Academic literature on the topic 'Laser beam joining'
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Journal articles on the topic "Laser beam joining"
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Choi, Hae Woon, and Jin Young Yoon. "Composite Polymer Joining by Laser Combined Hybrid Laser Process." Advanced Materials Research 875-877 (February 2014): 1362–66. http://dx.doi.org/10.4028/www.scientific.net/amr.875-877.1362.
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A novel hybrid process (2D scanner + LASER + CNC machining) was used to join transparent and opaque polymers. A 30W diode laser and a 3-axis CNC machining center were combined to accommodate a 2D scanning system for high flexibility and productivity. The scanning speed, the number of repetitions and the laser power were selected as parameters for the weld test. By combining CNC and laser, the productivity and accuracy were improved and manufacturing cost decreased accordingly. The maximum speed of 1130 mm/min was achieved with minimum power of 2Watt. The developed system demonstrated the joining of transparent PC and opaque ABS polymers by using 2 dimensional laser beam motion. The air gap could be minimized by using constant force on the upper holding plate, and preheating by the first run of the laser system. The weld bead decreased at the lower laser power and the higher laser scanning speed.
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Kessler, Benjamin, Dirk Dittrich, Berndt Brenner, Jens Standfuss, and Christoph Leyens. "Extension of the process limits in laser beam welding of thick-walled components using the Laser Multi-Pass Narrow-Gap welding (Laser-MPNG) on the example of the nickel-based material Alloy 617 occ." Welding in the World 65, no. 7 (April 15, 2021): 1359–71. http://dx.doi.org/10.1007/s40194-021-01112-4.
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AbstractThe joining of thick-walled components using beam-based joining techniques is content of worldwide research and development activities, but has not yet been established in industry. State of the art to weld nickel super alloys is currently a TIG narrow-gap welding. The present paper is focusing on a new specific laser beam welding process, the so-called Laser Multi-Pass Narrow-Gap welding (Laser-MPNG). It first explains the process principle based on 2D beam oscillation, the use of fiber lasers and the multi-pass principle. The potential of the Laser-MPNG welding process is demonstrated using the technically significant nickel-based material Alloy 617 occ. As a result, it was possible for the first time to realize a weld with a wall thickness of 140 mm free of cracks or bonding defects. Promising results of creep and low-cycle fatigue tests are used to show the potential that Laser-MPNG welded joints would have for future industrial applications.
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Köhler, Markus, Tamás Tóth, Andreas Kreybohm, Jonas Hensel, and Klaus Dilger. "Effects of Reduced Ambient Pressure and Beam Oscillation on Gap Bridging Ability during Solid-State Laser Beam Welding." Journal of Manufacturing and Materials Processing 4, no. 2 (April 29, 2020): 40. http://dx.doi.org/10.3390/jmmp4020040.
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In recent decades, beam welding processes have been set up as a key technology for joining applications in automotive engineering and particularly in gearbox manufacturing. Due to their high beam quality, energy efficiency, reliability as well as flexible beam guidance, modern solid-state lasers offer numerous advantages, but also pose increased requirements on the production and positional accuracy of the components for the joining process. In particular, small-focus diameters present a challenge for components with process-induced tolerances, i.e., disc carriers in automatic transitions. Furthermore, welding processes utilizing solid-state lasers show an increased spatter formation during welding at high welding speeds. Accordingly, the primary objective of the presented work consists in extending the current areas of application for solid-state laser beam welding in gearbox manufacturing through an improved process reliability regarding tolerance compensation and spatter formation. Therefore, this experimental study aimed to describe the effects of a dynamic beam oscillation in combination with a reduced ambient pressure in the process environment on both gap bridging ability and spatter formation during the laser beam welding of case hardening steel. For basic process evaluations, laser beam welding at reduced ambient pressure and laser beam welding with dynamic beam oscillation were initially studied separately. Following a basic process evaluation, samples for 2 mm full-penetration-welds with varying gap sizes were analyzed in terms of weld seam geometry and weld spatter formation.
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Vollertsen, Frank, and Michael Grupp. "Laser Beam Joining of Dissimilar Thin Sheet Materials." steel research international 76, no. 2-3 (February 2005): 240–44. http://dx.doi.org/10.1002/srin.200506003.
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Wottschel, Vitalij, and Frank Vollertsen. "CFRP-Aluminium Structures Realized by Laser Beam Joining Process." Advanced Materials Research 907 (April 2014): 89–96. http://dx.doi.org/10.4028/www.scientific.net/amr.907.89.
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Modern lightweight structures containing hybrid materials allow an improvement of the weight-specific properties. However, to exploit the potential as far as possible novel joint concepts are necessary, enabling an economic structure manufacturing. The DFG-researcher group Schwarz-Silber (FOR 1224) at the University of Bremen aims to explore and develop interface structures for advanced FRP-Al compounds. Considering textile, welding and casting techniques novel joint concepts are under development, in five interdisciplinary projects. Within their work the researcher group focuses on three concepts realizing the transition structures: the usage of wires (titanium), foils (titanium) and fibres (glass fibre) as transition elements between CFRP and aluminium. Typical examples for such hybrid structures can be found in products from the aerospace industry (e.g. hull segments), the car industry (e.g. CFRP roof structures), but also in general mechanical engineering (e.g. rotor blade elements). In this paper, the joint configuration based on titanium wires and a laser beam conduction welding process will be presented. As beam source a lamp pumped Nd:YAG laser (HL4006D) was used. First specimens obtained will be discussed with respect to their properties. It will be shown that the novel approach is in principle suitable to produce load-bearing CFRP-aluminium structures. The wire concept represents a parallel arrangement of miniaturized loop connections. It is characterized by joining a CF-Ti-textile to an aluminium sheet. A carbon fibre loop is threaded through a titanium wire loop by textile technologies on one side. On the side opposite to the CF, the titanium wire loops of the CF-Ti-textile are joined to an aluminium component by welding or casting. A double-sided laser beam heat conduction welding process was applied, for both concepts. During processing, the laser beam was travels along the aluminium edge. The titanium-aluminium structure is welded in two steps. During the first step (i.e. the first weld pass) the aluminium and titanium are heated by the defocused laser beam simultaneously on both sides. An aluminium melt pool is formed, supported by the action of gravity and a certain amount of pre-heating of the titanium-wire or the titanium-foils by the laser beam and by heat conduction through the aluminium melt pool. In the second, immediately subsequent step (i.e. the second weld pass), due to a pre-heating of the materials by the first pass and an increased heat transfer between both materials, a complete wetting of the titanium structures in the joining zone is achieved.
