0000000000341143
AUTHOR
Henri Andrzejewski
La compréhension et la maîtrise des jonctions hétérogènes titane-aluminium réalisés par faisceau laser
La presente etude est dediee a la comprehension des facteurs influencant la resistance mecanique d’un assemblage entre l’alliage de titane Ti6Al4V avec l’alliage d’aluminium AA5754 par faisceau laser Yb:YAG. Le plan d’experiences propose a permis de mettre en evidence les effets des parametres operatoires sur la composition et la morphologie de la zone fondue ainsi que l’identification des conditions operatoires les plus favorables. L’etude numerique multiphysique basee sur l’utilisation de la methode des elements finis prenant en compte les transferts de chaleur, la mecanique des fluides et le transport des especes, a demontre les consequences des differences de proprietes thermo-physiques…
The formation of intermetallics in dissimilar Ti6Al4V/copper/AISI 316 L electron beam and Nd:YAG laser joints
Abstract The welds of titanium alloys with steels suffer from the brittleness of resulting intermetallic compounds. In present study, we report the feasibility of Ti6Al4V to stainless steel AISI 316L welding through pure copper interlayer carried out by electron beam and pulsed Nd:YAG laser. The nature and the localization of intermetallic phases in these welds have been studied by SEM, EDS, XRD and microhardness measurements. The simplified scenario of weld formation has been proposed in order to understand the mechanism of weld formation and to explain the way local phase content determines the mechanical properties. It can be concluded that the insertion of 500 μm pure copper interlayer …
Applied multi-pulsed laser in surface treatment and numerical–experimental analysis
International audience; This paper presents a comparison between simulation and experimental results of the melting process of metallic material by a pulsed laser source Nd–YAG. The simulations of temperature and velocity fields of melted material were done by solving the transient heat transfer and fluid-flow equations. Variations of the thermophysical properties were considered. Furthermore, the model included the effects of the surface-tension gradient on the fluid surface and the buoyancy force. The simulation was useful in improving our understanding of the phenomena occurring in the treated material. Using a laser triangulation sensor, an experimental study was also conducted on the s…
The use of exploratory experimental designs combined with thermal numerical modelling to obtain a predictive tool for hybrid laser/MIG welding and coating processes
Abstract While hybrid laser welding and coating processes involve a large number of physical phenomena, it is currently impossible to predict, for a given set of influencing factors, the shape of the molten zone and the history of temperature fields inside the parts. This remains true for complex processes, such as the hybrid laser/MIG welding process, which consists in combining a laser beam with a MIG torch. The gains obtained result essentially from the synergy of the associated processes: the stability of the process, the quality of the seam realized, and the productivity are increased. This article shows how, by means of a reduced number of experiments (8), it is possible to predict th…
Numerical and Experimental Analysis of Convection Transfer During Melting by a Mono-Pulsed Laser
This paper presents a comparison between simulation and experimental results of the melting process of metallic material by a pulsed laser source Nd-YAG. Variations of the thermophysical properties were considered. Furthermore, the model included the effects of the surface-tension gradient on the fluid surface and the buoyancy force. The keyhole effect induced strong surface deformations and often formed cavities, which arre undesirable in the surface treatment process. An experimental study of the surface profile of the melted zones was also conducted to seek a relationship between the so-called keyhole effect and the laser triangulation measurements. The predicted Laser Melted Zone (LMZ) …
The numerical simulation of heat transfer during a hybrid laser–MIG welding using equivalent heat source approach
International audience; The present study is dedicated to the numerical simulation of an industrial case of hybrid laser-MIG welding of high thickness duplex steel UR2507Cu with Y-shaped chamfer geometry. It consists in simulation of heat transfer phenomena using heat equivalent source approach and implementing in finite element software COMSOL Multiphysics. A numerical exploratory designs method is used to identify the heat sources parameters in order to obtain a minimal required difference between the numerical results and the experiment which are the shape of the welded zone and the temperature evolution in different locations. The obtained results were found in good correspondence with …