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A comparison between induction pre-heating and induction post-heating of laser-induction hybrid welding on S690QL steel
摘要： In this paper, the di?erences of microstructure and performance of S690QL steel between induction pre-heating laser-induction hybrid welding (LIHW) and post-heating LIHW were compared via scanning electron microscope (SEM), energy-dispersive spectroscopy (EDS), electrical back-scattered di?raction (EBSD), and mechanical machines. The t8/5 values of both pre-heating and post-heating LIHW joints were shown to increase with inductor output power increasing from 60% to 80% and 100%, and each temperature curve of the post-heating LIHW weld center (WC) and heat-a?ected zone (HAZ) has two peak values. Through experimental and theoretical analyses, pre-heating LIHW joints were determined to mainly contain ferrite, bainite and little martensite, while the post-heating LIHW joints have more bainite. Except for the 80% inductor output power post-heating sample, the microstructures demonstrate dispersing phenomena, as well as weld defects. With increasing pre-heating LIHW inductor output powers, the proportion of ferrite rises, martensite and bainite contents decrease, and dislocation pileup occurs; these will lead to the decrease of microhardness and an increase in plasticity. However, in post-heating LIHW joints, the amounts of ferrite and martensite show a decreasing tendency, and the proportion of bainite tends to increase. The fracture pattern of pre-heating LIHW joints and post-heating LIHW joints is shown to be a dimple fracture, and the pre-heating LIHW joints have a better tensile strength and toughness. Thus, compared with post-heating LIHW, pre-heating LIHW is shown to be superior.
关键词： Performance,Microstructure,Laser-induction hybrid welding
更新于2025-11-28 14:24:20
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Autogenous fiber laser welding of 70/30 Cu-Ni alloy plates
摘要： Cupronickel alloys such as 70/30 Cu-Ni have excellent resistance to sea water corrosion and anti-fouling properties, and thus have been widely used for naval and offshore applications. Traditionally, arc welding and brazing processes have been used to weld such materials. In contrast, laser beam welding is a promising technology due to its high productivity, good process flexibility and reliability, and good welding integrity. In the present work, a high power fiber laser system is used to weld 5-mm thick 70/30 Cu-Ni alloy plates in a configuration of butt joints. Then, the laser welded joints are evaluated in terms of microstructures, defects, and mechanical properties (hardness, face and root bend, and tensile) in accordance with the applicable International Organization for Standardization and Defence Standard specifications.
关键词： Tensile Properties,Microstructure,Butt Joint,Cupronickel Alloy,Bend testing,Laser Welding
更新于2025-11-28 14:24:20
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Microstructure and properties of WC reinforced Ni-based composite coatings with Y <sub/>2</sub> O <sub/>3</sub> addition on titanium alloy by laser cladding
摘要： In this study, WC reinforced Ni-based composite coatings with Y2O3 addition were deposited on Ti-6Al-4V titanium substrate by laser cladding. The phases, microstructure, microhardness and wear resistance of the composite coatings were studied by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, microhardness tester and wear tester. The results showed that good metallurgical bonding was achieved between the composite coatings and substrate. The phases mainly were γ -Ni, TiC, TiB2, Ni3B, M23C6 and WC. Most of the WC was dissolved in small pieces of WC during the laser cladding process. The microhardness of the composite coatings was about 3 times that of the titanium substrate and the wear resistance of the composite coatings had a significant increase.
关键词： titanium alloy,microstructure,Laser cladding,Y2O3,WC,Ni-based composite coatings
更新于2025-11-28 14:24:20
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Laser in-situ synthesis of high aspect ratio TiB fiber bundle reinforced titanium matrix composite coating
摘要： In this study, coatings are fabricated with laser cladding technique on titanium alloy substrate using TiB2 powder (0.5 μm, 5 μm and 50 μm) as the cladding materials. The effects of different TiB2 particle sizes and different laser powers on the microstructure of laser cladding layer are investigated. The results reveal that the cladding layer of high aspect ratio TiB fiber bundle is formed when using 0.5 μm TiB2 as the cladding material under the condition of high laser power (2.5 kW) of TiB fiber bundle are formed when using 5 μm and 50 μm TiB2 as the cladding materials under the condition of different laser powers. Combined with the evolution of microstructure in the cladding layers, the formation mechanism of high aspect ratio TiB fiber bundle is discussed. Meanwhile, the cladding layer of high aspect ratio TiB fiber bundle exhibits the advantages of high hardness and high wear resistance, and the predominant wear mechanisms of TiB fiber bundle are cutting and fracture.
