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[Laser Institute of America ICALEO?? 2017: 36th International Congress on Applications of Lasers & Electro-Optics - Atlanta, Georgia, USA (October 22a??26, 2017)] International Congress on Applications of Lasers & Electro-Optics - A composite stellite alloy hardfacing with improved laser cladding behavior and wear resistance
摘要： To solve the existing wear and corrosion problems in power generation industry, this research investigates the wear and corrosion behavior of Stellite alloys in NaOH solution, which simulates the amine media in the feedwater service of power generation plants. The Stellite alloys under this study include Stellite 6 and a composite Stellite alloy. The composite Stellite alloy hardfacing, which consists of 70% Stellite 3 and 30% Stellite 21, is created via laser cladding for control valve seat sealing surfaces, aiming at enhancing hardness and wear resistance, compared with Stellite 6 hardfacing, and improving cracking in laser cladding process, compared with Stellite 3. The composite Stellite alloy hardfacing is made on 316 stainless steel substrate and it does not show any cracking. The microstructure of the hardfacing is analyzed using SEM, EDS and XRD. The hardness, dry sliding wear resistance and cavitation-erosion resistance in NaOH solution are evaluated. Stellite 6 hardfacing is prepared with the same laser process parameters and is also analyzed and tested under the same conditions with the composite Stellite alloy hardfacing for comparison. The experimental results and real industrial test demonstrate superior performance of the composite Stellite alloy hardfacing to Stellite 6 hardfacing for control valve seat sealing application.
关键词： Cavitation-erosion,Hardfacing via laser cladding,Stellite alloy,Dry-sliding wear
更新于2025-09-23 15:19:57
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Properties of Curved Parts Laser Cladding Based on Controlling Spot Size
摘要： In this study, a method based on controlling the laser spot size was proposed in the process of curved parts laser cladding, and the coatings obtained by this method were analysed through investigation of the microstructure, microhardness, adhesion property and wear resistance properties. The nonuniform rational B-spline surface (NURBS) reconstruction method was used to obtain the workpiece geometrical characteristics of laser cladding, and through the establishment of a mathematical model, the process of the laser beam working on the curved surface was simpli?ed as the intersection of the cylinder and curvature sphere. Then, the spot size was transformed into the area of a cylinder intersecting with a sphere, and by adjusting the laser head, the size of the laser spot was controlled in the threshold and interpolation points were obtained. The laser cladding trajectory was ensured by these interpolation points, and the experiment was carried out to study the properties of the coating. The results showed that the average coating thickness was about 1.07 mm, and the ?uctuation of coating thickness did not exceed 0.05 mm; also, there were no cracks or pores in the layer after penetrant ?aw detection. The SEM showed that the grains passed through the transition of plane crystal, cellular crystal, dendrite and equiaxed crystal from the bottom to the top of the layer. After 30 cycles of thermal shock tests, the cladding layer was still well bonded with the substrate and the microhardness and wear resistance were 2 times and 1.4 times higher than that of substrate, respectively.
关键词： microstructure,curved parts,properties,spot size,laser cladding
更新于2025-09-23 15:19:57
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Mechanical response of a Laser Cladding repaired structure: localization of plastic strain due to microstructure gradient
摘要： Laser Cladding is an additive manufacturing technology enabling to repair complex metallic components by removing the worn region and reconstructing locally the initial geometry. The aim of this work is to study the mechanical response of Inconel 718 repaired thin walls. More precisely, we perform an EBSD imaging and in-situ SEM tensile tests on specimen whose gauge section contains the interface between base material and repaired area. We observe the multiaxial strain patterns until failure at the grain level using a Digital Image Correlation method and superpose this pattern with the microstructure gradient induced by repair. The observations highlight a strain localization phenomenon in repaired structures mainly due to grain size effect.
