Journal articles: 'Conventional cladding'

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Ji, Xia, Jian Zhong Zhou, Feng Qiu, and Su Qing Jiang. "The Optimization of Processing Parameters and Experimental Investigation on Ni-Based Components Fabricated by Laser Cladding." Key Engineering Materials 407-408 (February 2009): 676–79. http://dx.doi.org/10.4028/www.scientific.net/kem.407-408.676.

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The optimization of processing parameters for laser cladding process based on Statistical Analysis System (SAS) software was investigated and the experimental investigation on Ni-based alloy components fabricated by laser cladding was carried out. The influences of the main processing parameters on the surface quality were analyzed, and the Ni-based components with superior surface quality were obtained by employing the optimum set of parameters. The surface morphology and microstructure of the components were analyzed. Results indicate that the surface of the cladding is rather smooth and the claddings have a unique microstructure consisting of primary dendrite. The laser cladding layer with integrated melt interface and without reheat cracking can be obtained by optimizing the process variables. The investigations show that the components fabricated by laser cladding process have better mechanical properties than that of the conventional manufacturing technology.

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del Val, J., R. Comesaña, F. Lusquiños, A. Riveiro, F. Quintero, and J. Pou. "Downscaling of conventional laser cladding technique to microengineering." Physics Procedia 5 (2010): 341–48. http://dx.doi.org/10.1016/j.phpro.2010.08.155.

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Chen, Huan, Xiaoming Wang, and Ruiqian Zhang. "Application and Development Progress of Cr-Based Surface Coatings in Nuclear Fuel Element: I. Selection, Preparation, and Characteristics of Coating Materials." Coatings 10, no. 9 (August 21, 2020): 808. http://dx.doi.org/10.3390/coatings10090808.

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To cope with the shortcomings of nuclear fuel design exposed during the Fukushima Nuclear Accident, researchers around the world have been directing their studies towards accident-tolerant fuel (ATF), which can improve the safety of fuel elements. Among the several ATF cladding concepts, surface coatings comprise the most promising strategy to be specifically applied in engineering applications in a short period. This review presents a comprehensive introduction to the latest progress in the development of Cr-based surface coatings based on zirconium alloys. Part I of the review is a retrospective look at the application status of zirconium alloy cladding, as well as the development of ATF cladding. Following this, the review focuses on the selection process of ATF coating materials, along with the advantages and disadvantages of the current mainstream preparation methods of Cr-based coatings worldwide. Finally, the characteristics of the coatings obtained through each method are summarized according to some conventional performance evaluations or investigations of the claddings. Overall, this review can help assist readers in getting a thorough understanding of the selection principle of ATF coating materials and their preparation processes.

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Pham, Hai V., Masaki Kurata, and Martin Steinbrueck. "Steam Oxidation of Silicon Carbide at High Temperatures for the Application as Accident Tolerant Fuel Cladding, an Overview." Thermo 1, no. 2 (July 27, 2021): 151–67. http://dx.doi.org/10.3390/thermo1020011.

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Since the nuclear accident at Fukushima Daiichi Nuclear Power Station in 2011, a considerable number of studies have been conducted to develop accident tolerant fuel (ATF) claddings for safety enhancement of light water reactors. Among many potential ATF claddings, silicon carbide is one of the most promising candidates with many superior features suitable for nuclear applications. In spite of many potential benefits of SiC cladding, there are some concerns over the oxidation/corrosion resistance of the cladding, especially at extreme temperatures (up to 2000 °C) in severe accidents. However, the study of SiC steam oxidation in conventional test facilities in water vapor atmospheres at temperatures above 1600 °C is very challenging. In recent years, several efforts have been made to modify existing or to develop new advanced test facilities to perform material oxidation tests in steam environments typical of severe accident conditions. In this article, the authors outline the features of SiC oxidation/corrosion at high temperatures, as well as the developments of advanced test facilities in their laboratories, and, finally, give some of the current advances in understanding based on recent data obtained from those advanced test facilities.

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Lisiecki, A., D. Ślizak, and A. Kukofka. "Laser cladding of Co-based metallic powder at cryogenic conditions." Journal of Achievements in Materials and Manufacturing Engineering 1, no. 95 (July 2, 2019): 20–31. http://dx.doi.org/10.5604/01.3001.0013.7622.

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Purpose: of this paper was demonstration a novel technique of laser cladding by experimentally composed Co-based metallic powder and forced cooling of the substrate by liquid nitrogen under cryogenic conditions, at the temperature -190°C, for producing clad layers with enhanced microstructure characteristic and properties. Design/methodology/approach: Technological tests of laser cladding were conducted by means of a high power fibre laser HPFL with maximum output power 3.0 kW, and six-axis robot. The experimental Co-based powder was composed for providing high abrasive wear resistance, high resistance for impact load, and also for corrosion resistance at elevated temperature. The unique and novel technique of forced cooling of the substrate was provided by immersing the specimens in the liquid nitrogen bath. The three coaxial nozzle head was designed and custom made to provide precise deposition of the powder delivered into the laser beam irradiation region. The scope of the study included tests of conventional laser cladding at free cooling in ambient air in a wide range of processing parameters, and also trials of laser cladding under cryogenic conditions. The test clad layers produced by conventional laser cladding and by the novel technique of laser powder deposition under cryogenic conditions were investigated and compared. Findings: The obtained results indicate that the novel technique of forced cooling the substrate by liquid nitrogen bath provides lower penetration depth, as well as low dilution of the clad, and also provides higher hardness of the clads. Additionally, it is possible shaping the geometry of the individual bead, providing high reinforcement and low width. Research limitations/implications: The presented results are based just on preliminary test of the novel technique of laser cladding under cryogenic conditions. Therefore, further study and detailed analyse of the influence of the cooling rate on the quality, microstructure, and properties of the deposited coatings are required. Practical implications: The study is focused on practical application of the novel technique for manufacturing of wear resistance coatings characterised with enhanced performance compared to conventional range of application of the laser cladding. Originality/value: Novel technique of laser cladding at forced cooling under cryogenic conditions was demonstrated. The powder used for cladding trials was experimentally composed (not commercially available). The experimental stand custom made was used with custom made powder feeding rate, and also with custom made coaxial nozzle head.

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Nagase, Fumihisa, Kan Sakamoto, and Shinichiro Yamashita. "Performance degradation of candidate accident-tolerant cladding under corrosive environment." Corrosion Reviews 35, no. 3 (August 28, 2017): 129–40. http://dx.doi.org/10.1515/corrrev-2017-0014.

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AbstractLight-water reactor (LWR) fuel cladding shall retain the performance as the barrier for nuclear fuel materials and fission products in high-pressure and high-temperature coolant under irradiation conditions for long periods. The cladding also has to withstand temperature increase and severe loading under accidental conditions. As lessons learned from the accident at the Fukushima Daiichi nuclear power station, advanced cladding materials are being developed to enhance accident tolerance compared to conventional zirconium alloys. The present paper reviews the progress of the development and summarizes the subjects to be solved for enhanced accident-tolerant fuel cladding, focusing on performance degradation under various corrosive environmental conditions that should be considered in designing the LWR fuel.

