WorldWideScience

Sample records for brazing

  1. Brazing

    International Nuclear Information System (INIS)

    This report is a compilation of published literature on high temperature brazing covering the period 1973-1978. The references are listed alphabetically with regard to the base material or combination of base materials to be brazed. Trade names are treated as base materials. The report contains approximately 1500 references, of which 300 are to patents

  2. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  3. Induction Brazing

    DEFF Research Database (Denmark)

    Henningsen, Poul

    Induction brazing is a fast and appropriate method for industrial joining of complex geometries and metal combinations. In all types of brazing processes it is important to heat the joint interface of the two materials to the same, high temperature. If one of the specimens is warmer than the other...... the work piece materials has large influence on the heating time and temperature distribution in induction heating. In order to ensure high and uniform temperature distribution near the interface of a joint between dissimilar materials the precise coil geometry and position is of great importance. The...... present report presents a combined numerical and experimental method for determination of appropriate/optimiged coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and...

  4. Brazing with plated alloys

    International Nuclear Information System (INIS)

    The use of braze alloy preforms on complex geometry components is at times a very difficult task requiring extensive handling of the parts or even tack welding of the preform to ensure that it is held in place. One method of overcoming these difficulties is the use of plated braze alloys (i.e., filler metals) applied directly to the braze region. Plating helps to avoid the potential for contamination resulting from handling and also ensures that the braze alloy is located properly. Examples are discussed in which an electroplated silver-copper alloy is used as an alternative to the BAg8 preforms and electroless nickel is used as a replacement for an amorphous Ni-P braze alloy foil. A toroidal cooling plate with helical flow channels was fabricated from oxygen-free high conductivity (OFHC) and brazed using the electroplated silver-copper alloy. The silver-copper braze alloy was applied to the copper substrate in a laminated fashion of alternating layers of silver and copper, which in combination approximated the eutectic composition (72% Ag-28% Cu by weight). Examination of the brazed assemblies indicated that in both cases the advantages of using plated braze alloys are numerous. These advantages include decreased labor, improved cleanliness and exactness of braze alloy placement. The primary disadvantage was an increased tendency for solidification defects presumably resulting from contaminants in the plating baths. This last observation is presently being examined in greater detail. The end results is that the assemblies brazed with the plated alloys were acceptable for the intended application and that the use of plating facilitated the successful assembly of these components

  5. Brazing zone structure at active brazing of alumina ceramics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Nowadays one of the most effective methods of joining of oxide ceramics with other elements of construction is active brazing based on using of active metals (Ti, Zr), which increase reactivity of brazing alloy relative to ceramic element of a joining.

  6. Advances in brazing science, technology and applications

    CERN Document Server

    2013-01-01

    Brazing processes offer enhanced control, adaptability and cost-efficiency in the joining of materials. Unsurprisingly, this has lead to great interest and investment in the area. Drawing on important research in the field, Advances in brazing provides a clear guide to the principles, materials, methods and key applications of brazing. Part one introduces the fundamentals of brazing, including molten metal wetting processes, strength and margins of safety of brazed joints, and modeling of associated physical phenomena. Part two goes on to consider specific materials, such as super alloys, filler metals for high temperature brazing, diamonds and cubic boron nitride, and varied ceramics and intermetallics. The brazing of carbon-carbon (C/C) composites to metals is also explored before applications of brazing and brazed materials are discussed in part three. Brazing of cutting materials, use of coating techniques, and metal-nonmetal brazing for electrical, packaging and structural applications are reviewed, alon...

  7. Vacuum Brazing of Accelerator Components

    Science.gov (United States)

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

    2012-11-01

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  8. Vacuum Brazing of Accelerator Components

    International Nuclear Information System (INIS)

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  9. Induction brazing of complex joints

    DEFF Research Database (Denmark)

    Henningsen, Poul; Zhang, Wenqi; Bay, Niels

    2003-01-01

    Induction brazing is a fast and appropriate method for industrial joining of complex geometries and metal combinations. In all types of brazing processes it is important to heat the joint interface of the two materials to the same, high temperature. If one of the specimens is warmer than the other......, or if the hottest area is located outside the joint interface, a number of defects may appear: the braze metal may flow away from the joint, the flux may burn off, poor binding of the braze metal may appear or the braze metal may be overheated. Joint geometry as well as electro-magnetic properties of...... the work piece materials has large influence on the heating time and temperature distribution in induction heating. In order to ensure high and uniform temperature distribution near the interface of a joint between dissimilar materials the precise coil geometry and position is of great importance. The...

  10. Development of vacuum brazing furnace

    International Nuclear Information System (INIS)

    In joining of components where welding process is not possible brazing processes are employed. Value added components, high quality RF systems, UHV components of high energy accelerators, carbide tools etc. are produced using different types of brazing methods. Furnace brazing under vacuum atmosphere is the most popular and well accepted method for production of the above mentioned components and systems. For carrying out vacuum brazing successfully it is essential to have a vacuum brazing furnace with latest features of modern vacuum brazing technology. A vacuum brazing furnace has been developed and installed for carrying out brazing of components of copper, stainless steel and components made of dissimilar metals/materials. The above furnace has been designed to accommodate jobs of 700mm diameter x 2000mm long sizes with job weight of 500kgs up to a maximum temperature of 1250 degC at a vacuum of 5 x 10-5 Torr. Oil diffusion pumping system with a combination of rotary and mechanical booster pump have been employed for obtaining vacuum. Molybdenum heating elements, radiation shield of molybdenum and Stainless Steel Grade 304 have been used. The above furnace is computer controlled with manual over ride facility. PLC and Pentium PC are integrated together to maneuver steps of operation and safety interlocks of the system. Closed loop water supply provides cooling to the system. The installation of the above system is in final stage of completion and it will be ready for use in next few months time. This paper presents insights of design and fabrication of a modern vacuum brazing furnace and its sub-system. (author)

  11. Vacuum brazing of metals (1961)

    International Nuclear Information System (INIS)

    We have studied brazing in vacuum aiming its application for the making of containers and apparatus meant for high vacuum (p -8 torr). We first define the wettability of a brazing alloy on a metal and we remind the influence of the various parameters which act on this wettability (nature of the solid, of the liquid, geometrical and physicochemical state of the surface, metallurgical reactions occurring at the interface, temperature, time). We give then the results of the tests carried out in order to determine the conditions of wettability in vacuum of some brazing alloys on metals which can be used for the above mentioned apparatus (stainless steel, aluminium, bronze, titanium, zirconium, kovar, nickel, copper). (author)

  12. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  13. Filler alloys for brazing in power industries

    International Nuclear Information System (INIS)

    The problem is discussed of using nickel-based high-temperature brazing solders in nuclear power engineering. Different types of brazing solders are compared with regard to brazing and mechanical properties and oxidation resistance. The advantages of nickel-based brazing solders include their melting temperature which is higher by 150 to 200 degC than the melting temperatures of common solders. The effects of different additions on melting temperature are discussed. It is advisable to use the above brazing solders under hydrogen reduction atmosphere at a temperature of -40 down to -75 degC or at a pressure of 10-3 down to 10-4 Pa. Currently manufactured nickel-based brazing solders may be used at a temperature of up to 1150 degC. (J.B.)

  14. Diffusion barriers in modified air brazes

    Science.gov (United States)

    Weil, Kenneth Scott; Hardy, John S; Kim, Jin Yong; Choi, Jung-Pyung

    2013-04-23

    A method for joining two ceramic parts, or a ceramic part and a metal part, and the joint formed thereby. The method provides two or more parts, a braze consisting of a mixture of copper oxide and silver, a diffusion barrier, and then heats the braze for a time and at a temperature sufficient to form the braze into a bond holding the two or more parts together. The diffusion barrier is an oxidizable metal that forms either a homogeneous component of the braze, a heterogeneous component of the braze, a separate layer bordering the braze, or combinations thereof. The oxidizable metal is selected from the group Al, Mg, Cr, Si, Ni, Co, Mn, Ti, Zr, Hf, Pt, Pd, Au, lanthanides, and combinations thereof.

  15. METHODS FOR BRAZING UNUSUAL METAL COMBINATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Bertossa, Robert C.

    1963-10-15

    A method for vacuum pressure braze cladding is described. Application of the method to Mo-OFHC Cu-type 316L stainlcss steel, Ta cladding on OFHC Cu, Nb with Ni, Ti and Zr on steels, and pure Be brazing to austenitic stalnless steel are discussed. The advantages of vacuumpressure bonding are also discussed. (P.C.H.)

  16. Theory and modeling of active brazing.

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, Frank B.; Miller, James Edward; Lechman, Jeremy B.; Givler, Richard C.

    2013-09-01

    Active brazes have been used for many years to produce bonds between metal and ceramic objects. By including a relatively small of a reactive additive to the braze one seeks to improve the wetting and spreading behavior of the braze. The additive modifies the substrate, either by a chemical surface reaction or possibly by alloying. By its nature, the joining process with active brazes is a complex nonequilibrium non-steady state process that couples chemical reaction, reactant and product diffusion to the rheology and wetting behavior of the braze. Most of the these subprocesses are taking place in the interfacial region, most are difficult to access by experiment. To improve the control over the brazing process, one requires a better understanding of the melting of the active braze, rate of the chemical reaction, reactant and product diffusion rates, nonequilibrium composition-dependent surface tension as well as the viscosity. This report identifies ways in which modeling and theory can assist in improving our understanding.

  17. Direct metal brazing to cermet feedthroughs

    International Nuclear Information System (INIS)

    An improved method for brazing metallic components to a cermet surface in an alumina substrate eliminates the prior art metallized layer over the cermet via and adjoining alumina surfaces. Instead, a nickel layer is applied over the cermet surface only and metallic components are brazed directly to this nickel coated cermet surface. As a result, heretofore unachievable tensile strength joints are produced. In addition, cermet vias with their brazed metal components can be spaced more closely in the alumina substrate because of the elimination of the prior art metallized alumina surfaces

  18. Influence of technological conditions during vacuum brazing on the aggressive behaviour of nickel brazing filler metal

    International Nuclear Information System (INIS)

    The effect of brazing temperature 1080, 1120 and 11900C and dwell at those temperatures in the range 1, 5, 30 and 180 min. as well as additional annealing at 10500C/120 min. on the degree of erosion and diffusion of 5 types of alloyed steels and also on the character of brazing alloy structure formation with the use of five Ni-based high temperature brazing alloys. On the basis of attained results of experimental investigation the general optimum conditions of vacuum brazing are determined. (orig.)

  19. Influence of brazing parameters and alloy composition on interface morphology of brazed diamond

    International Nuclear Information System (INIS)

    Active brazing is an effective technique for joining diamond or cBN grit to metallic substrates. This technique is currently used to manufacture superabrasive, high-performance tools. The investigation of interface reactions between diamond and active brazing alloys plays an important role in understanding and improving the brazing process and the resultant tool performance. Focused ion beam (FIB) milling enabled the high resolution investigation of these extremely difficult to prepare metal-diamond joints. The interfacial nanostructure is characterized by the formation of two layers of TiC with different morphologies. First a cuboidal layer forms directly on the diamond and reaches a thickness of approximately 70 nm. Then a second layer with columnar TiC crystals grows on the first layer into the brazing filler metal by a diffusion-controlled process. The combined thickness of both TiC layers varies between 50 nm and 600 nm depending on the brazing temperature and holding time

  20. Design of a braze alloy for fast epitaxial brazing of superalloys

    Science.gov (United States)

    Piegert, S.; Laux, B.; Rösier, J.

    2012-07-01

    For the repair of directionally solidified turbine components made of nickel-based superalloys, a new high-temperature brazing method has been developed. Utilising heterogeneous nucleation on the crack surface, the microstructure of the base material can be reproduced, i.e. single crystallinity can be maintained. In contrast to commonly used eutectic braze alloys, such as nickel-boron or nickel-silicon systems, the process is not diffusion controlled but works with a consolute binary base system. The currently applied epitaxial brazing methods rely on isothermal solidification diffusing the melting point depressants into the base material until their concentration is reduced so that the liquid braze solidifies. Contrary, the identified Ni-Mn consolute system enables a temperature driven epitaxial solidification resulting in substantially reduced process duration. The development of the braze alloys was assisted using the CALPHAD software Thermo-Calc. The solidification behaviour was estimated by kinetic calculations with realistic boundary conditions. Finally, the complete system, including braze alloy as well as substrate material, was modelled by means of DICTRA. Subsequently, the thermodynamic properties of the braze alloys were experimentally analysed by DSC measurements. For brazing experiments 300 μm wide parallel gaps were used. Complete epitaxial solidification, i.e. the absence of high-angle grain boundaries, could be achieved within brazing times being up to two orders of magnitude shorter compared to diffusion brazing processes. Theoretically and experimentally evaluated process windows reveal similar shapes. However, a distinct shift has to be stated which can be ascribed to the limited accuracy of the underlying thermodynamic databases.

