• JLA Vol:15 Iss:4 (Solution of two-temperature thermal diffusion model of laser–metal interactions)

    S. R. Vatsya
    Kuljit S. Virk
    Integrated Manufacturing Technologies Institute, National Research Council of Canada, 800 Collip Circle, London, Ontario N6G 4X8, Canada

    The two temperature coupled equations, modeling thermal diffusion during laser-induced ablation of metals, are solved under the assumptions that the electron and the lattice heat capacities, and the thermal conductivity remain constant in the process. In view of its practical value, the solution is initially obtained for the energy sources with a Gaussian distribution. The solution is then generalized to include a larger class of source terms for comparison with other results. Present analysis is vali...


  • JLA Vol:15 Iss:4 (Steel microstructures in autogenous laser welds)

    N. A. McPherson
    BAE Systems, Naval Ships, Glasgow, Scotland, United Kingdom

    H. Samson
    BAE Systems, Submarines, Barrow, England, United Kingdom

    T. N. Baker
    N. Suarez-Fernandez
    University of Strathclyde, Glasgow, Scotland, United Kingdom

    Autogenous Nd:YAG laser welding was carried out on austenitic stainless steel (316LN) and duplex stainless steel (2205). The structures were examined using optical and color etching metallography. This showed optically that the austenitic steel solidified as a totally austenitic structure, but the transmission electron microscopy (TEM) work confirmed the presence of ferrite. In the case o...


  • JLA Vol:15 Iss:4 (Strain gauge analysis of laser forming)

    S. P. Edwardson
    K. G. Watkins
    G. Dearden
    P. French
    Department of Engineering, Laser Group, The University of Liverpool, Liverpool L69 3GH, United Kingdom

    J. Magee
    National Centre for Laser Applications, NUI Galway, Ireland

    Laser forming has become a viable process for the shaping of metallic components, as a means of rapid prototyping and of adjusting and aligning. The laser forming process is of significant value to industries that previously relied on expensive stamping dies and presses for prototype evaluations. This investigation aims to complement the considerable amount of work already completed on two-dimensi...


  • JLA Vol:15 Iss:4 (Surface melting of Al&ndash;Cu&ndash;Mg alloy using a short-pulse, planar waveguide CO<sub>2</sub> laser for corrosion resistance improvement)

    M. G. Tsagkarakis
    F. J. Villarreal
    H. J. Baker
    D. R. Hall
    School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh EH14 4AS, United Kingdom

    S. W. Williams
    BAE Systems, Advanced Technology Centre, Filton, Bristol BS34 7QW, United Kingdom

    A newly available pulse format for planar waveguide carbon dioxide lasers has been investigated for surface melting treatment of Al-2024 using 35–40 μs duration pulses. A single-pass raster scan produces crack free surfaces, but with considerable surface modulation and stress. A double-pass treatment has been shown to relieve the stress and smooth the s...


  • JLA Vol:15 Iss:4 (Surface treatment of granite by high power diode laser)

    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, Spain

    Granite 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...


  • JLA Vol:15 Iss:4 (Welding of thick austenitic stainless steel using Nd:yttrium&ndash;aluminum&ndash;garnet laser with filler wire and hybrid process)

    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, Finland

    Autogenous 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...


  • JLA Vol:16 Iss:1 (Effect of excimer laser surface melting on intergranular corrosion cracking of the aluminum&ndash;lithium alloy 8090)

    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 Kong

    Excimer 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...


  • JLA Vol:16 Iss:1 (Influence of surface preparation and process parameters on the porosity generation in aluminum alloys)

    A. Haboudou
    P. Peyre
    CLFA, avenue Prieur de la Côte d’or, 94114 Arcueil, France

    A. B. Vannes
    Ecole Centrale de Lyon, Ecully, France

    The 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...


  • JLA Vol:16 Iss:1 (Laser annealing of silicon nanocrystal films formed by pulsed-laser deposition)

    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, Singapore

    We report the laser annealing effects on...


  • JLA Vol:16 Iss:1 (Laser surface treatment of magnesia partially stabilized zirconia for enhanced human skin fibroblast cell response)

    L. Hao
    J. Lawrence
    Manufacture Engineering Division, School of Mechanical and Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore

    Promoting 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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