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Suntiniwat, Pattanawit, Eakkachai Warinsiriruk, and Sutep Joy-A-Ka. "Single-Pass Cladding Process Using Hot-wire Gas Metal Arc Welding Technique." MATEC Web of Conferences 269 (2019): 01006. http://dx.doi.org/10.1051/matecconf/201926901006.

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The aim of this study is to improve cladding process productivity by high production rate with low dilution process by specifying technique as hot-wire GMAW process. The base metal of carbon steel A516 Gr70 was cladded by austenitic stainless steel 309LSi for creating a buttering layer and stainless steel 308LSi for hot-wire filler for topping a cladding layer in a one-pass run. The studied parameters this experiment consist of the feeding ratio of hot wire feeding speed per GMAW wire feeding speed and travel speed. Welding phenomenon during welding was observed by CCD camera with specifying the optical device to see the appropriate condition. The result showed the hot-wire GMAW cladding process could reduce cycle time 3.5 times compare with conventional FCAW cladding process. Moreover, dilution of this process could decrease lower than 15% with acceptable FN 3 on the top of weld surface. Therefore, single pass cladding process achieved by using this method with low dilution by still keep microstructure capability.

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Wang, Jing Yi, and Yu Kun Bai. "Analysis of Dispersion Properties of Chirped Long-Period Fiber Grating Based on Two Fiber Analysis Models." Advanced Materials Research 1030-1032 (September 2014): 20–24. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.20.

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In this paper, the difference of core-mode effective refractive indices (RIs) and the long-period fiber grating (LPFG) resonant wavelength in an uniaxial-crystal fiber resulted from two fiber analysis models were demonstrated and analyzed. The two models are two-layered medium model which is normally used for conventional single-mode optical communications fiber and three-layered medium model. Using Transfer Matrix Method (TMM) based on Coupled-Mode Theory (CMT), the different dispersion properties of chirped long-period fiber gratings (CLPFG) calculated by both models were compared. The result shows that the difference of the core-mode effective RIs is significant especially when the cladding radius and cladding mode order are small, which indicates the limitation of the two-layer model, and that reducing the cladding radius and increasing the cladding mode order can improve the CLPFG dispersion compensation capability effectively. This paper provides guidance to the design and accurate analysis of CLPFG based dispersion compensator (DC).

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Qadri, Syed N., Woohong Kim, Shyam Bayya, Brandon Shaw, Syed B. Qadri, Joseph Kolis, Bradley Stadelman, and Jasbinder Sanghera. "Epitaxial Growth of Single Crystal YAG for Optical Devices." Coatings 11, no. 6 (May 27, 2021): 644. http://dx.doi.org/10.3390/coatings11060644.

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We report the latest progress on fabrication of rare earth doped single crystal yttrium aluminum garnet (YAG) core/undoped YAG cladded fibers. Rare-earth doped single crystal core fibers were grown with laser heated pedestal growth methods. In a second step, epitaxial methods were used to grow a single crystalline undoped YAG cladding onto the core fiber. Hydrothermal and liquid phase epitaxy methods utilize the core doped fiber as the seed. X-ray diffraction of cladding reveals an equilibrium (110) morphology. Energy-dispersive X-ray spectroscopy analysis shows there is minimal diffusion of rare-earth dopants into the cladding structure. The use of scandium doping is shown to substitute at the Al3+ site, thereby allowing an additional tunability of refractive index of core structure material besides conventional Y3+ site dopants. The use of these epitaxial growth methods enables material compatibility, tuning of refractive index, and conformal growth of cladding structures onto core fibers for optical devices.

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Oberländer, B. C., and E. Lugscheider. "Comparison of properties of coatings produced by laser cladding and conventional methods." Materials Science and Technology 8, no. 8 (August 1992): 657–65. http://dx.doi.org/10.1179/mst.1992.8.8.657.

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Sultana, Jakeya, Md Saiful Islam, Cristiano M. B. Cordeiro, Alex Dinovitser, Mayank Kaushik, Brian W.-H. Ng, and Derek Abbott. "Terahertz Hollow Core Antiresonant Fiber with Metamaterial Cladding." Fibers 8, no. 2 (February 17, 2020): 14. http://dx.doi.org/10.3390/fib8020014.

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A hollow core antiresonant photonic crystal fiber (HC-ARPCF) with metal inclusions is numerically analyzed for transmission of terahertz (THz) waves. The propagation of fundamental and higher order modes are investigated and the results are compared with conventional dielectric antiresonant (AR) fiber designs. Simulation results show that broadband terahertz radiation can be guided with six times lower loss in such hollow core fibers with metallic inclusions, compared to tube lattice fiber, covering a single mode bandwidth (BW) of 700 GHz.

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ley, John Bart, Paul Denney, and Al Grubowski. "Using Fiber Optics for Laser Cladding." Journal of Ship Production 8, no. 03 (August 1, 1992): 157–62. http://dx.doi.org/10.5957/jsp.1992.8.3.157.

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In many Navy structures, there are many large components that are coated for wear protection (valve seats) and/or for corrosion protection (hatch seals) that require periodic refurbishment. This refurbishment is normally accomplished using conventional arc welding processes which in many cases require that the part be removed from the structure to properly control the pre-weld, interpass, and post-weld temperatures as required by the materials used. The removal of such large components, the thermal requirements, and the resulting distortion can greatly increase the cost for refurbishment. The Navy Manufacturing Technology Office (MANTECH) of the Office of the Assistant Secretary of the Navy has been funding two major programs through Mare Island Naval Shipyard, Naval Sea Systems Command (NAVSEA 5142), and the Applied Research Laboratory, The Pennsylvania State University (ARL Penn State) to decrease such high refurbishment costs. The first program is the development of high-powered laser cladding processes for the refurbishment of components that can be removed from the ship and into a laser materials processing facility. The second, and the primary topic of this paper, is the development of a shipboard laser materials processing system that utilizes fiber optics.

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Zhang, Penghao, Li Zhang, Zhongyu Wang, Shuang Chen, and Zhendong Shang. "A Strain-Transfer Model of Surface-Bonded Sapphire-Derived Fiber Bragg Grating Sensors." Applied Sciences 10, no. 12 (June 26, 2020): 4399. http://dx.doi.org/10.3390/app10124399.

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An improved strain-transfer model was developed for surface-bonded sapphire-derived fiber Bragg grating sensors. In the model, the core and cladding of the fiber are separated into individual layers, unlike in conventional treatment that regards the fiber as a unitive structure. The separation is because large shear deformation occurs in the cladding when the core of the sapphire-derived fiber is heavily doped with alumina, a material with a high Young’s modulus. Thus, the model was established to have four layers, namely, a core, a cladding, an adhesive, and a host material. A three-layer model could also be obtained from the regressed four-layer model when the core’s radius increased to that of the cladding, which treated the fiber as if it were still homogeneous material. The accuracy of both the four- and three-layer models was verified using a finite-element model and a tensile-strain experiment. Experiment results indicated that a larger core diameter and a higher alumina content resulted in a lower average strain-transfer rate. Error percentages were less than 1.8% when the four- and three-layer models were used to predict the transfer rates of sensors with high and low alumina content, respectively.

