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Manufacturing profile-free copper foil using laser shock flattening
摘要： Copper foil is a key material of printed circuit boards and plays an important role in the conductance of electric circuits and interconnection of electronic components. When high-frequency signals were transmitted in rough copper foil wires, the conductor resistance, wire loss, and signal loss increased because of the skin effect. To reduce the negative influence of the skin effect and improve the quality of the copper foil, a laser shock flattening (LSF) method was proposed to manufacture profile-free copper foil with high performance. It was concluded that the better flattening effect for large-area profile-free copper foil could be achieved at a pulse energy of 0.25 J and an overlap rate of 25%, and its surface roughness decreased by 67.0% from 52.1 nm to 17.2 nm. Subsequently, to determine the mechanism for the flattened deformation of copper foil induced by LSF, the microstructures of the copper foil before and after flattening were characterised using transmission electron microscopy. A higher dislocation density and a few deformation twins were found in the profile-free copper foil. Ultimately, nano-indentation, micro-tensile, and electrochemical corrosion tests indicated that the mechanical properties and corrosion resistance of the copper foil were significantly improved by LSF. This technique would enable the successful fabrication of large-area profile-free copper foil with high performance for the emerging applications of ultra-high-frequency signal communication and printed circuit board manufacture.
关键词： Corrosion resistance,Mechanical properties,Flattened deformation mechanism,Microstructures,Laser shock flattening,Profile-free copper foil
更新于2025-09-23 15:21:01
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Selective laser melting 316L/CuSn10 multi-materials: Processing optimization, interfacial characterization and mechanical property
摘要： Adopting selective laser melting (SLM), a typical technology of additive manufacturing (AM), to form multi-material metallic composites is a challenging and promising field. In this study, SLM 316L/CuSn10 multi-material composites was an innovative attempt to develop functional and structural materials with excellent properties of steel and copper alloys. Dense 316L/CuSn10 specimens with no interfacial macrocracks were successfully fabricated. Results showed that the Vickers microhardness gradually decreased from 329.5±12.5 HV in 316L region to 172.8HV±7.4 in CuSn10 region. The ultimate tensile strength and flexural strength of 316L/CuSn10 sample was 210 MPa, which was higher than the steel/copper alloys fabricated by other methods. It indicated an ideal interfacial bonding condition of 316L/CuSn10 multi-material, which was benefited from sufficient agitation of the molten pools and elements diffusion in the term of continuous distribution of elements and the enrichment of the heterogeneous alloy phases. Also, the grain refinement by re-melting and recrystallization upgraded the bonding performance at the interface. Finally, the 316L/CuSn10 lattice structure was formed by SLM, hinting at the prospects for industrial applications of steel/copper multi-material by SLM in future.
关键词： Selective laser melting (SLM),Mechanical properties,Interface,316L/CuSn10,Multi-material,Microstructure
更新于2025-09-23 15:21:01
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Study on the Microstructure and Properties of Al/Cu Laser Filled Solder Joint
摘要： Using IPG-YLS-4000 fiber laser to weld T2 copper plate and LY16 aluminum alloy plate, using Zn-10%Al flux cored wire as filler material, the microstructure of the joint was observed and analyzed by SEM and EDS, and the effects of laser power, welding speed and welding line energy on the mechanical properties of the joint were studied. The results show that the joints are mainly divided into copper side brazing area, weld center area and aluminum side fusion welding area. Among them, there are two interface reaction layers composed of intermetallic compound (IMC) in the copper side brazing area, the first layer is CuZn compound in the form of strip, and the second layer is Al2Cu phase in the form of shoot. The central area of the weld is mainly composed of massive α-Al phase and branched β-Zn phase. The tensile strength of the joint increases first and then decreases with the increase of laser power, welding speed and welding line energy. The thickness of IMC layer grows linearly with the increase of line energy. The best process parameters: when the laser power is 2200 W, the welding speed is 0.9 m/min, the welding line energy is 1446.67 J/cm, the IMC layer thickness is 10.11 μm, and the tensile strength reaches the maximum value, 252.6 MPa.
