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Welding of Dissimilar Steel/Al Joints Using Dual-Beam Lasers with Side-by-Side Configuration
摘要： Welding of dissimilar steel/Al lapped joints of 1.5 mm in thickness was carried out by using dual-beam laser welding with side-by-side configuration. The effect of the major process parameters including the dual-beam power ratio of (Rs) and dual-beam distance (d1) on the steel/Al joint characteristics was investigated concerning the weld shape, interface microstructures, tensile resistance and fracture behavior. The results show that dual-beam laser welding with side-by-side configuration produces soundly welded steel/Al lapped joints free of welding defects. The processing parameters of Rs and d1 have a great influence on the weld appearance, the weld penetration in the Al alloy side (P2) and the welding defects. Variation in the depth of the P2 and the locations at the Al/weld interface cause heterogeneous microstructures in the morphology and the thickness of the intermetallic compound (IMC) layers. In addition, electron back scattered diffraction (EBSD) phase mapping reveals that the IMC layer microstructures formed at the Al/weld interface include the needle-like θ-Fe4Al13 phases and compact lath η-Fe2Al5 layers. Some very fine θ-Fe4Al13 and η-Fe2Al5 phases generated along the weld grain boundaries of the steel/Al joints are also confirmed. Finally, there is a matching relationship between the P2 and the tensile resistance of steel/Al joints, and the maximum tensile resistance of 109.2 N/mm is obtained by the steel/Al joints produced at the Rs of 1.50 during dual-beam laser welding with side-by-side configuration. Two fracture path modes have taken place depending on the P2, and relatively high resistance has been achieved for the steel/Al joints with an optimum P2.
关键词： dual-beam laser welding,tensile resistance,side-by-side configuration,EBSD phase mapping,steel/Al joint
更新于2025-11-28 14:24:20
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Interface characterization and mechanical properties of dual beam laser welding-brazing Al/steel dissimilar metals
摘要： The DP590 steel to AA7075 Al-alloy with lap configuration is successfully joined by dual beam laser welding-brazing without using filler metal. Through the introduction of the derived laser beam, the wetting angle, wetting distance and the thickness of intermetallic compound (IMC) layer are well improved and controlled. It is found that the wettability of liquid Al on steel improves with the increase of laser power, i.e. the wetting angle decreasing from 25.3° to 17.8° and the wetting distance increasing from 2.17 mm to 3.19 mm as the laser power increasing from 1.0 kW to 1.6 kW. Two kinds of IMC exist at brazing interface, one is η-phase (Fe2Al5) with flatten morphology closing to the steel side and the other is θ-phase (FeAl3) with needle-like morphology adjacent to the welding-brazing seam. The thickness of IMC layer increases from 8.37 μm to 12.12 μm with increasing laser power from 1.0 kW to 1.6 kW. Tensile test shows that both the wettability and the IMC thickness have influence on the welding-brazing joint strength. Poor wettability and too thick IMC layer will result in lower strength and fracture occurred in brazing interface. The optimal joint tensile strength of 123.7 MPa on average is achieved with the laser power of 1.4 kW.
关键词： Tensile strength,Welding-brazing,IMC,Dual beam laser,Al/steel dissimilar metals
更新于2025-11-28 14:24:20
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Viscoelasticity Measurements by an Optofluidic Micro-Rheometer
摘要： During the last decades, microrheology attracted a significant attention thanks to the possibility of investigating the viscoelastic properties of complex systems (e.g. cells and soft materials) at micrometer scale. The inherent low-consumption of sample offered by microrheology makes it the ideal candidate to study the rheological properties of precious/limited materials. In active microrheology, optical or magnetic forces enable trapping and manipulation of micro-probes in the fluid under test. The probe’s response to external stimuli is used to derive the rheological properties of the surrounding medium. While this approach has been already reported in the scientific literature mainly using optical tweezers [1], in this document we propose a different system configuration based on a dual beam laser trap, previously exploited to realize a simple viscometer [2,3]. The here proposed device has all the features of a rheometer, also allowing to measure the elastic properties, and has the advantage of requiring a lower beam intensity while being able to apply larger forces with respect to standard optical tweezers. Additionally the system can be easily integrated in a glass substrate, requiring just an external connection to a CW-laser source and a low-magnification objective for sample observation.
关键词： optical tweezers,dual beam laser trap,microrheology,viscoelastic properties,rheometer
更新于2025-09-12 10:27:22