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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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Influence of process parameters on thermal cycle and intermetallic compounds formation in high speed laser weld-brazing of aluminium-steel angle joints
摘要： AA6016-T4 aluminium and DX56D+Z140M steel sheets were joined by fluxless laser weld-brazing process with ER4043 AlSi5 filler wire at high brazing speed. The configuration studied corresponds to typical automotive roof/body-side angle joints. At the interface, the measurements of thermal cycle are performed with K-thermocouples. The results are compared to simulated thermal cycles obtained through SYSWELD Software. Thermal cycles are evaluated with the maximal temperature reached, the time of interaction at high temperature and the cooling speed. Several combinations of laser power and brazing speed are both investigated experimentally and by simulation to study their influence on the thermal cycle and the intermetallic layer thickness. Thermal cycles are discretized to calculate the theoretical growth of the intermetallic compounds with a diffusion-based model. The result is compared to experimental intermetallic layer measured with optical microscopy. The power tends to influence both the maximal temperature and the cooling speed whereas the brazing speed only influences the maximal temperature. The calculation demonstrates the capability to distinguish the process configuration which will lead to the thickest intermetallic layer.
关键词： fluxless laser weld-brazing,simulation,Fe-al dissimilar joints,intermetallic layer calculation,thermal cycle,process parameters
更新于2025-09-12 10:27:22
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Low Conductivity Decay of Sn–0.7Cu–0.2Zn Photovoltaic Ribbons for Solar Cell Application
摘要： The present study applied Sn–0.7Cu–0.2Zn alloy solders to a photovoltaic ribbon. Intermetallic compounds of Cu6Sn5 and Ag3Sn formed at the Cu/solder/Ag interfaces of the module after re?ow. Electron probe microanalyzer images showed that a Cu–Zn solid-solution layer (Zn accumulation layer) existed at the Cu/solder interface. After a 72 h current stress, no detectable amounts of Cu6Sn5 were found. However, a small increase in Ag3Sn was found. Compared with a Sn–0.7Cu photovoltaic module, the increase of the intermetallic compounds thickness in the Sn–0.7Cu–0.2Zn photovoltaic module was much smaller. A retard in the growth of the intermetallic compounds caused the series resistance of the module to slightly increase by 9%. A Zn accumulation layer formed at the module interfaces by adding trace Zn to the Sn–0.7Cu solder, retarding the growth of the intermetallic compounds and thus enhancing the lifetime of the photovoltaic module.
关键词： photovoltaic ribbon,Sn–0.7Cu–0.2Zn,intermetallic compounds,Zn accumulation layer
更新于2025-09-12 10:27:22
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The Quest for Zero Loss: Unconventional Materials for Plasmonics
摘要： There has been an ongoing quest to optimize the materials used to build plasmonic devices: first the elements were investigated, then alloys and intermetallic compounds, later semiconductors were considered, and, most recently, there has been interest in using more exotic materials such as topological insulators and conducting oxides. The quality of the plasmon resonances in these materials is closely correlated with their structure and properties. In general gold and silver are the most commonly specified materials for these applications but they do have weaknesses. Here, it is shown how, in specific circumstances, the selection of certain other materials might be more useful. Candidate alternatives include TixN, VO2, Al, Cu, Al-doped ZnO, and Cu–Al alloys. The relative merits of these choices and the many pitfalls and subtle problems that arise are discussed, and a frank perspective on the field is provided.
关键词： plasmonics,conducting oxides,topological insulators,intermetallic compounds,figure-of-merit,material selection
更新于2025-09-11 14:15:04
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[IEEE 2019 41st Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC) - Berlin, Germany (2019.7.23-2019.7.27)] 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - An Improved Liquid Metal Mask Printing enabled Fast Fabrication of Wearable Electronics on Fabrics <sup>*</sup>
摘要： The rare earth con?guration entropy dependence of the crystal structure, microstructure and magnetic properties for SmCo5 based intermetallic compounds has been systematically investigated by using power X-ray diffraction, scanning electron microscopy with energy dispersive spectroscopy and magnetic measurement. The studies show that the single phase with CaCu5 type structure forms in (Sm1/2Nd1/2)Co5, (Sm1/3Nd1/3Y1/3)Co5 and (Sm1/4Nd1/4Y1/4Tb1/4)Co5. The formation of single phase is derived from Miedema's model due to the mixing enthalpy of 0 kJ$mol(cid:1)1 at rare earth site. The high entropy (Sm1/4Nd1/4Y1/4Tb1/4)Co5 intermetallic compound is obtained due to its con?guration entropy of 1.39R and rare earth equiatomic ratio at Sm site. The morphologic images show that the grains are growing and agglomerating with doping equiatomic rare earth Y and Tb. The magnetization of sample cannot reach saturation within the maximum ?eld of 30 kOe at room temperature, the magnetizing curve follows the Langevin model for SmCo5 and (Sm1/2Nd1/2)Co5, and the modi?ed Langevin model for (Sm1/3Nd1/3Y1/3)Co5 and (Sm1/4Nd1/4Y1/4Tb1/4)Co5, respectively. The ?tted magnetization is going down with substitution of nonmagnetic Y and heavy rare earth Tb due to the diluting magnetic effect of nonmagnetic Y substitution for Sm and the weakened effects on moment of Tb moment arrangement antiparallel to that of Co. The coercivity tends to decrease due to the agglomeration and growth of grains. It implies that the con?guration entropy seems to have little effect on the room temperature magnetizing process.