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Lakshminarayanan, A. K., and K. L. Harikrishna. "Role of Overlap Ratio on the Microstructure of Friction Stir Multiseam Cladded Copper-Stainless Steel Lap Joints." Materials Science Forum 979 (March 2020): 102–6. http://dx.doi.org/10.4028/www.scientific.net/msf.979.102.

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Dissimilar welding of copper to stainless steel using conventional welding processes usually exhibits defects such as solidification cracks, lack of fusion and deterioration in mechanical properties due to the difference in the base metal properties. This is mainly due to minimum solubility of copper in stainless steel. Use of solid state welding such as friction stir welding can be potential solution to this problem. This study is carried out with the aim of cladding copper sheet on a stainless steel by friction stir welding variant known as friction stir cladding. Considering practical applications, to clad copper over stainless steel sheet, multi seam friction stir cladding procedure must be adopted. Though many parameters need to be considered, overlap ratio is one of significant factor which affects the microstructure of clad joints. Hence, five overlap ratios namely 0%, 25 %, 50 %, 75% and 100 % were used to fabricate the dissimilar friction stir copper-stainless steel clad joints. Microstructural analysis was carried out at different regions of clad joints using optical microcopy and correlated with bond strength values

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Wang, L., G. Kister, B. Ralph, J. D. R. Talbot, and G. F. Fernando. "Conventional E-glass fibre light guides: self-sensing composite based on sol–gel cladding." Smart Materials and Structures 13, no. 1 (December 15, 2003): 73–81. http://dx.doi.org/10.1088/0964-1726/13/1/009.

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Knight, J. C., T. A. Birks, B. J. Mangan, and P. St J. Russell. "Microstructured Silica as an Optical-Fiber Material." MRS Bulletin 26, no. 8 (August 2001): 614–17. http://dx.doi.org/10.1557/mrs2001.154.

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Conventional optical fibers are fabricated by creating a preform from two different glasses and drawing the preform down at an elevated temperature to form a fiber. A waveguide core is created in the preform by embedding a glass with a higher refractive index within a lower-index “cladding” material. Over the last few years, researchers at several laboratories have demonstrated very different forms of optical-fiber waveguides by using a drawing process to produce two-dimensionally microstructured materials in the form of fine “photoniccrystal fibers” (PCFs). One such waveguide is represented schematically in Figure 1. It consists of a silica fiber with a regular pattern of tiny airholes that run down the entire length. The optical properties of the microstructured silica cladding material enable the formation of guided waves in the pure silica core.

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Riquelme, Ainhoa, María Dolores Escalera-Rodríguez, Pilar Rodrigo, and Joaquin Rams. "Laser Cladding of In Situ Al-AlN Composite on Light Alloys Substrate." Key Engineering Materials 724 (December 2016): 66–70. http://dx.doi.org/10.4028/www.scientific.net/kem.724.66.

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In situ metal matrix composites are novel composites in which the reinforcement is formed within the parent alloy by controlling chemical reactions during the composite fabrication. In recent years, there have been attempts to produce AlN composites utilizing the reactions between molten Al and a reactive gas. However, the conventional processing methods are sub-optimal and result in porosity, interface matrix-reinforcement deterioration, and high processing costs. The aim of this research is to develop a methodology to manufacture good-quality in situ Al-AlN composites in a cost effective way. In situ Al-AlN composite was synthesized with a laser cladding equipment. This composite powder can be directly deposited as coating on aluminum alloys conventionally used in the transport sector. The increase in the coatings tribological properties was demonstrated.

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Lee, Jungeon, Hyung Jun Park, Seunghak Chai, Gyu Ri Kim, Hwanwoong Yong, Suk Joo Bae, and Daeil Kwon. "Review on Quality Control Methods in Metal Additive Manufacturing." Applied Sciences 11, no. 4 (February 23, 2021): 1966. http://dx.doi.org/10.3390/app11041966.

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Metal additive manufacturing (AM) has several similarities to conventional metal manufacturing, such as welding and cladding. During the manufacturing process, both metal AM and welding experience repeated partial melting and cooling, referred to as deposition. Owing to deposition, metal AM and welded products often share common product quality issues, such as layer misalignment, dimensional errors, and residual stress generation. This paper comprehensively reviews the similarities in quality monitoring methods between metal AM and conventional metal manufacturing. It was observed that a number of quality monitoring methods applied to metal AM and welding are interrelated; therefore, they can be used complementarily with each other.

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Tariku, F., H. Ge, B. S. Kaskel, R. J. Kudder, M. R. Mitchell, and R. E. Link. "Moisture Response of Sheathing Board in Conventional and Rain-Screen Wall Systems with Shiplap Cladding." Journal of Testing and Evaluation 39, no. 3 (2011): 102973. http://dx.doi.org/10.1520/jte102973.

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Kovaříková, Ingrid, Frantisek Kolenic, and Erika Hodúlová. "Research of Laser Clad Properties with Globular WC in Abrasive Wear Resistance." Applied Mechanics and Materials 309 (February 2013): 121–25. http://dx.doi.org/10.4028/www.scientific.net/amm.309.121.

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Laser cladding technology is creating layers with higher wear resistance in compared to conventional technologies of creating surfaces. The aim of this paper was the study of the composite clad properties of globular deposits WC. Required characteristics of certain surfaces can be achieved by a combination of more materials and coatings. Various metal powders can be applied alternately on surface and so to create a specific system layers.

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Winter, Thomas, James Huggins, Richard Neu, Preet Singh, and Chaitanya S. Deo. "Fretting Wear Behavior of APMT Steel at 350°C for Reactor Fuel Cladding Application." MRS Advances 1, no. 35 (2016): 2495–500. http://dx.doi.org/10.1557/adv.2016.532.

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ABSTRACTIn support of a recent surge in research to develop an accident tolerant reactor, accident tolerant fuels and cladding candidates are being investigated. Relative motion between the fuel rods and fuel assembly spacer grids can lead to excessive fuel rod wear and, in some cases, to fuel rod failure. Based on industry data, grid-to-rod-fretting (GTRF) has been the number one cause of fuel failures within the U.S. pressurized water reactor (PWR) fleet, accounting for more than 70% of all PWR leaking fuel assemblies. APMT, an Fe-Cr-Al steel alloy, is being examined for the I2S-LWR project as a possible alternative to conventional fuel cladding in a nuclear reactor due to its favorable performance under LOCA conditions. Tests were performed to examine the reliability of the cladding candidate under simulated fretting conditions of a pressurized water reactor (PWR). The contact is simulated with a rectangular and a cylindrical specimen over a line contact area. A combination of SEM analysis and wear & work rate calculations are performed on the samples to determine their performance and wear under fretting. While APMT can perform favorably in loss of coolant accident scenarios, it also needs to perform well when compared to Zircaloy-4 with respect to fretting wear.

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Kołodziejczak, Paweł, Dariusz Golański, Tomasz Chmielewski, and Marcin Chmielewski. "Microstructure of Rhenium Doped Ni-Cr Deposits Produced by Laser Cladding." Materials 14, no. 11 (May 22, 2021): 2745. http://dx.doi.org/10.3390/ma14112745.

