• AIP Publishing
• AVS: Science & Technology of Materials, Interfaces, and Processing
• Acoustical Society of America
• American Association of Physicists in Medicine
• American Association of Physics Teachers
• American Crystallographic Association, Inc.
• Chinese Physical Society
• Chinese Society of Theoretical and Applied Mechanics
• Laser Institute of America
• The Society of Rheology

The Journal of Laser Applications (JLA) is the scientific platform of the Laser Institute of America (LIA) and is published in cooperation with the American Institute of Physics (AIP). The high-quality articles cover a broad range from fundamental and applied research and development to industrial applications. Therefore, JLA is a reflection of the state-of-R&D in photonic production, sensing and measurement as well as Laser safety. Due to the current grand societal challenges such as resource saving, energy, mobility, health and defense the foci and trends of applied photonics have been changing over the past years, significantly. Hence, the structure of JLA has been improved to meet these trends, yet maintaining the structure according to scientific areas of competence.

Editor's Picks

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  Simulated investigation on the deformation of double laser beam bilateral and simultaneous welding for aircraft panel

  dx.doi.org/10.2351/1.4916082

  An experimental and numerical investigation of double laser beam bilateral and simultaneous welding is carried out in this paper. A dedicated heat source model is developed based on a combined heat source with coordinate transformation and mirroring. Several groups of heat source parameters are assigned, and the simulated results based on these heat source parameters are compared with the experimental results. The deformation after welding for a seven stringers welding panel is predicted by finite element analysis. To optimize the welding sequence, four welding schemes are applied to the simulation. Comparing the simulated results, the scheme 3 is thought to be the best weld sequence for the smallest welding distortion.

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  Wear and corrosion resistant laser coatings for hydraulic piston rods

  dx.doi.org/10.2351/1.4914503

  Hydraulic piston rods on oil and gas drilling platforms, hydro-power stations, chemical plants, and underground mines are exposed to severe tribo-corrosive conditions under static and dynamic mechanical loads. Piston rods made of carbon, quenched and tempered (QT) and stainless steels are frequently surface coated with methods such as thermal spraying, hard chrome plating, and overlay welding. Unfortunately, several premature failures have been reported particularly in marine applications due to insufficient coating properties. Laser cladding has recently drawn lot of attention in this field due to high coating quality and significant improvements in productivity. In this study, several potential Fe-, Ni-, and Co-based alloys were laser clad on carbon and QT steels. Their corrosion and mechanical performances were explored in long-term salt spray, immersion, hardness, abrasive wear, and four-point bending fatigue tests. Most of the laser coatings outperformed hard chrome in corrosion properties, but hardness values were somewhat lower. In single point abrasion tests (scratch tests), the hardest laser coatings, however, outperformed hard chrome due to brittle nature of hard chrome layers. Postmachining induced significant superficial hardness increases in laser coatings, which was the main reason for good wear performance. Fatigue performance was strongly dependent on material pairs, presence of cladding defects, and applied loads.

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  Explanation of penetration depth variation during laser welding under variable ambient pressure

  dx.doi.org/10.2351/1.4913455

  It has been observed that the penetration depth during laser welding (LW) under vacuum or reduced ambient pressure could be significantly greater than that during welding under atmospheric pressure. Previous explanations of this phenomenon usually limit to specific wavelength laser welding and have difficulties in explaining why the variation will disappear, as the welding speed increases. Here, we propose that this variation is caused by the temperature difference of keyhole wall under variable ambient pressure based on a correct physical description of related processes. A new surface pressure model, dependent on ambient pressure, is proposed for describing the evaporation process during laser material interaction under variable ambient pressure. For laser welding of a 304 stainless steel with 2.0 kW laser power and 3 m/min welding speed, it is shown that the average keyhole wall temperature is around 2900 K under atmospheric pressure, and only around 2300 K under vacuum, which results in significant penetration depth variations. Interestingly, it is also shown that as the welding speed increases, the average temperature of the front keyhole wall gradually rises due to the reduction of the mean incident angle of laser, and the magnitude of this increase is larger in welding under vacuum than under atmospheric pressure. It allows us to explain why the penetration depth improvement decreases to zero with the increase of welding speed.

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  Active reduction of waviness through processing with modulated laser power

  dx.doi.org/10.2351/1.4906622

  A new approach to the reduction of the waviness of metal surfaces is based on laser remelting with modulated laser power. Waviness reduction is reached due to the modification of direction of solidification of a molten pool. The changes of the molten pool are induced by laser radiation in which amplitude is modulated in accordance with initial topography of surface. The laser process with modulated laser power allows decreasing the waviness up to 80%–95% depending of the wavelength of the initial structure. Results are given for milled steel 1.2343. This new approach shows better results in comparison with laser polishing with nonmodulated laser power.

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  Power modulation to stabilize laser welding of copper

  dx.doi.org/10.2351/1.4906127

  Due to its high electric and thermal conductivity, copper has a wide range of applications. Many of those require an efficient and reliable welding process most preferably performed with laser beams. The low absorptivity of copper at a wavelength of 1 μm together with its high heat conductivity however make remote laser welding of copper a challenging task. With the currently commercially available lasers, welds with penetration depths of several millimeters in copper can only be achieved at comparatively low welding speeds (v < 10 m/min), which, however, leads to numerous defects such as melt ejections and pores. In this paper, we discuss the approach of laser power modulation to stabilize the welding of copper. It is demonstrated that the modulation of the laser power with the appropriate parameters significantly improves the weld quality. The influence of the average power, the modulation amplitude, welding speed, focal diameter, and modulation frequency on the welding quality is discussed.