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AlPO <sub/>4</sub> in Silica Glass Optical Fibers: Deduction of Additional Material Properties
摘要： A silica clad optical ?ber with a core comprised of SiO2, P2O5, Al2O3, and AlPO4 is analyzed in order to determine the impact of AlPO4 when added to silica. A chromatic dispersion curve is presented, from which the nonlinear refractive index is estimated to be similar to that of silica. When doped into SiO2, AlPO4 decreases the thermo-optic coef?cient (slightly), decreases the acoustic velocity, broadens the Brillouin spectral width through increased viscoelastic damping, and reduces the strength of the dependence of Brillouin frequency on temperature. Findings herein indicate that AlPO4 has a near-zero value of p12. It also is found that the ?ber does not have complete AlPO4 formation, with some P2O5 formation in Al2O3-rich regions of the ?ber. Given the relevance of AlPO4 to high power active ?ber technology, the presented data can be used for designing ?bers with enhanced performance characteristics, such as those with elevated threshold for the onset of stimulated Brillouin scattering.
关键词： Fiber optics,phosphorus,aluminum,?ber lasers,?ber nonlinear optics,optical materials,optical ?ber testing,glass
更新于2025-09-11 14:15:04
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Radiation Hardness of Perovskite Solar Cells Based on Aluminum‐Doped Zinc Oxide Electrode Under Proton Irradiation
摘要： Perovskite solar cells (PSCs) have gained increasing interest for space applications. However, before they can be deployed into space, their resistance to ionizing radiations, such as high-energy protons, must be demonstrated. Herein, the effect of 150 keV protons on the performance of PSCs based on aluminum-doped zinc oxide (AZO) transparent conducting oxide (TCO) is investigated. A record power conversion efficiency of 15% and 13.6% is obtained for cells based on AZO under AM1.5G and AM0 illumination, respectively. It is demonstrated that PSCs can withstand proton irradiation up to 1013 protons cm?2 without significant loss in efficiency. From 1014 protons cm?2, a decrease in short-circuit current of PSCs is observed, which is consistent with interfacial degradation due to deterioration of the Spiro-OMeTAD holes transport layer during proton irradiation. The structural and optical properties of perovskite remain intact up to high fluence levels. Although shallow trap states are induced by proton irradiation in perovskite bulk at low fluence levels, charges are released efficiently and are not detrimental to the cell’s performance. This work highlights the potential of PSCs based on AZO TCO to be used for space applications and gives a deeper understanding of interfacial degradation due to proton irradiation.
关键词： space,aluminum-doped zinc oxide,perovskite solar cells,proton irradiation
更新于2025-09-11 14:15:04
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Light Metals 2015 (Hyland/Light) || SiC Particle Detection in Liquid Aluminum via Laser Induced Breakdown Spectroscopy
摘要： Aluminum alloy castings are becoming commonplace for critical applications in the automotive and aerospace industries where materials failure is not an option. Tight control over cleanliness of the melt (mitigation of solid particle inclusions and dissolved gases) and microstructure must be achieved. Very few techniques exist that can quantitatively measure inclusion levels in-situ. The use of laser-induced breakdown spectroscopy (LIBS) has shown promise as a technique to quantify solid particles, wanted and unwanted, in aluminum melts. SiC particles were added to pure aluminum and analyzed with LIBS, and traditional metallography. An algorithm, based on the Nalimov test, was used to differentiate between LIBS signal from the matrix and particles. Initial tests show a linear relationship between SiC concentration and LIBS signal.