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Yuce, Celalettin. "The Effect of Laser Beam Wobbling Mode on Weld Bead Geometry of Tailor Welded Blanks." Academic Perspective Procedia 3, no. 1 (October 25, 2020): 282–90. http://dx.doi.org/10.33793/acperpro.03.01.58.
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As a higher weight leads to increased fuel consumption for the automobile industry, the body in white must be lighter to compensate for the weight of additional components. Therefore, tailored blanks are used, which reinforce the body in white only in areas where a higher strength or stiffness is necessary. The applicability of laser welding processes with its numerous advantages, such as low heat input and production efficiency, is often limited when joining imperfect edges steel sheets due to small gap bridging ability. To overcome this limit, recent developments in the laser industry have introduced a novel method to wider the applications of lasers through the utilization of fast beam oscillation techniques, also known as laser beam wobbling. In this study, the effects of the four different amplitudes (0.5 mm, 1 mm, 1.5 mm and 2 mm) of circular laser beam oscillation patterns on the weld bead geometry and microhardness distribution were investigated. The results revealed that the weld bead width increased with the increase of wobble amplitude. Moreover, the tensile strengths of the welded blanks were higher than the AHSS base metal for all amplitude levels.
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Mirski, Zbigniew, Kazimierz Granat, and Sebastian Stano. "Possibilities of laser-beam joining cemented carbides to steel." Welding International 30, no. 3 (April 24, 2015): 187–91. http://dx.doi.org/10.1080/09507116.2014.937620.
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OBUNAI, Kiyotaka, Takuya MATSUMOTO, Tadao FUKUTA, and Koichi OZAKI. "Study of Numerical Calculation for Laser Beam Joining Process." Journal of The Adhesion Society of Japan 53, no. 6 (June 1, 2017): 217–22. http://dx.doi.org/10.11618/adhesion.53.217.
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Bauernhuber, Andor, and Tamás Markovits. "HYBRID JOINING OF STEEL AND PLASTIC MATERIALS BY LASER BEAM." TRANSPORT 29, no. 2 (May 22, 2013): 217–22. http://dx.doi.org/10.3846/16484142.2013.785445.
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Hybrid joining of metals and plastics in order to produce lightweight parts is of growing interest in the manufacturing processes of vehicles, electrical devices and biomedical applications. In this study, the joining of PMMA plastic (poly methyl metacrylate) and unalloyed steel were investigated by the authors. The authors successfully joined PMMA and steel by means of Nd:YAG laser and carried out tensile tests to measure the joining strength. Experimental results showed that the joint strength is influenced by the heating time, the penetration depth of the steel workpieces in the plastic, by the surface roughness of steel and by the time elapsed between bonding and tearing of the samples.
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Ma, Binghui, Xiaonan Wang, Chunhuan Chen, Dongran Zhou, Peiquan Xu, and Xiujuan Zhao. "Dissimilar Welding and Joining of Cemented Carbides." Metals 9, no. 11 (October 28, 2019): 1161. http://dx.doi.org/10.3390/met9111161.
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Cemented carbides have been widely used in aerospace, biomedical/wearable sensor, automobile, microelectronic, and other manufacturing industries owing to their superior physical and chemical properties at elevated temperatures. These superior properties, however, make it difficult to process these materials using conventional manufacturing methods. In this article, an overview of the welding and joining processes of cemented carbide and steel is given, followed by a few examples of welding processes. Cemented carbides can be successfully joined by sinter-bonding, brazing and soldering, laser beam welding, tungsten inert gas (TIG) welding, diffusion welding, friction welding, electron-beam welding, and chemical vapor deposition. An overview of the benefits and drawbacks of brazing and soldering of cemented carbide and steel is presented, including reports on joint design, processes, and selection of brazing filler metals. The laser welding of cemented carbide and steel is addressed and reviewed, including reports on gap bridging ability, the inclusion/absence of filler metals, interlayers, and laser/TIG hybrid welding. Finally, a section is devoted to explaining the main issues remaining in the welding and joining of cemented carbide, corresponding solutions, and future work required.
Dissertations / Theses on the topic "Laser beam joining"
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Coelho, Rodrigo Santiago. "Joining of light-weight materials by friction stir welding and laser beam welding." Berlin Bochum Dülmen London Paris Europ. Univ.-Verl, 2008. http://d-nb.info/994359489/04.
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Fedina, Tatiana. "Laser beam-material interaction in Powder Bed Fusion." Licentiate thesis, Luleå tekniska universitet, Produkt- och produktionsutveckling, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-84303.
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The acceptance of additive manufacturing (AM) depends on the quality of final parts and the process repeatability. Recently, many studies have been dedicated to the establishment of the relationship between the process behavior and material performance. Phenomena such as laser-material interaction, melt pool dynamics, ejecta formation and particle movement behavior on a powder bed are of a particular interest for the AM community as these events directly influence the outcome of the process. Another aspect, which hinders the adoption of AM, is the need for cost-efficient powder materials and their sustainable processing and subsequent recycling. The research work presented in this thesis, to a certain degree, covers the above mentioned scientific aspects and focuses on the behavior of gas and water atomized steel powders in laser powder bed fusion (LPBF). Paper I demonstrates a comparative study of dissimilarly-shaped gas and water atomized low alloy steel powders regarding their processability, packing capacities, particle movement behavior and powder performance in LPBF. The impact of chemical composition and morphology of the powders on the process behavior was revealed. Powder spattering and melt pool instabilities were discussed in detail. Paper II explains the role of ejecta in the recycled powder and the changing behavior of the material due to ejecta pick-up. The impact of multiple powder recycling on the degradation of low alloy steel powder in laser powder bed fusion was studied. Oxygen content, particle size and ejecta occurrence gradually increased after each recycling step and were identified as the main contributors to the property alterations observed in the powder during recycling. In addition, a direct correlation between the increase in oxygen with repeated recycling and a more frequent spatter ejection after each recycle was established. Paper III is a successor of Paper I and contains a research on the particle movement and denudation behavior on a powder bed when using near-spherical and non-spherical steel powders. The influence of particle morphology on the dynamics of arbitrary-shaped powder particles was studied by applying an analytical correlation formula to calculate the drag force exerted on powder particles of various shape. Particle entrainment of gas and water atomized powders in front of the laser beam was measured, revealing a significant difference in the powder transfer towards the melt pool.
