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Laser induced breakdown spectroscopy application to reaction-diffusion studies in nuclear materials
摘要： We explore the possible use of Laser Induced Breakdown Spectroscopy (LIBS) to analyze active materials in hot cells or even inside nuclear reactors where high radiation levels prevent the use of conventional techniques. LIBS measurements of the reaction-diffusion process in alloys used in the nuclear industry were compared with standard techniques such as micrography, scanning electron microscopy, and energy dispersive X-rays spectroscopy. The LIBS capability to qualitatively detect the above process was established. Also, the average speed of the reaction-diffusion process was measured through a temperature-dependent effective parameter K.
关键词： Zirconium Alloys,LIBS,Nuclear Materials,Diffusion
更新于2025-09-23 15:19:57
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Development of technology for robotic laser welding of thin-walled products from heat-resistant alloys
摘要： The results of testing the modes of robotic laser welding of spatial welded joints of thin-walled products from heat-resistant steels are considered. Comparative studies of the influence of the parameters of various methods of industrial welding on the metallography of the weld and the technological strength of the welded joint are presented. The resistance of welded joints against the formation of crystallization (hot) cracks is evaluated.
关键词： heat-resistant alloys,robotic laser welding,technological strength,metallography,crystallization cracks,thin-walled products
更新于2025-09-23 15:19:57
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On the application of laser shock peening for retardation of surface fatigue cracks in laser beam-welded AA6056
摘要： The present study aims to investigate the extent to which the fatigue behaviour of laser beam-welded AA6056-T6 butt joints with an already existing crack can be improved through the application of laser shock peening. Ultrasonic testing was utilized for in situ (nondestructive) measurement of fatigue crack growth during the fatigue test. This procedure allowed the preparation of welded specimens with surface fatigue cracks with a depth of approximately 1.2 mm. The precracked specimens showed a 20% reduction in the fatigue limit compared with specimens without cracks in the as-welded condition. Through the application of laser shock peening on the surfaces of the precracked specimens, it was possible to recover the fatigue life to the level of the specimens tested in the as-welded condition. The results of this study show that laser shock peening is a very promising technique to recover the fatigue life of welded joints with surface cracks, which can be detected by nondestructive testing.
关键词： fatigue crack,aluminium alloys,laser beam welding,ultrasonic crack tip diffraction,residual stress,laser shock peening
更新于2025-09-23 15:19:57
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Effect of Laser Positioning on the Microstructure and Properties of NiTi-Copper Dissimilar Laser Welds
摘要： Dissimilar pulsed laser welding of 400-lm NiTi and Cu wires was used to investigate the effect of laser positioning on NiTi-Cu joint performance. Laser positioning was found to have a significant role in the microstructure due to the difference in mixing patterns and composition distributions. Homogenous element distribution was observed in both the NiTi offset and the centerline joints, while complex mixing patterns were observed in the Cu offset joints. Changing the laser position resulted in a change in alloy content in the weld pool that affected the mixing patterns, and the phases that were formed in the weld zone of each sample. By moving the laser beam from NiTi toward Cu, NiTi and NiTiCu in the weld zone were replaced by pure Cu which resulted in a decreased average hardness from 512 to 158 HV. However, high hardness values were found inside the weld zone of Cu offset welds due to the presence of hard and brittle ternary intermetallic compounds. The 100-lm Cu offset joint displayed the worst mechanical response due to its inhomogeneous microstructure and the presence of cracks and pores. It was shown that positioning the laser beam on the NiTi or on the centerline resulted in a better transition in microstructure that led to acceptable mechanical properties without optimizing laser parameters or inserting any interlayers.
关键词： dissimilar welding,copper,laser welding,laser positioning,shape-memory alloys,NiTi alloy
更新于2025-09-23 15:19:57
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Controlled aggregation of Ag nanoparticles on oxide templates on nitinol by electrodeposition
摘要： Nitinol is an unusual material for hard-tissue replacements because of their unique superelasticity, biocompatibility, and low elastic modulus. Nitinol surface was modified by plasma electrolytic oxidation with an aim to produce oxide film on the surfaces for inhibiting Ni ion release. In addition, various Ag structures were constructed on the oxide templates on nitinol using electrodeposition in an AgC2H3O2-based solution for improving the antibacterial ability. Control of the electrolyte by collagen concentration caused a change in Ag shape and aggregation. Preferred growth along Ag (111) by orientated attachment of the Ag led to the formation of Ag dendrites in the AgC2H3O2 solution. Spherical Ag nanostructures, which were well dispersed on the templates, were obtained by electrodeposition in an AgC2H3O2-collagen solution on templates. Increasing the concentration of collagen caused aggregated Ag to form coarse spherical structures with a non-uniform distribution.