关键词： TiB fiber bundle,Microstructure,Wear,Laser cladding,Hardness
更新于2025-11-28 14:24:20
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Influence of Al-Si coating on microstructure and mechanical properties of fiber laser welded 22MnB5 steel
摘要： Fiber laser welding of as-received 22MnB5 steel with Al-10wt.%Si coating in butt configuration was performed. The influence of Al-Si coating on microstructure transformation and mechanical properties including tensile tests, fatigue tests and Erichsen cupping tests was investigated. Ferrite with Al enrichment (1.37 wt%) was found in the fusion zone (FZ) of coated welded joints with 15% area proportion, while nearly entire martensite structure composed the FZ in the case of de-coated joint. The strain localization was more likely to accumulate at the martensite/martensite interface rather than the ferrite/martensite interface due to the higher kernel average misorientation (KAM) values. Microhardness of the FZ in coated welded joints dropped by 50HV compared with that of de-coated welded joints. However, tensile properties were not affected since failure occurred at base metal (BM). Fatigue samples of coated welded joints showed better performance than the de-coated ones, suggesting that the ferrite in the FZ had positive effect on fatigue lives under cycling load conditions. The Erichsen cupping tests showed similar Erichsen values (5.60 mm and 5.67 mm) for de-coated and coated welded joints. An opposite effect of ferrite on Erichsen cupping tests was obtained. The peak force required for deformation dropped by 35% with Al-10wt.%Si coating.
关键词： Microstructure,Al-Si coating,Mechanical properties,Fiber laser welding,22MnB5 steel
更新于2025-11-28 14:24:20
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Tailoring Properties of Microcavity In-line Mach-Zehnder Interferometer by the Microcavity Enlargement using Femtosecond Laser
摘要： This work presents a theoretical analysis and experimental verification of fine-tuning of the spectral response and refractive index (RI) sensitivity of microcavity in-line Mach-Zehnder interferometer (μIMZI). The μIMZIs were fabricated using femtosecond (fs) laser micromachining in standard single-mode fibers as circular cavities with a diameter of 60 μm. Next, the structures underwent fs laser post-processing, which included fabrication of an additional cavity with the same diameter but shifted by 15 μm or 30 μm against the center of the initial microcavity. Different depths of the additional structures were investigated. The enlargement of the microcavity allows for tailoring the spectral response, i.e., it shifts the interference pattern by more than 200 nm, with no introduction of any additional losses and distortions in the spectrum. As the additional effect, regardless of the size of the extension, the sensitivity of the enlarged μIMZI was improved by 32%.
关键词： Fiber optics sensors,Laser materials processing,Interferometry,Microcavities,Microstructure fabrication
更新于2025-11-28 14:23:57
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Laser and hybrid laser welding of type 316L(N) austenitic stainless steel plates
摘要： The effect of laser, Hybrid Laser-Tungsten inert gas (HLT) and Hybrid Laser-Metal inert gas (HLM) welding processes on the microstructure and mechanical properties of 5.6 mm thick 316L(N) stainless steel weld joints have been studied. The differences in weld metal microstructure and mechanical properties of the weld joints were evaluated and discussed. Weld bead geometry, ferrite number (FN), solidification mode, secondary dendrite arm spacing, hardness and tensile properties are compared. Laser weld joint showed narrow weld bead profile and a higher cooling rate than the hybrid laser arc weld joints and the weld metal manifested austenitic solidification mode. HLT weld displayed coarser weld metal microstructure due to higher heat input and austenitic ferritic solidification mode. HLM process possesses moderate heat input and cooling rate. The HLM weld metal exhibited ferritic austenitic solidification mode and 2.5 FN. The hardness of weld metal was higher in hybrid welding processes due to the higher ferrite content. HLM weld joint has higher yield strength, ultimate tensile strength and ductility compared to that of the other weld joints. HLM welding process also permits higher gap tolerance with filler metal addition and is recommended for welding of type 316L(N) stainless steel.
关键词： ferrite,stainless,welding,microstructure,steel,Laser,hybrid,solidification,316L(N),arc
更新于2025-11-21 11:24:58
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Laser Alloying of Surface of Ti-5.5Al-2Zr-1Mo-1?V Titanium near-α-Alloy Prepared Via Melted by Pulsed Laser Radiation TiC Particles
摘要： Laser alloying of the surface of Ti-5.5Al-2Zr-1Mo-1 V titanium near-α-alloy was carried out in order to improve the surface properties. The surface of the titanium alloy was being melted by pulsed laser radiation while TiC alloying powder component was being supplied to the laser irradiation zone. As a result of laser alloying, partial melting of the powder particles of titanium carbide and mixing them with the substrate metal resulted in the formation of new disperse TiC phases in the form of dendrites and highly dispersed phases. It is shown that laser alloying of Ti-5.5Al-2Zr-1Mo-1 V titanium near-α-alloy by pulsed laser radiation leads to a 1.4 times increase in hardness of the surface of the titanium alloy and reduces friction coefficient 1.2 times.