关键词： SEM tensile tests,Laser Cladding,Inconel 718,strain localization,EBSD,microstructure gradient,Digital Image Correlation
更新于2025-09-23 15:19:57
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Surface Functionalization of Polyethylene by Silicon Nitride Laser Cladding
摘要： Functional coatings are commonly applied to biomaterials in order to improve their properties. In this work, polyethylene was coated with a silicon nitride (Si3N4) powder using a pulsed laser source in a nitrogen gas atmosphere. Several analytical techniques were used to characterize the functionalized surface of the polymer, including Raman spectroscopy, laser microscopy, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Antibacterial properties were tested in vitro against Staphylococcus epidermidis. The Si3N4 coating sensibly reduced the amount of living bacteria when compared to the uncoated polymer. Osteoconductivity was also tested in vitro using SaOS-2 osteosarcoma cells. The presence of Si3N4 coating resulted in an increased amount of hydroxyapatite. Coating of polyethylene with silicon nitride may lead to improved performance of indwelling orthopaedic or less invasive medical devices.
关键词： laser cladding,polyethylene,antibacterial,osteointegration,silicon nitride
更新于2025-09-23 15:19:57
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AMORPHOUS/NANOCRYSTALLIZATION OF TiN-TiB <sub/>2</sub> REINFORCED LASER CLAD COMPOSITES
摘要： Laser cladding (LC) of the Stellite6-BN-Cu-Y2O3 pre-placed powders on the Ti-6Al-4V alloy substrate formed the bulk TiN and needle-like Ti-B compounds reinforced composites, which improved the wear resistance of the substrate surface. The results showed that lots of the amorphous-nanocrystalline phases were produced in such composites; the proper content of Cu was used to reˉne microstructures, also a large number of the nanocrystals can be formed; the elements such as Co, Ni and Fe in Stellite6 favored the amorphous phase to be formed. The addition of Y2O3 improved the °uidity of the liquid metal, also retarding the growth of the dendrite, leading the ˉne microstructures to be formed, improving the property of the LC composites.
关键词： nanocrystals,amorphous phase,surface modiˉcation,Laser cladding
更新于2025-09-23 15:19:57
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Influence of Processing Parameters on the Microhardness Property of Laser Cladded Titanium Powder
摘要： Laser cladding techniques of additive manufacturing has been globally embraced in the most efficient means of maintenance of steel rail. Nano-composite of titanium has been used as covering layer. The processing parameters of the laser power was varied between 1.0 kW and 2.0 kW while the scanning speed, powder and gas flow rate were kept at constant. Design expert 11 software environment was used to analyze the results derived with a full factorial experiment design guide. The microhardness profiling was performed at a load of 500 g and at a dwelling time of 15 s with the microhardness indenter 20 (cid:2)(cid:3)(cid:4) (cid:5)(cid:6)stance was maintained between indentations. An almost uniform weight of Titanium powder was cladded at different variation of processing parameters. A predictive microhardness equation was generated and termss runs intercept of an orthogonal shape. The model terms were found to be significant with logical relationships. It was found that the microhardness increases as the laser power increased.
关键词： microhardness,factorial experiment,steel rail,laser cladding,nano-composite
更新于2025-09-23 15:19:57
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Corrosion wear and electrochemical corrosion behaviors of laser cladded amorphous FeSiB coating in 3.5% NaCl solution
摘要： An amorphous FeSiB composite coating was fabricated on S355 structural steel using a laser cladding. The corrosion wear and electrochemical corrosion behaviors of FeSiB coating in 3.5% NaCl solution were investigated using a wear tester and electrochemical workstation. The results show that the FeSiB coating with the hardness of 601 HV is primarily composed of amorphous and crystal phases of α–Fe(Si) and Fe2B. The average coefficients of friction (COFs) of FeSiB coating at the wear loads of 3, 5 and 7 N loads are 0.888, 0.751, and 0.564, respectively, which deceases with the increase of wear loads; and the corresponding wear rates are 7.60, 8.02 and 10.04 μm3?N–1?m–1, respectively. The corrosion potentials of FeSiB coating and substrate are –0.718 and –1.042 V, respectively, exhibiting that the corrosion potential of FeSiB coating shifts positively, its corrosion resistance was higher than that of substrate.