  1. Design of a braze alloy for fast epitaxial brazing of superalloys

    International Nuclear Information System (INIS)

    For the repair of directionally solidified turbine components made of nickel-based superalloys, a new high-temperature brazing method has been developed. Utilising heterogeneous nucleation on the crack surface, the microstructure of the base material can be reproduced, i.e. single crystallinity can be maintained. In contrast to commonly used eutectic braze alloys, such as nickel-boron or nickel-silicon systems, the process is not diffusion controlled but works with a consolute binary base system. The currently applied epitaxial brazing methods rely on isothermal solidification diffusing the melting point depressants into the base material until their concentration is reduced so that the liquid braze solidifies. Contrary, the identified Ni-Mn consolute system enables a temperature driven epitaxial solidification resulting in substantially reduced process duration. The development of the braze alloys was assisted using the CALPHAD software Thermo-Calc. The solidification behaviour was estimated by kinetic calculations with realistic boundary conditions. Finally, the complete system, including braze alloy as well as substrate material, was modelled by means of DICTRA. Subsequently, the thermodynamic properties of the braze alloys were experimentally analysed by DSC measurements. For brazing experiments 300 μm wide parallel gaps were used. Complete epitaxial solidification, i.e. the absence of high-angle grain boundaries, could be achieved within brazing times being up to two orders of magnitude shorter compared to diffusion brazing processes. Theoretically and experimentally evaluated process windows reveal similar shapes. However, a distinct shift has to be stated which can be ascribed to the limited accuracy of the underlying thermodynamic databases.

  2. Braze Process Optimization Involving Conventional Metal/Ceramic Brazing with 50Au-50Cu Alloy

    Energy Technology Data Exchange (ETDEWEB)

    MALIZIA JR.,LOUIS A.; MEREDITH,KEITH W.; APPEL,DANIEL B.; MONROE,SAUNDRA L.; BURCHETT,STEVEN N.; STEPHENS JR.,JOHN J.

    1999-12-15

    Numerous process variables can influence the robustness of conventional metal/ceramic brazing processes. Experience with brazing of hermetic vacuum components has identified the following parameters as influencing the outcome of hydrogen furnace brazed Kovar{trademark} to metallized alumina braze joints: (a) Mo-Mn metallization thickness, sinter fire temperature and porosity (b) Nil plate purity, thickness, and sinter firing conditions (c) peak process temperature, time above liquidus and (d) braze alloy washer thickness. ASTM F19 tensile buttons are being used to investigate the above parameters. The F19 geometry permits determination of both joint hermeticity and tensile strength. This presentation will focus on important lessons learned from the tensile button study: (A) the position of the Kovar{trademark} interlayer can influence the joint tensile strength achieved--namely, off-center interlayers can lead to residual stress development in the ceramic and degrade tensile strength values. Finite element analysis has been used to demonstrate the expected magnitude in strength degradation as a function of misalignment. (B) Time above liquidus (TAL) and peak temperature can influence the strength and alloying level of the resulting braze joint. Excessive TAL or peak temperatures can lead to overbraze conditions where all of the Ni plate is dissolved. (C) Metallize sinter fire processes can influence the morphology and strength obtained from the braze joints.

  3. High temperature brazing of diamond tools

    Institute of Scientific and Technical Information of China (English)

    YAO Zheng-jun; SU Hong-hua; FU Yu-can; XU Hong-jun

    2005-01-01

    A new brazing technique of diamond was developed. Using this new technique optimum chemical and metallurgical bonding between the diamond grits and the carbon steel can be achieved without any thermal damages to diamond grits. The results of microanalysis and X-ray diffraction analysis reveal that a carbide layer exists between the diamond and the matrix, which consists of Cr3C2, Cr7C3 and Cr23C6. Performance tests show that the brazed diamond core-drill has excellent machining performance. In comparison with traditional electroplated diamond core-drill, the brazed diamond core-drill manufactured using the new developed technique has much higher machining efficiency and much longer operating life.

  4. Brazing of inconel 600 and SUS304 stainless steel with used of rapidly solidified nickel-base brazing foil

    Energy Technology Data Exchange (ETDEWEB)

    Miyazawa, Yasuyuki; Ariga, Tadashi (Tokai Univ., Tokyo (Japan))

    1992-05-01

    In this study, the clad material which have been brazed with the nickel-base heat resistant alloy; Inconel 600 on AISI304 stainless steel has been produced by the brazing using three types of nickel-base brazing foils. The three types of nickel-base brazing foils are 7Cr(4.5Si-7.0Cr-3.0B-3.0Fe-Ni bal.), 5Cr(4.5Si-5.0Cr-3.0B-3.0Fe-Ni bal.) and 10Cr(4.5Si-10.0Cr-3.0B-3.0Fe-Ni bal.). Brazing was done in an electrical resistant furnace in an argon gas atmosphere. The brazing temperatures employed in this study were 1050, 1100, 1150, 1200 and 1250degC and the brazing times were 10, 30, 60 and 120 min for all types of brazing foils. The property of the joint was estimated by the mechanical properties, microstructures and distributions of the elements which were investigated by SEM and EPMA. The brazed joint was obtained for all of brazing conditions in this study. The shear strength of the specimen increased with increasing brazing time except at 1050degC. At 1050degC, the shear strength of the specimen was not influenced by brazing time. In this case, the break of the specimen during the shear test occurred in the brazed layer. At 1250degC, the value of 450 MPa was obtained as the maximum shear strength in this study; the break of the specimen occurred in the base metal. The shear strength of the specimen increased with increasing brazing temperature. The shear strength of the specimen increased with increasing chromium content in the brazing foil to 7 mass%. (J.P.N.).

  5. Brazing of inconel 600 and SUS304 stainless steel with used of rapidly solidified nickel-base brazing foil

    International Nuclear Information System (INIS)

    In this study, the clad material which have been brazed with the nickel-base heat resistant alloy; Inconel 600 on AISI304 stainless steel has been produced by the brazing using three types of nickel-base brazing foils. The three types of nickel-base brazing foils are 7Cr(4.5Si-7.0Cr-3.0B-3.0Fe-Ni bal.), 5Cr(4.5Si-5.0Cr-3.0B-3.0Fe-Ni bal.) and 10Cr(4.5Si-10.0Cr-3.0B-3.0Fe-Ni bal.). Brazing was done in an electrical resistant furnace in an argon gas atmosphere. The brazing temperatures employed in this study were 1050, 1100, 1150, 1200 and 1250degC and the brazing times were 10, 30, 60 and 120 min for all types of brazing foils. The property of the joint was estimated by the mechanical properties, microstructures and distributions of the elements which were investigated by SEM and EPMA. The brazed joint was obtained for all of brazing conditions in this study. The shear strength of the specimen increased with increasing brazing time except at 1050degC. At 1050degC, the shear strength of the specimen was not influenced by brazing time. In this case, the break of the specimen during the shear test occurred in the brazed layer. At 1250degC, the value of 450 MPa was obtained as the maximum shear strength in this study; the break of the specimen occurred in the base metal. The shear strength of the specimen increased with increasing brazing temperature. The shear strength of the specimen increased with increasing chromium content in the brazing foil to 7 mass%. (J.P.N.)

  6. Active Metal Brazing and Characterization of Brazed Joints in Titanium to Carbon-Carbon Composites

    Science.gov (United States)

    Singh, M.; Shpargel, T. P.; Morscher, G. N.; Asthana, R.

    2006-01-01

    The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSiI. The joint microstructures were examined using optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading. A tube-on-plate tensile test was used to evaluate joint strength of Ti-tube/ C-C composite joints. The load-carrying ability was greatest for the Cu-ABA braze joint structures. This system appeared to have the best braze spreading which resulted in a larger braze/C-C composite bonded area compared to the other two braze materials. Also, joint loadcarrying ability was found to be higher for joint structures where the fiber tows in the outer ply of the C-C composite were aligned perpendicular to the tube axis when compared to the case where fiber tows were aligned parallel to the tube axis.

  7. Brazing of photocathode RF gun structures in Hydrogen atmosphere: Process qualification, effect of brazing on RF properties and vacuum compatibility

    International Nuclear Information System (INIS)

    In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) compatible photocathode RF gun structure developed at our Centre. The choice of brazing alloy and its form, brazing clearance between parts to be joined and the brazing cycle adopted have been qualified through metallographic examination of identical joints on an OFE copper prototype that was cut open after brazing. The quality of brazed joint not only affects the UHV compatibility of the gun, but also influences the RF parameters finally achieved. A 2-D electromagnetic code, SUPERFISH, was used to predict the variation in RF parameters before and after brazing considering actual brazing clearances provided between the parts to be joined. Results obtained from low power RF measurements on the brazed gun structure confirm the integrity of the brazed joints and show good agreement with those predicted by electromagnetic simulations. The brazed gun structure has been leak-tested and pumped down to a vacuum level limited by the vacuum compatibility of the flange-fittings employed in the setup.

  8. Brazing of photocathode RF gun structures in Hydrogen atmosphere: Process qualification, effect of brazing on RF properties and vacuum compatibility

    Science.gov (United States)

    Kak, Ajay; Kulshreshtha, P.; Lal, Shankar; Kaul, Rakesh; Ganesh, P.; Pant, K. K.; Abhinandan, Lala

    2012-11-01

    In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) compatible photocathode RF gun structure developed at our Centre. The choice of brazing alloy and its form, brazing clearance between parts to be joined and the brazing cycle adopted have been qualified through metallographic examination of identical joints on an OFE copper prototype that was cut open after brazing. The quality of brazed joint not only affects the UHV compatibility of the gun, but also influences the RF parameters finally achieved. A 2-D electromagnetic code, SUPERFISH, was used to predict the variation in RF parameters before and after brazing considering actual brazing clearances provided between the parts to be joined. Results obtained from low power RF measurements on the brazed gun structure confirm the integrity of the brazed joints and show good agreement with those predicted by electromagnetic simulations. The brazed gun structure has been leak-tested and pumped down to a vacuum level limited by the vacuum compatibility of the flange-fittings employed in the setup.

  9. Development of brazing technique for a 1.6 cell BNL/SLAC/UCLA type photocathode guns by hydrogen brazing

    International Nuclear Information System (INIS)

    Two prototypes of a 1.6 cell BNL/SLAC/UCLA type RF photocathode gun, a precision machined RF structure capable of supporting gradients in excess of 80 MV/m, have been successfully brazed and leak rates of 10-10 mbar l/s have been achieved. Brazing, is carried out in two steps in a hydrogen furnace, it involves joining of two RF cavities, 6 cylindrical ports, one rectangular waveguide and one seal plate. The cavities and waveguide are made of copper and the ports and seal plate are of stainless steel. Fixtures were designed and fabricated indigenously to maintain the required assembly tolerances during brazing. This was important for brazing of ports, two of which are brazed to one cavity at an angle of 22.50 at diametrically opposite locations, and the remaining four are brazed to the other cavity in mutually perpendicular orientations. All joints were brazed using copper-silver eutectic (72-28) alloy in foil and wire forms. This paper discusses the brazing requirement, design of fixtures, and the procedure adopted for brazing of the photocathode gun. The paper also discusses results of the tests carried out to qualify the brazed joints. (author)

  10. Properties of active-brazed HPSN-steel joints

    Energy Technology Data Exchange (ETDEWEB)

    Wippel, V. [Technische Univ., Graz (Austria). Abt. fuer Werkstoffe und Schweisstechnik; Holzner, G. [Technische Univ., Graz (Austria). Abt. fuer Werkstoffe und Schweisstechnik; Cerjak, H. [Technische Univ., Graz (Austria). Abt. fuer Werkstoffe und Schweisstechnik

    1995-12-31

    In this paper, the creation of very strong HPSN-ceramic compounds with HPSN and steel by active-brazing is described. The brazin-partners are hot-pressed silicon-nitride (HPSN) and the metallic part is the martensite steel X23 CrNi17. As active-braze commercially available silver and silver-copper brazes were used. (orig./MM)

  11. Brazing of sensors for high-temperature steam instrumentation systems

    International Nuclear Information System (INIS)

    Procedures are developed for brazing a ceramic-to-metal seal and for laser welding of sensor subassemblies into tube walls, induction brazing thermocouples through a tube wall, and furnace brazing triaxial cables, thermocouples, and a vent tube to a guide tube study three-dimensional phenomena in the upper plenum and core of a pressurized water reactor during the reflood stage of a loss-of-coolant accident. 8 refs

  12. Short cycle brazing of an alumina dispersion strengthened copper alloy

    International Nuclear Information System (INIS)

    An alumina dispersion strengthened copper alloy (with 0.07 wt, % alumina) has been proposed for several specialized applications in fusion reactors, such as the stabilizer in superconducting magnets and the structural material for divertors and limiters. In this research, brazed joints of the alumina dispersion strengthened copper alloy were developed using resistance heating brazing. The BCuP-3 brazing alloy was chosen based upon its low activation characteristics. Brazing was conducted using a GLEEBLE 1500 system with which time, temperature, and stress were precisely controlled. Butt-brazed joints with different brazing times were evaluated based on tensile and bending fatigue properties. Results from these tests reveal that the optimum braze time is approximately 1 minute at 8000C with a holding stress of 0.5 MPa. Metallography examinations were conducted on both the as brazed structure and the fracture surfaces. In the former, a transition layer (about 10 μm tick) was formed between the braze metal and the base alloy. Microhardness measurements across the braze did not show any hardening or softening effect due to the brazing process. Metallography of the fractured tensile and fatigue samples showed that cracks always penetrated through the interface between the transition layer and the braze metal. Semiquantitative energy dispersive x-ray spectroscopy (EDS) analysis was also performed across the joint. Profiles of P and Ag showed that P diffused very quickly into base metal along grain boundaries. A strong Al peak (associated with the detection of Al2O3) was found that corresponded with the transition layer. The presence of the alumina particles in the transition zone restricts the grain growth process in this region, resulting in relatively fine grain size

  13. Study on alumina-alumina brazing for application in vacuum chambers of proton synchrotron

    International Nuclear Information System (INIS)

    The paper describes an experimental study to standardize vacuum brazing process to obtain satisfactory high purity alumina brazed joints for application in rapid cycle proton synchrotron machine. Two different brazing routes, adopted for making alumina-alumina brazed joints, included (i) multi-step Mo-Mn metallization and brazing with BVAg-8 alloy and (ii) advanced single-step active brazing with CuSil-ABA alloy. Brazed alumina specimens, prepared by both the routes, yielded ultra high vacuum compatible, helium leak tight and bakeable joints. Active-brazed specimens exhibited satisfactory strength values in tensile and four-point bend tests. Metallized-brazed specimens, although exhibited relatively lower tensile strength than the targeted value, displayed satisfactory flexural strength in four-point bend test. The results of the study demonstrated that active brazing is the simple and cost effective alternative to conventional metallization route for producing satisfactory brazed joints for application in rapid cycle proton synchrotron machine. (author)

  14. Reactive Boride Brazing on Low-Alloy Automotive Grade Steel

    Science.gov (United States)

    Palanisamy, B.; Upadhyaya, A.