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Mi, Yongcui. "Novel beam shaping and computer vision methods for laser beam welding." Licentiate thesis, Högskolan Väst, Avdelningen för produktionssystem (PS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-16970.
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Laser beam welding has been widely applied in different industrial sectors due to its unique advantages. However, there are still challenges, such as beam positioning in T-joint welding, and gap bridging in butt joint welding,especially in the case of varying gap width along a joint. It is expected that enabling more advanced control to a welding system, and obtaining more in-depth process knowledge could help to solve these issues. The aim of this work is to address such welding issues by a laser beam shaping technology using a novel deformable mirror together with computer vision methods and also to increase knowledge about the benefits and limitations with this approach. Beam shaping in this work was realized by a novel deformable mirror system integrated into an industrial processing optics. Together with a wave front sensor, a controlled adaptive beam shaping system was formed with a response time of 10 ms. The processes were monitored by a coaxial camera with selected filters and passive or active illumination. Conduction mode autogenous bead-on-plate welding and butt joint welding experiments have been used to understand the effect of beam shaping on the melt pool geometry. Circular Gaussian, and elliptical Gaussian shapes elongated transverse to and along the welding direction were studied. In-process melt pool images and cross section micrographs of the weld seams/beads were analyzed. The results showed that the melt pool geometry can be significantly modified by beam shaping using the deformable mirror. T-joint welding with different beam offset deviations relative to the center of the joint line was conducted to study the potential of using machine learning to track the process state. The results showed that machine learning can reach sufficient detection and estimation performance, which could also be used for on-line control. In addition, in-process and multidimensional data were accurately acquired using computer vision methods. These data reveal weaknesses of current thermo-fluid simulation model, which in turn can help to better understand and control laser beam welding. The obtained results in this work shows a huge potential in using the proposed methods to solve relevant challenges in laser beam welding.Lasersvetsning används i stor utsträckning i olika industrisektorer på grund av dess unika fördelar. Det finns emellertid fortfarande utmaningar, såsom rätt positionering av laserstrålen vid genomträngningssvetsning av T-fogar och hantering av varierande spaltbredd längs fogen vid svetsning av stumfogar. Sådana problem förväntas kunna lösas med avancerade metoder för automatisering, metoder som också förväntas ge fördjupade kunskaper om processen. Syftet med detta arbete är att ta itu med dessa problem med hjälp av en teknik för lasereffektens fördelning på arbetsstycket, s.k. beam shaping. Det sker med hjälp av en ny typ av i realtid deformerbar spegel tillsammans med bildbehandling av kamerabilder från processen. För- och nackdelar med detta tillvägagångssätt undersöks.Beam shaping åstadkoms med hjälp av ny typ av deformerbart spegelsystem som integreras i en industriell processoptik. Tillsammans med en vågfrontsensor bildas ett adaptivt system för beam shaping med en svarstid på 10 ms. Processen övervakas av en kamera linjerad koaxialt med laserstrålen. För att kunna ta bilder av svetspunkten belyses den med ljus av lämplig våglängd, och kameran är försedd med ett motsvarande optiskt filter. Försök har utförts med svetsning utan tillsatsmaterial, direkt på plåtar, svetsning utan s.k. nyckelhål, för att förstå effekten av beam shaping på svetssmältans geometri. Gauss fördelade cirkulära och elliptiska former, långsträckta både tvärs och längs svetsriktningen har studerats. Bilder från svetssmältan har analyserats och även mikrostrukturen i tvärsnitt från de svetsade plåtarna. Resultaten visar att svetssmältans geometri kan modifieras signifikant genom beam shaping med hjälp av det deformerbara spegelsystemet. Genomträngningssvetsning av T-fogar med avvikelser relativt foglinjens centrum genomfördes för att studera potentialen i att använda maskininlärning för att fånga processens tillstånd. Resultaten visade att maskininlärning kan nå tillräcklig prestanda för detektering och skattning av denna avvikelse. Något som också kan användas för återkopplad styrning. Flerdimensionell processdata har samlats i realtid och analyserats med hjälp av bildbehandlingsmetoder. Dessa data avslöjar brister i nuvarande simuleringsmodeller,vilket i sin tur hjälper till med att bättre förstå och styra lasersvetsning.Resultaten från detta arbete uppvisar en god potential i att använda de föreslagna metoderna för att lösa relevanta utmaningar inom lasersvetsning.
Till licentiatuppsats hör 2 inskickade artiklar, som visas inte nu.
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John, Björn. "Verwendung instationärer Gasströme in der Laserfügetechnik." Universitätsverlag Chemnitz, 2018. https://monarch.qucosa.de/id/qucosa%3A31240.