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The addition of Rhenium up to 6% to Ni-Cr alloys can dramatically improve the corrosion and oxide resistance of deposited coatings at high operating temperatures. Ni-Cr+Re layers can be successfully produced using conventional powder metallurgy, high rate solidification (HRS), or magnetron sputtering methods. However, in industrial applications, high-performance deposition methods are needed, e.g., laser cladding. Laser cladding has several advantages, e.g., metallurgical bonding, narrow heat-affected zone (HAZ), low dilution, and slight thermal damage to the substrate. In this paper, a powder Ni-Cr composite with 1% (wt.) of Rhenium was produced, then deposited onto a steel substrate (16Mo3) by laser cladding to assess the micro and macrostructural properties of the obtained layers. Besides the macro and microscopic observations, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) microanalysis of the deposit and HAZ as well as microhardness measurements have been conducted. The microstructure observations revealed four subareas of HAZ gradually changing from the fusion line towards the base material. Maximum hardness occurred in the HAZ, mainly in areas closer to the clad/substrate interface, reaching up to 350–400 HV. No sudden changes in the composition of the deposit and the area of fusion line were observed.

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Hussein, A. A., Samar Reda Al-Sayed, Salah I. Hassab Elnaby, Adel A. Nofal, and Haytham Elgazzar. "Prominent Achievements of Laser Surface Treatment of Martensitic Stainless Steel and Alpha-Beta 6/4 Titanium Alloy." Key Engineering Materials 786 (October 2018): 87–97. http://dx.doi.org/10.4028/www.scientific.net/kem.786.87.

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Conventional surface treatment processes are known to suffer from several limitations. Among them are energy consumption, complex heat treatment schedules and non-controllable heat affected zones. On the other side, when a high powered laser beam is used as a source of heat for surface treatment it will obviate most of these limitations. Laser surface engineering is one of these advanced surfacing technologies that receive growing interest to improve the surface properties of metals such as hardness, wear and corrosion resistance. Such treatments may be divided into two main categories: (i) those which only involve microstructural modification e.g. laser hardening and laser melting and (ii) other processes which lead to dual changes in microstructure and surface chemistry such as laser alloying and laser cladding. This paper comprises the experimental findings of two significant examples for laser surface engineering. The first study is concerned with surface hardening of AISI 416 martensitic stainless steel whereas the second study involves laser surface cladding of Ti-6Al-4V alloy. The outcome of the first work is a notable improvement of toughness at the same level of hardness and wear resistance as compared to the conventional hardening treatment. Additionally, the optimum condition for combined wear resistance, impact toughness and corrosion resistance was recorded at a laser heat input value of 21 J•mm-2. The second study is concerned with laser surface cladding of the titanium alloy with a powder blend composed of 60 wt% of WC and 40 wt% NiCrBSi alloy, by means of a high power Nd:YAG 2.2 kW laser. The best clad layers were obtained at a specific heat input of 60 J•mm-2. More than three-fold enhancement of the microhardness of the clad layers was achieved combined with a remarkable improvement of the alloy wear resistance.

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Pérez, A. T., Maria Angeles Montealegre, J. L. Arias, G. Castro, P. Rey, M. González, and F. Bouzada. "Laser Cladding of Nickel Alloy with Ceramic Nanopowder on Steel as Coating in Corrosive Media." Materials Science Forum 706-709 (January 2012): 2552–58. http://dx.doi.org/10.4028/www.scientific.net/msf.706-709.2552.

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There is a need in different industry sectors to improve the performance of material surface under corrosive environments, which cannot be fulfilled by conventional surface modifications and coatings. NiCrMoNb alloy is nickel alloy commonly used as coating in corrosive media at high temperatures. The aim of this work is to produce nickel alloy nanocomposite coatings on steel by laser cladding. They are obtained by laser melting blown powder on the steel surface. The powder precursor is obtained by mechanical milling of a NiCrMoNb alloy micropowder (20-63 μm) with yttria nanopowder (10-30 nm). A comparison between conventional nickel alloy laser cladded coating and nickel alloy with nanoparticles laser cladded coatings, regarding their microstructure, mechanical properties (hardness, wear resistance) and corrosion behavior, is established.

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Chan, Lydia, Islam Shyha, Dale Dryer, and John Hamilton. "Optimisation of Weld Overlay Cladding Parameters Using Full-Factorial Design of Experiment." Materials Science Forum 880 (November 2016): 54–58. http://dx.doi.org/10.4028/www.scientific.net/msf.880.54.

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Weld Overlay Cladding (WOC) shares the same scientific principals as conventional welding where there are multiple governing factors that control the process and outcome. The present work employs a Design of Experiment (DoE) approach to optimising process parameters for cladding a nickel superalloy onto low alloy steel with the aim to improve productivity and quality. The arc current, the clad metal heating current were identified as the key process variables for this stage of experimentation. A full-factorial 4-by-2 test was carried out to identify the optimal levels. Results showed that there is a mild positive trend between the height of individual strings of beads and both variables. However no relationship was established with the depth of penetration, nor with the height of single or double layer stacks. The optimal level of the variables was therefore chosen to be the one that has the highest productivity rate as there were no significant differences. Further experimentation has been planned and described in this paper.

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Alvarado, M. A., M. V. Pelegrini, I. Pereyra, T. A. A. de Assumpção, L. R. P. Kassab, and M. I. Alayo. "Fabrication and characterization of aluminum nitride pedestal-type optical waveguide." Canadian Journal of Physics 92, no. 7/8 (July 2014): 951–54. http://dx.doi.org/10.1139/cjp-2013-0587.

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In this paper we present the fabrication and characterization of pedestal-type optical waveguides using aluminum nitride (AlN) as core layer. To the best knowledge of the authors, the utilization of AlN as core layer in pedestal-type waveguides has not been studied. The AlN thin films were obtained by radio frequency reactive magnetron sputtering from a pure aluminum target. The AlN refractive index was determined by ellipsometry. The optical waveguides were fabricated by the pedestal technique, which consists in etching the silicon oxide lower cladding layer before depositing the core layer. Thus, the waveguide geometrical definition is simplified because etching the AlN core is not necessary. AlN thin films of 0.6, 1, and 1.2 μm thick were deposited on thermally grown silicon dioxide using crystalline silicon (100) as substrate. The pedestal profile was defined using conventional photolithography, followed by plasma etching of the cladding layer. Optical propagation losses were measured for pedestal heights of 1 μm and widths from 1 to 100 μm.

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Watanabe, Hideo, Yoshiki Saita, Katsuhito Takahashi, and Kazufumi Yasunaga. "Desorption of Implanted Deuterium in Heavy Ion-Irradiated Zry-2." Quantum Beam Science 5, no. 2 (April 26, 2021): 9. http://dx.doi.org/10.3390/qubs5020009.

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To understand the degradation behavior of light water reactor (LWR) fuel-cladding tubes under neutron irradiation, a detailed mechanism of hydrogen pickup related to the point defect formation (i.e., a-component and c-component dislocation loops) and to the dissolution of precipitates must be elucidated. In this study, 3.2 MeV Ni3+ ion irradiation was conducted on Zircaloy-2 samples at room temperature. Thermal desorption spectroscopy is used to evaluate the deuterium desorption with and without Ni3+ ion irradiation. A conventional transmission electron microscope and a spherical aberration-corrected high-resolution analytical electron microscope are used to observe the microstructure. The experimental results indicate that radiation-induced dislocation loops and hydrides form in Zircaloy-2 and act as major trapping sites at lower (400–600 °C) and higher (700–900 °C)-temperature regions, respectively. These results show that the detailed microstructural changes related to the hydrogen pickup at the defect sinks formed by irradiation are necessary for the degradation of LWR fuel-cladding tubes during operation.

