JLA Vol:15 Iss:4 (Surface treatment of granite by high power diode laser)
Authors:
J. Pou
C. Trillo
R. Soto
A. F. Doval
M. Boutinguiza
F. Lusquin˜os
F. Quintero
M. Pe´rez-Amor
Departamento Fı´sica Aplicada, Universidad de Vigo, Lagoas-Marcosende 9, 36280 Vigo, SpainGranite stones have been used from times immemorial as structural element for public works and construction of every kind of building. At present, granite stones are used widely for fac¸ades, paving and flooring; polished being the most commonly used surface finish type. Recent years have seen a dramatic increase in the demand of granite plates having a rougher, more “rus...
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JLA Vol:15 Iss:4 (Welding of thick austenitic stainless steel using Nd:yttrium–aluminum–garnet laser with filler wire and hybrid process)
Authors:
Tommi Jokinen
Miikka Karhu
VTT Industrial Systems, P.O. Box 17021, FIN 53851 Lappeenranta, Finland
Veli Kujanpa¨a¨
Lappeenranta University of Technology, P.O. Box 20, FIN 53851 Lappeenranta, FinlandAutogenous laser welding has shown many advantages over traditional welding methods in numerous applications. However, there could be even more applications, but due to the power levels of present high power lasers, depth of penetration is limited. One way to overcome this limitation is to use multipass laser welding, in which a narrow gap and a filler wire are applied. By this process thick sections can be welded with a smaller heat inpu...
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JLA Vol:16 Iss:1 (Effect of excimer laser surface melting on intergranular corrosion cracking of the aluminum–lithium alloy 8090)
Authors:
T. M. Yue
C. P. Chan
L. J. Yan
H. C. Man
Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University, Hung Hom, Hong KongExcimer laser surface melting of the aluminum alloy 8090 has been conducted with the aim of improving the intergranular corrosion resistance of the alloy. Both the results of the electrochemical and the intergranular corrosion cracking immersion tests show that the laser treatment significantly increases the intergranular corrosion resistance of the alloy, especially when the material is treated in nitrogen gas. The improvement in intergranu...
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JLA Vol:16 Iss:1 (Influence of surface preparation and process parameters on the porosity generation in aluminum alloys)
Authors:
A. Haboudou
P. Peyre
CLFA, avenue Prieur de la Côte d’or, 94114 Arcueil, France
A. B. Vannes
Ecole Centrale de Lyon, Ecully, FranceThe 4 kW cw Nd:yttrium–aluminum–garnet laser welding of solid solution hardened A5083 (5% Mg) and precipitation-hardened A356 (7% Si) alloys, sensitive to porosity formation was carried out at different welding speeds, under He gas shielding, and for partial penetration conditions, on bead on plate configuration. The porosity formation was examined through observation and evaluation of weld beads, based on x-ray radiography inspection coupled with image analysis, and quantification of gas...
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JLA Vol:16 Iss:1 (Laser annealing of silicon nanocrystal films formed by pulsed-laser deposition)
Authors:
C. F. Tan
X. Y. Chen
Laser Microprocessing Laboratory and Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, Singapore
Y. F. Lu
Department of Electrical Engineering, University of Nebraska, Lincoln, Nebraska 68588-0511
Y. H. Wu
B. J. Cho
J. N. Zeng
Laser Microprocessing Laboratory and Silicon Nano Device Laboratory, Department of Electric and Computer Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260, SingaporeWe report the laser annealing effects on...
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JLA Vol:16 Iss:1 (Laser surface treatment of magnesia partially stabilized zirconia for enhanced human skin fibroblast cell response)
Authors:
L. Hao
J. Lawrence
Manufacture Engineering Division, School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, SingaporePromoting or inhibiting cell adhesion to biomaterials is often crucial to the proper function of a biomaterial. In order to induce a surface with better bioactivity for promoting the bonding between the tissue and this bioinert ceramic interface, an industrial CO2 laser was used to alter the surface properties of magnesia (MgO)-partially stabilized zirconia (PSZ) with various laser power densities. The general effects of CO2 laser radiation on the MgO–PSZ ...
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JLA Vol:16 Iss:1 (Laser-assisted chemical cleaning for oxide-scale removal from carbon steel surfaces)
Authors:
Hyunkyu Lim
Dongsik Kim
Department of Mechanical Engineering, POSTECH, Pohang 790-784, KoreaThe article introduces a novel laser chemical processing technique for removing thin oxide layers on low-carbon steel surfaces by combining laser-induced shock waves and the chemical cleaning technique that is currently utilized in the conventional oxide-scale removal. A Q-switched Nd:yttritium–aluminum–garnet laser (wavelength 1064 nm, full width at half maximum 6 ns) induces optical breakdown in the acid solution, producing intense pressure waves which act as a noncontact scale breaker. It has been demonstrated that the novel process leads to substa...
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JLA Vol:16 Iss:1 (Laser-induced electrochemical characteristics of aluminum alloy 2024-T3)
Authors:
Olga Kachurina
Tammy L. Metroke
Kai Dou
Department of Physics, Oklahoma State University, Stillwater, Oklahoma 74078Laser-induced surface modification of aluminum alloy 2024-T3 was investigated as laser intensity dependence of surface composition and patterning related to electrochemical characteristics using techniques of environmental scanning electron microscopy (ESEM), potentiodynamic scan, and electrochemical impedance spectroscopy (EIS). Analysis of surface composition using ESEM and EIS indicated that laser fluences in a range of 1.1–1.3 J/cm2 were found to preferentially reduce the copper concentration in the alloy surf...
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JLA Vol:16 Iss:1 (Metallic vapor ejection effect on melt pool dynamics in deep penetration laser welding)
Authors:
Re´my Fabbro
Mohammed Hamadou
Frederic Coste
CLFA (Coope´ration Laser Franco-Allemande), 16 bis, Avenue Prieur de la Côte d’Or, 94114 Arcueil Cedex, FranceThe hydrodynamics phenomena involved during the laser welding process are very complex. Among the possible involved mechanisms controlling the hydrodynamics of the weld pool, it is well known that the melt displacement resulting of the local pressure applied to the liquid surface as a result of the evaporation process, plays an important role. We would like to show in this article that, using specific experiments based on twin or triple spot interaction geometry, the fricti...
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JLA Vol:16 Iss:1 (Nd:yttritium–aluminum–garnet laser welding of copper to stainless steel)
Authors:
Hongwei Shen
Mool C. Gupta
Applied Research Center, College of Engineering and Technology, Old Dominion University, Newport News, Virginia 23606Systematic laser welding experiments were conducted on dissimilar metal of copper and 300 series stainless steel using a high average power Lumonics JK 701H Nd:yttritium–aluminum–garnet laser. The laser melt penetration depth and width in copper and stainless steel were evaluated as a function of the laser parameters. The results reveal that melting of copper demands much higher average power, shorter pulse duration, and lower welding speed than melting stainless steel. If the laser beam is focused on the int...
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