    2011-11-01

    Brazing is a widely used process to improve the performance of steels used in automotive applications. The substrate material is often exposed to harsh conditions in these applications and may affect the service life of the component. Reactive boride brazing aims to improve the mechanical properties of the substrate material by forming a ceramic-metal composite coating in a single-step process in situ. In this study, sintered Ancor 4300 low-alloy steel is used as the substrate with chromium-rich braze and chromium-lean braze materials. The mechanical properties of the brazed samples were studied in detail using microindentation hardness measurements and the transverse rupture test. The results indicate that the brazed superlayer has a 10 times higher hardness. There was a significant improvement in the transverse rupture strength of the steel brazed with the chromium-rich boride as compared to the pure substrate material. In an effort to reduce processing time, green compacts of the substrate were also directly brazed and yielded favorable results.

  15. Brazing molybdenum and tungsten for high temperature service

    International Nuclear Information System (INIS)

    Investigations were conducted to develop vacuum brazes for molybdenum and tungsten which can be used in seal joint applications up to 1870 K (1597 C, 2907 F). Joints were attempted in molybdenum, tungsten and tungsten--molybdenum. The braze materials included: Ti--10Cr powder, Ti--30V wire, Ti--65V wire, V wire, Ni electroplate, MoB--50MoC powder mixture, V--50Mo powder mixture, Mo--15MoB2 powder mixture and Mo--49V--15MoB2 powder mixture. Braze temperature ranged from 1900 K (1627 C, 2961 F) to 2530 K, (2257 C, 4095 F), and leak-tight joints were made with all braze materials except Ti--10Cr. After heat treatments up to 1870 K (1597 C, 2907 F) Kirkendall voiding was found to cause leakage of some of the joints made with only substitutional alloying elements. However, adding base metal powders to the braze or narrowing the root opening eliminated this problem. Kirkendall voiding was not a problem when interstitial elements were a major ingredient in the braze material. Shear testing of Ti--65V, V, MoB--50MoC and V--50Mo brazed molybdenum at 1670 K (1397 C, 2547 F) indicated strengths equal to or better than the base metal. Ti--65V, V--50Mo and MoB--50MoC brazed joints were exposed to basalt at 1670 K (1397 C, 2547 F) for 3 h without developing leaks

  16. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    Science.gov (United States)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  17. Copper phosphorus brazing for copper tubing. Dohaikan no rindo rozuke

    Energy Technology Data Exchange (ETDEWEB)

    Kanai, A. (Industrial Research Institute of Kanagawa Prefecture, Kanagawa (Japan))

    1993-04-01

    This paper explains copper phosphorus torch brazing for copper tubing used in construction facilities as the main object of discussion. Copper phosphorus brazing requires no flux in brazing copper with copper and copper with bronze because of self-fluxing action of phosphorus. Jointing steel tubing with copper tubing is impossible. Brazing is possible even at temperatures below the liquid-phase line where good beads can be obtained. It allows larger tolerance for clearance than soldering and silver brazing. In the working process, the final clean surface turns to bright copper while producing flux, Cu3P, slag and gas P2O5. According to void prediction based on the relation of clearance between a copper tube and a joint with capillary rising height, a brazed joint without a defect can be obtained if the nominal diameter is 32A or less. Six kinds of copper phosphorus brazing fillers are specified in JIS, the best filler being BCuP-3. The suitable temperature for brazing is in high temperature zones of about 800[degree]C, but a work is performed preferably while watching fillet being formed at about 700[degree]C. The minimum required penetration depth should be twice as much as the steel tube wall thickness, while the minimum bonding area should be quadruple as much. 10 figs., 1 tab.

  18. Soldering and brazing safety guide: A handbook on space practice for those involved in soldering and brazing

    Science.gov (United States)

    This manual provides those involved in welding and brazing with effective safety procedures for use in performance of their jobs. Hazards exist in four types of general soldering and brazing processes: (1) cleaning; (2) application of flux; (3) application of heat and filler metal; and (4) residue cleaning. Most hazards during those operations can be avoided by using care, proper ventilation, protective clothing and equipment. Specific process hazards for various methods of brazing and soldering are treated. Methods to check ventilation are presented as well as a check of personal hygiene and good maintenance practices are stressed. Several emergency first aid treatments are described.

  19. Comparison of brazed joints made with BNi-1 and BNi-7 nickel-base brazing alloys

    Directory of Open Access Journals (Sweden)

    Zorc, Borut

    2000-04-01

    Full Text Available Kinetics of the processes are different with different types of brazing alloys. Precipitation processes in the parent metal close to the brazing gap are of great importance. They control the mechanical properties of the joint area when the brittle eutectic has disappeared from the gap. A comparative study of brazed joints on austenitic stainless alloys made with BNi-7 (Ni-P type and BNi-1 (Ni-Si-B type brazing alloys was made. Brazing alloys containing phosphorus behave in a different manner to those containing boron.

    Las aleaciones de níquel se producen mediante tres sistemas de aleación: Ni-P, Ni-Si y Ni-B. Durante las reacciones metalúrgicas con el metal de base, la eutéctica frágil en la separación soldada puede transformarse en la solución dúctil-sólida con todas aleaciones. La cinética del proceso varía según el tipo de aleación. Los procesos de precipitación en el metal de base cerca de la separación soldada son de mucha importancia, ya que controlan las propiedades mecánicas de la área de unión después de desaparecer la eutéctica frágil de la separación. Se ha hecho un análisis comparativo de uniones soldadas en aleaciones austeníticas inoxidables realizadas con aleaciones BNi-7 (tipo Ni-P y BNi-1 (tipo Ni-Si-B. Las aleaciones que contienen fósforo se comportan de una manera diferente, tanto con el cambio de la eutéctica a la solución sólida, como con los procesos de precipitación en el metal de base cerca de la unión soldada.

  20. Laser brazing with filler wire for galvanized steel sheets

    Institute of Scientific and Technical Information of China (English)

    Feng Xiaosong; Li Liqun; Chen Yanbin; Zhou Shanbao

    2005-01-01

    The process properties and interface behavior of CO2 laser brazing with automatic wire feed for galvanized steel sheets were investigated , in which the brazing filler metal was CuSi3 and no flux was used. As to the appearance quality of the brazing seams, the roles of the processing parameters, such as brazing speed, wire feeding rate, inclination and feeding direction of the wire, laser power, spot diameter and heating position, were assessed. The further investigation indicates that the behavior of the active elements Si, Mn and Zn are significantly influenced by energy input. At the interface, the microstructure of the base metal was composed of columnar crystals and the acicalar α solid solution was found on the filler metal side.

  1. Improved Assembly for Gas Shielding During Welding or Brazing

    Science.gov (United States)

    Gradl, Paul; Baker, Kevin; Weeks, Jack

    2009-01-01

    An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

  2. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    OpenAIRE

    S. Muthuraman

    2013-01-01

    - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs) were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressur...

  3. Preliminary Process Design of ITER ELM Coil Bracket Brazing

    Science.gov (United States)

    LI, Xiangbin; SHI, Yi

    2015-03-01

    With the technical requirement of the International Thermonuclear Experimental Reactor (ITER) project, the manufacture and assembly technology of the mid Edge Localized Modes (ELM) coil was developed by the Institute of Plasma Physics, Chinese Academy of Science (ASIPP). As the gap between the bracket and the Stainless Steel jacketed and Mineral Insulated Conductor (SSMIC) can be larger than 0.5 mm instead of 0.01 mm to 0.1 mm as in normal industrial cases, the process of mid ELM coil bracket brazing to the SSMICT becomes quiet challenging, from a technical viewpoint. This paper described the preliminary design of ELM coil bracket brazing to the SSMIC process, the optimal bracket brazing curve and the thermal simulation of the bracket furnace brazing method developed by ANSYS. BAg-6 foil (Bag50Cu34Zn16) plus BAg-1a paste (Bag45CuZnCd) solders were chosen as the brazing filler. By testing an SSMICT prototype, it is shown that the average gap between the bracket and the SSMIC could be controlled to 0.2-0.3 mm, and that there were few voids in the brazing surface. The results also verified that the preliminary design had a favorable heat conducting performance in the bracket.

  4. Brazing of Stainless Steel to Yttria-Stabilized Zirconia Using Gold-Based Brazes for Solid Oxide Fuel Cell Applications

    Science.gov (United States)

    Singh, M.; Shpargel, T. P.; Asthana, R.

    2007-01-01

    Two gold-base active metal brazes (gold-ABA and gold-ABA-V) were evaluated for oxidation resistance to 850 C, and used to join yttria-stabilized zirconia (YSZ) to a corrosion-resistant ferritic stainless steel for possible use in solid oxide fuel cells. Thermogravimetric analysis and optical microscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy were used to evaluate the braze oxidation behavior, and microstructure and composition of the YSZ/braze/steel joints. Both gold-ABA and gold-ABA-V exhibited nearly linear oxidation kinetics at 850 C, with gold-ABA-V showing faster oxidation than gold-ABA. Both brazes produced metallurgically sound YSZ/steel joints due to chemical interactions of Ti and V with the YSZ and steel substrates.

  5. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  6. Characterisation of Ga-coated and Ga-brazed aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Ferchaud, E. [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Christien, F., E-mail: frederic.christien@univ-nantes.fr [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Barnier, V. [Ecole Nationale Superieure des Mines, MPI, CNRS UMR5146, Centre SMS, 158 Cours Fauriel, 42023 Saint Etienne (France); Paillard, P. [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France)

    2012-05-15

    This work is devoted to the brazing of aluminium using liquid gallium. Gallium was deposited on aluminium samples at {approx} 50 Degree-Sign C using a liquid gallium 'polishing' technique. Brazing was undertaken for 30 min at 500 Degree-Sign C in air. EDS (Energy Dispersive X-ray Spectroscopy) and AES (Auger Electron Spectroscopy) characterisation of Ga-coated samples has shown that the Ga surface layer thickness is of ten (or a few tens of) nanometres. Furthermore, aluminium oxide layer (Al{sub 2}O{sub 3}) was shown to be 'descaled' during Ga deposition, which ensures good conditions for further brazing. Cross-section examination of Ga-coated samples shows that liquid gallium penetrates into the aluminium grain boundaries during deposition. The thickness of the grain boundary gallium film was measured using an original EDS technique and is found to be of a few tens of nanometres. The depth of gallium grain boundary penetration is about 300 {mu}m at the deposition temperature. The fracture stress of the brazed joints was measured from tensile tests and was determined to be 33 MPa. Cross-section examination of brazed joints shows that gallium has fully dissolved into the bulk and that the joint is really autogenous. - Highlights: Black-Right-Pointing-Pointer Aluminium can be brazed using liquid gallium deposited by a 'polishing' technique. Black-Right-Pointing-Pointer The aluminium oxide layer is 'descaled' during liquid Ga 'polishing' deposition. Black-Right-Pointing-Pointer EDS can be used for determination of surface and grain boundary Ga film thickness. Black-Right-Pointing-Pointer The surface and grain boundary Ga film thickness is of a few tens of nm. Black-Right-Pointing-Pointer Surface and grain boundary gallium dissolves in the bulk during brazing.