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Das Ziel der vorliegenden Arbeit bestand in der Integration einer Technologie zur Erzeugung zeitlich alternierender (gepulster) Gasströme auf dem Gebiet der Laserfügetechnik. Für die technische Realisierung implizierte dies spezifische Anpassungen der drei Systemkernelemente (Stelleinheit, Messstrecke, Regelung) bzw. eine vollständige Neukonzeption des Technologieaufbaus. Die somit dem Anwender zur Verfügung stehenden neuen Parameter ermöglichten eine positive Beeinflussung des Fügeprozesses bzw. der Schweißergebnisse. Über die zeitliche Steuerung des Gasvolumenstroms in Korrespondenz zum Laserstrahlschweißprozess gelang es, mit Schutzgaspulsen eine Krafteinwirkung auf die Schmelze hervorzurufen und dadurch eine Verbesserung in Hinblick auf die Einschweißcharakteristik von lasergeschweißten Nähten zu realisieren.The present study focuses on the integration of a technology for generating temporally alternating (pulsed) gas flows in the field of laser welding. The technical realization required the specific adaptation of the three core elements of the system (valve, section of measurements, control system) or rather a completely new concept of the technological setup. The new parameters allow for a positive influence on the joining process and on the results of welding, respectively. By means of temporal control of the gas volume flow in combination with a laser welding process, it was possible to produce a force effect on the molten.
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Svenman, Edvard. "Inductive measurement of narrow gaps for high precision welding of square butt joints." Licentiate thesis, Högskolan Väst, Forskningsmiljön produktionsteknik(PTW), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-10150.
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A recent method in aero engine production is to fabricate components from smaller pieces, rather than machining them from large castings. This has made laser beam welding popular, offering high precision with low heat input and distortion, but also high productivity. At the same time, the demand for automation of production has increased, to ensure high quality and consistent results. In turn, the need for sensors to monitor and control the laser welding process is increasing. In laser beam welding without filler material, the gap between the parts to be joined must be narrow. Optical sensors are often used to measure the gap, but with precise machining, it may become so narrow that it is difficult to detect, with the risk of welding in the wrong position. This kind of problems can cause severe welding defects, where the parts are only partially joined without any visible indication. This thesis proposes the use of an inductive sensor with coils on either side of the gap. Inducing currents into the metal, such a sensor can detect even gaps that are not visible. The new feature of the proposal is based on using the complex response of each coil separately to measure the distance and height on both sides of the gap, rather than an imbalance from the absolute voltage of each coil related to gap position. This extra information allows measurement of gap width and misalignment as well as position, and decreases the influence from gap misalignment to the position measurement. The sensor needs to be calibrated with a certain gap width and height alignment. In real use,these will vary, causing the sensor to be less accurate. Using initial estimates ofthe gap parameters from the basic sensor, a model of the response can be used to estimate the measurement error of each coil, which in turn can be used for compensation to improve the measurement of the gap properties.The properties of the new method have been examined experimentally, using a precise traverse mechanism to record single coil responses in a working range around a variable dimension gap, and then using these responses to simulate a two coil probe. In most cases errors in the measurement of weld gap position and dimensions are within 0.1 mm.The probe is designed to be mounted close to the parts to be welded, and will work in a range of about 1 mm to each side and height above the plates. This is an improvement over previous inductive sensors, that needed to be guided to the mid of the gap by a servo mechanism.
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Noori, Rahim Abadi Seyyed Mohammad Ali. "Investigation of Melt Pool Thermo-hydrodynamic Behaviour inLaser Beam Welding ofTi-6Al-4V through Numerical Simulation." Licentiate thesis, Högskolan Väst, Avdelningen för svetsteknologi (SV), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-17410.
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Laser is an efficient and widely used heat source in metal processing suchas welding and additive manufacturing. It has some great advantages compared to the other conventional heat sources like electron beam and arc namely: ability of handling complicated joint geometries and producing large components. Laser beam welding encompasses many complex physical phenomena such asheat transfer, metal melting, flow and solidification, free surface deformation, evaporation and possibly vaporization. The aim of this research work istwo-fold: gain deeper process understanding and improve the model reliability. Deeper process understanding is sought on the effect of beam shaping on themelt pool. To achieve improved model reliability, a good support consists in using qualitative experimental data representing the process. Thus, 3D validation of the melt pool geometry is performed while it was usually 2D inprevious research works. Furthermore, a new calculation procedure for laser absorption is introduced. To conduct this research work, a Computational Fluid Dynamics approach is used. A solver, capable of tracking the deformation of the melt free surface, is developed in OpenFOAM. Concerning beam shaping, it is found that not only the melt pool size as previously known but also the melt flow pattern is modified through elongating the beam shape.This last result could not be revealed by former studies as the non-transparent media hinders optical observation. New in-process quantitative measurements performed by a project partner are used to test the model. Weaknesses of the former absorptivity models are highlighted, as well as the limitations of the proposed model. Finally, the results show that the proposed absorptivity model function of local surface conditions leads to much better agreement with experimental results compared to the former constant absorptivity model. The maximum discrepancy compared to the experimental measurement, which is observed for the melt pool depth, can indeed be reduced to about 10%.Laser är en effektiv och allmänt använd värmekälla vid svetsning och additiv tillverkning. Den har några viktiga fördelar jämfört med andra konventionella värmekällor såsom elektronstråle och elektrisk ljusbåge, nämligen: den kan ofta användas till komplicerade svetsgeometrier, och den kan producera stora komponenter. Lasersvetsning involverar olika sammansatta fysikaliska fenomen såsom värmeöverföring, metallsmältning, flöde, stelning, ytdeformation, avdunstning och i vissa fall förångning. Syftet med mitt forskningsarbete är tvåfaldigt: att få en djupare processförståelse och att förbättra modellens tillförlitlighet. Fördjupad processförståelse eftersträvades för att förstå hur formen på laserstrålen påverkar svetssmältan. För att uppnå förbättrad modellsäkerhet behövs experimentella data av hög kvalitet som representerar processen. Således utfördes 3D-validering av smältgeometrin medan det vanligtvis var 2D i tidigare forskningsarbeten. Dessutom har en ny modell för laserabsorption föreslagits. I forskningen har numerisk strömningssimulering (Computational Fluid Dynamics) använts för att simulera processen och en numerisk lösare, som kan spåra deformationen av den rörliga smälta ytan, är utveckladi programvaran OpenFOAM. Beträffande laserstrålens utbredning visar resultaten att svetssmältans storlek och även svetssmältansflöde modifieras genom att laserstråleformen förlängs. Medan den förra är känd från tidigare experimentella studier upptäcktes den senare inte före denna studie eftersomdet icke-transparenta mediet hindrar optisk observation. Nya (in-process) kvantitativa mätningar utförda av en projektpartner har använts för att testa modellerna. Svagheter i den tidigare absorptionsmodellen framhävdes, liksom begränsningarna i den föreslagna modellen. Slutligen visade resultaten att den föreslagna modellen där laserabsorptionen är en funktion av lokala ytförhållanden ledde till en bättre overensstämmelse med mätningar jämfört med den tidigare modellen med konstant laserabsorbtion. Den maximala avvikelsen jämfört med experimentell mätning, som observerades med avseende på smältbassängsdjupet, kunde reduceras till cirka 10%.