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Alvarez, Piera, M. Montealegre, Jose Pulido-Jiménez, and Jon Arrizubieta. "Analysis of the Process Parameter Influence in Laser Cladding of 316L Stainless Steel." Journal of Manufacturing and Materials Processing 2, no. 3 (August 15, 2018): 55. http://dx.doi.org/10.3390/jmmp2030055.

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Laser Cladding is one of the leading processes within Additive Manufacturing technologies, which has concentrated a considerable amount of effort on its development. In regard to the latter, the current study aims to summarize the influence of the most relevant process parameters in the laser cladding processing of single and compound volumes (solid forms) made from AISI 316L stainless steel powders and using a coaxial nozzle for their deposition. Process speed, applied laser power and powder flow are considered to be the main variables affecting the laser cladding in single clads, whereas overlap percentage and overlapping strategy also become relevant when dealing with multiple clads. By setting appropriate values for each process parameter, the main goal of this paper is to develop a processing window in which a good metallurgical bond between the delivered powder and the substrate is obtained, trying simultaneously to maintain processing times at their lowest value possible. Conventional metallography techniques were performed on the cross sections of the laser tracks to measure the effective dimensions of clads, height and width, as well as the resulting dilution value. Besides the influence of the overlap between contiguous clads and layers, physical defects such as porosity and cracks were also evaluated. Optimum process parameters to maximize productivity were defined as 13 mm/s, 2500 W, 30% of overlap and a 25 g/min powder feed rate.

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Bjelajac, Edvard, Tomaž Vuherer, and Gorazd Lojen. "Weld Cladding of s355 Steel with Rectangular Electrode Covered Rutile 2000 s Coating." Advanced Technologies & Materials 43, no. 2 (December 15, 2018): 28–33. http://dx.doi.org/10.24867/atm-2018-2-005.

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Weld cladding or weld overlay is a frequently used method for repair welding of damaged surfaces and for production of different surface coatings. The conventional coated electrodes have a circular cross-section. In order to increase the productivity and to decrease dilution and the depth of the heat affected zone (HAZ), the geometry of the electrode core was modified. Experimental weld cladding was carried out with rutile coated electrodes of rectangular cross-sections of 12.56×1 mm2, and for reference, also with a conventional φ 4 mm electrode Rutilen 2000 S. The coating of rectangular electrodes was identical and the core material almost identical to the materials of the standard electrode. The base material was the structural steel 355JR. The goal of investigation was to determine the welding parameters for the rectangular electrodes and to compare geometries and mechanical properties of the welds. Hardness and the dimensions of weld metal and HAZ were measured. Results with the 6.28×2 mm 2 and 6.28×2 mm electrode were similar to the results with the standard electrode. However, with the 12.56×1 mm2 rectangular electrode, significantly lower currents were sufficient to obtain a good quality of the deposition layer. Due to possibility to weld with currents as low as 80-100 A, shallower and smaller HAZs and less dilution can be achieved with the rectangular 12.56×1 mm2 electrode than with standard cylindrical φ 4 mm electrode.

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Khalina, Abdan, E. S. Zainudin, Abdul Rahman Mohd Faizal, H. Jalaluddin, A. H. Umar, and W. N. W. N. Syuhada. "Development of Biocomposite Wall Cladding from Kenaf Fibre by Extrusion Molding Process." Key Engineering Materials 471-472 (February 2011): 239–44. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.239.

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Nowadays, natural fibre-thermoplastics composites (NFPC) are replacing the conventional wood and timber due to its lower cost, avoid deforestation, higher strength-to-weight ratio and resistant to termites. These composites can be utilized for non-structural components of a building system such as decking, wall cladding, floor tiles and window frame. A natural fiber/plastic composite was produced by extrusion molding process to create a wall cladding profile. The raw materials used for the composites are 40% kenaf fibre and 60% polypropylene (PP). These materials were compounded through a twin-screw extruder and then cut into pellets. The moisture content found in the kenaf/PP composites (KPC) pellets was 2.89%. Therefore, the pellets required to be oven dried every time right before entering the hopper of the extruder. The temperature along the barrel was set to 180°C and the die head temperature is set to 165°C. At the end of the extrusion molding process, pressurized air was used for cooling the profile. Then, samples of the wall cladding were taken back to the laboratory for product quality assurance. Measurements of the samples show that the product experiences 3% of shrinkage in term of width and 1% of shrinkage in term of thickness. Water absorption test indicates an increase of 13.6% of weight after 24 hours immersion of water. Impact strength test was also conducted on the wall cladding samples and the mean result was 2.55 kJ/m². Tensile test on the extruded KPC product indicates a low tensile strength at 4.51 MPa and tensile modulus of 205.01 MPa. The sample also proven to be light weight as the density of the material was found to be 0.618g/cm³.

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Li, Liqun, Faming Shen, Yuandong Zhou, and Wang Tao. "Comparative study of stainless steel AISI 431 coatings prepared by extreme-high-speed and conventional laser cladding." Journal of Laser Applications 31, no. 4 (November 2019): 042009. http://dx.doi.org/10.2351/1.5094378.

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Silva, Neander Furtado, Lilian Maciel Furtado Silva, and Ígor Lacroix. "Generating NURBS cladding and structures with parametric programming and BIM." PARC Pesquisa em Arquitetura e Construção 11 (August 17, 2020): e020016. http://dx.doi.org/10.20396/parc.v11i0.8657350.

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The process of designing and building curvilinear architectures is still challenging. The use of multiple applications with distinctive design paradigms are unlikely to disappear. The interoperability used here was not only the conventional one. It was also ‘live’, in ‘real time’, with two of the applications involved opened and running simultaneously. A design workflow based on the use of form-forming applications connected via parametric programming to building information modeling, BIM, was proposed. The main objective was to facilitate designing and building curvilinear architectures and their supporting structures using simultaneously two different design paradigms. The tools needed in our research can be summarized as follows: NURBS Lofting for surface creation, contouring for modular slicing and structural axis grid definition, sweeping along axes for surface creation of the curved beams of I profile and paneling for the subdivision of curved surfaces into planar fractions. Parametric programming was used to automate sweeping along axes to generating curved I-beams and paneling to subdivide the NURBS surfaces into planar fractions. To the best of our knowledge, our major contribution resides in defining a workflow and developing new algorithms for facilitating designing NURBS surfaces and corresponding supporting structures through ‘live’ interoperability among different applications.

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Ou, Zhi Long, Yong Qin Yu, Jia Rong Zheng, Ji Shun Wang, Xue Chen, Pei Guang Yan, and Chen Lin Du. "In-Fiber Mach-Zehnder Interferometer Fabricated by Femtosecond Laser." Advanced Materials Research 658 (January 2013): 232–36. http://dx.doi.org/10.4028/www.scientific.net/amr.658.232.