关键词： Deposition,shape memory alloys (SMA),Biomaterials,Electrochemistry
更新于2025-09-23 15:19:57
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Investigating Various Permutations of Copper Iodide/FeCu Tandem Materials as Electrodes for Dye-Sensitized Solar Cells with a Natural Dye
摘要： This work presents the synthesis and deposition of CuI and FeCu materials on copper substrates for dye-sensitized solar cell applications. FeCu is a metastable alloy of iron and copper powders and possesses good optical and intrinsic magnetic properties. Coupled with copper iodide as tandem layers, the deposition of these two materials was permutated over a pure copper substrate, characterized and then tested within a solar cell. The cell was sensitized with a natural dye extracted from a local desert plant (Calotropis Gigantea) and operated with an iodine/triiodide electrolyte. The results show that the best layer arrangement was Cu/FeCu/CuI, which gave an efficiency of around 0.763% (compared to 0.196% from reported cells in the literature using a natural sensitizer).
关键词： natural sensitizers,copper iodine,FeCu alloys,dye-sensitized solar cells,Calotropis Gigantea,ball milling
更新于2025-09-23 15:19:57
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High thermal stability and fast speed phase change memory by optimizing GeSbTe with Scandium doping
摘要： Phase change materials along the GeTe-Sb isoelectronic tie line are proved to be promising host material for optimization, based on which the well-known golden composition is developed. Here, Sc doped Ge2Sb1Te2 has been proposed for phase change memory (PCM) application, showing higher thermal stability and faster operation speed than those of the golden composition. The fast speed of 40 ns, high 10-year data retention of 160 °C, and good endurance of 6×105 cycles have made Sc0.2Ge2Sb1Te2 a promising candidate for PCM application. The impact of Sc on the microstructure is believed to be essential for those improvements in PCM.
关键词： Ge-Sb-Te alloys,High thermal stability,Fast speed,Phase change memory
更新于2025-09-19 17:15:36
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Structural and electrical properties of Sb<sub>x</sub>W<sub>1-x</sub>Se<sub>2</sub> (0, 0.5) ternary alloys
摘要： In present article, we demonstrated for the first time the synthesis and properties of SbXW1-XSe2 (0, 0.5) ternary alloys. The crystals of SbXW1-XSe2 (0, 0.5) ternary alloys were grown by direct vapour transport technique. The XRD results confirm the 2H-hexagonal lattice structure with P63/mmc space group and grown crystals are highly crystallographic c-axis oriented. The screw dislocation mechanism is predominating in the growth process of Sb0.5W0.5Se2 crystals. The results of electrical characterization show n-type semiconducting nature. The Raman spectra exhibit peaks corresponding to out of plane A1g, in-plane E2g and 2LA modes of vibration which is attributing the 2H-polymorph of grown SbXW1-XSe2 (0, 0.5) ternary alloys. The results shows substitution of Sb (+5) on W (+4) lattice site due to similar ionic size. The band gap tailoring from 0.93 to 1.40 eV is achieved, suggesting the effective way to tune the material characteristics for high performance devices.
关键词： structural properties,SbXW1-XSe2 (0,Growth of single crystal,0.5) ternary alloys,electrical transport
更新于2025-09-19 17:15:36
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Laser processing as a high-throughput method to investigate microstructure-processing-property relationships in multiprincipal element alloys
摘要： A direct laser deposition processing method was applied to construct compositional and microstructural libraries of AlxCoCrFeNi in an efficient and high-throughput manner. Among the compositions (x ? 0.51 e1.25) and quench rates (26e6400 K/s) studied, most of the laser deposited alloys exhibit a cellular microstructure, similar to the cast materials. The microstructural feature sizes were found to follow a power law relationship with the quench rate. The dependence of the microhardness on microstructural length scale was also investigated and observed to follow a Hall-Petch relationship. This study indicates that laser processing is an effective method for rapidly and efficiently evaluating multiprincipal element alloys and their microstructures.
关键词： Direct laser deposition,High-entropy alloys,Mechanical property,Microstructure
更新于2025-09-19 17:13:59
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CoCr alloy processed by Selective Laser Melting (SLM): effect of Laser Energy Density on microstructure, surface morphology, and hardness
摘要： Selective Laser Melting (SLM) was used to realize Co-28Cr-6Mo samples. Several process parameters were considered, resulting in a wide range of Laser Energy Density (LED). The study was focused on the investigation of both process and material-related aspects, such as surface morphology, laser tracks dimension and defects formation mechanisms. In addition, macro (HRC) and microhardness (HV0.5) was assessed. A correlation between LED value and density, surface quality, microstructural features and hardness of SLM parts was defined. The final goal was to identify, for the biomedical Co-28Cr-6Mo alloy, the optimal LED window to be considered in order to maximize the overall quality of SLM parts.
关键词： Additive Manufacturing (AM),Biomaterial,Selective Laser Melting (SLM),Laser Beam Melting (LBM),Co28Cr6Mo,Co-based alloys
更新于2025-09-19 17:13:59