scholarly journals Characterization of dissimilar aluminum-copper material joining by controlled dual laser beam

2021 ◽  
Author(s):  
Joon Ho Cha ◽  
Hae Woon Choi
Keyword(s):  
Laser Beam ◽  
Power Distribution ◽  
Near Infrared ◽  
Weld Zone ◽  
Tensile Tests ◽  
Bead Width ◽  
Single Beam ◽  
The Core ◽  
Beam Laser ◽  
Dual Laser

Abstract Laser technology has many advantages in welding for the manufacture of EV battery packs. Aluminum (Al) and copper (Cu) are welded using a dual laser beam, suggesting the optimum power distribution for the core and ring beams. Due to the very high reflectance of Cu and Al exposed to near-infrared lasers, the material absorbs a very small amount of energy. Compared to single beam laser welding, dual beam welding has significantly improved surface quality by controlling surface solidification. The study focused on the quality of weld surface beads, weld properties and tensile strength by varying the output ratio of the core beam to the ring beam. Optimal conditions of Al6061 were a 700 W core beam, a 500 W ring beam and 200 mm/s of weld speed. For the C1020P, the optimum conditions were a center beam of 2500 W, a ring beam of 3000 W and a welding speed of 200 mm/s. In laser lap welding of Al-Al and Al-Cu, the bead width and the interfacial bead width of the joint increased as the output increased. The penetration depth did not change significantly, but small pores were formed at the interface of the junction. Tensile tests were performed to demonstrate the reliability of the weld zone, and computer simulations provided analysis of the heat distribution for optimal heat input conditions.

A Comparison of Characteristics of Periodic Surface Micro/Nano Structures Generated Via Single Laser Beam Direct Writing and Particle Lens Array Parallel Beam Processing

2021 ◽  
Author(s):  
Fatema Rajab ◽  
Anmar K. Al-Jumaily ◽  
Tayf Tariq A.S ◽  
Sorin Laurentiu Stanescu ◽  
Ahmad W. AlShaer ◽  
...  
Keyword(s):  
Laser Beam ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Periodic Surface ◽  
Lens Array ◽  
Single Beam ◽  
Beam Laser ◽  
Nano Structures ◽  
Single Laser ◽  
Surface Patterns

Abstract Changing material surface micro/nano structures using laser beam texturing is a valuable approach in wide applications such as control of cell/bacterial adhesion and proliferation, solar cells and optical metamaterials. Here we report a comparison of the characteristics of surface micro/nano structures produced using single beam laser direct writing and particle lens array parallel laser beam patterning. A Nd:YVO4 nanosecond pulsed laser at 532 nm wavelength was used in the laser direct writing method to texture the stainless steel surface submerged in water and in air with different scanning patterns. Changes in surface morphology, wettability, surface chemistry and optical reflectivity were analyzed. In the particle lens array method, an excimer nanosecond laser at 248 nm wavelength was adopted to produce surface patterns on GeSbTe (GST) film coated on a polycarbonate substrate by splitting and focusing a single laser beam into millions of parallel breams. Single beam laser direct writing shows that the surface of high roughness and oxygen percentage content presented high wettability and low reflectivity characteristics. However, the controllability of the type of surface micro/nano patterns is limited. The parallel laser beam processing using particle lens array allows rapid production of user designed periodic surface patterns at nano-scale overcoming the optical diffraction limit with a high degree of controllability. Controlling the uniformity of the particle lens array is a challenge.

Optical Trapping and Manipulation of Polymer Spheres and HeLa Cell Organelles

2015 ◽  
Vol 1117 ◽  
pp. 60-64
Author(s):  
Anna Statsenko ◽  
Ginga Ito ◽  
Wataru Inami ◽  
Yoshimasa Kawata ◽  
Leonid Poperenko
Keyword(s):  
Hela Cell ◽  
Infrared Radiation ◽  
Near Infrared ◽  
Living Cells ◽  
Near Infrared Radiation ◽  
Cell Organelles ◽  
Single Beam ◽  
Beam Laser ◽  
Laser Trap ◽  
Polymer Spheres

Two types of single beam laser traps have been built. Laser trap using visible light is used to optically trap micro-and nanosized polymer spheres. Laser trap using near infrared radiation is used to avoid optical damage when used to manipulate living cells. Manipulation of internal organelle was successfully demonstrated.

scholarly journals Dual Laser Beam Processing of Semiconducting Thin Films by Excited State Absorption

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1256
Author(s):  
Christoph Wenisch ◽  
Sebastian Engel ◽  
Stephan Gräf ◽  
Frank A. Müller
Keyword(s):  
Zinc Oxide ◽  
Excited State ◽  
Laser Beam ◽  
Excited State Absorption ◽  
Fused Silica ◽  
Laser Beams ◽  
Nanosecond Laser ◽  
Pulse Delay ◽  
Single Beam ◽  
Dual Laser