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Kumara, Chamara. "Microstructure Modelling of Additive Manufacturing of Alloy 718." Licentiate thesis, Högskolan Väst, Avdelningen för avverkande och additativa tillverkningsprocesser (AAT), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-13197.
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In recent years, additive manufacturing (AM) of Alloy 718 has received increasing interest in the field of manufacturing engineering owing to its attractive features compared to those of conventional manufacturing methods. The ability to produce complicated geometries, low cost of retooling, and control of the microstructure are some of the advantages of the AM process over traditional manufacturing methods. Nevertheless, during the building process, the build material undergoes complex thermal conditions owing to the inherent nature of the process. This results in phase transformation from liquid to solid and solid state. Thus, it creates microstructural gradients in the built objects, and as a result,heterogeneous material properties. The manufacturing process, including the following heat treatment that is used to minimise the heterogeneity, will cause the additively manufactured material to behave differently when compared to components produced by conventional manufacturing methods. Therefore, understanding the microstructure formation during the building and subsequent post-heat treatment is important, which is the objective of this work. Alloy 718 is a nickel-iron based super alloy that is widely used in the aerospace industry and in the gas turbine power plants for making components subjected tohigh temperatures. Good weldability, good mechanical properties at high temperatures, and high corrosion resistance make this alloy particularly suitablefor these applications. Nevertheless, the manufacturing of Alloy 718 components through traditional manufacturing methods is time-consuming and expensive. For example, machining of Alloy 718 to obtain the desired shape is difficult and resource-consuming, owing to significant material waste. Therefore, the application of novel non-conventional processing methods, such as AM, seems to be a promising technique for manufacturing near-net-shape complex components.In this work, microstructure modelling was carried out by using multiphase-field modelling to model the microstructure evolution in electron beam melting (EBM) and laser metal powder directed energy deposition (LMPDED) of Alloy 718 and x subsequent heat treatments. The thermal conditions that are generated during the building process were used as input to the models to predict the as-built microstructure. This as-built microstructure was then used as an input for the heat treatment simulations to predict the microstructural evolution during heat treatments. The results showed smaller dendrite arm spacing (one order of magnitude smaller than the casting material) in these additive manufactured microstructures, which creates a shorter diffusion length for the elements compared to the cast material. In EBM Alloy 718, this caused the material to have a faster homogenisation during in-situ heat treatment that resulting from the elevated powder bed temperature (> 1000 °C). In addition, the compositional segregation that occurs during solidification was shown to alter the local thermodynamic and kinetic properties of the alloy. This was observed in the predicted TTT and CCT diagrams using the JMat Pro software based on the predicted local segregated compositions from the multiphase-field models. In the LMPDED Alloy 718 samples, this resulted in the formation of δ phase in the interdendritic region during the solution heat treatment. Moreover, this resulted in different-size precipitation of γ'/γ'' in the inter-dendritic region and in the dendrite core. Themicro structure modelling predictions agreed well with the experimental observations. The proposed methodology used in this thesis work can be an appropriate tool to understand how the thermal conditions in AM affect themicro structure formation during the building process and how these as-built microstructures behave under different heat treatments.
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Tomashchuk, Iryna. "Assemblage hétérogène cuivre-inox et TA6V-inox par les faisceaux de haute énergie : compréhension et modélisation des phénomènes physico-chimiques." Phd thesis, Université de Bourgogne, 2010. http://tel.archives-ouvertes.fr/tel-00651486.
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La présente étude est dédiée à la compréhension des mécanismes de malaxage intervenant lors du soudage de matériaux dissimilaires par des sources de haute énergie et en particulier sur deux couples de matériaux présentant des problèmes métallurgiques différents : * cuivre - inox (lacune de miscibilité, différence de propriétés thermophysiques),* TA6V- inox (oxydation, formation de phases intermétalliques fragilisant la soudure).Pour le premier couple de matériaux, le soudage par laser Nd:YAG continu et par faisceau d'électrons a été utilisé. L'étude des évolutions de la morphologie des soudures, de la composition et de la microstructure des zones fondues ainsi que des propriétés mécaniques a permis de proposer des hypothèses sur les mécanismes de formation du mélange hétérogène à solubilité limitée. Afin de quantifier les phénomènes physiques intervenant en soudage continu de matériaux dissimilaires, la modélisation numérique a été mise en œuvre en utilisant le logiciel FEM "Comsol Multiphysics". Une série des modèles simulant les champs de températures, les mouvements convectifs et le malaxage (diffusion, méthode level set, méthode des champs de phases) a été créée. Dans le cas du laser, la formulation pseudo-stationnaire du transfert de chaleur basée sur la géométrie du capillaire simplifiée et la convection a été couplée avec les problèmes 2D de diffusion et de malaxage des matériaux dans différents plans horizontaux. En soudage par faisceau d'électrons, la morphologie de la microstructure a nécessité une formulation temporelle. Le modèle multiphysique final en couplage complet (solution multiphysique simultanée) reproduit le processus de formation d'une structure périodique de solidification lors du soudage par faisceau d'électrons et permet d'expliquer l'aspect des structures alternées entre matériaux immiscibles ou présentant de grandes différences de propriétés thermophysiques.Le deuxième couple de matériaux présente des problèmes métallurgiques majeurs liés à la formation des phases intermétalliques rendant l'assemblage direct par fusion impossible. La composition locale devient donc l'aspect-clef de la formation d'une soudure correcte : l'introduction d'un troisième matériau (cuivre) ayant une meilleure compatibilité avec le titane est nécessaire. Pour pouvoir déterminer les fenêtres optimales des conditions opératoires, les modèles numériques, créés précédemment, ont été adaptés pour quatre procédés de l'assemblage : faisceau d'électrons, soudage lasers Nd:YAG continu et pulsé, brasage par laser avec apport de fil. L'analyse élémentaire des microstructures dans les soudures résistantes mécaniquement a permis de développer le scénario de la solidification d'une zone fondue et de comprendre l'influence de la composition aux interfaces sur la résistance mécanique des assemblages.Les modèles numériques multiphysiques créés au cours de cette étude permettent l'accès rapide à la grande quantité d'information sur le comportement de la zone fondue en fonction des paramètres de soudage en se basant sur le nombre des données de départ relativement limité et sur quelques hypothèses simplificatrices. L'approche multiphysique à la modélisation de soudage permet de reproduire la forme de la zone fondue, visualiser les écoulements du liquide et cartographier la distribution de certains éléments avec une bonne corrélation avec les résultats expérimentaux. L'ensemble des modèles permet de déterminer les conditions opératoires répondant aux critères fixes en fonction de la métallurgie d'un couple hétérogène.