关键词： Tribological tests,Laser alloying,Microstructure,Titanium alloy
更新于2025-11-21 11:20:48
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Laser additive manufacturing of biodegradable magnesium alloy WE43: a detailed microstructure analysis
摘要： WE43, a magnesium alloy containing yttrium and neodymium as main alloying elements, has become a well-established bioresorbable implant material. Implants made of WE43 are often fabricated by powder extrusion and subsequent machining, but for more complex geometries laser powder bed fusion (LPBF) appears to be a promising alternative. However, the extremely high cooling rates and subsequent heat treatment after solidification of the melt pool involved in this process induce a drastic change in microstructure, which governs mechanical properties and degradation behaviour in a way that is still unclear. In this study we investigated the changes in the microstructure of WE43 induced by LPBF in comparison to that of cast WE43. We did this mainly by electron microscopy imaging, and chemical mapping based on energy-dispersive X-ray spectroscopy in conjunction with electron diffraction for the identification of the various phases. We identified different types of microstructure: an equiaxed grain zone in the center of the laser-induced melt pool, and a lamellar zone and a partially melted zone at its border. The lamellar zone presents dendritic lamellae lying on the Mg basal plane and separated by aligned Nd-rich nanometric intermetallic phases. They appear as globular particles made of Mg3Nd and as platelets made of Mg41Nd5 occurring on Mg prismatic planes. Yttrium is found in solid solution and in oxide particles stemming from the powder particles’ shell. Due to the heat influence on the lamellar zone during subsequent laser passes, a strong texture developed in the bulk material after substantial grain growth.
关键词： Rapid solidification,Microstructure,Bone scaffolds,Electron microscopy,Biodegradable implants,WE43,Laser powder bed fusion,Magnesium
更新于2025-11-21 11:20:48
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Effect of incorporation of sulphur on the structural, morphological and optical studies of CdSe thin films deposited by solution processed spin coating technique
摘要： Ternary compound semiconductor CdSexS1-x (x = 1, 0.8, 0.6, 0.4, 0.2 and 0) thin films were prepared on glass substrates by using simple solution processed spin coating technique. Cadmium acetate, sodium selenosulfate and thiourea were used as source materials for Cd2+, Se2? and S2? ions, while triethanolamine was used as a capping agent. The 25% concentred NH4OH solution was used as a complex reagent and also used to adjust the pH of the final solution ~ 11. The deposition conditions (rotation speed 2000 rpm for 30 s and substrate dried in the air at 120 °C for 2 min) were remain same for all the samples. The as-deposited thin films on glass substrate were annealed at 350 °C for 30 min. The X-ray diffraction pattern shows that all the samples were polycrystalline in the nature with hexagonal structure. The most of prepared thin films were highly textured along (002) plane and peak position for plane (002) is shifted with change in composition ‘x’. The average crystallite size in CdSexS1-x thin films were found between 62.6 nm to 93.4 nm. Scanning electron microscopy images showed uniform deposition morphology with spherical shaped grains distributed over entire glass substrate. Samples CdSe0.8S0.2 and CdSe0.6S0.4 thin films indicated interesting morphological features with the combination of spherical shaped nanoparticles and interconnected nanofibers which form hierarchical flowerlike micro-structure. Energy dispersive X-Ray studies confirmed that thin films were having approximately same stoichiometry of atomic ratio of elements Cd, Se and S as present in volumetric ratio of the reactants in chemical solution. Fourier transform infrared studies confirmed the formation of the Cd(Se,S) bonding in materials. The optical band gap of CdSexS1-x thin films were found as direct band gap in the range of 1.82 eV to 2.32 eV. As the incorporation of sulphur element increases, the band gap of CdSexS1-x thin film also increases. The CdSexS1-x thin films can be used as absorption layer in solar photovoltaic cell which is due to wide and fine tenability of the energy band gap.
关键词： Nanofibers,Spin coating,Absorption layer,cadmium sulfide,Cadmium selenide,Hierarchical flowerlike microstructure,Ternary compound semiconductor
更新于2025-11-21 11:18:25