,在420MPa应力水平下进行了室温高周振动疲劳测试,并进行了扫描电镜观察和X射线衍射仪物相分析。研究结果表明:激光冲击强化后,试片疲劳寿命是原始状态试片寿命的2.4倍,激光冲击强化的强冲击波作用使金属发生高应变率塑性变形,以及随之产生的较大较深残余压应力,是金属疲劳性能提高的主要原因。 相似文献
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对激光二极管端面泵浦Cr4+:YAG被动调QNd:YAG激光器输出特性进行了实验研究.实验研究发现,激光器输出功率及脉冲重复频率随谐振腔长度增大而增大.为解释这一实验现象,测量了泵浦光斑在激光晶体内尺寸,同时计算了激光晶体及Cr4+:YAG晶体内的基模激光光斑半径随谐振腔长度变化.分析结果表明:激光晶体内泵浦光斑尺寸远小于激光晶体内基模光斑半径,腔模间交叠效率较低;当腔长增加时,激光晶体内的基模激光光斑减小,腔模间交叠效率增加,从而导致输出功率及脉冲重复频率随腔长增加而增加;另外,Cr4+:YAG晶体内光斑半径也随谐振腔长度减小,引起Cr4+:YAG晶体漂白时间缩短,导致脉冲重复频率随腔长增加而增加. 相似文献
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Progress in material research and processing industry is fueled by the technique of pulsed laser deposition (PLD).
High energy excimer lasers enable this technique since every material is amenable to their high photon energies. Spectral
properties, temporal pulse and laser beam parameters of state of the art excimer lasers will be compared with frequency converted
Nd:YAG lasers.
Both quality and longevity of the deposited layers strongly depend on the degree of accuracy achieved in the thin film ablation
and subsequent deposition process. 相似文献
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A High-Energy Good-Beam-Quality Krypton-Lamp-Pumped Nd:YAG Solid-State Laser with One Pump Cavity 下载免费PDF全文
We investigate a high-energy good-beam-quality krypton-lamp-pumped pulsed Nd: YA G solid-state laser with one pump cavity. The symmetrical resonator laser is developed and is rated at 80 J with beam parameter product 12mm mrad. The total system electro-optics efficiency of the lamp-pumped YAG laser is as high as 3.3% and the stability of output energy is ±2% with pulse width tunable between 0.1 ms and 10ms. The experimental results are consistent with the theoretical analysis and simulation. 相似文献