  7. Deformation of ductile braze layer in a joint element under cyclic thermal loads

    International Nuclear Information System (INIS)

    The structural lifetime of a brazed joint is affected by the plastic behavior of ductile filler metal. In this work, elastoplastic analysis is performed on a CFC/Cu/TZM bonded joint for different thermal loading cases. The evolution of strains in the braze layer during the brazing process is analyzed. It is shown that the temperature dependence of the flow curves exerts considerable influence on the deformation behavior of the filler metal interlayer. The deformation characteristics of the braze layer under thermal cycling are investigated. The effect of thermal gradient on the plastic deformation of the braze is discussed. The fatigue lifetime of the copper braze layer is estimated. High heat flux (HHF) cycling tests are conducted on a CFC/Cu/TZM brazed joint in an electron beam facility. The microstructure of the deformed copper braze is presented. The flow morphologies and corresponding slip mechanisms are discussed. (orig.)

  8. Method of temperature rising velocity and threshold control of electron beam brazing

    Institute of Scientific and Technical Information of China (English)

    Xuedong Wang; Shun Yao

    2005-01-01

    In order to accommodate electron beam to the brazing of the joints with various curve shapes and the brazing of thermo sensitive materials, the method of electron beam scanning and brazing temperature control was developed, in which electron beam was controlled to scan according to predefined scanning track, and the actual temperature rising velocity of the brazed seam was limited in an allowed scope by detecting the brazed seam temperature, calculating the temperature rising velocity and adjusting the beam current during the brazing process; in addition, through the setting of the highest allowed temperature, the actual temperature of the brazed seam could be controlled not exceeding the threshold set value, and these two methods could be employed alone or jointly. It is shown that high precision temperature control in electron beam brazing could be realized and the productivity be increased by the proposed method.

  9. Effects of Rare Earths on Properties of Ti-Zr-Cu-Ni Base Brazing Filler Alloys

    Institute of Scientific and Technical Information of China (English)

    Ma Tianjun; Kang Hui; Wu Yongqin; Qu Ping

    2004-01-01

    The effects of the addition of rare earths on the properties of Ti-Zr-Cu-Ni base brazing filler alloys and the mechanical microstructure and properties were studied for the brazed-joints in the vacuum brazing of TC4 by comparing synthetical properties of two kinds of filler metals.The results indicate that the filler metals added with rare earths have lower melting point, better wettability and higher mechanical properties in the brazing joints.

  10. Study on vacuum brazing of high purity alumina for application in proton synchrotron

    International Nuclear Information System (INIS)

    Highlights: • Study compares Mo–Mn metallization and active brazing routes for joining alumina. • Targeted application: UHV chamber of proton synchrotron. • Both kinds of joints were UHV compatible with helium leak rate <1.1 × 10−10 mbar l/s. • Active brazed joints met tensile and flexural strength design requirement (>50 MPa). • Active brazing is a simpler and economical route for joining high purity alumina. - Abstract: The paper describes an experimental study to evaluate two different vacuum brazing processes to obtain high purity alumina (99.7%) joints suitable for application in rapid cycle proton synchrotron. Two different brazing routes, adopted for making alumina–alumina brazed joints, included (i) multi-step Mo–Mn metallization, followed by brazing with BVAg-8 alloy and (ii) advanced single-step active brazing with CuSil-ABA® alloy. Both the brazing routes yielded helium leak tight and ultra-high vacuum (pressure < 10−9 mbar) compatible joints. Active-brazed specimens exhibited tensile and mean flexural strengths of 62 and 110 MPa, respectively. Metallized-brazed specimens, although associated with relatively lower tensile strength (35 MPa) than the targeted value (>50 MPa), displayed higher mean flexural strength of 149 MPa. The results of the study demonstrated that active brazing is a simple and cost effective alternative to conventional multi-step metallization route for producing quality joints of high purity alumina for application in rapid cycle proton synchrotron machine

  11. High-temperature brazing for reliable tungsten-CFC joints

    International Nuclear Information System (INIS)

    The joining of tungsten and carbon-based materials is demanding due to the incompatibility of their chemical and thermophysical properties. Direct joining is unfeasible by the reason of brittle tungsten carbide formation. High-temperature brazing has been investigated in order to find a suitable brazing filler metal (BFM) which successfully acts as an intermediary between the incompatible properties of the base materials. So far only low Cr-alloyed Cu-based BFMs provide the preferential combination of good wetting action on both materials, tolerable interface reactions, and a precipitation free braze joint. Attempts to implement a higher melting metal (e.g. Pd, Ti, Zr) as a BFM have failed up to now, because the formation of brittle precipitations and pores in the seam were inevitable. But the wide metallurgical complexity of this issue is regarded to offer further joining potential

  12. Direct brazing of ceramics, graphite, and refractory metals

    International Nuclear Information System (INIS)

    ORNL has been instrumental in the development of brazing filler metals for joining ceramics, graphite, and refractory metals for application at temperatures above 10000C. The philosophy and techniques employed in the development of these alloys are presented. A number of compositions are discussed that have been satisfactorily used to braze ceramics, graphite, and refractory metals without a prior surface treatment. One alloy, Ti--25 percent Cr--21 percent V, has wet and flowed on aluminum oxide and graphite. Further, it has been utilized in making brazes between different combinations of the three subject materials. The excellent flowability of this alloy and alloys from the Ti--Zr--Ge system is evidenced by the presence of filler metal in the minute pores of the graphite and ceramics

  13. A review of oxide, silicon nitride, and silicon carbide brazing

    International Nuclear Information System (INIS)

    There is growing interest in using ceramics for structural applications, many of which require the fabrication of components with complicated shapes. Normal ceramic processing methods restrict the shapes into which these materials can be produced, but ceramic joining technology can be used to overcome many of these limitations, and also offers the possibility for improving the reliability of ceramic components. One method of joining ceramics is by brazing. The metallic alloys used for bonding must wet and adhere to the ceramic surfaces without excessive reaction. Alumina, partially stabilized zirconia, and silicon nitride have high ionic character to their chemical bonds and are difficult to wet. Alloys for brazing these materials must be formulated to overcome this problem. Silicon carbide, which has some metallic characteristics, reacts excessively with many alloys, and forms joints of low mechanical strength. The brazing characteristics of these three types of ceramics, and residual stresses in ceramic-to-metal joints are briefly discussed

  14. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    Directory of Open Access Journals (Sweden)

    S. Muthuraman

    2013-08-01

    Full Text Available - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressure drop increased proportionally with the mass flux and the vapor quality and inversely with the condensation temperature and the chevron angle.

  15. Brazing and inertia welding of dissimilar metal tubing

    International Nuclear Information System (INIS)

    A movable pump limiter is currently being built for the Tore Supra tokamak in Cadarace, France. Part of the assembly has dispersion-strengthened Cu cooling tubes joined to an AISI 316L stainless steel transition sleeve. The steel sleeve is subsequently welded into a 315L manifold. This study was made to evaluate the feasibility of brazing or inertia welding the dissimilar metal, tubing-sleeve transition. An alumina-strengthened copper alloy (DSCu) was selected for the module cooling tubes. The 316L transition pieces varied in diameter from the same nominal size as the DSCu pieces when inertial welding, to a 12.7 mm (1/2 in.) O.D. to accommodate a lap joint when brazing. The wall thickness of the inertia welded 316L pieces was varied to determine the overlap effect on the weld quality. Ag-28Cu, Ag-27.6Cu-4.5Ti, Au-37Cu-3In, and Au-18Ni (wt%) filler metals were chosen for brazing and the braze microstructures and strengths were evaluated. The best wetting was achieved with the Au based filler metals. All of the brazed joints were hydrostatically pressure tested to 10.34 MPa (1500 psi) without a failure. In all cases, an excellent metallurgical bond with a relatively small cold worked region was produced. The inertia welded samples were also pressure and tensile tested under the same test conditions that were used to evaluate the brazed samples. The welds passed the 10.34 MPa hydrostatic pressure inspection and failed under a tensile load in the DSCu piece away form the weld interface. Brazing and inertia welding were successfully used to join DSCu to 316L. The Au-based filler metals produced the best brazes with joint strengths of 480 MPa. The inertia welds had slightly higher strengths, but both failed away from the joint in the DSCu tube. All of these samples passed a 10.34 MPa hydrostatic pressure test. These processes allow flexibility in designing and fabricating a dissimilar metal transition joint

  16. Microwave-assisted brazing of alumina ceramics for electron tube applications

    Indian Academy of Sciences (India)

    2016-04-01

    Alumina was joined with alumina using microwave-assisted and conventional brazing methods at 960$^{\\circ}$C for 15 min using TiCuSil (68.8Ag–26.7Cu–4.5Ti in wt.%) as the brazing alloy. The brazed joints were characterizedby X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Vickers microhardness evaluation, brazing strength measurement and helium leak test. X-ray diffraction analysis confirmed the formationof Ti-based compounds at the substrate-filler alloy interfaces of the microwave and conventionally brazed joints. The elemental compositions at the joint cross-section were determined by energy dispersive X-ray analysis. Vickers microhardness measurement indicated reliable joint performance for the microwave-assisted brazed joints during actual application in an electron tube. Brazing strength measurement and helium leak test provided the evidence forgood alumina-alumina joint formation.

  17. Field installed brazed thermocouple feedthroughs for high vacuum experiments

    Science.gov (United States)

    Anderson, P. M.; Messick, C.

    1983-12-01

    In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer O ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs were used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: (1) melting temperature in excess of the 250 C (482 F) bakeout temperature; (2) no high vapor pressure elements; (3) good wetting properties when used in air with acceptable flux; and (4) good wettability to 300 series stainless steel and Inconel.

  18. Enhanced corrosion protection by microstructural control of aluminium brazing sheet

    NARCIS (Netherlands)

    Norouzi Afshar, F.

    2013-01-01

    Aluminium brazing sheet is a sandwich material made out of two aluminium alloys (AA4xxx/AA3xxx) and is widely used in automotive heat exchangers. One of the main performance criteria for heat exchanger units is the lifetime of the product. The lifetime of the heat exchanger units is determined by th

  19. Brazed boron-silicon carbide/aluminum structural panels

    Science.gov (United States)

    Arnold, W. E., Jr.; Bales, T. T.; Brooks, T. G.; Lawson, A. G.; Mitchell, P. D.; Royster, D. M.; Wiant, R.

    1978-01-01

    Fluxless brazing process minimizes degradation of mechanical properties composite material of silicon carbide coated boron fibers in an aluminum matrix. Process is being used to fabricate full-scale Boron-Silicon Carbide/Aluminum-Titanium honeycomb core panels for flight testing and ground testing.

  20. Joining of beryllium by braze welding technique: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Banaim, P.; Abramov, E. [Ben-Gurion Univ. of the Negev, Beersheba (Israel); Zalkind, S.; Eden, S.

    1998-01-01

    Within the framework of some applications, there is a need to join beryllium parts to each other. Gas Tungsten Arc Braze Welds were made in beryllium using 0.3 mm commercially Aluminum (1100) shim preplaced at the joint. The welds exhibited a tendency to form microcracks in the Fusion Zone and Heat Affected Zone. All the microcracks were backfilled with Aluminum. (author)

  1. Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM

    Directory of Open Access Journals (Sweden)

    Armen Kvryan

    2016-04-01

    Full Text Available The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 M NaCl, corrosion occurred at the braze-316L interface preceded by preferential dissolution of the Cu-rich phase within the braze alloy. Braze corrosion was driven by galvanic couples between the braze alloys and stainless steel as well as between different phases within the braze microstructure. Microgalvanic corrosion between phases of the braze alloys was investigated via SKPFM to determine how corrosion of the brazed joints developed.

  2. The experiment progress of bracket brazing to SSMIC for the ITER ELM prototype coil

    International Nuclear Information System (INIS)

    Highlights: • In this study, the experimental research of brackets brazing to stainless steel jacketed, Mineral Insulated Conductor (SSMIC) of the first Edge Localized Modes (ELMs) prototype coil for ITER has been made. • The technology for controlling the fluidity of silver-based brazing alloy is developed to meet the bracket brazing. • Brazing experiments to find the reason for cracks are carried out and the improved brazing technologies to restrain the cracks in the Inconel 625 jacket with silver-based alloy are developed. - Abstract: The first Edge Localized Modes (ELMs) prototype coil for International Thermonuclear Experimental Reactor (ITER) has been manufactured in the Institute of Plasma Physics, CAS (ASIPP) at 2014. The all 19 brackets need to braze to the stainless steel jacketed, Mineral Insulated Conductor (SSMIC) for transporting the nuclear heating in the brackets to the water-cooled SSMIC. Silver-based alloy is the only candidate brazing filler for the bracket brazing due to the limitation from melting point temperature and strength. In this paper, firstly, the experimental study for controlling the fluidity of silver-based brazing alloy is developed. And then, the brazing experiment of prototype bracket is introduced to develop the brazing process and some cracks in the Inconel 625 jackets surface appeared unexpectedly. The microstructures and tensile performance study of the cracked Inconel 625 jacket were made to explore the reason for cracks and the improved brazing technologies to suppress the cracks are developed. Finally, the bracket brazing experiment for the first ELM prototype coil is carried out, In spite of this, some cracks also appear in the Inconel 625 jackets

  3. Brazing of AM-350 stainless steel LWBR fuel rod support grids (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Ebejer, L.P.

