科研趋势
历年科研结果应用趋势一目了然
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A comparison of microstructure and mechanical properties of laser cladding and laser-induction hybrid cladding coatings on full-scale rail
摘要： With the rapid development of high-speed and heavy-haul trains, the surface damages of rails are becoming more and more severe, and how to promote the surface strength of the rail and prolong its service life with high efficiency are becoming extremely important. Laser cladding (LC), with small heat affected zone (HAZ) and low dilution, is a promising novel way to hardface and repair the rail. However, there are two great barriers for the traditional LC to apply on full-scale rails: one is how to prevent the coating from cracking under the rapid heating and cooling cycle; the other is how to eliminate the martensite structure in HAZ, which may threaten the safety of railway transportation due to its high hardness and low fracture toughness and usually be forbidden in almost all the Railway Standards over the world. In this paper, laser-induction hybrid cladding (LIHC) was innovatively proposed to deposit Ni-based coatings on a full-scale rail. The cracking behaviors, microstructures and mechanical properties of the coatings and HAZs by LC, LIHC with induction pre-heating (pre-LIHC) and LIHC with induction post-heating (post-LIHC) were studied systemically. The results indicate that the cracking and martensite transformation occurred in the HAZ can only be prevented by post-LIHC, where fine pearlite with smaller pearlite block size and lower interlamellar spacing formed instead. Therefore, the abrupt change of microstructure and mechanical properties in the HAZ could be avoided by post-LIHC, and the hardness, strength and toughness of the rails can be improved significantly. The post-LIHC technology shows the potentiality to hardface and repair the full-scale rail.
关键词： Martensite,Microhardness distribution,Toughness,Laser-induction hybrid cladding (LIHC),Full-scale rail,Strength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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Quasi-continuous-wave laser surface melting of aluminium alloy: Precipitate morphology, solute segregation and corrosion resistance
摘要： A quasi-continuous wave laser surface melting is performed on 2219 aluminium alloy to improve the corrosion resistance. The fast cooling rate and the multi-directional solidification behavior of the process transform large and long-chained constituent particles into fine and isolated circular precipitates with alleviated solute segregation. The improved corrosion resistance is due to formation of low-flaw-density passive film, reduction of the driving force for corrosion and improvement of the re-passivation capability of the modified surface. The large and long-chained constituent particles are the preferred sites for corrosion initiation and propagation.
关键词： C: Segregation,B: Polarization,C: Pitting corrosion,A: Aluminium,B: EPMA更新于2025-11-28 14:24:20
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Computational and Experimental Investigation of Micro-Hardness and Wear Resistance of Ni-Based Alloy and TiC Composite Coating Obtained by Laser Cladding
摘要： The influence of processing parameters on the micro-hardness and wear resistance of a Ni-based alloy and titanium carbide (TiC) composite cladding layer was studied. Mathematical models were developed to predict the micro-hardness and wear resistance of the cladding layer by controlling the laser cladding processing parameters. Key processing parameters were the laser power, scanning speed, gas flow, and TiC powder ratio. The models were validated by analysis of variance and parameter optimization. Results show that the micro-hardness is positively correlated with laser power and TiC powder ratio, where the TiC powder ratio shows the most significant impact. The wear volume decreased with an increasing TiC powder ratio. The targets for the processing parameter optimization were set to 62 HRC for micro-hardness and a minimal volume wear. The difference between the model prediction value and experimental validation result for micro-hardness and wear volume were 1.87% and 6.33%, respectively. These models provide guidance to optimize the processing parameters to achieve a desired micro-hardness and maximize wear resistance in a composite cladding layer.
关键词： Ni35A + TiC composite,laser cladding,central composite design,wear resistance,micro-hardness更新于2025-11-28 14:24:20
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Microstructural evolution and wear performance of the high-entropy FeMnCoCr alloy/TiC/CaF2 self-lubricating composite coatings on copper prepared by laser cladding for continuous casting mold
摘要： The FeMnCoCr high-entropy alloy/TiC/CaF2 self-lubricating coatings were successfully prepared on a Cu–Zr–Cr alloy for continuous casting mold by laser cladding for wear-resistance. The intriguing ?nding was that the laser-cladded FeMnCoCr is mainly composed of face-centered cubic and hexagonal close-packed solid solution phases. During the cladding process, the FeMnCoCr/TiC or the FeMnCoCr/TiC/CaF2 mixed suf?ciently with Cu matrix, while FeMnCoCr exhibited a spherical shape owing to being insoluble in Cu. The average hardness of the FeMnCoCr/TiC/CaF2 self-lubricating high-entropy alloy (HEA) coatings was twice that of the pure FeMnCoCr HEA coating. By addition of TiC, the friction coef?cient and wear rate were decreased from 0.35 and 3.68 × 10?15 mm3/m to 0.27 and 3.06 × 10?15 mm3/m, respectively. When CaF2 was added, the friction coef?cients and wear rate were decreased to 0.16 and 2.16 × 10?15 mm3/m, respectively, which was 54% lower than the pure FeMnCoCr HEA coating. The main wear mechanism of the FeMnCoCr coating is abrasive wear while that of the FeMnCoCr/TiC coating is abrasive and adhesion wear. But adhesion wear is dominant for the FeMnCoCr/TiC/CaF2 coating.