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Yalukova, Olga. "Interaction mechanisms of pulsed laser beams at different wavelengths with matter." Licentiate thesis, Luleå, 2004. http://epubl.luth.se/1402-1757/2004/029.
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Chatterjee, Subhradeep. "Microstructure Development During Laser And Electron Beam Welding Of Ti/Ni Dissimilar Joints." Thesis, 2006. http://hdl.handle.net/2005/601.
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Fusion welding of dissimilar metals constitutes a crucial processing stage in a variety of applications, and the use of high energy beams (HEB) like lasers and electron beams for such welding applications has several advantages, such as, precision, narrow heat affected zone, and consequently, low distortion. An understanding of microstructural evolution in the weld is a prerequisite for producing sound joints with desired properties. HEB welding of similar metals have been studied extensively. In contrast, fewer studies have been directed toward understanding the fundamental aspects of solidification of dissimilar welds. This thesis presents an effort in that direction by exploring microstructural evolution in Ti/Ni dissimilar welds.
Welding of Ti/Ni serves to illustrate the fundamental differences that distinguish dissimilar welding from the welding of similar metals. These are: (i) Thermophysical properties of the base metals are, in general, different, and this can have important consequences in the heat transfer conditions. (ii) Composition can vary over an wide range, the extreme being for the case of a pure binary couple, and the solid–liquid interface cannot be defined by a single liquidus isotherm. (iii) In addition to the surface energy driven Marangoni convection, a strong solutal convection can arise due to a large difference in the density of the base metals. (iv) Nucleation of phases assumes greater importance, especially in systems with intermediate phases.
We have carried out laser and electron beam welding (LW and EBW) experiments in a butt welding geometry to join Ti/Ni dissimilar couples. Weld microstructures were characterised using scanning and transmission electron microscopy (SEM and TEM); composition information was obtained from energy dispersive spectroscopy (EDS) of Xrays in the SEM. In addition to the pure binary couple, we have also studied electron beam welding of Ti/Ni with a thin Ta interlayer. We summarise our findings in each set of experiments in the following sections.
Laser welding of Ti/Ni
We have studied partial penetration welds obtained within the range of experimental parameters used in our study. These welds show the following interesting features:
1. The welds are asymmetric with respect to the initial joint. Despite its higher melting point, Ti melts more than Ni due to its lower thermal diffusivity, making the average composition of the weld richer in Ti (Ti–40at.%Ni).
2. Composition changes very steeply near the fusion interfaces in both Ti and Ni with associated microstructural changes. The variation is of much lesser magnitude in the rest of the weld, reflecting a well mixed melt pool on a macroscopic scale.
3. Growth of base metal grains into the weld pool at the fusion interfaces is severely restricted at both Ti and Ni ends.
4. The Ti fusion interface is marked by a band consisting of Ti2Ni dendrites which grow toward the Ti base metal.
5. Layered structures form at the Ni fusion interface. The sequence of the layers is: solid solution (Ni)→ Ni3Ti→ Ni3Ti+NiTi eutectic → NiTi. We note the absence of the (Ni)+Ni3Ti eutectic in this sequence.
6. NiTi and Ti2Ni are the major phases that appear in the bulk of the weld. Volume fraction and morphology of NiTi vary almost periodically to form microstructural bands.
7. Solid state transformation of NiTi results in the formation of the Rphase and martensite, which reflect the composition heterogeneity in the weld. Sometimes, Ni4Ti3 precipitates are observed also, providing indirect evidence of nonequilibrium solidification.
8. Nitrogen pickup from the atmosphere during welding leads to the formation titanium nitride dendrites in the weld.
9. Solutal convection and buoyancy forces manifest themselves through the segregation of the lighter nitride and Ti2Ni phases toward the top surface of the weld; the heavier liquid forms blocky NiTi in the bottom half of the weld.
These observations stand in striking contrast with the microstructures of conventional welds. We have proposed a set of composition and temperature profiles in the weld which reflect the diffusive and advective transport processes; when combined with thermodynamic information from the Ti–Ni phase diagram to yield spatial liquidus temperature profiles, these profiles can adequately explain most of the results. Our observations illustrate the importance of (a) nucleation, and (b) the inhomogeneous nature of the melt in which growth takes place. They also highlight the role of convective currents in bringing about local fluctuations in composition and temperature leading to ‘low velocity bands’.
