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The relation between magnesium evaporation and laser absorption and weld penetration in pulsed laser welding of aluminum alloys: Experimental and numerical investigations
摘要： It is observed that in laser welding of aluminum alloys, magnesium can evaporate, and the weld penetration is dependent on Mg content of the alloy and Mg loss from the weld pool. In this research, it is proposed that the presence of Mg not in the base metal alloy, but rather the presence of Mg vapor in the plasma plume over the weld pool affects the laser absorption, and it is through this phenomenon that the weld profile and penetration is affected. Numerical simulation was performed to determine the relationship between the weld profile to estimate the effective laser absorption coefficient of four Al alloys and in parallel EPMA technique was used to determine the Mg losses of the weld metals. The combined analysis of the results showed that increasing the laser pulse energy (decreasing laser pulse frequency), Mg evaporation is increased, and that, in turn, increased the effective laser absorption coefficient. However, more laser power absorption does not necessarily mean more weld penetration. Laser absorption results in weld penetration, once the threshold Mg evaporation rate of 200 × ?10 6g/cm2 is passed.
关键词： Pulsed laser welding,Effective absorption coefficient,Aluminum alloys,Evaporation,Magnesium content,Penetration depth
更新于2025-09-23 15:21:01
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Conductive and convective heat transfer during welding of AISI316L stainless steel using pulsed Nd: YAG laser
摘要： Conductive and convective heat transfers during an autogenous butt joint welding of AISI 316L stainless steel sheets using pulsed Nd: YAG laser have investigated. An FEA based three-dimensional model was developed to receive the transient thermal responses across the weld pool and the predicted results are compared with experimental observations. The heat transfer in the keyhole region, melt ?ow directions around the keyhole and heat affected zone are computed for consecutive pulse irradiation during laser welding and the same was investigated on far with experiment. The temperature distribution have predicted in terms of inward heat ?ux and Paclet number to investigate the heat and mass transportation in the weld pool. These results have taken for discussion and found that has a close association with experimental results.
关键词： Peclet Number,Pulsed laser welding,Melt ?ow,316L Stainless steel,Moving heat source,Heat transfer
更新于2025-09-16 10:30:52
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Microstructure development in Pulsed Laser Welding of Dual Phase Steel to Aluminium Alloy
摘要： Lap joining of aluminium 6061 and dual phase (DP 600) steel was carried out in pulse welding mode using a high power diode laser. The effect of laser parameters (laser power, scanning speed and pulse duration) on the microstructural evolution during conduction welding was studied. The large difference in thermal and physical properties of DP 600 and Al 6061 alloy results in the formation of brittle intermetallic phases along the interface of the weld zone. At a laser power of 4 kW, scanning speed of 5 mm/s and pulse duration of 10 ms the thickness of the intermetallic phase formed was found to be reduced i.e. in the range of 1- 7 μm. The porosity in the weld zone were mainly due to the entrapment of the zinc vapors during welding because of its low vaporization temperature compared to DP 600 and Al 6061 alloy. Microstructural characterization of the intermetallic phases was done using scanning electron microscopy, X-ray diffraction and the phase composition were characterized using energy dispersive spectroscopy. The micro-hardness testing was to evaluate the mechanical properties of the lap joint. A maximum hardness of 461 HV was observed along the weld- aluminium interface owing to the presence of hard and brittle Fe2Al5 and FeAl3 intermetallic phases.
关键词： Dual phase steel,Intermetallic phases,Pulsed laser welding,Aluminium alloys
更新于2025-09-12 10:27:22
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Effect of energy parameters of pulsed laser welding of Zr-1%Nb alloy on metal contamination with gases and properties of welds
摘要： Effect of pulsed laser welding parameters (pulse energy and duration, frequency, welding speed and, as a result, overlapping factor) on properties of E110 (Zr-1%Nb) alloy welds is presented. Butt welded joints of two identical plates with a thickness of 0.5 mm were investigated. EDS analysis of a surface layer of the welds was done, initial hydrogen concentration in the weld metal was measured and influence of absorbed gases (oxygen, nitrogen, carbon and hydrogen) on tensile strength, microhardness, hydrogen absorption rate and corrosion resistance of the welds was evaluated. The weld metal contained initial hydrogen concentration within the limits set by standards. However, mixing argon flows with atmospheric gases caused the weld metal contamination with oxygen, nitrogen and carbon. As a result, inclusions of complex chemical composition and surface branching microcracks were formed. They were stress raisers where weld failures occurred. Furthermore, it was the reason of increased hydrogen absorption rate and decreased corrosion resistance of the weld metal. The obtained results showed that absence of discoloration on surfaces of the welded joints did not guarantee metal purity and, as a consequence, required performance properties. Future research is required to determine the optimal overlapping factor; shielding gas compositions (Ar, He or their mixture) and flow rates; configuration and inclination angle of nozzles as well as distance from the nozzles to the weld zone.
关键词： Pulsed laser welding,Metal contamination,Corrosion resistance,Hydrogen content,Zirconium alloy,Hydrogen absorption rate
更新于2025-09-12 10:27:22