关键词： Inclusions,LIBS,Metal Cleanliness,Liquid Aluminum
更新于2025-09-11 14:15:04
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Pore Closure Effect of Laser Shock Peening of Additively Manufactured AlSi10Mg
摘要： This article reports on an exceptional insight provided by nondestructive X-ray tomography of the same samples before and after laser shock peening (LSP). The porosity in two additively manufactured aluminum alloy (AlSi10Mg) tensile samples before and after LSP was imaged using identical X-ray tomography settings and overlap of the data was performed for direct comparison. The results indicate clearly that near-surface pores are closed by the process, while internal pores remain unaffected. LSP has become well known as a method to improve the fatigue properties of materials, including those of additively manufactured aluminum alloys. This improvement is usually attributed to the compressive residual stress induced by the process. The additional effect of closure of near-surface pores that is illustrated in this work is of interest for additive manufacturing because additive manufacturing is not yet able to produce completely pore-free components. Since the critical pore initiating fatigue cracks are always attributed to surface or subsurface pores, the closure of these pores may play an additional role in improving the fatigue properties. While more work remains to unravel the relative importance of near-surface porosity compared to the compressive residual stress effect, this work clearly shows the effect of LSP—closing of pores near the surface. For the processing conditions demonstrated here, all pores up to 0.7 mm from the surface are closed without damaging the surface, while higher peening power results in surface damage.
关键词： additive manufacturing,laser shock peening,X-ray tomography,aluminum alloys,laser powder bed fusion
更新于2025-09-11 14:15:04
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Ring-like laser spot welding of Ti grade2 to AAl3105-O using AlSiMg filler metal
摘要： A pulsed Nd:YAG laser welding of 1 mm thick Ti (grade 2) to 0.5 mm thick AA3105-O was performed by a ring-like spot joining. A 0.15 mm thick Al-12Si-2.5Mg alloy was used as a filler metal. Intermetallic compounds of Ti3Al, Ti2Al, TiAl, Ti(Al,Si)3 and Mg2Si were observed respectively from Ti towards Al sides at the fusion zone. Si and Mg increased the strength of the Al re-solidified zone near the Ti-Al interface because of their easy dissolution in the Al. Exothermic effect of the Mg addition resulted in porosity in the welding zone. Joint strength of up to 98% of the Al base metal was obtained, which was much 14 % higher than that achieved by autogenous welding.
关键词： Titanium,Filler Metal,Laser Spot Welding,Microstructure and Mechanical Properties,Aluminum Alloy
更新于2025-09-11 14:15:04
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High-Temperature Selective Emitter Design and Materials: Titanium Aluminum Nitride Alloys for Thermophotovoltaics
摘要： The efficiency of a thermophotovoltaic (TPV) system depends critically upon the spectral selectivity and stability of an emitter, which may operate most effectively at temperatures in excess of 1000 °C. We computationally design and experimentally demonstrate a novel selective emitter design based on multilayer nanostructures, robust to off-normal emission angles. A computational search of the material and temperature compatibility space of simple emitter designs motivates new material classes and identifies several promising multilayer nanostructure designs for both TPV absorber and emitter applications. One such structure, comprising a thin (<100 nm) tunable TixAl1?xN (TiAlN) absorber and refractory oxide Bragg reflector is grown on W metal foil. In agreement with simulations, the emitter achieves record spectral efficiency (43.4%) and power density (3.6 W/cm2) for an emitter with at least 1 h of high temperature (>800 °C) operation.
关键词： solar thermophotovoltaics,titanium aluminum nitride,selective emitters,optical coating,atomic layer deposition
更新于2025-09-11 14:15:04
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Effect of Different Forms of Application of a Laser Surface Treatment on Fatigue Crack Growth of an AA6013-T4 Aluminum Alloy
摘要： This work analyzes the effect of surface-localized laser heating treatment on the fatigue crack growth (FCG) rate on region II of the sigmoidal da/dN 3 DK curve of an aerospace-grade AA6013-T4 aluminum alloy sheet with 1.3 mm thickness. The in?uence on microstructure changes is also evaluated. Aiming to improve the FCG resistance without changing the mechanical behavior of the alloy, a Yb:?ber laser beam is defocused to generate a laser spot diameter of 2 mm, using 200 W power and a laser speed of 2 mm/s. Two laser lines are applied over fatigue C(T) specimens in two different forms: on only one and on both lateral specimen surfaces. Guinier–Preston zones, dispersoids and coarse constituent particles are found on the base material. On the heat-treated material, the same precipitates and also b￠ and Q￠ precipitates are found. These microstructural variations due to the laser thermal cycle, together with the presence of induced compressive residual stresses, improved the fatigue behavior of the material. The FCG retardation is optimized when two laser lines were applied on both lateral surfaces of the specimen.
