• JLA Vol:7 Iss:4 (Production of Fe–noble metal surface alloys using laser beams)

    M. Manohar
    C. E. Albright
    B. E. Wilde

    A new method to produce iron‐noble metal surface alloys is described. Quenched‐and‐tempered AISI 4135 steel was electroplated with Pd, Pt and Au and laser surface melting was carried out to produce the respective surface alloys. CW CO2 laser power levels of 50, 100 and 200 W were employed. Auger depth profiling showed that alloying was achieved with Pt and Pd at all three power levels, but only at 200 W with Au.


  • JLA Vol:8 Iss:1 (Comparison of aluminum alloy welding characteristics with 1 kW CO and CO<sub>2</sub> lasers)

    Bu¨lent A. Mehmetli
    Kunimitsu Takahashi
    Shunichi Sato
    Institute of Research and Innovation, Laser Laboratory 1201 Takada, Kashiwa&hyphen;shi, Chiba 277, Japan

    Welding characteristics of various aluminum alloys (A1100, A2017, A5083, A6063, A7N01) are investigated with CW CO and CO2 lasers near 1 kW power level. The beam characteristics of both lasers at the welding point are similar, so that a comparison can be made of the effect of the wavelength difference. The welding characteristics are assessed by measuring the size of the weld bead. It is found that the threshold power between heat&hyphen;conduction and deep&hyphen;penetration typ...


  • JLA Vol:8 Iss:1 (Frequency&ndash;time characteristics of air&hyphen;borne signals from laser welds)

    D. Farson
    K. Hillsley
    J. Sames
    R. Young

    The acoustic emissions from laser lap welds in stainless steel sheet were recorded and analyzed. The acoustic signals emanating from the weld were sensed with an instrument microphone and analyzed using short&hyphen;time Fourier spectra to characterize their time&hyphen;frequency distributions. It was determined that the acoustic spectrum of good&hyphen;quality, full&hyphen;penetration welds could be differentiated from the spectra of poor&hyphen;quality welds, defined as either partial&hyphen;penetration welds or welds having a gap between the sheets being joined. A novel, relatively simple class...


  • JLA Vol:8 Iss:1 (Laser polarimeters: Overview of recent developments, design and applications)

    Vi´ctor Fajer Avila
    Center for the Development of Scientific Equipment and Instruments, Ministry of Science Techonology and Environment, Havana, Cuba

    Research carried out in Cuba has led to the design and construction of automatic polarimeters that use the He&hyphen;Ne laser as a luminous source and work on a magnetooptic principle of measurement. Physical and chemical investigations including the use of the He&hyphen;Ne laser as a light source are discussed. The principle of measurement for the design and construction of polarimeters, resulting in three different types of these instruments, is described. Finally, applications for magnetooptic polarimetry are described,...


  • JLA Vol:8 Iss:1 (Laser technology at the Oak Ridge National Laboratory)

    Marc L. Simpson
    John C. Miller
    Doug H. Lowndes
    Oak Ridge National Laboratory, PO Box 2008 Oak Ridge, TN 37831, U.S.A.

    Researchers at the Department of Energy (DOE) facilities at Oak Ridge perform a variety of basic and applied research involving lasers and laser technology. One of the major strengths at Oak Ridge is the combination of core capabilities in optical materials, optical diagnostics, and sensors. Communities benefiting from these core capabilities include environmental, biomedical, and industrial sponsors. Industry can interact with Oak Ridge in a variety of ways: with Cooperative Research and Development Agreements (CRADAs), through Work ...


  • JLA Vol:8 Iss:1 (Recent progress in laser surface treatment: <emph type="4">I</emph>. Implications of laser wavelength)

    W. Bloehs
    B. Gru¨nenwald
    F. Dausinger
    H. Hu¨gel
    Institute fu¨r Strahlwerkzeuge, Universita¨t Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany

    The coupling mechanisms of laser radiation and the mechanisms of heat transport in the workpiece are considered. Starting from the well&hyphen;known basics of Fresnel absorption — valid only for smooth and clean surfaces — further effects of coupling are examined. Studies on the effects of surface modifications inherent to all industrial parts and process conditions are presented. The more appropriate term coupling rate is introduced: This describes the r...


  • JLA Vol:8 Iss:2 (Enhancement of adhesion in coated steels through excimer laser surfacing)

    M. Olfert
    R. E. Mueller
    W. Duley
    T. North
    J. Hood
    D. Sakai

    Galvanize and galvanneal steel sheet are used extensively by the automotive industry. Through a process of excimer laser surface treatment, we have succeeded in significantly enhancing the adhesion characteristics of these coated steels. Preliminary adhesion tests have been carried out via simple ‘T’ peel testing, using a hot melt nylon resin as the adhesive substrate. The peel test results indicate that, for particular processing conditions, enhanced adhesion exceeding the cohesive strength of the nylon adhesive can be obtained. The results...


  • JLA Vol:8 Iss:2 (High power calibration of commercial power meters using an NIST&hyphen;traceable secondary standard)

    Michael L. Lander
    John O. Bagford
    Daniel B. Seibert
    Robert J. Hull

    For the past 19 years, the Laser Hardened Materials Evaluation Laboratory (LHMEL), located at Wright&hyphen;Patterson AFB, OH, has maintained a number of calibrated high energy power measurement devices capable of measuring CO2 powers up to 150 kW. These devices, calibrated annually to the National Institute for Standards & Technology (NIST) high energy standard calorimeters, serve as secondary standards for in&hyphen;house calibration of LHMEL's commercial power heads and calorimeters. Recent discussions with academic and industrial laser users have ident...


  • JLA Vol:8 Iss:2 (Laser materials processing at Sandia National Laboratories)

    James L. Jellison
    Michael J. Cieslak
    Sandia National Laboratories, Albuquerque, NM 87185, U.S.A.

    This paper describes the laser materials processing capabilities at Sandia National Laboratories. Some of the advances in the understanding of various aspects of laser materials processing which have been made by the laser materials processing team at Sandia are discussed.


  • JLA Vol:8 Iss:2 (Low power laser heat treatment to improve fatigue life of low carbon steel)

    David E. Fly
    J. T. Black
    Ben Singleton

    An industrial laser cutting machine tool was used to harden 1117 and 1144 steel to examine effects on fatigue life. Transformation hardening leaves residual compressive stresses at the surface, which greatly enhance fatigue life in addition to increasing the hardness. The laser, which creates localized heating, allows faster cooling rates than conventional heat treatment methods. As a result, the application of the laser facilitates the hardening of low carbon steel which is not hardenable by conventional methods.



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