更新于2025-11-28 14:24:20
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A facile method to fabricate a novel 3D porous silicon/gold architecture for surface enhanced Raman scattering
摘要： Si-based surface enhanced Raman scattering (SERS) sensing technology is a powerful tool for the detection of various chemical and biological species. Further improvement of the simplicity, stability, sensitivity, and low cost of Si-based SERS platforms is still in great demand for real applications. In this study, the facile fabrication of three-dimensional (3D) porous Si/Au SERS platform with attractive SERS performances was reported. The developed method relied on laser-induced dendrite-like microstructure on the surface of Al-Si cast alloy followed by dealloying Al from the laser treated surface, leaving a 3D dendrite-like porous Si substrate. By sputtering, the substrate was coated with Au film to form 3D porous Si/Au SERS platform. Such 3D porous Si/Au SERS platform had high SERS sensitivity that enabled ultralow concentration detection of R6G molecules down to 10-15 M with enhancement factor in the range of 1011 to 1012. The relative standard deviation of 6.2% was obtained from 15 random SERS spectrum, indicating superior reproducibility of the as-fabricated 3D porous Si/Au SERS platform.
关键词： laser,porous Si/Au,SERS,dealloying更新于2025-11-28 14:24:20
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High temperature wear performance of laser cladding Co06 coating on high-speed train brake disc
摘要： Abnormal wear sometimes occurs on the high speed train brake disc surface in winter time. In this paper, Co-based alloy powders were deposited by laser cladding technology to improve the wear resistance of train brake discs. Sliding wear at room temperature, 200℃, 400℃ and 600℃ were conducted to investigate the wear behavior. Microstructure, hardness, and phase composition of Co06 cladding layers were also studied. The results showed that Co06 cladding layer exhibited better wear resistance than the substrate, with different wear mechanisms at high temperatures. Co06 cladding layers also exhibited better high temperature oxidation resistance than the substrate. Cr23C6 played a significant role in anti-friction.
关键词： high temperature wear behavior,laser cladding,high speed train,brake disc更新于2025-11-28 14:24:20
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Physical Origin of Early Failure for Contaminated Optics
摘要： Laser-Induced optical breakdown often occurs unexpectedly at optical intensities far lower than those predicted by ultra-short pulse laser experiments, and is usually attributed to contamination. To determine the physical mechanism, optical coatings were contaminated with carbon and steel microparticles and stressed using a 17 kW continuous-wave laser. Breakdown occurred at intensity levels many orders of magnitude lower than expected in clean, pristine materials. Damage thresholds were found to strongly follow the bandgap energy of the film. A thermal model incorporating the particle absorption, interface heat transfer, and free carrier absorption was developed, and it explains the observed data, indicating that surface contamination heated by the laser thermally generates free carriers in the films. The observed bandgap dependence is in direct contrast to the behavior observed for clean samples under continuous wave and long-pulse illumination, and, unexpectedly, has similarities to ultra-short pulse breakdown for clean samples, albeit with a substantially different physical mechanism.
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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智能分析： Yokogawa AQ6370D是一款性能卓越的光谱分析仪，适用于光通信领域以及光放大器（EDFA）的测量和评估。其高波长分辨率、精准度和宽动态范围使其成为实验室和工业环境中的理想选择。虽然设备体积较大且预热时间较长，但其丰富的接口和出色的显示屏设计弥补了这些不足，整体是一款值得推荐的光谱分析仪。获取实验方案
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智能分析： ZEISS EVO系列是一款高性能?？榛璧缱酉晕⒕?，适用于材料科学、生命科学及工业质量控制等领域。其先进的技术特性包括高分辨率、广泛加速电压范围和集成EDS系统。该产品操作直观，支持多用户环境，适合科学研究和工业应用。然而，价格信息缺失以及潜在的维护成本可能是其需要注意的方面。总体而言，ZEISS EVO系列表现优秀，值得推荐给专业用户。获取实验方案 -
智能分析： ZEISS Crossbeam系列是蔡司公司推出的一款高端光电分析设备，结合了场发射扫描电子显微镜（FE-SEM）和聚焦离子束（FIB）的功能，适用于材料科学、纳米技术和半导体行业等多个领域。其高分辨率成像能力和自动化样品制备功能使其成为高通量分析的理想选择。此外，该设备支持多种检测器，具备强大的多功能性，是高精度研究和工业应用的利器。然而，由于其高端定位，设备成本较高且操作需要专业技能。总体而言，该设备表现卓越，为科学研究和工业应用提供了先进的解决方案。获取实验方案 -
智能分析： Axio Observer是一款专为金相学研究设计的倒置显微镜系统，以其高效的设计和蔡司知名的光学技术为特色。它能够快速、灵活地分析大量样品，并支持自动化操作，适用于多种应用场景，包括晶粒尺寸分析、非金属夹杂物检测等。然而，其重量较大且光源寿命较短，可能对使用者提出了额外的维护和空间管理需求。总体而言，这款产品在性能和可靠性方面表现出色，特别适合专业实验室使用。获取实验方案 -
型号：ZEISS LSM 990 Spectral Multiplex
智能分析： ZEISS LSM 990 Spectral Multiplex是一款定位于高端科研机构的光谱成像系统，具有卓越的光谱分辨率和自动化功能，适用于复杂的生物、医学及材料科学实验。其高效的荧光标签分离能力和多功能自动化设计为用户提供了强大的实验支持。然而，高昂的价格和一定的学习曲线可能对中小型实验室构成挑战。总体而言，这是一款性能优越、适应性强的高端实验设备。获取实验方案 -
智能分析： ZEISS Sigma 300 with RISE是蔡司公司推出的一款高端光谱分析仪，集成了拉曼成像和扫描电子显微镜技术，能够提供高质量的化学和结构分析。其功能强大，支持多领域应用，但设备价格较高且操作学习曲线可能较陡。适用于科研机构和高端实验室，是材料科学和生命科学领域的理想选择。获取实验方案