    1979-02-01

    A brazing process has been developed wherein several hundred stamped AM-350 stainless steel sheet metal components, wire components and machined bar components were simultaneously joined together to fabricate about 400 grids of different sizes for the LWBR fuel rod support system. High temperature (2110F +- 20F) vacuum brazing was employed using Ni--Cr--Si braze alloy filler metal in the form of paste. Techniques employed in the assembly, braze alloy application and fixturing of grids to achieve adequate dimensional control are discussed in detail. The brazing thermal cycle as related to the complex metallurgical process of both AM-350 stainless steel and the Ni--Cr--Si braze alloy is also discussed.

  4. Active metal brazing of titanium to high-conductivity carbon-based sandwich structures

    International Nuclear Information System (INIS)

    Reactive brazing technology was developed and processing parameters were optimized for the bonding of titanium tubes, graphite foam, and high-conductivity carbon-carbon composite face sheets using the active braze Cusil-ABA paste and foils. The microstructure and composition of the joints, examined using scanning electron microscopy coupled with energy-dispersive spectroscopy, showed good bonding and braze penetration in all systems when braze paste was used. The hardness values of the brazed joints were consistent for the different specimen stacking configurations. Mechanical testing of Ti tube/foam/C-C composite structures both in tension and shear showed that failure always occurred in the foam material demonstrating that the brazed joint was sufficient for these types of sandwich structures

  5. Dissimilar joint characteristics of SiC and WC-Co alloy by laser brazing

    Science.gov (United States)

    Nagatsuka, K.; Sechi, Y.; Nakata, K.

    2012-08-01

    SiC and WC-Co alloys were joined by laser brazing with an active braze metal. The braze metal based on eutectic Ag-Cu alloy with additional Ti as an active element ranging from 0 to 2.8 mass% was sandwiched by the SiC block and WC-Co alloy plate. The brazing was carried out by selective laser beam irradiation on the WC-Co alloy plate. The content of Ti in the braze metal was required to exceed 0.6 mass% in order to form a brazed joint with a measurable shear strength. The shear strength increased with increasing Ti content up to 2.3 mass%Ti and decreased with a higher content.

  6. Effect of Heat Treatment on High Temperature Stress Rupture Strength of Brazing Seam for Nickel-base Superalloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam especially morphology of phase and boride was observed and the strength of brazing seam was measured in this process. The results show that heat treatment can enhance high-temperature stress rupture strength by improving the microstructure of brazing seam. The strength of brazing seam after solution heat treatment decreases in comparison with that only after diffusion treatment while aging treatment after solution heat treatment increases the strength of brazing seam.

  7. Active brazed diamond and cubic boron nitride interfacial nanostructure and application

    International Nuclear Information System (INIS)

    Active brazing is an effective technique for joining diamond or cBN grit onto metallic substrates. Current use of this technique is being made for super abrasive, high performance tools. The lecture will give an overview over different aspects such as (i) tool performance in selected applications, (ii) interfacial nanostructure between super abrasive grit and brazing alloys matrix, (iii) attempts to computer model such interface reactions and (iv) recent improvements of the abrasion resistance of the brazing alloy itself. Super abrasive tools with outstanding performance in applications such as grinding, honing or stone cutting can be manufactured by a single-layer of brazed diamond or cBN grit. A method to obtain regular grit patterns will be presented. Examples of prototype tools and their performance in different applications will be shown. The investigation of interface reactions between diamond and active brazing alloys plays an important role to further improve the brazing process and resulting tool performance. The interfacial nanostructure is characterised by a thin reaction layer of Ti with diamond and cBN, respectively. Results for Ag- and Cu-based brazing alloys will be presented and discussed in view of the influence of brazing process parameters and brazing alloy matrix. Computer modelling of the thermodynamics and kinetics of the interface reactions may allow optimising the process parameters. This requires reliable databases currently being built up. The potential of such methods in ceramic to metal joining will be described. The abrasion resistance of brazing alloys itself plays an important role for tool performance. A new method to achieve a dispersion of nano sized TiC precipitates in the alloy matrix by addition of an organic binder, decomposing during brazing will be presented. In an outlook further applications of brazed diamond grit, such as thermal management materials will be discussed. (author)

  8. The constitutive response of brazing alloys and the residual stresses in ceramic-metal joints

    OpenAIRE

    Galli, Matteo; Botsis, Ioannis

    2008-01-01

    Nowadays the joining of dissimilar materials is often the only solution to fulfill the complex requirements of high technology applications. One of the fields in which the research activity is more intense and promising is that of the brazing of ceramics with metals. The performance of brazed ceramic-metal joints is limited by residual stresses which develop in the bonded assembly as it cools down after brazing. The magnitude and influence of these stresses can be particularly high because of...

  9. The constitutive response of brazing alloys and the residual stresses in ceramic-metal joints

    OpenAIRE

    Galli, Matteo

    2007-01-01

    Nowadays the joining of dissimilar materials is often the only solution to fulfill the complex requirements of high technology applications. One of the fields in which the research activity is more intense and promising is that of the brazing of ceramics with metals. The performance of brazed ceramic-metal joints is limited by residual stresses which develop in the bonded assembly as it cools down after brazing. The magnitude and influence of these stresses can be particularly high because of...

  10. Microstructural characteristics of WC-Co and tool steel brazed joint

    Energy Technology Data Exchange (ETDEWEB)

    Young-Sub, K.; Sook-Hwan, K. [Reliability Assessment Team, Research Institute of Industrial Science and Technology, Pohang (Korea)

    2001-07-01

    The current study used Ni base alloys, which reveals the excellent high temperature properties, as filler metals for brazing of WC-Co and tool steel to get the solid joint strength. The strength and the microstructures of brazed joints for different filler metals were examined. The optimum brazing condition and heat treatment condition were obtained through precipitation reaction and microstructural characteristics at the joints. (orig.)

  11. Active metal brazing of different metals to aluminium nitride ceramics

    International Nuclear Information System (INIS)

    During recent years aluminium nitride ceramics for substrates, coolers and components have found more applications in micro- and power electronics. Aluminium nitride ceramic with high thermal conductivity, small CTE and good thermal shock resistance is used in aeronautical equipment as well as in drive systems of undergrounds and high speed trains. Different metals and alloys can be bonded to AIN by the so-called 'AMB-process'. The bonding mechanism is based on the use of so-called active metals like Ti, Zr, Hf. Copper conductor lines can be brazed onto AIN-substrates and components, resistor sheets can be applied on ceramic water coolers and a couple of other metals and alloys like tantalium, titanium, KOVAR and steel can be attached to AIN-ceramics by active brazing. Processing, analytical aspects and some special applications will be discussed. (author)

  12. New hermetic sealing material for vacuum brazing of stainless steels

    Science.gov (United States)

    Hildebrandt, S.; Wiehl, G.; Silze, F.

    2016-03-01

    For vacuum brazing applications such as in vacuum interrupter industry Hermetic Sealing Materials (HSM) with low partial pressure are widely used. AgCu28 dominates the hermetic sealing market, as it has a very good wetting behavior on copper and metallized ceramics. Within recent decades wetting on stainless steel has become more and more important. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. Umicore Technical Materials has developed a new copper based HSM, CuAg40Ga10. The wettability on stainless steel is significantly improved compared to AgCu28 and the total silver content is reduced by almost 44%. In this article the physical properties of the alloy and its brazed joints will be presented compared to AgCu28.

  13. An unconventional set-up for fluxless brazing of aluminium

    CERN Document Server

    Loos, Robert

    1999-01-01

    In order to successfully braze aluminium alloy assemblies without the use of oxide-removing fluxes, an evironment with very low contaminant level is mandatory. This is mostly achieved by using a vacuum furnace. Brazing under inert gas of sufficient purity is also possible. The method reported upon here makes use of a stainless steel bag which can enter a traditional air furnace. The bag is evacuated, giving a well distributed mechanical pressure on the parts to join. The intrinsic handicap of poor vacuum is compensated by regular inert gas flushing, even at high temperatures. The set-up works rather well, and the idea is believed to yield a valuable strategic and economic option, for the realization of special equipment as well as for prototyping work. We intend to use the principle for the CMS Preshower cooling screens.

  14. Welding and brazing of the JET machine components

    International Nuclear Information System (INIS)

    The report covers the techniques used for joining the various parts of the machine. The difficulties encountered during the welding and brazing of similar and dissimilar metals are underlined and the solutions adopted to solve them are indicated. The vast experience gained by those involved in the processes of joining the various parts of the JET machine components, and the lessons learnt are summarized in this report. (author)

  15. Thermovision researches of temperature fields distribution in GMA brazed joints of solar collectors

    Directory of Open Access Journals (Sweden)

    A. Klimpel

    2008-05-01

    Full Text Available Purpose: of this study was to investigate of temperature fields distribution during GMA brazing of solar collectors.Design/methodology/approach: IR-pictures were recorded with 50 Hz frequency. After recording, thermovision pictures were analyzed in Irbis software module. This software permit to matching recording parameters, identification of temperature values in arbitrary picture points, assign temperature profiles.Findings: distribution of temperature fields in the GMA brazed joints in the function of GMA brazing parameters and brazing techniques was established.Research limitations/implications: basic information about distribution of temperature fields in the GMA brazed joints is the background of the researches of GMA brazing parameters providing highest quality joints.Practical implications: results of this paper are the data of the temperature fields distribution during GMA brazing of solar collectors joints recorded by IR-camera. This data are important to set an optimal brazing parameters.Originality/value: the researches were provided using newest filler material for GMA brazing of solar collectors parts using IR recording equipment.

  16. A corrosion study on vacuum brazed joints of LINAC

    International Nuclear Information System (INIS)

    A 10 MeV, S-band electron linac has been developed at RRCAT for industrial applications. At present, the in-house fabricated accelerating structure, is under continuous operation and has been tested at beam power more than 4.2 kW. The accelerating structure of electron linac comprises RF couplers, buncher section and regular section. The accelerating structure is made of OFE copper and is fabricated by vacuum brazing of cavities and coupler components using BVAg-8 and Palcusil-5 as braze filler metals (BFM). During accelerator operation, RF power is dissipated on cavities surface and the resultant heat is removed by circulating low conductivity water (LCW) in cooling jackets built around the accelerating structure whose inner part is maintained under vacuum. Corrosion characteristics of OFE copper brazed joints in LCW environment is of utmost importance towards development of reliable industrial linac. Therefore, a study has been undertaken to investigate corrosion possibilities in the cooling circuit which can limit the life of accelerating structures

  17. A study on brazing of Glidcop® to OFE Cu for application in Photon Absorbers of Indus-2

    International Nuclear Information System (INIS)

    The paper describes an experimental study aimed at standardizing brazing procedure for joining Glidcop to OFE Cu for its application in upgraded photon absorbers of 2.5 GeV synchrotron radiation source, Indus-2. Two different brazing routes, involving brazing with silver base (BVAg-8) and gold base (50Au/50Cu) alloys, were studied to join Glidcop to OFE Cu. Brazing with both alloys yielded helium leak tight and bakeable joints with acceptable shear strengths.

  18. Development of optimum process parameters and a study of the effects of surface roughness on brazing of copper

    International Nuclear Information System (INIS)

    Highlights: • New brazing process parameters corresponding to the greatest shear strength have been developed. • An effective interaction of brazing filler metal (BFM) and base metal was observed at the interface for the sample brazed at 650 °C/5 min. • The possibility of formation of hard intermetallic compounds of Cu, Sn, and P have been justified in view of high-strength braze joint. • The surface roughness with an average Ra value of around 0.20 μm was found to be the most appropriate for brazing of copper conducted at the specified process parameters. - Abstract: Brazing experiments on commercially-pure copper plates, using brazing filler metal (MBF-2005), are conducted at temperatures in the range of 650–750 °C for time-durations in the range of 5–15 min. Shear tests for braze-joints involved use of a universal testing machine. Based on the shear-test results, a new brazing cycle has been developed that corresponds to the greatest shear strength of the braze-joint. The brazing cycle has been performed under a controlled dry-argon atmosphere in a tube furnace. Microscopic observations were made by use of both optical and electron microscopes; whereas surface roughness measurements were made by using a TR100 Surface Roughness Tester. It is found that successful brazing and good wetting can be achieved by the least voids by using an average surface roughness (Ra value) for the base material

  19. Interfacial microstructure and performance of brazed diamond grits with Ni-Cr-P alloy

    International Nuclear Information System (INIS)

    The reaction mechanism of the interface among diamond, commercial Ni-Cr-P alloy and steel substrate has been studied by optical microscopy, scanning electron microscope, X-ray diffraction and Raman spectroscopy. The reaction layers formed among diamond, brazing alloy and steel substrate produced good wettability of diamond grits for achieving better quality tools. The reaction layer between diamond and brazing alloy comprised a reaction layer of brazing alloy and a reaction layer of diamond. Cr7C3 and Cr3C2 formed in the reaction layer of brazing alloy was the main reason for improving the bonding strength of Ni-Cr alloy to the diamond grits. A reaction layer of diamond may be a graphitization layer formed on the surface of diamond under high temperature brazing. The reaction layer of brazing alloy and steel substrate was the co-diffusion of Ni, Cr and Fe between the brazing alloy and the steel substrate. The life and sharpness of brazed diamond boring drill bits fabricated in this study were superior to the electroplated one in the market owing to its high protrusion and bonding strength.