关键词： electrochemical corrosion,amorphous FeSiB composite coating,coefficient of friction (COF),wear mechanism,laser cladding (LC)
更新于2025-09-23 15:19:57
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Effects of Low-Temperature Tempering on Microstructure and Properties of the Laser-Cladded AISI 420 Martensitic Stainless Steel Coating
摘要： Post-treatment is crucial to improve the comprehensive performance of laser-cladded martensitic stainless steel coatings. In this work, a low-temperature tempering treatment (210 ?C), for the ?rst time, was performed on the laser-cladded AISI 420 martensitic stainless steel coating. The microstructure and properties of the pre- and post-tempering specimens were carefully investigated by XRD, SEM, TEM, a micro-hardness tester, a universal material testing machine and an electrochemical workstation. The results show that the as-cladded AISI 420 stainless steel coating mainly consisted of martensite, austenite, Fe3C and M23C6 carbides. The phase constituent of the coating remained the same, however, the martensite decomposed into ?ner tempered martensite with the precipitation of numerous nano-sized Fe3C carbides and reverted austenite in the as-tempered specimen. Moreover, a slight reduction was found in the micro-hardness and tensile strength, while a signi?cant increase in elongation was achieved after tempering. The fractography showed a transition from brittle fracture to ductile fracture accordingly. The as-tempered coating exhibited a striking combination of mechanical properties and corrosion resistance. This work can provide a potential strategy to enhance the overall properties of the laser-deposited Fe-based coating for industrial applications.
关键词： microstructure,laser cladding,low-temperature tempering,properties,stainless steel coating
更新于2025-09-19 17:15:36
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Influence of Al2O3 addition on the hardness and in vitro corrosion behavior of laser synthesized Ti-Al2O3 coatings on Ti-6Al-4V
摘要： Titanium alloy (Ti-6Al-4V) has been mostly used for medical implants due to its good chemical and mechanical properties. However, this alloy has tendency to emanate toxic V and Al due to its low corrosion resistance in body conditions. In this work, an experimental study of laser cladding Ti-Al2O3 coatings with different Al2O3 fractions (5 wt.% Al2O3, 8 wt.% Al2O3, and 10 wt.% Al2O3) was carried out to establish a coating which could improve the hardness and corrosion resistance of Ti-6Al-4V alloy. Laser parameters of 900 W power, 0.6 m/min laser scan speed, and 2 l/min powder feed were used in this research. The microstructure, phase constituents, microhardness, and corrosion of the resultant coatings were characterized by scanning electron microscope (SEM), optical microscope (OPM), X-Ray Diffractometer (XRD), Vicker hardness tester, and potentiostat respectively. Results showed that a defect free coating was achieved at a coating with less Al2O3 content. Increase in Al2O3 addition resulted in increment of hardness with Ti-10 wt.% Al2O3 coating achieving an optimum hardness of about 2.2 times greater than that of the substrate. Moreover, considerable increment in corrosion resistance of Ti-6Al-4Valloy was achieved after laser deposition of various Ti-Al2O3 admixed coatings. An optimal corrosion rate reduction of about 81% and polarization resistance increment of 709% over the substrate were achieved at Ti-5 wt.% Al2O3 due to low porosity within the coating layer. It has been established that fabricating Ti-Al2O3 on Ti6Al4V through laser could be used in improving the surface hardness values and corrosion resistance.
关键词： Ti-Al2O3 coatings,Corrosion behavior,Laser cladding,Hardness properties,Ti-6Al-4Valloy
更新于2025-09-19 17:15:36
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Analysis of laser cladding of Titanium alloy
摘要： In this study, laser cladding of Grade 5 Titanium alloy Ti6Al4V was investigated with the main goal being to optimize the cladding process by specifically optimizing the scanning speed. The scanning speed was varied from 0.5m/min to 3.5m/min in increments of 0.5m/min; while the other parameters were kept constant. Thereafter, a geometrical analysis, porosity analysis, microscopic analysis in the form of optical microscopy and SEM, atomic force microscopic analysis, Vickers microhardness testing and corrosion testing were all performed to ascertain the integrity of the clads and to optimize the process. These tests were corroborated and it was revealed that a scanning speed of 1.5m/min yielded the best all-round clad, i.e. most efficient while maintaining the quality at a relatively high level and can therefore be recommended for typical cladding processes.
关键词： titanium,Laser-metal deposition,laser cladding,scanning speed
更新于2025-09-19 17:13:59