Vacuum Brazing of Accelerator Components

Singh, Rajvir; Pant, Kamal K.; Lal, Shankar; Yadav, D P; Garg, Sandeep; Raghuvanshi, V. K.; Mundra, G.

doi:10.1088/1742-6596/390/1/012025

Cited by 11 publications

(4 citation statements)

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“…[1][2][3]. In case of nuclear industries, various combinations of materials are continuously being used and explored for many critical components and products like fusion reactors, particle accelerators, and heat exchangers [4][5][6][7][8][9]. Copper (Cu) has high thermal conductivity, whereas stainless steel (SS) has high strength and nature of corrosion resistance.…”

Section: Introductionmentioning

confidence: 99%

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Microstructures and Properties of Copper to Stainless Steel Joints by Hybrid FSW

Joshi

Badheka

2017

Metallogr. Microstruct. Anal.

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The present research article is focused to investigate the heating-and cooling-assisted friction stir welding (FSW) on dissimilar copper to stainless steel joints along with normal FSW. Gas tungsten arc welding torch was applied for heating-assisted source in front of the FSW tool, wherein preheating current was varied as 20, 40, and 60 A with rest of constant FSW parameters. Similarly, cooling-assisted FSW was performed by compressed air and water behind the FSW tool for constant FSW parameters, wherein the compressed air flow rate was varied as 15 and 30 PSI and water cooling was applied with 75 ml/ min one after another. Weld properties of assisted approaches were compared with normal FSW on the scale of macrostructure and microstructure analysis, tensile testing, and microhardness properties. The obtained results reveal that the normal FSW of dissimilar copper to stainless steel joint was observed as superior relative to assisted approaches. Surface oxides were observed for the welds of heating-assisted FSW and cooling-assisted FSW of compressed air. Elimination of surface oxides was noted for FSW assisted by water cooling. Highest tensile strength was reported for normal FSW relative to heating-assisted FSW and cooling-assisted FSW. Tensile strength was deteriorated as cooling conditions increase. The microstructures of the stir zone were observed as metal matrix type with Cu matrix and SS particles, wherein SS particles were reported as in random distribution with its varying size. Major defects were reported around the largely dispersed SS particles inside Cu matrix.

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Section: Introductionmentioning

confidence: 99%

“…Copper (Cu) has high thermal conductivity, whereas stainless steel (SS) has high strength and nature of corrosion resistance. Thus, the dissimilar joint of Cu to SS is apt for the first wall and diverter of nuclear application [4][5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Microstructures and Properties of Copper to Stainless Steel Joints by Hybrid FSW

Joshi

Badheka

2017

Metallogr. Microstruct. Anal.

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“…0.1 mm, since with a smaller gap due to the viscosity of the molten filler, the filling velocity will be very small, and with a larger gap, there will be no capillary effect. The thermal coefficient of expansions should also be considered in vacuum brazing of dissimilar metals before once deciding on the clearances [6].…”

Section: Design Of Partsmentioning

confidence: 99%

Experimental fine-advancement of vacuum brazing processes for fabrication of S-Band RF coupling cells

Davtyan,

Isunts,

Dekhtiarov

et al. 2023

J. Inst.

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The technology of high vacuum brazing for fabrication of S-Band RF coupling cell unit is given. The brazing in high vacuum conditions provides a vacuum-tight and more precise connection with the use of special high-purity fillers. Based on the material and design of the part, as well as the shape of the filler, it is necessary to develop filler channels and gaps that will be of the most optimal shape and size. High-purity silver-copper alloys of the BV Ag-30, BV Ag-8, and BV Ag-29 brands were used as fillers. Rectangular flanges for brazing with waveguides are made of GlidCop AL-25, and the CF flange for the beamline tube is made of stainless steel. Brazing processes were carried out under high vacuum conditions in an upgraded precision vacuum brazing system, which is developed at CANDLE Synchrotron Research Institute. Using the recorded data and experimental results, optimal modes for fine-advancement of vacuum brazing processes for fabrication of S-Band RF coupling cell unit are developed.

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“…A limited number of studies describe that the process is performed using a diffusion bonding furnace with hydraulic load equipment in the temperature range of 600-1000 • C [13,14]. Moreover, recently there has been an interest in Cu-Cu bonded structures with advanced mechanical properties that can be used for the construction of bar-wound stators in vehicles [15] or as components in particle accelerators [16,17]. High-temperature bonding technology is compatible with these applications as the existence of thermal deformation phenomena does not consist of a deterrent factor.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Copper Thermocompression Diffusion Bonding under Vacuum: Microstructural and Mechanical Characteristics

Samouhos

Peppas

Angelopoulos

et al. 2019

Metals

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The optimization of the autogenous diffusion copper bonding via thermocompression at vacuum environment was investigated. The influence of various bonding parameters on the interdiffusion efficiency was studied in detail at the micro (SEM-EBSD) and nano (TEM) scales. Bonding at 1000 °C for 90 min under pressure (10 MPa) presented optimum structural and mechanical results. Under these conditions, interdiffusion phenomena were observed at a significant extent through the swelling transformation of existing fine grains or the formation of equiaxed copper grains with an orientation parallel to the bond interface. Transmission electron microscopy revealed the importance of the grain size of the base material on the bond quality. In the regions with fine-sized copper grains, the formation of small equiaxed recrystallized twins was observed. Their length within the bonding zone was in the order of 200 and 400 nm. On the contrary, in the regions with coarse grains the interdiffusion was poorer. The processing temperature and duration presented a significant effect on the bonding strength (BS). BS exceeded 100 MPa in case of processing conditions of T ≥ 850 °C and t ≥ 60 min, while the maximum BS value achieved (≈180 MPa) was comparable with the respective value of the base material. The microhardness of the optimum bond reached 55 HV—slightly higher in comparison to the hardness of the initial copper material. The results indicated that the proposed thermocompression process is appropriate for the production of Cu-Cu bonded structures that can be potentially used as electrical components under mechanical stress.

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Vacuum Brazing of Accelerator Components

Cited by 11 publications

References 0 publications

Microstructures and Properties of Copper to Stainless Steel Joints by Hybrid FSW

Microstructures and Properties of Copper to Stainless Steel Joints by Hybrid FSW

Experimental fine-advancement of vacuum brazing processes for fabrication of S-Band RF coupling cells

Optimization of Copper Thermocompression Diffusion Bonding under Vacuum: Microstructural and Mechanical Characteristics

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