  20. Experimental study of W-Eurofer laser brazing for divertor application

    Energy Technology Data Exchange (ETDEWEB)

    Munez, C.J., E-mail: claudio.munez@urjc.es [Dept. de Tecnologia Mecanica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain); Garrido, M.A. [Dept. de Tecnologia Mecanica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain); Rams, J.; Urena, A. [Dept. de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain)

    2011-11-15

    Highlights: > Laser brazing system as a suitable technique to joint W and Eurofer alloys. > High residual stresses at the bonding were produced. > Laser brazing of powder metallurgy W alloys added porosity in the solidified pool. > The CSM methodology as a suitable technique to discriminate zones of welding joints. - Abstract: This work can be considered as a preliminary evaluation of the potential of laser brazing for joining tungsten based alloys to reduced activation ferritic-martensitic steels (Eurofer). Brazing of tungsten and EUROFER alloys using a 55Ni-45Ti alloy as a brazer and a high power diode laser (HPDL) as a power source has been investigated. The brazed joints showed solidified pools with good superficial aspect and a high degree of wettability with the both parent sheets, presumably because of the active effect of titanium. Metallurgical brazeability was investigated and nanoindentation measurements were done to evaluate local hardening and stiffness effects associated to dilution phenomena.

  1. Development of Zn50 Brazing Alloy for Joining Mild Steel to Mild Steel (SAE1018

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2014-09-01

    Full Text Available This work has developed new brazing alloys for joining mild steel to mild steel (SAE1018 at a lower temperature. The alloys blends and error analysis were done by experimental design software (Design Expert 8.0.7.1. Design of experiments was done by Scheffe quadratic mixture method. The liquidus temperatures were predicted by calculation of phase diagrams of the alloying metals. The brazing alloys were produced by gravity technique and melted using silicon carbide graphite crucible. The quality of the brazing alloys was analyzed by optical microscopy (OM, atomic absorption spectroscopy (AAS and fourier transform infrared spectroscopy (FT-IR. Brazed joints were produced by torch method with a commercial flux. Brazing temperatures (liquidus were tracked by a digital infrared/laser pyrometer. Some mechanical properties studied were tensile strength and hardness. Finally, brazed joints produced from the developed brazing alloys were compared to that produced from muntz brass. Six (6 brazing alloys were successfully developed. Zinc and manganese were the main components, to which were added; 3 to 4 %wt silver and 11 to15 %wt modifying element. The microstructure showed a typical eutectic structure with zinc-rich phase distributed uniformly in the matrix with a combination of different sizes of dendrite, rounded blocks of compounds and hypoeutectic structures. AAS results indicated minimal out-gassing of zinc and FT-IR results indicated very low presence of atmospheric gas. The range of brazing temperature for best results was recorded from 690.90 to 735.10 0C. The joints produced from the developed brazing alloys had acceptable strengths with improved stress-strain behaviour compared to muntz brass.

  2. A preliminary study of cladding steel with NiTi by microwave-assisted brazing

    International Nuclear Information System (INIS)

    Nickel titanium (NiTi) plate of 1.2 mm thickness was successfully clad on AISI 316L stainless steel substrate by a microwave-assisted brazing process. Brazing was conducted in a multimode microwave oven in air using a copper-based brazing material in tape form. The brazing material was melted in a few minutes by microwave-induced plasma initiated by conducting wires surrounding the brazing assembly. Metallographic study by scanning-electron microscopy (SEM) and compositional analysis by energy-dispersive spectroscopy (EDS) of the brazed joint revealed metallurgical bonding formed via inter-diffusion between the brazing filler and the adjacent materials. A shear bonding strength in the range of 100-150 MPa was recorded in shear tests of the brazed joint. SEM and X-ray diffractometry (XRD) analysis for the surface of as-received NiTi plate and NiTi cladding showed similar microstructure and phase composition. Nanoindentation tests also indicated that the superelastic properties of NiTi were essentially retained. The cavitation erosion resistance of the NiTi cladding was essentially the same as that of as-received NiTi plate, and higher than that obtained in laser or TIG (tungsten-inert gas) surfacing. The high resistance could be attributed to avoidance of dilution and defect formation in the NiTi clad since the cladding did not undergo melting and solidification in the brazing process. Electrochemical tests also recorded similar corrosion resistance in both as-received NiTi and NiTi cladding. Thus, the present study indicates that microwave-assisted brazing is a simple, economical, and feasible process for cladding NiTi on 316L stainless steel for enhancing cavitation erosion resistance

  3. A preliminary study of cladding steel with NiTi by microwave-assisted brazing

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, K.Y. [Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China); Cheng, F.T. [Department of Applied Physics, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)]. E-mail: apaftche@polyu.edu.hk; Man, H.C. [Department of Industrial and Systems Engineering, Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

    2005-10-25

    Nickel titanium (NiTi) plate of 1.2 mm thickness was successfully clad on AISI 316L stainless steel substrate by a microwave-assisted brazing process. Brazing was conducted in a multimode microwave oven in air using a copper-based brazing material in tape form. The brazing material was melted in a few minutes by microwave-induced plasma initiated by conducting wires surrounding the brazing assembly. Metallographic study by scanning-electron microscopy (SEM) and compositional analysis by energy-dispersive spectroscopy (EDS) of the brazed joint revealed metallurgical bonding formed via inter-diffusion between the brazing filler and the adjacent materials. A shear bonding strength in the range of 100-150 MPa was recorded in shear tests of the brazed joint. SEM and X-ray diffractometry (XRD) analysis for the surface of as-received NiTi plate and NiTi cladding showed similar microstructure and phase composition. Nanoindentation tests also indicated that the superelastic properties of NiTi were essentially retained. The cavitation erosion resistance of the NiTi cladding was essentially the same as that of as-received NiTi plate, and higher than that obtained in laser or TIG (tungsten-inert gas) surfacing. The high resistance could be attributed to avoidance of dilution and defect formation in the NiTi clad since the cladding did not undergo melting and solidification in the brazing process. Electrochemical tests also recorded similar corrosion resistance in both as-received NiTi and NiTi cladding. Thus, the present study indicates that microwave-assisted brazing is a simple, economical, and feasible process for cladding NiTi on 316L stainless steel for enhancing cavitation erosion resistance.

  4. Microstructure and phase constitution near the interface of Cu/3003 torch brazing using Al Si La Sr filler

    International Nuclear Information System (INIS)

    It has been mainly studied in this paper on brazing of Cu to Al using Al.Si filler metal. The optimized scanning rate of 2.5 mm/s is first obtained through simulating the temperature field of Cu Al brazing process based on ANSYS software. Then the brazing of Cu C11000 to Al 3003 using Al.Si.La.Sr filler is carried out by torch brazing technology. It is found that the brazing seam region is mainly consisted of α Al solid solution and CuAl2 IMC. Further experimental results also show that the rare earth element La in filler metal can not only refine the grain, but also promote the dispersion of intermetallic compounds into the brazing seam, which significantly improves the brazing seam microstructure and mechanical properties of the joints

  5. Microstructure and strength of brazed joints of TiB2 cermet to TiAl-based alloys

    Institute of Scientific and Technical Information of China (English)

    李卓然; 冯吉才; 曹健

    2003-01-01

    In this study, TiB2 cermet and TiAl-based alloy are vacuum brazed successfully by using Ag-Cu-Ti filler metal. The microstructural analyses indicate that two reaction products, Ti(Cu, Al)2 and Ag based solid solution (Ag(s.s)), are present in the brazing seam, and the interface structure of the brazed joint is TiB2/TiB2+ Ag(s.s) /Ag(s.s)+Ti(Cu, Al)2/Ti(Cu, Al)2/TiAl. The experimental results show that the shear strength of the brazed TiB2/TiAl joints decreases as the brazing time increases at a definite brazing temperature. When the joint is brazed at 1 223 K for 5 min, a joint strength up to 173 MPa is achieved.

  6. Braze welding of cobalt with a silver–copper filler

    Directory of Open Access Journals (Sweden)

    Everett M. Criss

    2015-01-01

    Full Text Available A new method of joining cobalt by braze-welding it with a silver–copper filler was developed in order to better understand the residual stresses in beryllium–aluminum/silicon weldments which are problematic to investigate because of the high toxicity of Be. The base and filler metals of this new welding system were selected to replicate the physical properties, crystal structures, and chemical behavior of the Be–AlSi welds. Welding parameters of this surrogate Co–AgCu system were determined by experimentation combining 4-point bending tests and microscopy. Final welds are 5 pass manual TIG (tungsten inert gas, with He top gas and Ar back gas. Control of the welding process produces welds with full penetration melting of the cobalt base. Microscopy indicates that cracking is minimal, and not through thickness, whereas 4-point bending shows failure is not by base-filler delamination. These welds improve upon the original Be–AlSi welds, which do not possess full penetration, and have considerable porosity. We propose that utilization of our welding methods will increase the strength of the Be–AlSi weldments. The specialized welding techniques developed for this study may be applicable not only for the parent Be–AlSi welds, but to braze welds and welds utilizing brittle materials in general. This concept of surrogacy may prove useful in the study of many different types of exotic welds.

  7. A Compendium of Brazed Microstructures For Fission Power Systems Applications

    Science.gov (United States)

    Locci, Ivan E.; Bowman, Cheryl L.

    2012-01-01

    NASA has been supporting design studies and technology development for fission-based power systems that could provide power to an outpost on the Moon, Mars, or an asteroid. Technology development efforts have included fabrication and evaluation of components used in a Stirling engine power conversion system. This investigation is part of the development of several braze joints crucial for the heat exchanger transfer path from a hot-side heat exchanger to a Stirling engine heat acceptor. Dissimilar metal joints are required to impart both mechanical strength and thermal path integrity for a heater head of interest. Preliminary design work for the heat exchanger involved joints between low carbon stainless steel to Inconel 718, where the 316L stainless steel would contain flowing liquid metal NaK while Inconel 718, a stronger alloy, would be used as structural reinforcement. This paper addressed the long-term microstructural stability of various braze alloys used to join 316L stainless steel heater head to the high conductivity oxygen-free copper acceptor to ensure the endurance of the critical metallic components of this sophisticated heat exchanger. The bonding of the 316L stainless steel heater head material to a copper heat acceptor is required to increase the heat-transfer surface area in contact with flowing He, which is the Stirling engine working fluid.

  8. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    International Nuclear Information System (INIS)

    Highlights: • We created brazed joints between tungsten and EUROFER 97, Cu and SS316L with Au80Cu19Fe1 filler. • No elemental transitions were detected between the W and the AuCuFe filler in either direction. • Transition regions between filler to EUROFER97/316L showed similar elastic modulus and hardness to the filler. • Smooth elemental and mechanical properties transition were detected between the filler and Cu. - Abstract: In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported

  9. Diffusion bonding and brazing of high purity copper for linear collider accelerator structures

    Science.gov (United States)

    Elmer, J. W.; Klingmann, J.; van Bibber, K.