关键词： aluminum alloy,microstructure,fatigue crack growth,residual stresses,laser surface treatment
更新于2025-09-11 14:15:04
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[IEEE 2018 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Campinas (2018.10.8-2018.10.10)] 2018 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Study of the fabrication of pedestal based-optical waveguides for applications in nonlinear optics
摘要： In this work we present the details regarding the fabrication process of pedestal based optical waveguides, using different materials with large optical nonlinearities as core layer. With the pedestal fabrication process it is possible to use novel materials that are highly inert to chemical etchants or alloys composed of heavy metal elements, since this technique does not require etching of the core material itself. Lateral confinement of light is performed through the fabrication of pedestals by Reactive Ion Etching (RIE) on the lower cladding. The last step in the fabrication process is the deposition of the core layer and, for this reason, etching this layer is no longer necessary. The materials used as core layer are Aluminum Nitride and Titanium oxynitride films, due to the fact that these materials present a great potential for the fabrication of Nonlinear Optics integrated devices.
关键词： nonlinear optics,aluminum nitride,Pedestal waveguide,titanium oxynitride
更新于2025-09-11 14:15:04
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Al–Cu Alloy Fabricated by Novel Laser-TIG Hybrid Additive Manufacturing
摘要： Owing to its high strength to weight ratio, Al–Cu alloy is extensively used in the aeronautic and aerospace industries. However, there are some shortcomings in the additive manufacturing of Al–Cu alloy, such as cracks and poor strength. In this work, Al–Cu (2219-Al) specimens with excellent mechanical properties were fabricated by laser-TIG hybrid additive manufacturing. From microstructural studies, the average grain size in the laser zone (LZ) decreased to 14.4 μm, which was approximately 40.3% smaller than that in the arc zone (AZ). A {100} texture could be observed along the deposition direction. Under the influence of laser stirring, Cu in the LZ was distributed more uniformly than in the AZ. An incoherent θ phase, at the nanoscale, was discovered in both the AZ and the LZ. Its crystal orientation relationship was described as [110]α∥[002]θ, (110)α∥(002)θ between the α-Al matrix and the θ phase. The semi-coherent θ′ phase was observed in the LZ. Meanwhile, the θ′ phase characterized a good coherent relationship with the α-Al matrix, which resulted in low phase boundary energy. Furthermore, the deposited specimens exhibited a yield strength of 155.5 ± 7.9 MPa and an ultimate tensile strength of 301.5 ± 16.7 MPa, with an elongation of 12.8 ± 2.8%. These mechanical properties were higher than in specimens fabricated by TIG, CMT and SLM methods. The improved properties were predominately related to the smaller size of eutectics, the uniform distribution of Cu and the semi-coherent θ′ phases in the LZ. The combined effect of laser and arc can yield components with excellent mechanical properties, promoting the material for an expansive range of applications.
关键词： Additive manufacturing,Mechanical properties,Microstructure evaluation,Laser-TIG hybrid,Aluminum alloy
更新于2025-09-11 14:15:04
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A Monochromatic Soft X-ray Generation from Femtosecond Laser-produced Plasma with Aluminum
摘要： A tabletop ultrafast soft x-ray has been generated from the laser-produce plasma with a femtosecond pulsed Ti:Sapphire laser. The estimated total ?ux of Al Kα is of 2.2 × 109 photons/sec in 4π radian and the parameters related to the optical performance were obtained. The tungsten/silicon multilayer, ?at quartz and bent thallium acid phthalate (TLAP) crystal were used for monochromatization of soft x-ray to re?ne the aluminum Kα radiation and compared the respective value of E/ΔE. To estimate the size of the x-ray source beam generated by a fs laser, the approximation using the FWHM obtained from the x-ray beam scan near the focal point was discussed, and the size of the diameter was about 9.76 μm.
关键词： Monochromatic,Aluminum,Soft x-ray,XRD,Femtosecond laser
更新于2025-09-11 14:15:04