关键词： intermetallic compound,Al/Cu laser welding,microstructure,mechanical properties,Zn-10%Al flux cored wire
更新于2025-09-23 15:21:01
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Experimental and numerical investigation of selective laser meltinga??induced defects in Tia??6Ala??4V octet truss lattice material: the role of material microstructure and morphological variations
摘要： The remarkable progress in additive manufacturing has promoted the design of architected materials with mechanical properties that go beyond those of conventional solids. Their realization, however, leads to architectures with process-induced defects that can jeopardize mechanical and functional performance. In this work, we investigate experimentally and numerically as-manufactured defects in Ti–6Al–4V octet truss lattice materials fabricated with selective laser melting. Four sets of as-manufactured defects, including surface, microstructural, morphological, and material property imperfections, are characterized experimentally at given locations and orientations. Within the characterized defects, material property and morphological defects are quanti?ed statistically using a combination of atomic force microscopy and micro–computed tomography to generate representative models that incorporate individual defects and their combination. The models are used to assess the sensitivity to as-manufactured defects. Then, the study is expanded by tuning defects amplitude to elucidate the role of the magnitude of as-designed defects on the mechanical properties of the lattice material.
关键词： mechanical properties,octet truss lattice,additive manufacturing,defects,Ti–6Al–4V,selective laser melting
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Structural and Optical Properties of Two-Stage CuInSe <sub/>2</sub> Thin Films Studied by Real Time Spectroscopic Ellipsometry
摘要： In this paper, a robotic cell rotation method based on the minimum rotation force is presented to adjust oocyte orientation in biological applications. In this method, the minimum rotation force, which can control the rotation angle (RA) of the oocyte quantitatively and generate minimum oocyte deformations, is derived through a force analysis on the oocyte in rotation. To exert this force on the oocyte, the moving trajectories (MT) of the injection micropipette (IM), are determined using mechanical properties of the oocytes. Further, by moving the IM along the designed MT, the rotation force control is achieved. To verify the feasibility of this method, a robotic rotation experiment for batch porcine oocytes are performed. Experimental results demonstrate that this system rotates the oocyte a10t an average speed of 28.6s/cell and with a success rate of 93.3%. More importantly, this method can generate much less oocyte deformations during cell rotation process compared with the manual method, while the average control error of RA in each step is only 1.2 (versus averagely 8.3 in manual operation), which demonstrates that our method can effectively reduce cell deformations and improve control accuracy of the RA.
关键词： micro-operation,force control,Cell mechanical properties,cell rotation
更新于2025-09-23 15:21:01
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Laser-arc hybrid welding of 12- and 15-mm thick structural steel
摘要： High-power lasers are very effective in welding of plates thicker than 10 mm due to the keyhole mode. High-power intensity generates a vapor-filled cavity which provides substantial penetration depth. Due to the narrow and deep weld geometry, there is susceptibility to high hardness and weld defects. Imperfections occur due to keyhole instability. A 16-kW disk laser was used for single-pass welding of 12- to 15-mm thick plates in a butt joint configuration. Root humping was the main imperfection and persisted within a wide range of process parameters. Added arc source to the laser beam process may cause increased root humping and sagging due to accelerated melt flow. Humping was mitigated by balancing certain arc and other process parameters. It was also found that lower welding speeds (< 1.2 m/min) combined with lower laser beam power (< 13 kW) can be more positive for suppression of humping. Machined edges provided more consistent root quality and integrity compared with plasma cut welded specimens. Higher heat input (> 0.80 kJ/mm) welds provided hardness level below 325 HV. The welded joints had good Charpy toughness at ? 50 °C (> 50 J) and high tensile strength.
关键词： Mechanical properties,Toughness,Thick steel,Hybrid welding,High strength steel,Laser welding
更新于2025-09-23 15:21:01
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Directed energy deposition of Al 5xxx alloy using Laser Engineered Net Shaping (LENS??)
摘要： Here, we present directed energy deposition (DED) of wrought-like Al 5xxx AlMg alloy by Laser Engineered Net Shaping (LENS?). A transition from an Al 5083 gas atomized powder feedstock to Al 5754 characteristics of the as-deposited material due to selective evaporation of Mg was observed. Density values obtained by X-ray micro-computed tomography (μ-CT) were compared to those obtained by the Archimedes method. The latter indicated a relative density as high as 99.26%. Possible origins of porosity are discussed. The as-deposited material was comprised of both equiaxed and columnar grains with no preferred crystallographic orientation and mean grain size of 36 μm. The Young's modulus, yield stress, ultimate tensile strength, fracture strain, Poisson's ratio, and total ultimate strain energy (toughness) were determined by uniaxial tensile tests combined with digital image correlation (DIC). Fractography complemented the mechanical testing. A pulse-echo ultrasonic non-destructive test was used to obtain more accurate values of the Young's and shear moduli and to adjust the value of the yield strength accordingly. The measured mechanical properties meet the requirements of international standards for wrought Al 5754 in its annealed condition.