    2001-05-01

    Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC). Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi) and 3.45 MPa (500 psi)], and on two different diamond machined surface finishes. Brazes were made using pure silver, pure gold, and gold-nickel alloys, and different heating rates produced by both radiation and induction heating. Braze materials were applied by both physical vapor deposition (PVD) and conventional braze alloy shims. Results of the diffusion bonding experiments showed that bond strengths very near that of the copper base metal could be made at bonding temperatures of 700 °C or higher at 3.45 MPa bonding pressure. At lower temperatures, only partial strength diffusion bonds could be made. At low bonding pressures (3.45 kPa), full strength bonds were made at temperatures of 800 °C and higher, while no bonding (zero strength) was observed at temperatures of 700 °C and lower. Observations of the fracture surfaces of the diffusion bonded samples showed the effects of surface finish on the bonding mechanism. These observations clearly indicate that bonding began by point asperity contact, and flatter surfaces resulted in a higher percentage of bonded area under similar bonding conditions. Results of the brazing experiments indicated that pure silver worked very well for brazing under both conventional and high heating rate scenarios. Similarly, pure silver brazed well for both the PVD layers and the braze alloy shims. The gold and gold-containing brazes had problems, mainly due to the high diffusivity of gold in copper. These problems led to the necessity of overdriving the temperature to ensure melting, the presence of porosity in the joint, and very wide braze joints. Based on the overall findings of this study, a two-step joining method

  10. Vacuum Brazing of Beryllium Copper Components for the National Ignition Facility

    International Nuclear Information System (INIS)

    A process for vacuum brazing beryllium copper anode assemblies was required for the Plasma Electrode Pockels Cell System, or PEPC, a component for the National Ignition Facility (NIF). Initial problems with the joint design and wettability of the beryllium copper drove some minor design changes. Brazing was facilitated by plating the joint surface of the beryllium copper rod with silver 0.0006 inch thick. Individual air sampling during processing and swipe tests of the furnace interior after brazing revealed no traceable levels of beryllium

  11. Structure and stresses in high dimension brazed joints of cermets and steel

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2012-02-01

    Full Text Available Purpose: of this paper is description of stresses in brazing joints of different physical and mechanical properties and evaluation of microstructure and mechanical properties of large dimensional vacuum brazed joints of WC–Co (ISO K05, Fe-TiC sinter plates (Ferro–Titanit Nicro 128 and precipitation hardened stainless steel of 14-5 PH (X5CrNiMoCuNb14-5 using copper as the brazing filler metal.Design/methodology/approach: Microscopic examinations with the use of scanning electron microscope were performed to establish microstructure of the joint. Shear strength Rt and tensile strength Rm of the joints have been defined.Findings: It have been state, that the basic factors decreasing strength of the joint, which can occur during vacuum brazing of the WC-Co, Fe-TiC sinters - Cu brazing filler metal - 14-5 PH steel joints are diffusive processes leading to exchange of the cermets and brazing filler metal elements. They can have an unfavourable influence on ductility and quality of the joint..Research limitations/implications: Results of numerical calculations of three-dimensional models of cermets and steel brazed joints stresses are presented. Particular attention was paid to stresses occurring in joints of large brazing surfaces. It was shown that joints microstructure and mechanical properties depend on chemical composition filler and parent materials, diffusion process during brazing, leading of the cermets and filler metal components replacement as well as joint gap thickness. The thickness of the joints and parent materials have an essential influence on the value of the local stress.Practical implications: As a result of conducted experiments criteria for generating high dimension coatings of cermets plates brazed to steel. The PM Fe-TiC and PM WC - Co composite plates vacuum-brazed to steel as cutting coatings have been worked out and applied in industry.Originality/value: An original value of the paper is to prove the tendency of

  12. Active Metal Brazing and Characterization of Brazed Joints in C-C and C-SiC Composites to Copper-Clad-Molybdenum System

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2008-01-01

    Carbon/carbon composites with CVI and resin-derived matrices, and C/SiC composites reinforced with T-300 carbon fibers in a CVI SiC matrix were joined to Cu-clad Mo using two Ag-Cu braze alloys, Cusil-ABA (1.75% Ti) and Ticusil (4.5% Ti). The brazed joints revealed good interfacial bonding, preferential precipitation of Ti at the composite/braze interface, and a tendency toward delamination in resin-derived C/C composite. Extensive braze penetration of the inter-fiber channels in the CVI C/C composites was observed. The Knoop microhardness (HK) distribution across the C/C joints indicated sharp gradients at the interface, and a higher hardness in Ticusil than in Cusil-ABA. For the C/SiC composite to Cu-clad-Mo joints, the effect of composite surface preparation revealed that ground samples did not crack whereas unground samples cracked. Calculated strain energy in brazed joints in both systems is comparable to the strain energy in a number of other ceramic/metal systems. Theoretical predictions of the effective thermal resistance suggest that such joined systems may be promising for thermal management applications.

  13. Brazing technology of Ti alloy/stainless steel dissimilar metal joint at system integrated modular advanced reactor

    International Nuclear Information System (INIS)

    For the technoldogy development of brazing Ti alloy to stainless steel joints used at SMART, the status of brazing technology development, brazing processes, and the brazing technology of Ti alloy and stainless steel are reviewed. Because fusion welding process cannot be applied due to the formation of intermetallic compounds in the weld metal, brazing joint was selected at the design. The joint part is assembled with a thread composed with male part of Ti alloy tube and female part of stainless tube. The gap in the thread will be filled with brazing filler metal. However, brittle Ti-Fe intermetallic compounds are formed at the surface of stainless steel through the diffusion of Ti at the melt. Brazing conditions should be set-up to reduce the formation of intermetallic compounds. For that, 3 kinds of Ag filler metals were selected as the candidates and heating will be done with induction and electric furnaces. Through measuring of joint strength according to the control of pre- and post-braze treatment, heating rate and heating time, optimal brazing method will be fixed. To qualify the brazing procedure and performance and to check defects in final product, the inspection plan will be established according to the req2wuirements of AWS and ASME

  14. Brazing techniques for side-coupled electron accelerator structures

    International Nuclear Information System (INIS)

    The collaboration between the Los Alamos National Laboratory and the National Bureau of Standards (NBS), started in 1979, has led to the development of an advanced c-w microtron accelerator design. The four 2380-MHz NBS accelerating structures, containing a total of 184 accelerating cavities, have been fabricated and delivered. New fabrication methods, coupled with refinements of hydrogen-furnace brazing techniques described in this paper, allow efficient production of side-coupled structures. Success with the NBS RTM led to Los Alamos efforts on similar 2450-MHz accelerators for the microtron accelerator operated by the Nuclear Physics Department of the University of Illinois. Two accelerators (each with 17 cavities) have been fabricated; in 1986, a 45-cavity accelerator is being fabricated by private industry with some assistance from Los Alamos. Further private industry experience and refinement of the described fabrication techniques may allow future accelerators of this type to be completely fabricated by private industry

  15. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Sérgio Ivan dos Santos

    2004-06-01

    Full Text Available The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness. The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a hard metal substrate, taking into account the effect of the brazing temperature and time. The temperature range studied was from 800 to 980 °C and the brazing time ranged from 3 to 40 min. The obtained results could be used to optimize the costs and time required to the production of high performance cutting tools with brazed diamond wafers.

  16. Development of Induction Brazing System for Sealing Instrumentation Feed through Part of Nuclear Fuel Test Rig

    International Nuclear Information System (INIS)

    To test the performance of nuclear fuels, coolant needs to be circulated through the test rig installed in the test loop. Because the pressure and temperature of the coolant is 15.5 MPa and 300 .deg. C respectively, coolant sealing is one of the most important processes in fabricating a nuclear fuel test rig. In particular, 15 instrumentation cables installed in a test rig pass through the pressure boundary, and brazing is generally applied as a sealing method. In this study, an induction brazing system has been developed using a high frequency induction heater including a vacuum chamber. For application in the nuclear field, BNi2 should be used as a paste, and optimal process variables for Ni brazing have been found by several case studies. The performance and soundness of the brazed components has been verified by a tensile test, cross section test, and sealing performance test

  17. An Investigation on Corrosion Behavior of a Multi-layer Modified Aluminum Brazing Sheet

    Directory of Open Access Journals (Sweden)

    Liu Wei

    2016-01-01

    Full Text Available The corrosion behavior of a multi-layer modified aluminum brazing sheet (AA4045/3003Mod./AA7072/AA4045 was investigated. The results shows that, the existence of BDP, which forms at the interface between clad and core layer during brazing, changes the corrosion form of the air side of the material from inter-granular corrosion to local exfoliation corrosion. The addition of anti-corrosion layer makes the corrosion form of the water side from inter-granular corrosion into uniform exfoliation corrosion. Compared to the normal triple-layer brazing sheet at the same thickness, the time to perforation of the modified four-layer brazing sheet is increased by more than 200%.

  18. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II project will advance innovative, cost effective and reliable nano-phase exothermic RCC joining processes (ExoBrazeTM) in order to be able to reinforce...

  19. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MRi is proposing, with its partner, Exotherm Corp (Camden, NJ) to demonstrate the feasibility of using exothermic brazing to join RCC (or C:SiC) composites to...

  20. Braze Welding TIG of Titanium and Aluminium Alloy Type Al – Mg

    Directory of Open Access Journals (Sweden)

    Winiowski A.

    2016-03-01

    Full Text Available The article presents the course and the results of technological tests related to TIG-based arc braze welding of titanium and AW-5754 (AlMg3 aluminium alloy. The tests involved the use of an aluminium filler metal (Al99.5 and two filler metals based on Al-Si alloys (AlSi5 and AlSi12. Braze welded joints underwent tensile tests, metallographic examinations using a light microscope as well as structural examinations involving the use of a scanning electron microscope and an X-ray energy dispersive spectrometer (EDS. The highest strength and quality of welds was obtained when the Al99.5 filler metal was used in a braze welding process. The tests enabled the development of the most convenient braze welding conditions and parameters.

  1. Interface structure and mechanical property of aluminum cooler vacuum brazing joint

    Institute of Scientific and Technical Information of China (English)

    FENG Tao; LOU Song-nian; WU Lu-hai; LI Ya-jiang

    2006-01-01

    A kind of aluminum cooler was manufactured by means of vacuum brazing technique, and the cooler was examined by hydraulic pressure test. The result indicates that the test pressure of the cooler can reach 15 MPa. The fracture of the brazing joint belongs to the mixture type. There are secondary cracks, dimples, cleavage plane and grain-boundary features on the failure surface.The cracking process of aluminum cooler is as follows. The cracks are initiated on the interface, then expand under sub-critical state.When the stress on the remained zone reaches the maximum notch tensile strength of the brazing joint or the crack length reaches the critical value that the brazing joint fracture toughness property permits, the cooler will break sharply.

  2. Simulation on Thermal Integrity of the Fin/Tube Brazed Joint of Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    Yiyu QIAN; Feng GAO; Fengjiang WANG; Hui ZHAO

    2003-01-01

    In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the therma

  3. Brazing of 14-5 PH steel and WC-Co sinterson considerable dimension surfaces

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2007-03-01

    Full Text Available Purpose: of this paper is study of structure properties of considerable surfaces vacuum brazed joints of WC-Co sinters and precipitation hardened stainless steel of 14-5 PH using copper and silver-copper as the brazing filler metal.Design/methodology/approach: the joints are used in large dimension spinning nozzles of a die for polyethylene granulation, in that considerable strength and ductility of the joints are required. Structure and mechanical properties of joints have been described. Shear strength Rt and tensile strength Rm of the joints have been defined.Findings: to have been state, that the basic factors decreasing quality of the joint, which can occur during vacuum brazing of the WC-Co ISO K05 sinter – Cu or Ag-Cu brazing filler metal – 14-5 PH steel joints are diffusive processes leading to exchange of elements of cermets and the brazing filler metal and creation of intermetalics in the joint. It can have an unfavourable influence on ductility of sinters and quality of joint. As a result of brazing tests the influence of means and parameters of the brazing on quality of a joint was determined.Research limitations/implications: as a result of the experiments scheme of the joint structure WC-Co ISO K05 sinter – Cu brazing filler metal – 14-5 PH steel joint and WC-Co ISO K05 sinter – Cu brazing filler metal – 14-5 PH have been described.Practical implications: as a result of conducted experiments a production of spinning nozzle of a die for polyethylene granulation with a vacuum-brazed with a WC-Co ISO K05 sinters plates cutting surface of large surfaces on precipitation hardened stainless steel 14-5 PH have been worked out and industrial applied.Originality/value: the basic factors decreasing quality of the joint, which can occur while vacuum brazing of stainless steels and cermets have been determined.

  4. Strength of vacuum brazed joints for repair; Haallfasthet hos reparationer utfoerda med vakuumloedning

    Energy Technology Data Exchange (ETDEWEB)

    Berglin, Leif [Siemens Industrial Turbomachinery AB, Finspaang (Sweden)

    2005-04-01

    Strength data are missing for braze joints. Repaired components cannot fully make use of the strength of the braze, and lifetime will be underestimated. The goal of the project was to generate material data to be able to prolong the lifetime of the components. Two different material combinations were tested, 12% Chromium steel brazed with BNi-2, and a nickel base alloy, IN792 brazed with BNi-5. Tensile testing at room temperature and elevated temperature was performed in the project. Target group is purchasers and suppliers of repaired components. A tensile test specimen with butt joint was developed in the project. The used test specimen worked well for the 12% Chromium steel. The results from testing show that proof stress and tensile strength are strongly depending on the joint gap, particularly at room temperature. High strength, close to base material strength, was achieved with joint gaps smaller than 50{mu}m. For wider joint gaps, strength was lower. Strength was approximately 25% of base material strength for joint gaps over 100{mu}m. The results can be explained by changes in microstructure. Joint gaps wider than 50{mu}m showed evidence of two-phase structure. At 500 deg C, the results also showed a connection between joint gap, microstructure and strength. The generated strength data can be used for calculations of lifetime for repaired components. Two different process errors were discovered in the manufacturing process of the brazed IN792 test specimens. The generated material data are therefor erroneous. The reason for this was two manufacturing errors. The tack welding was done with too high heat input. The surfaces of the joint gap became oxidised and the oxide hindered wetting of the braze. The second reason was that the brazing was done without the prescribed hold time at maximum temperature. The melting of the braze was therefor not completed when cooling started. As a result, the strength of the IN792 specimens was low at both temperatures.

  5. THERMAL FIELD MODELING IN THE MIG / MAG - CMT BRAZE-WELDING PROCESS OF GALVANIZED SHEETS

    OpenAIRE

    GHEORGHE SIMA; ELENA STELA MUNCUT

    2013-01-01

    This paper deals with some technical aspects of the optimization process braze-welding of galvanized steel sheet with a thickness of 0.7-1.5 mm. The braze-welding process is presented systemic, highlighting the input and output variables (of the zinc layer and intermetallic layer characteristics). It is presented the test for statistical analysis performed on a four-level factorial experiment aimed at studying the influence of the main simultaneously welding parameters of the welding technolo...