We present a unique dual laser beam processing approach based on excited state absorption by structuring 200 nm thin zinc oxide films sputtered on fused silica substrates. The combination of two pulsed nanosecond-laser beams with different photon energies—one below and one above the zinc oxide band gap energy—allows for a precise, efficient, and homogeneous ablation of the films without substrate damage. Based on structuring experiments in dependence on laser wavelength, pulse fluence, and pulse delay of both laser beams, a detailed concept of energy transfer and excitation processes during irradiation was developed. It provides a comprehensive understanding of the thermal and electronic processes during ablation. To quantify the efficiency improvements of the dual-beam process compared to single-beam ablation, a simple efficiency model was developed.

scholarly journals An Analysis of the Mechanical and Metallurgical Behavior of AISI 4130 Steel After Co2 Laser Beam Welding Process

2020 ◽  
Vol 9 (4) ◽  
pp. 2230-2234
Keyword(s):  
Laser Beam ◽  
Weld Joint ◽  
Focal Point ◽  
Focal Length ◽  
Research Work ◽  
Weld Zone ◽  
Laser Beam Welding ◽  
Welding Process ◽  
Bead Width ◽  
Aisi 4130

Alloy metal has received special attention in the aerospace and defense areas. The AISI 4130 alloy steel had been also considered, since it is applied in landing gears, small aircrafts engine cradles, and besides general industries. The Laser Beam Welding of high strength metals obtained small Weld Zone and better quality with good appearance. In this research work, a Laser Beam Welding (LBW) is used to weld AISI 4130. The experiments are conducted accordingly combination of Taguchi L25 based 5 levels of Laser Power, Speed, Angle, Focal Length and Focal Point Position. The AISI 4130 weld joint Bead Width and tensile strength are measured and analysed by ANOVA. Microstructure and SEM with EDAX are using to analysis the AISI 4130 weld joint.

scholarly journals High-contrast and resolution near-infrared photometry of the core of R136

2021 ◽  
Vol 503 (1) ◽  
pp. 292-311
Author(s):  
Zeinab Khorrami ◽  
Maud Langlois ◽  
Paul C Clark ◽  
Farrokh Vakili ◽  
Anne S M Buckner ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Outer Region ◽  
Mass Range ◽  
Mass Function ◽  
Large Magellanic Cloud ◽  
Star Forming ◽  
The Core ◽  
Very Large Telescope ◽  
30 Doradus

ABSTRACT We present the sharpest and deepest near-infrared photometric analysis of the core of R136, a newly formed massive star cluster at the centre of the 30 Doradus star-forming region in the Large Magellanic Cloud. We used the extreme adaptive optics of the SPHERE focal instrument implemented on the ESO Very Large Telescope and operated in its IRDIS imaging mode for the second time with longer exposure time in the H and K filters. Our aim was to (i) increase the number of resolved sources in the core of R136, and (ii) to compare with the first epoch to classify the properties of the detected common sources between the two epochs. Within the field of view (FOV) of 10.8″ × 12.1″ ($2.7\,\text {pc}\times 3.0\, \text {pc}$), we detected 1499 sources in both H and K filters, for which 76 per cent of these sources have visual companions closer than 0.2″. The larger number of detected sources enabled us to better sample the mass function (MF). The MF slopes are estimated at ages of 1, 1.5, and 2 Myr, at different radii, and for different mass ranges. The MF slopes for the mass range of 10–300 M⊙ are about 0.3 dex steeper than the mass range of 3–300 M⊙, for the whole FOV and different radii. Comparing the JHK colours of 790 sources common in between the two epochs, 67 per cent of detected sources in the outer region (r > 3″) are not consistent with evolutionary models at 1–2 Myr and with extinctions similar to the average cluster value, suggesting an origin from ongoing star formation within 30 Doradus, unrelated to R136.

Near-infrared-ray computed tomography with an 808 nm laser beam and high spatial resolutions

2021 ◽  
Vol 92 (1) ◽  
pp. 013702
Author(s):  
Eiichi Sato ◽  
Yasuyuki Oda ◽  
Sohei Yoshida ◽  
Kunihiro Yoshioka ◽  
Hodaka Moriyama ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Laser Beam ◽  
Near Infrared ◽  
Near Infrared Ray

scholarly journals Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
A. R. Sufizadeh ◽  
S. A. A. Akbari Mousavi
Keyword(s):  
Electron Beam ◽  
Electron Beam Welding ◽  
Weld Zone ◽  
Tensile Tests ◽  
Beam Current ◽  
Aisi 316L ◽  
Cooling Rates ◽  
Minimum Width ◽  
Optimum Sample ◽  
Aisi 4340

Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

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