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We have demonstrated several MZIs based on two spaced 3-dB LPFGs with different interference lengths in conventional SMFs fabricated in air by femtosecond laser pulses with the duration of 200 fs and the repetition rate of 250 kHz. Experimental results show that the average fringe spatial period increases with the resonance wavelength, while decreases with the interference length in approximately inverse proportion. The dominant cladding mode interfering with core mode has been calculated. The MZI sensitivity on temperature, refractive index and strain with a length of 16mm has also been investigated.

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Zhou, Hua Xiang, Zheng Zhou, and Jing Ping Liu. "High Temperature Cylinder Sleeve Design Research Self-Lubricating Materials." Applied Mechanics and Materials 628 (September 2014): 53–58. http://dx.doi.org/10.4028/www.scientific.net/amm.628.53.

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Cylinder Liner design innovation goal is energy conservation. As the main friction parts engine cylinder liner, reducing friction energy is energy saving basic requirements. Materials research cylinder sleeve is one of the main cylinder liner saving research. Through the piston ring and cylinder liner surface friction dual material hard phase, self-lubricating phase, toughening phase analysis, select compatibility, high strength, heat resistance, good high temperature performance, ease of manufacture, price rational matrix material and an appropriate proportion of nanoscale hard material, self-lubricating materials, ductile materials, using appropriate methods cladding and processing, design developed high-temperature self-lubricating cylinder sets of advanced materials. The latest international high temperature, wear-resistant, self-lubricating materials research: modern nanoα-Al2O3+Ni-base alloy composite materials, Ti2B/Fe metal-ceramic composites, metals and ceramics NiCr-Cr3C2 particles CaF2 self-lubricating composite alloy powder material, NiCr/Cr3C2-WS2 self-lubricating wear-resistant materials were studied and found to TiC, Al2O3 is hard reinforcing phase, CaF self-lubricating phase, NiCr/TiC eutectic toughening phase, high-temperature self-lubricating wear-resistant nanocomposite, and Cr18Ni9 class alloy as base material, by laser cladding method enables conventional cylinder liners manufacturing technological breakthroughs, has practical value.

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Lisiecki, Aleksander, and Dawid Ślizak. "Hybrid Laser Deposition of Fe-Based Metallic Powder under Cryogenic Conditions." Metals 10, no. 2 (January 28, 2020): 190. http://dx.doi.org/10.3390/met10020190.

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The purpose of this study was to demonstrate the novel technique of laser deposition of Fe-based powder under cryogenic conditions provided by a liquid nitrogen bath. Comparative clad layers were produced by conventional laser cladding at free cooling conditions in ambient air and by the developed process combining laser cladding and laser gas nitriding (hybrid) under cryogenic conditions. The influence of process parameters and cooling conditions on the geometry, microstructure, and hardness profiles of the clad layers was determined. The optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), and XRD test methods were used to determine the microstructure and phase composition. The results indicate that the proposed technique of forced cooling the substrate in a nitrogen bath during the laser deposition of Fe-based powder is advantageous because it provides favorable geometry of the clad, low dilution, a narrow heat-affected zone, a high hardness and uniform profile on the cross-sections, homogeneity, and refinement of the microstructure. The influence of the forced cooling on microstructure refinement was quantitatively determined by measuring the secondary dendrite arm spacing (SDAS). Additionally, highly dispersed nanometric-sized (200–360 nm) precipitations of complex carbides were identified in interdendritic regions.

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Piro, Markus, Dion Sunderland, Winston Revie, Steve Livingstone, Ike Dimayuga, Alain Douchant, and Michael Wright. "POTENTIAL MITIGATION STRATEGIES FOR PREVENTING STRESS CORROSION CRACKING FAILURES IN HIGH-BURNUP CANDU FUEL." CNL Nuclear Review 7, no. 2 (December 1, 2018): 127–46. http://dx.doi.org/10.12943/cnr.2016.00011.

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Potential mitigation strategies for preventing stress corrosion cracking (SCC) failures in CANDU fuel cladding that are based on lessons learned on both domestic and international fronts are discussed in this paper. Although SCC failures have not been a major concern in CANDU reactors in recent decades, they may resurface at higher burnup for conventional fuels or with nonconventional fuels that are currently being investigated, such as MOX or thoria-based fuels. The motivation of this work is to provide the foundation for considering possible remedies for SCC failures. Three candidate remedies are discussed, namely improved fabrication methods for fuel appendages, barrier-liner cladding, and fuel doping. In support of this effort, recent advances in experimental characterization methods are described—methods that have been successfully used in non-nuclear materials that can be used to further elucidate SCC behaviour in CANDU fuel. The overall objective is to outline a path forward for characterizing material behaviour as an essential part of investigating remedies to SCC failure. This will allow increased fuel discharge burnup, maximum linear power, and plant manoeuvrability, while maintaining a high degree of reliability.

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Habib, M. Ahasan, Li Qun Ruan, Ryuji Kimura, P. Manikandan, and Kazuyuki Hokamoto. "Cladding of Titanium and Magnesium Alloy by Explosive Welding Using Underwater Shockwave Technique and Effect on Interface." Materials Science Forum 767 (July 2013): 160–65. http://dx.doi.org/10.4028/www.scientific.net/msf.767.160.

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The wide use of clad joints in practical application has been inhibited due to the difficulty in welding certain combinations such as tungsten/-copper, molybdenum/-copper and magnesium with aluminum, titanium and stainless steel. These material combinations are generally classified as difficult to weld by conventional material joining techniques due to the vast difference in material properties and the degradation of mechanical properties of the joints. Explosive welding is here a viable alternative technique. Explosive welding is a solid-phase welding process that uses the energy of a detonating explosive to create a strong metallurgical bond. This technique has achieved impressive success in the joining of metallurgically incompatible combinations that are otherwise impossible to join by conventional welding techniques. Though the technique is suitable for joining only thin plates, it is efficient in joining some difficult to join combinations like magnesium with aluminum, titanium and stainless steel. In this paper, the result of welding titanium and magnesium was reported.

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38

Kim, Dae Yun, You Na Lee, Joon Han Kim, Yonghee Kim, and Young Soo Yoon. "Applicability of Swaging as an Alternative for the Fabrication of Accident-Tolerant Fuel Cladding." Energies 13, no. 12 (June 19, 2020): 3182. http://dx.doi.org/10.3390/en13123182.

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We suggest an alternative to conventional coating methods for accident-tolerant fuel (ATF) cladding. A Zircaloy-4 tube was inserted into metal tubes of different materials and the inserted tubes were subjected to physical force at room temperature. The manufactured tube exhibited a pseudo-single tube (PST) structure and had higher thermal stability than a Zircaloy-4 tube. Optical microscopy and scanning electron microscopy images showed that the PST had a uniform and well-bonded interface structure, i.e., no gaps or voids were found at the interface between the inner and outer tubes. Energy-dispersive X-ray spectroscopy analysis confirmed that the metal components did not interdiffuse at the interface of the PST, even after being kept at 600 and 900 °C for 1 h and rapidly cooled to room temperature. Unlike pure Zircaloy-4 tubes, Zircaloy-4/stainless use steel (SUS) 316 PST did not show significant structural collapse, even after being stored at 1200 °C for 1 h. Based on these results, if a PST was fabricated using a Zircaloy-4 tube thinner than the Zircaloy-4 tube used in this study and an outer tube of micron-scale thickness, swaging may be a feasible alternative to Zircaloy-4-based ATF cladding.