Electron beam welding of Ti/Ni
We have carried out full penetration EBW of thin plates of Ti and Ni. The major observations are: (i) Average composition of the weld is in the Ni–rich side of the phase diagram (Ni–40at.%Ti). (ii) Fusion interface microstructures are very similar to that in LW exhibiting restricted base metal growth (although little amount of epitaxy can be seen in the Ni side), growth of Ti2Ni dendrites toward the base metal at the Ti fusion interface and the sequence of layers at the Ni interface: (Ni)→ Ni3Ti→ Ni3Ti+NiTi. Unlike LW, however, Ni3Ti, instead of NiTi, reappeared after the third layer on the Ni side. (iii) General microstructure consists of the Ni3Ti+NiTi eutectic, which appears in several anomalous as well as regular morphologies. (iv) Formation of NiTi is restricted mostly to regions near the Ti fusion interface. (v) Segregation of Ni3Ti was observed in a few places. The most prominent change in the microstructure compared to LW is a shift from the Ti2Ni– NiTi phases in the bulk of the weld to a Ni3Ti+NiTi eutectic structure. This is a direct consequence of the shift in the average composition of the weld to the Ni– rich side. The occurrence of different anomalous and regular eutectic structures bear similarity with bulk undercooling experiments conducted on eutectic systems having a strongly faceting phase as one of its constituents. The asymmetric coupled zone, along with composition and temperature fluctuation due to fluid flow, can be attributed to the origin of these structures.
Electron beam welding of Ti/Ni with a Ta interlayer
Motivated by the report of superior mechanical properties of Ti/Ni welds with an interlayer of Ta, whose melting point is much higher than those Ni and Ti, we performed EBW experiments using a Ni–Ta– Ti configuration. The key observations are: (i) The process is inherently unsteady in nature, and results in partial and irregular melting of the Ta interlayer. This partial melting essentially divides the weld into Ni–rich and Ti–rich halves. (ii) Microstructure near the fusion interface in Ni and Ti show similarities with that of the pure binary Ti/Ni welds; the phases here, however, contain Ta as a ternary addition. (iii) Microstructure in the Ti–rich half consists of dendrites of the Ni(Ti,Ta) phase with a high Ti:Ta ratio, and an eutectic formed between this phase and a (Ti,Ta)2Ni phase having significant amount of Ta. Two Ni(Ti,Ta) type phases dominate the microstructure in the Ni–rich half: the phase having a higher Ti:Ta ratio forms cells and dendrites, whereas the one of a lower Ti:Ta ratio creates an interdendritic network. (iv) Regions near the unmolten Ta layer in the middle show the formation of a sawtoothlike Ta–rich faceted phase of composition (Ta,Ti)3Ni2. Since very scarce thermodynamic data exist for the Ni–Ta–Ti ternary system, we have taken cues from the binary phase diagrams to understand the microstructural evolution. Such extrapolation, although successful to some extent, fails where phases which have no binary equivalents start to appear.
In summary, in this thesis, we explore microstructural evolution in the Ti/Ni dissimilar welds under the different settings of laser and electron beam welding processes. This study reveals a variety of phenomena occurring during dissimilar welding which lead to the formation of an extensive range of microstructural features. Although a few questions do remain, most results can be rationalised by drawing from, and extending the knowledge gained from previous studies by introducing physical and thermodynamic arguments.
Books on the topic "Laser beam joining"
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United States. National Aeronautics and Space Administration., ed. Joining of ceramics for high temperature applications. Washington, DC: National Aeronautics and Space Administration, 1987.
Find full textBook chapters on the topic "Laser beam joining"
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Darwish, Saied, Naveed Ahmed, and Abdulrahman M. Alahmari. "Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques." In Machining, Joining and Modifications of Advanced Materials, 171–269. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1082-8_17.
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Darwish, Saied, Naveed Ahmed, and Abdulrahman M. Alahmari. "Erratum to: Laser Beam Machining, Laser Beam Hybrid Machining, and Micro-channels Applications and Fabrication Techniques." In Machining, Joining and Modifications of Advanced Materials, E1. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1082-8_18.
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Schanz, Jochen, Markus Hofele, Leonhard Hitzler, Markus Merkel, and Harald Riegel. "Laser Polishing of Additive Manufactured AlSi10Mg Parts with an Oscillating Laser Beam." In Machining, Joining and Modifications of Advanced Materials, 159–69. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1082-8_16.
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Schanz, Jochen, Markus Hofele, Leonhard Hitzler, Markus Merkel, and Harald Riegel. "Erratum to: Laser Polishing of Additive Manufactured AlSi10Mg Parts with an Oscillating Laser Beam." In Machining, Joining and Modifications of Advanced Materials, E3. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-1082-8_19.
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Laukant, H., C. Wallmann, M. Korte, and Uwe Glatzel. "Flux-Less Joining Technique of Aluminium with Zinc-Coated Steel Sheets by a Dual-Spot-Laser Beam." In Sheet Metal 2005, 163–70. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-972-5.163.
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Schmitt, Felix, and Alexander Olowinsky. "Laser Beam Micro-Joining." In Micro-Manufacturing Engineering and Technology, 185–201. Elsevier, 2010. http://dx.doi.org/10.1016/b978-0-8155-1545-6.00012-0.
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Schmitt, Felix, and Alexander Olowinsky. "Laser Beam Micro-joining." In Micromanufacturing Engineering and Technology, 613–35. Elsevier, 2015. http://dx.doi.org/10.1016/b978-0-323-31149-6.00026-8.
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Melhem, George Nadim. "Aerospace Fasteners: Use in Structural Applications." In Encyclopedia of Aluminum and Its Alloys. Boca Raton: CRC Press, 2019. http://dx.doi.org/10.1201/9781351045636-140000240.