关键词： High entropy,Single phase,SmCo5 intermetallic compound,Magnetic property
更新于2025-09-11 14:15:04
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Influence of electrodeposited Cu-Ni layer on interfacial reaction and mechanical properties of laser welded-brazed Mg/Ti lap joints
摘要： A fiber laser welding-brazing procedure has been developed for joining AZ31B magnesium alloy to Cu-Ni coated Ti-6Al-4V titanium sheet using AZ92D filler wire. The effect of the interlayer arrangements (AZ31B/Ni-Cu/Ti-6Al-4V and AZ31B/Cu-Ni/Ti-6Al-4V) on appearance, interfacial reaction and mechanical properties were investigated at different heat input. It was found that the feasibility of this process depends strongly on the pre-existing Cu-Ni layer on the Ti surface that promotes wetting of the AZ92 filler. Within the range of 1200–1600 W, defect free joints in both interlayer arrangements. Depending on the interlayer arrangements chosen, different reactions layers formed inside the joint region. Nevertheless, at optimum heat input (1400 W), Ti2Ni mingled with Ti3Al interfacial reaction products was produced along the fusion zone (FZ)-Ti brazed interface in both interlayer arrangements. The tensile-shear fracture load of the joints produced at the optimum laser power reached a maximum value of 2016.5 N for AZ31B/Ni-Cu/Ti-6Al-4V and 2014.6 N for AZ31B/Cu-Ni/Ti-6Al-4V, representing an efficiency of 71% compared to AZ31B alloy. Under suitable heat input, the joints failed at the fusion zone of the AZ31B base metal. In contrast, incomplete brazing or large volume of intermetallics at the brazed interface resulted in interfacial failure at lower/higher heat input.
关键词： Laser welding-brazing,Mg alloy,Intermetallic compounds (IMCs),Ti alloy,Microstructure
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Influence of indium addition on wetting characteristics of Sn-3Ag-0.5Cu solder alloy on Cu substrate
摘要： This work investigates the effect of Indium (In) addition, 0.5 wt.% In, on the wettability of the Sn–3Ag–0.5Cu (SAC305) ternary pb-free solder alloy. Adding In to SAC305 decreased the contact angles (θ) of the Sn-2.5Ag-0.5Cu-0.5In quaternary pb-free solder alloy decreased which were measured by using of the sessile drop method at various temperatures (250, 280 and 310 °C) on Cu substrate in Ar atmosphere. Microstructures, inter-metallic phases, and melting temperatures of alloys were characterized by optic microscope and scanning electron microscope and energy dispersive X-ray spectroscopy, X-ray diffraction, and differential scanning calorimeter, and effects of the amount of In on microstructure were investigated. The results indicated that when the addition of In was 0.5 wt.%, the change in melting temperature of Sn–2.5Ag-0.5Cu–0.5In solder was negligible, but the contact angles (θ) of the solder alloy decreased which were measured by using of the sessile drop method at various temperatures. The lowest θ was obtained as 45.22° for Sn–2.5Ag-0.5Cu– 0.5In alloy at 310 °C. The formation of intermetallic compounds (IMC) between the Pb-free solder alloys and the Cu substrate was observed. Thus, If the amounts of indium and silver are optimized, the Sn-2Ag-0.5Cu-0.5In quaternary solder alloy may be a suitable potential candidate to replace conventional Sn-3.0Ag-0.5Cu solder to provide economic gain in solder alloy production.
关键词： Indium addition,Sn-3Ag-0.5Cu solder alloy,Cu substrate,wettability,intermetallic compounds
更新于2025-09-04 15:30:14