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Wang, Xiu Ping, and Zhong Jiao He. "Highly Birefringent Extruded Elliptical-Hole Photonic Crystal Fiber." Advanced Materials Research 663 (February 2013): 387–91. http://dx.doi.org/10.4028/www.scientific.net/amr.663.387.

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Highly birefringent extruded elliptical-hole photonic crystal fibers (PCFs) with single defect and double defect are proposed and investigated, which are supposed to be achieved by extruding conventional triangular-lattice circular-hole PCFs. Comparative research on the birefringence and the confinement loss of the proposed PCFs with single defect and double defect is presented. Simulated results show that the proposed extruded elliptical-hole PCFs with single defect and double defect can be with high birefringence up to the order of 10-2. Confinement loss increases when the ellipticity of the air hole of the proposed PCFs increases, which nevertheless can be overcome by increasing the ring number or the area of the air holes in the fiber cladding.

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40

Chun, C. M., S. Desai, and T. A. Ramanarayanan. "Metal Dusting Resistant Copper-Based Materials." Corrosion 68, no. 9 (June 1, 2012): 810–21. http://dx.doi.org/10.5006/0609.

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Cu and Cu-based alloy coatings suppress carbon transfer to the metal surface from carbon-supersaturated gaseous environments. The metal dusting resistance of such coatings has been investigated in CO-H2 gas mixtures at temperatures ranging from 450°C to 700°C. Conventional plating and cladding methods have been used to deposit Cu-based materials on the surfaces of commercial materials such as 2.25Cr-0.5Mo steel and carbon steel. In addition to the performance of Cu-based materials under laboratory conditions, the effect of alloying elements such as Sn, Zn, Ni, Si, and Al in Cu on the corrosion process and the coating/substrate interface stability are discussed with particular attention to commercial scale applications.

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Pospíšil, Tomáš, Jan Pěnčík, Libor Matějka, Libor Matějka, Alena Kalužová, and Darina Dostálová. "Solution of Thermal Bridge under the Opening in the Cladding by Means of Support Structure for a Doors Threshold Made of Thermal Insulation Composite Material." Key Engineering Materials 531-532 (December 2012): 404–8. http://dx.doi.org/10.4028/www.scientific.net/kem.531-532.404.

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In the process of sustainable construction is the emphasis placed on saving energy, reducing use of natural resources, increase the life cycle of materials by recycling, etc. Rising energy prices put increasing emphasis of builders and investors to better solution of thermal bridges. Solution can be done using a conventional materials, but also advanced materials meet the requirement of a sustainable construction and a reducing consumption of natural resources and extending of the life cycle of material. An example of such material is the thermal insulation composite material. This new developed material with low coefficient of thermal conductivity below the value of 0.100 W/mK is made of recycled waste polymer and recycled filler in the form of granules from recycled glass. In the paper are compared two variants of solution of thermal bridge under the opening in the cladding. In the first variant a wooden door opening in the perimetral cladding is deposited on a support structure for a doors threshold made of a thermal insulation composite material. In the second variant is used a lower shaped brick block. The variants of different foundation of a wooden door opening are compared in terms of a lowest surface temperature and of a temperature factor of the inner surface fRsi and its critical value fRsi,cr according to ČSN 73 0540-2 and ČSN EN ISO 10211.

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Raghukandan, Krishnamorthy, P. Tamilchelvan, and N. Meikandan. "A Study of the Weld Zones on Explosive Cladded Titan12/Ss 304 L Plates." Materials Science Forum 566 (November 2007): 285–90. http://dx.doi.org/10.4028/www.scientific.net/msf.566.285.

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Explosive cladding is a non-conventional, solid-phase bonding technique in which bonding between two plates is produced by their high velocity collision induced by the use of explosives. Attempts were made to explosive clad Titanium-Stainless steel (SS 304 L) plates (3.5 and 3.0 mm thick respectively). The experiments were designed to analyze the bonding interface parallel to the detonation direction. The presence of intermetallics, caused by the melting at the interface due to kinetic energy dissipation, was observed in some locations. The process parameters of the explosive welding of Titanium-Stainless steel combination are defined using the microstructural observations, microhardness at the interface, the results of X-ray diffraction study. A weldability window is also constructed for explosive welding of Ti /Ss.

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KIM, SEONGKU, K. GEARY, W. YUAN, H. R. FETTERMAN, C. ZHANG, C. WANG, W. H. STEIER, et al. "METAL-DEFINED PASSIVE POLYMER OPTICAL WAVEGUIDES OPERATING AT BOTH 1.31 AND 1.55 μm WAVELENGTHS." Journal of Nonlinear Optical Physics & Materials 14, no. 03 (September 2005): 391–97. http://dx.doi.org/10.1142/s0218863505002840.

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We report experimental results demonstrating novel metal-defined passive polymer optical waveguides with low loss in electro-optic polymers for the first time. The polymer optical waveguides are created using a metal film on the top of an upper cladding without any conventional etching process. The fabricated waveguides have excellent lateral optical mode confinement at both 1.31 and 1.55 μm wavelengths, resulting in a fiber-to-lens optical insertion loss of ~7 dB at 1.55 μm and ~4.5 dB at 1.31 μm wavelength in 3.5 cm long devices. We also present the optical loss dependence of the waveguides as a function of optical wavelength. These results may be used in the complex design of integrated polymer lightwave circuits that require a simpler and inexpensive fabrication process.

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Klinger, Liliana, and James R. Griffith. "Fluoropolymer barriers to stress corrosion in optical fibers." Journal of Materials Research 2, no. 6 (December 1987): 876–83. http://dx.doi.org/10.1557/jmr.1987.0876.

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Some recent studies on fluoropolymers that exhibit substantially increased barrier properties against the migration of moisture when compared to conventional fiber coating materials, and as a result may offer unique advantages for use in optical fiber applications, are reported. Moisture vapor permeability studies of cis-trans fluoropolyol polyacrylate indicate that it can offer up to an order of magnitude reduction in H2O permeability relative to commercially available UV curable acrylate coatings. Experimentally determined permeability coefficients were of the order of 10−12 g cm−2 s−1 cm/mm Hg and diffusion coefficients were of the order of 10−10 cm2 s−1. In addition to improved barrier properties, incorporation of fluorine into the polymer structure lowers the index of refraction of the polymer enabling a material to be tailored for use as a cladding in conjunction with silica glass. The index of refraction of cis-trans fluoropolyol polyacrylate was determined, using index matching oils, to be 1.437 (lower than the silica core) permitting its use as a cladding. Other material parameters relevant to fiber coatings have also been measured. The elastic modulus E of the material was determined to be 1010 dyn/cm2 with a slow drop to 108 dyn/cm2 at the glass transition temperature ∼45°C. In addition, an improved formulation of cis-trans fluoropolyol polyacrylate is presented that allowed in-line coating of the optical fiber in an oxygen environment.