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Aircraft components need to be selected and manufactured to adequately combat the environment, temperature, loading, compatibility, and so on. When structural materials such as aluminum alloys or fiber-reinforced polymer composites need to be joined in aircraft, the selection of fasteners, bolts, rivets, adhesives, and other methods need to be quantitatively assessed in order that the correct design for the component and joining method is identified. There is a variety of fasteners, bolts, and rivets, made using a variety of materials. Aluminum rivets are often used to join aluminum components in an aircraft. Rivets do not perform well under tension loading, but perform better in shear, thus limiting the application specifically for these purposes. Bolts are designed to clamp material together, and even though the bolt may be adequate to support a particular structure and load requirement, consideration must also be given to the modulus of elasticity and stiffness of the components that are being clamped together. Therefore, an understanding of each of the materials being clamped or joined together is necessary. Bolts manufactured from steel, for instance, have coatings applied in order to help protect them from corrosion. The use of composites translates to a reduced number of rivets and fasteners to be used. Drilling of holes into composites to insert fasteners poses many challenges because the fibers are damaged, a region of high stress concentration may be formed, and the hole is a site for the ingress of water or moisture. The insertion of aluminum fasteners or the contact of aluminum components with carbon fibers creates galvanic corrosion due to the large difference in electrical potential. Titanium alloy (Ti-6Al-4V) is a typical fastener where there is composite joining due to its better compatibility (elimination of galvanic corrosion) and increased strength properties. Substitution of rivets and fasteners for welding is also on the increase in aircraft because laser beam welding (LBW) and friction stir welding both reduce cracking, porosity, and better properties achieved due to deeper penetration, and reduce the heat-affected zone which would typically be undesirable with conventional arc welding such as metal inert gas and tungsten inert gas welding. The shear and compressive stresses are increased, and fatigue cracking, weight, and cost are also reduced as a result of LBW, including the elimination of stresses and corrosion associated with rivets and the elimination of adhesives. Dissimilar metals such as the 7000 series and the 2000 series can be joined with a filler metal compatible to both metals to mitigate galvanic corrosion.
Conference papers on the topic "Laser beam joining"
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Legewie, F., L. Bosse, M. Wild, A. Gillner, and R. Poprawe. "Laser beam joining for the micro technology." In ICALEO® ‘98: Proceedings of the Laser Materials Processing Conference. Laser Institute of America, 1998. http://dx.doi.org/10.2351/1.5059202.
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Adamiec, Janusz, Andrzej Grabowski, and Aleksander Lisiecki. "Joining of an Ni-Al alloy by means of laser beam welding." In Laser Technology VII: Applications of Lasers, edited by Wieslaw L. Wolinski, Zdzislaw Jankiewicz, and Ryszard Romaniuk. SPIE, 2003. http://dx.doi.org/10.1117/12.520719.
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Schubert, Emil, Ingo Zerner, and Gerd Sepold. "Laser beam joining of material combinations for automotive applications." In Lasers and Optics in Manufacturing III, edited by Leo H. J. F. Beckmann. SPIE, 1997. http://dx.doi.org/10.1117/12.281079.
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Kaufmann, Stefan, Andreas Otto, and Gerhard Luz. "Laser beam joining of optical fibers in silicon V-grooves." In Symposium on High-Power Lasers and Applications, edited by Henry Helvajian, Koji Sugioka, Malcolm C. Gower, and Jan J. Dubowski. SPIE, 2000. http://dx.doi.org/10.1117/12.387575.
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Курынцев, Сергей Вячеславович, and Андрей Владиленович Евлампьев. "LASER WELDING OF T-BEAM FROM HETEROGENEOUS ALLOYS." In Высокие технологии и инновации в науке: сборник избранных статей Международной научной конференции (Санкт-Петербург, Июль 2020). Crossref, 2020. http://dx.doi.org/10.37539/vt186.2020.82.54.013.
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В данной работе пересматривается процесс лазерной сварки для соединения стали 18ГСА (DH36) с алюминиевым сплавом 5083 (AA5083) из конфигурации нахлесточного соединения в тавровое, используя уже имеющиеся исследования. In this paper, the laser welding process for joining steel 18GSA (DH36) with aluminum alloy 5083 (AA5083) from the configuration of lap joint to T-joint is reviewed using existing studies. Pre-treatment of materials before welding is also considered.
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Kügler, Helge, Anton Geier, Christoph Mittelstädt, Felix Möller, and Thomas Seefeld. "Gap tolerant joining of 22MnB5 steel by laser hybrid welding with beam oscillation and laser brazing with two laser beams." In ICALEO® 2014: 33rd International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing. Laser Institute of America, 2014. http://dx.doi.org/10.2351/1.5063114.
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Wu, Qiang, Norbert Lorenz, Kevin Cannon, Changhai Wang, Andrew J. Moore, and Duncan P. Hand. "Hermetic joining of micro-devices using a glass frit intermediate layer and a scanning laser beam." In ICALEO® 2008: 27th International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing. Laser Institute of America, 2008. http://dx.doi.org/10.2351/1.5061370.
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Hedrich, H. D., H. G. Mayer, G. Haufler, M. Kopf, and N. Reheis. "Joining of ODS-Superalloys." In ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-411.
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A stable oxide dispersoid distribution in the metal matrix, a textured orientation and a coarse grain structure with high grain aspect ratio are characteristics of ODS-super-alloys. This grain structure is the reason for enhanced mechanical properties, oxidation and corrosion resistance at high temperature unobtainable in other superalloys. Therefore ODS-alloys are promising materials for advanced combustion engines and energy generation units. The ferritic ODS-alloy permits operating temperatures up to 1350°C. In order to produce complex and high temperature resistant components suitable joining methods are technically and economically significant. This paper presents first results of investigations of joining the new iron-base-ODS-alloy PM 2000 developed by Metallwerk Plansee. The following joining techniques are under investigation: gas tungsten-arc welding, laser beam welding and electron beam welding as fusion welding techniques and diffusion bonding as a solid state joining technique. Joining is done in recrystallized and in unrecrystallized condition. Pre- and post-heat treatment procedures were applied and tested to improve the joint strength.
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Russek, U. A. "Laser beam welding of polymers with high power diode lasers joining innovation for micro and macro technologies." In ICALEO® 2001: Proceedings of the Laser Materials Processing Conference and Laser Microfabrication Conference. Laser Institute of America, 2001. http://dx.doi.org/10.2351/1.5059900.
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Miyamoto, Isamu, and Hiroshi Maruo. "Novel laser beam shaping optics: LSV optics applications to transformation hardening and ceramic joining." In ICALEO® ‘92: Proceedings of the Laser Materials Processing Symposium. Laser Institute of America, 1992. http://dx.doi.org/10.2351/1.5058545.
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