关键词： Additive manufacturing (AM),Mechanical properties,Micro-computed tomography (μ-CT),Laser Engineered Net Shaping (LENS?),Directed energy deposition (DED),Aluminum alloys
更新于2025-09-23 15:21:01
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Influence of processing parameters on mechanical and fatigue properties of 316??L steel manufactured by selective laser melting
摘要： The Selective Laser Melting process involves multiple factors that are detrimental to fatigue life. It is crucial to select optimal processing parameters to avoid internal porosity, source of early failure through crack initiation mechanisms. Surface condition, especially high roughness values, may also be a critical factor for crack initiation. Influence of surface condition must be studied in the industrial context, where parts may not be completely machined before implementation. This work first focused on finding optimal parameters for producing low-porosity 316 L parts by the SLM process. Once a suitable set of parameters was found, a set of samples was characterized mechanically. Fatigue samples were then produced and submitted to various surface treatments (machining, polishing, …), while some were left as-built. They were then tested in high-cycle fatigue and S-N curves produced for each sample type. This study indicates that high-cycle fatigue life of SLM 316 L is generally inferior to wrought 316 L, with as-built samples exhibiting lower fatigue limits. This was explained by surface roughness acting as crack initiation sites. Porosity was also found to be a very significant factor in fatigue life of SLM 316 L.
关键词： Fatigue,Processing parameters,Selective laser melting,316 L,Mechanical properties
更新于2025-09-23 15:21:01
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Influence of Plasma Transfer Arc Cladding of NiCrBFe filler powder on microstructure and tensile properties of Titanium Grade 2 and Ti 6Al-4V alloy dissimilar joint prepared by laser beam welding
摘要： The present investigation deals with the effect of Plasma Transfer Arc Cladding (PTAC) of 60%Ni30%CrB10%Fe filler powder on microstructure and tensile properties of Titanium Grade 2 and Ti 6Al-4V alloy dissimilar joint done by laser beam welding. In laser beam welding, full depth of penetration was achieved using the laser beam power of 1300 W, welding speed of 200 mm/min and focus distance of 10 mm. Tensile studies showed that all the failures occurred in the fusion zones of as-welded, dissimilar weldments and PTAC coated samples. Failure analysis was performed using Comsol software and the results were obsersed as well-in accordance with the experimental results. Finite element studies showed the better accuracy results while comparing both experie-mental and simulation results. The microstructure and mechanical properties studies were conducted on as-welded, dissimilar weldments and PTAC coated samples by scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive spectrum (EDS), and X-ray diffraction (XRD) respectively. XRD displayed the slight presence of compressive residual stress in PTAC coated samples. The microstrcture studies conducted at the fusion zone revealed that more amount of coarse grain boundaries were converted into α-Fe. The avearge heat inputs (Hi) were applied in the coated samples that converted the α + β phase structure into TiNi + TiCrFe boundarys. PTAC coated samples showed the average hardness value of 313 HV and dissimilar weldments exhibited the hardness value of 290 HV. The present study concluded that the corrosion resistance of coated materials was improved owing to the better tensile and bending strength of material.
关键词： Mechanical Properties,Plasma Transfer Arc Cladding,Finite element analysis,NiCrBFe filler powder,Laser beam welding
更新于2025-09-23 15:21:01
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Experimental investigation on Ytterbium fiber laser butt welding of Inconel 625 and Duplex stainless steel 2205 thin sheets
摘要： In this study, welding of Superalloy Inconel 625 and duplex stainless steel 2205 (DSS 2205) has been successfully performed through Ytterbium fiber laser at different heat inputs. With decreasing energy input, width of the weld bead narrowed and the mechanical properties of the joint improved. Characterization of the weld joint was carried out using Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), and micro-hardness testing. No solidification cracks or porosity was observed in the microstructure of the weld metal (WM). Cellular dendritic and columnar dendritic grains were main grain types observed in the weld metal. At heat input of 43 J/mm, inter-dendritic arms of the weld metal witnessed more segregation of Molybdenum and Niobium in comparison of welded samples at heat input of 21.5 J/mm. Carbides of Cr, Mo and Ni are formed in the weld joint interface as revealed by the XRD analysis. Tensile strength study reveals the maximum strength of 890 MPa when the heat supplied is low i.e. 21.5 J/mm. This strength value is more than that of the base metal (DSS 2205). The result obtained in terms of comprehensive structure-property correlation, recommends the effectiveness of laser beam welding for joining of the said dissimilar alloys.
关键词： Mechanical properties,Laser beam welding,Duplex stainless steel 2205,Microstructure,Inconel 625
更新于2025-09-23 15:19:57