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Hoppe, Niklas, Christian Rothe, Arda Celik, María Félix Rosa, Wolfgang Vogel, Daniel Widmann, Lotte Rathgeber, et al. "Single waveguide silicon-organic hybrid modulator." Advances in Radio Science 15 (September 21, 2017): 141–47. http://dx.doi.org/10.5194/ars-15-141-2017.

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Abstract. We present a novel silicon-organic hybrid modulator based on an integrated dual-mode interferometer. The modulator offers a compact, simplified design and enhanced robustness to on-chip fluctuations of temperature compared to conventional Mach-Zehnder based systems. A prototype modulator showing a voltage dependent transmission spectrum is obtained by cladding a dual-mode waveguide in a 250 nm silicon-on-insulator technology with a customized organic electro-optic layer. Estimated phase shifts and corresponding figures of merit are discussed in this contribution. The used organic layer is based on the guest-host approach with customized donor-π-acceptor chromophore embedded and poled in a poly(methylmethacrylate) matrix. The presented prototype is to the best of the authors' knowledge the first integrated single waveguide silicon-organic hybrid modulator.

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SUN, RUJIAN, YINGCHUN GUAN, and YING ZHU. "DEVELOPMENT OF LASER SURFACE TECHNOLOGIES FOR ANTI-CORROSION ON MAGNESIUM ALLOYS: A REVIEW." Surface Review and Letters 23, no. 04 (June 15, 2016): 1630003. http://dx.doi.org/10.1142/s0218625x16300033.

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Magnesium (Mg) alloys have been increasingly used in industries and biomaterial fields due to low density, high specific strength and biodegradability. However, poor surface-related properties are major factors that limit their practical applications. This paper mainly focuses on laser-based anti-corrosion technologies for Mg alloys, beginning with a brief review of conventional methods, and then demonstrates the feasibility of laser surface technologies including laser surface melting (LSM), laser surface alloying (LSA), laser surface cladding (LSC) and laser shock peening (LSP) in achieving enhancement of corrosion resistance. The mechanism and capability of each technique in corrosion resistance is carefully discussed. Finally, an outlook of the development of laser surface technology for Mg alloy is further concluded, aiming to serve as a guide for further research both in industry applications and biomedical devices.

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Zhang, Kai, Wei Jun Liu, and Xiao Feng Shang. "Characteristics of Laser Aided Direct Metal Powder Deposition Process for Nickel-Based Superalloy." Materials Science Forum 534-536 (January 2007): 457–60. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.457.

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Laser additive direct deposition of metals is a new rapid manufacturing technology, which combines with computer aided design, laser cladding and rapid prototyping. The advanced technology can build fully-dense metal components directly from CAD files without a mould or tool. With this technology, a promising rapid manufacturing system called “Laser Metal Deposition Shaping (LMDS)” is being constructed and developed. Through the LMDS technology, fully-dense and near-net shaped metallic parts can be directly obtained through melting coaxially fed powder with a laser. In addition, the microstructure and mechanical properties of the as-formed samples were tested and analyzed synthetically. The results showed significant processing flexibility with the LMDS system over conventional processing capabilities was recognized, with potentially lower production cost, higher quality components, and shorter lead time.

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Kabir Yakasai, Izaddeen, Pg Emeroylariffion Abas, Norazanita Hj Shamsuddin, and Feroza Begum. "Design and simulation of rotated hexagonal porous core photonic crystal fibre with improved effective material loss and dispersion properties." Indonesian Journal of Electrical Engineering and Computer Science 20, no. 1 (October 1, 2020): 75. http://dx.doi.org/10.11591/ijeecs.v20.i1.pp75-81.

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A thorough modal characterization, centred on the full vectorial finite element method (FEM) has been used to model and numerically investigate a porous core photonic crystal fibre (PC-PCF), which may potentially be integrated into Terahertz (1012 Hz) compact systems. The proposed fibre consists of a rotated hexagonal core surrounded by a conventional hexagonal cladding. It has been shown that effective material loss (EML), core power fraction and dispersion profile are 0.019 cm-1, 51.7% and 0.5 ± 0.04 ps/THz/cm within 1 THz bandwidth, respectively. Based on simulated results and noncomplex design, it is envisaged that the proposed fibre can be realised for industrial THz applications.

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Chau, Yuan-Fong, Han-Hsuan Yeh, and Din Ping Tsai. "Analysis of High Birefringence of Four Types of Photonic Crystal Fiber by Combining Circular and Elliptical Air Holes in Fiber Cladding." Advances in Nonlinear Optics 2008 (2008): 1–6. http://dx.doi.org/10.1155/2008/239037.

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This paper presents a numerical study of high birefringence induced by four types (Type 1–4) of different sizes of elliptical air holes in photonic crystal fibers (PCFs). The numerical simulation is carried out by using the finite element method. The statistical correlations between the birefringence and the various parameters are obtained. Based on our results, the birefringence is found to be largely dependent on the variation of the normalized frequency, size ratio, effective area of the circular and elliptical air holes, and the ring number of cladding. Two of our suggested structures, Type 1 and Type 3, can considerably enhance the birefringence in PCFs leading to values as high as7.697×10−3and8.002×10−3, respectively, which are much higher than that obtained by a conventional step-index fiber.

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Lisiecki, Aleksander, and Dawid Ślizak. "Hybrid Laser Deposition of Composite WC-Ni Layers with Forced Local Cryogenic Cooling." Materials 14, no. 15 (August 2, 2021): 4312. http://dx.doi.org/10.3390/ma14154312.

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The purpose of this study was to demonstrate the effect of forced and localized cooling by nitrogen vapours stream under cryogenic conditions during laser deposition of WC-Ni powder on the geometry, microstructure of clad layers and dry sliding wear resistance of the coatings. For this purpose, comparative tests were performed by conventional laser cladding at free cooling conditions in ambient air and by the developed novel process of laser deposition with additional localized cooling of the solidifying deposit by nitrogen vapours stream. Due to presence of gaseous nitrogen in the region of the melt pool and solidifying deposit, the process was considered as combining laser cladding and laser gas nitriding (performed simultaneously), thus the hybrid process. The influence of the heat input and cooling conditions on the geometrical features, dilution rate, share of carbides relative to the matrix, and the fraction share of carbides, as well as hardness profiles on cross sections of single stringer beads was analysed and presented. The XRD, EDS analysis and the sieve test of the experimental powder were used to characterize the composite WC-Ni type powder. The OM, SEM, EDS and XRD test methods were used to study the microstructure, chemical and phase composition of clad layers. Additionally, ball-on-disc tests were performed to determine the wear resistance of representative coatings under dry sliding conditions. The results indicate that the novel demonstrated technique of localized forced cooling of the solidifying deposit has advantageous effect, because it provides approximately 20% lower penetration depth and dilution, decreases tendency for tungsten carbides decomposition, provides more uniform distribution and higher share of massive eutectic W2C-WC carbides across the coating. While the conventionally laser cladded layers show tendency for decomposition of carbide particles and resolidifying dendritic complex carbides mainly M2C, M3C and M7C3 containing iron, nickel, and tungsten, and with Ni/Ni3B matrix. The quantitative relationship between heat input, cooling conditions and the carbides grain size distribution as well as carbides share in relation to the matrix was determined.

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Journal articles on the topic 'Conventional cladding'

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