  6. The characteristics of brazed plate heat exchangers with different chevron angles

    OpenAIRE

    M. Amala Justus Selvam; Senthil Kumar P.; S. Muthuraman

    2009-01-01

    Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs) were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45_, 35_, and 20_ were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressure ...

  7. The metallurgy, mechanics, modelling and assessment of dissimilar material brazed joints

    International Nuclear Information System (INIS)

    At the heart of any procedure for modelling and assessing the design or failure of dissimilar material brazed joints there must be a basic understanding of the metallurgy and mechanics of the joint. This paper is about developing this understanding and addressing the issues faced with modelling and predicting failure in real dissimilar material brazed joints and the challenges still to be overcome in many cases. An understanding of the key metallurgical features of such joints in relation to finite element modelling is presented in addition to a study of the mechanics and stress state at an abrupt interface between two materials. A discussion is also presented on why elastic singularities do not exist based on a consideration of the assumption of an abrupt change in material properties and plasticity in the vicinity of the joint. In terms of modelling real dissimilar material brazed joints; there are several barriers to accurately capturing the stress state in the region of the joint and across the brazed layer and these are discussed in relation to a metallurgical study of a real dissimilar material brazed joint. However, this does not preclude using a simplified modelling approach with a representative braze layer in design and failure assessment away from the interface. In addition modelling strategies and techniques for assessing the various failure mechanisms of dissimilar material brazed joints are discussed. The findings from this paper are applicable to dissimilar material brazed joints found in a range of applications; however the references listed are primarily focussed on work in fusion research and development.

  8. Brazing of 14-5 PH steel and WC-Co sinterson considerable dimension surfaces

    OpenAIRE

    J. Nowacki

    2007-01-01

    Purpose: of this paper is study of structure properties of considerable surfaces vacuum brazed joints of WC-Co sinters and precipitation hardened stainless steel of 14-5 PH using copper and silver-copper as the brazing filler metal.Design/methodology/approach: the joints are used in large dimension spinning nozzles of a die for polyethylene granulation, in that considerable strength and ductility of the joints are required. Structure and mechanical properties of joi...

  9. Study on cold metal transfer welding–brazing of titanium to copper

    International Nuclear Information System (INIS)

    Highlights: • Cold metal transfer welding–brazing of titanium to copper was performed. • Increasing wire feed speed or groove angle will get satisfied Ti/Cu joint. • Increasing wire feed speed or groove angle will increase tensile load. • Ti/Cu CMT butt joint has dual characteristics of fusion welding and brazing. - Abstract: 3 mm Pure titanium TA2 was joined to 3 mm pure copper T2 by Cold Metal Transfer (CMT) welding–brazing process in the form of butt joint with a 1.2 mm diameter ERCuNiAl copper wire. The welding–brazing joint between Ti and Cu base metals is composed of Cu–Cu welding joint and Cu–Ti brazing joint. Cu–Cu welding joint can be formed between the Cu weld metal and the Cu groove surface, and the Cu–Ti brazing interface can be formed between Cu weld metal and Ti groove surface. The microstructure and the intermetallic compounds distribution were observed and analyzed in details. Interfacial reaction layers of brazing joint were composed of Ti2Cu, TiCu and AlCu2Ti. Furthermore, crystallization behavior of welding joint and bonding mechanism of brazing interfacial reaction were also discussed. The effects of wire feed speed and groove angle on the joint features and mechanical properties of the joints were investigated. Three different fracture modes were observed: at the Cu interface, the Ti interface, and the Cu heat affected zone (HAZ). The joints fractured at the Cu HAZ had higher tensile load than the others. The lower tensile load fractured at the Cu interface or Ti interface was attributed to the weaker bonding degree at the Cu interface or Ti interface

  10. Tensile fracture characterization of braze joined copper-to-CFC coupon assemblies

    Science.gov (United States)

    Trester, P. W.; Valentine, P. G.; Johnson, W. R.; Chin, E.; Reis, E. E.; Colleraine, A. P.

    1996-10-01

    A vacuum brazing process was used to join a broad spectrum of carbon-fiber reinforced carbon matrix composite (CFC) materials, machined into cylindrical coupons, between coupons of oxygen-free copper, the braze alloy was a copper-base alloy which contained only low activation elements (Al, Si, and Ti) relative to a titanium baseline specification. This demonstration was of particular importance for plasma facing components (PFCs) under design for use in the Tokamak Physics Experiment (TPX); the braze investigation was conducted by General Atomics for the Princeton Plasma Physics Laboratory. A tensile test of each brazed assembly was conducted. The results from the braze processing, testing, and fracture characterization studies of this reporting support the use of CFC's of varied fiber architecture and matrix processing in PFC designs for TPX. Further, the copper braze alloy investigated is now considered to be a viable candidate for a low-activation bond design. The prediction of plasma disruption-induced loads on the PFCs in TPX requires that joint strength between CFC tiles and their copper substrate be considered in design analysis and CFC selection.

  11. Microstructure, mechanical properties and chemical degradation of brazed AISI 316 stainless steel/alumina systems

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, O.C. [Instituto Superior de Engenharia do Porto (ISEP), Rua Dr. Antonio Bernardino de Almeida 431, 4200-072 Porto (Portugal)], E-mail: omp@isep.ipp.pt; Barbosa, M.A. [Instituto de Engenharia Biomedica (INEB), Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Roberto Frias s/n, 4200-465 Porto (Portugal)

    2008-05-15

    The main aims of the present study are simultaneously to relate the brazing parameters with: (i) the correspondent interfacial microstructure, (ii) the resultant mechanical properties and (iii) the electrochemical degradation behaviour of AISI 316 stainless steel/alumina brazed joints. Filler metals on such as Ag-26.5Cu-3Ti and Ag-34.5Cu-1.5Ti were used to produce the joints. Three different brazing temperatures (850, 900 and 950 deg. C), keeping a constant holding time of 20 min, were tested. The objective was to understand the influence of the brazing temperature on the final microstructure and properties of the joints. The mechanical properties of the metal/ceramic (M/C) joints were assessed from bond strength tests carried out using a shear solicitation loading scheme. The fracture surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The degradation behaviour of the M/C joints was assessed by means of electrochemical techniques. It was found that using a Ag-26.5Cu-3Ti brazing alloy and a brazing temperature of 850 deg. C, produces the best results in terms of bond strength, 234 {+-} 18 MPa. The mechanical properties obtained could be explained on the basis of the different compounds identified on the fracture surfaces by XRD. On the other hand, the use of the Ag-34.5Cu-1.5Ti brazing alloy and a brazing temperature of 850 deg. C produces the best results in terms of corrosion rates (lower corrosion current density), 0.76 {+-} 0.21 {mu}A cm{sup -2}. Nevertheless, the joints produced at 850 deg. C using a Ag-26.5Cu-3Ti brazing alloy present the best compromise between mechanical properties and degradation behaviour, 234 {+-} 18 MPa and 1.26 {+-} 0.58 {mu}A cm{sup -2}, respectively. The role of Ti diffusion is fundamental in terms of the final value achieved for the M/C bond strength. On the contrary, the Ag and Cu distribution along the

  12. Microstructure and characteristics of high dimension brazed joints of cermets and steel

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2009-12-01

    Full Text Available Purpose: In the article a state of the question concerning stresses in brazing joints of different physical and mechanical properties was appraised as well as possibility of their decrease due to use of different techniques from technological experiments to numerical methods. Evaluation of microstructure and mechanical properties of large dimensional vacuum brazed joints of WC – Co and Ferro Titanit Nicro 128 sinters and precipitation hardened stainless steel of 14 –5 PH (X5CrNiMoCuNb14-5 using copper and silver – copper as the brazing filler metal.Design/methodology/approach: Microscopic examinations with the use of scanning electron microscope (SEM were performed to establish microstructure and diffusion influences on creation of intermetallic phases in the joint. Shear strength Rt and tensile strength Rm of the joints have been defined. It have been state, that the basic factors decreasing quality of the joint, which can occur during vacuum brazing of the WC - Co ISO K05 sinter – Cu or Ag - Cu brazing filler metal – 14 -5 PH steel joints are diffusive processes leading to exchange of the cermets and brazing filler metal elements and creation of intermetallic in the joint. It can have an unfavourable influence on ductility and quality of the joint.Findings: Results of numerical calculations of two-dimensional models of brazed joints for different sizes of surfaces brazed at a constant width of solder gap are presented. Particular attention was paid to stresses occurring in joints of large brazing surfaces.Results of the investigate proved that joints microstructure and mechanical properties depend on filler and parent materials, diffusion process during brazing, leading to exchange of the cermets components and filler metal as well as joint geometry (mainly gap thickness.Practical implications: The results have been applied in surfaces are used in large dimension spinning nozzles of a die for polyethylene granulation, in that

  13. Tensile Creep Properties of the 50Au-50Cu Braze Alloy

    International Nuclear Information System (INIS)

    The 50Au-50CU (wt.%) alloy is a solid-solution strengthened braze alloy used extensively in conventional, hermetic metal/ceramic brazing applications where low vapor pressure is a requirement. Typical metal/ceramic base materials would be KovarTM alloy and metallized and Ni-plated 94% alumina ceramic. The elevated temperature mechanical properties are important for permitting FEA evaluation of residual stresses in metal/ceramic brazes given specific geometries and braze cooldown profiles. For material with an atomic composition of 76.084 at.% CL 23.916 Au (i.e., on the Cu-rich side of Cu3Au) that was annealed for 2 hr. at 750 ampersand deg;C and water quenched a Garofalo sinh equation was found to adequately characterize the minimum strain rate data over the temperature mnge 450-850 ampersand deg;C. At lower temperatures (250 arid 350 ampersand deg;C), a conventional power law equation was found to characterize the data. For samples held long periods of time at 375 ampersand deg;C (96 hrs.) and slowly cooled to room temperature, a slight strengthening reaction was observed: with the stress necessary to reach the same strain rate increasing by about 15% above the baseline annealed and quenched data. X-ray diffiction indicates that the 96 hr at 375 ampersand deg;C + slow cool condition does indeed order. The microhardness of the ordered samples indicates a value of 94.5 VHN, compared to 93.7 VHN for the baseline annealed and quenched (disordered FCC) samples. From a brazing perspective, the relative sluggishness of this ordering reaction does not appear to pose a problem for braze joints cooled at reasonable rates following brazing

  14. Elemental analysis of brazing alloy samples by neutron activation technique

    International Nuclear Information System (INIS)

    Two brazing alloy samples (C P2 and C P3) have been investigated by Neutron activation analysis (NAA) technique in order to identify and estimate their constituent elements. The pneumatic irradiation rabbit system (PIRS), installed at the first egyptian research reactor (ETRR-1) was used for short-time irradiation (30 s) with a thermal neutron flux of 1.6 x 1011 n/cm2/s in the reactor reflector, where the thermal to epithermal neutron flux ratio is 106. Long-time irradiation (48 hours) was performed at reactor core periphery with thermal neutron flux of 3.34 x 1012 n/cm2/s, and thermal to epithermal neutron flux ratio of 79. Activation by epithermal neutrons was taken into account for the (1/v) and resonance neutron absorption in both methods. A hyper pure germanium detection system was used for gamma-ray acquisitions. The concentration values of Al, Cr, Fe, Co, Cu, Zn, Se, Ag and Sb were estimated as percentages of the sample weight and compared with reported values. 1 tab

  15. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Science.gov (United States)

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-05-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  16. Impairment induced by chronic occupational cadmium exposure during brazing process

    International Nuclear Information System (INIS)

    Cadmium (CD) is considered a metal of the 20th century to which all inhabitants of develop societies are exposed. Long-term occupational and environmental exposure to CD often results in renal dysfunction as the kidney is considered the critical target organ. The aim of this work was to evalutate both resporatory and renal manifestations induced by occupational exposure to CD compounds during brazing process, and suggesting a protocol for prevention and control for CD- induced health effects. This study was conducted on 20 males occupationally exposed workers. They are divided into two groups: Group-1 included (10) exposed smokers and group-2 included (10) exposed non-smokers. Results of both groups were compared with those of 10 healthy age and sex matched non-smokers. All subjects were subjected to detailed history taking and laboratory investigations including blood and urinary CD, liver profile (SGOT, SGPT and alkline phosphates), kindey function tests (blood urea, creatinine and urinary beta2- microglobulin). The level of Cd in the atmosphere of the work plase air was also assessed to detect the degree of exposure as it was about 6 times greater than thesave level (1 mu /m3).(1) This study demonstrated elevation levels of blood CD, urea, creatinine and urinary CD and beta2 -microglobulin for both exposed worker groups than the controls. In additions no appreciable were noted for liver function tests, although the levels fell within normal range

  17. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Science.gov (United States)

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-03-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  18. The Integration of Vacuum Brazing into Heat Treatment - A Progressive Combined Process

    Institute of Scientific and Technical Information of China (English)

    Ingo Reinkensmeier; Henkjan Buursen

    2004-01-01

    The continuous constructive challenge to improve the functionality and efficiency of components always results in higher demands on production engineering, against the background of the generally increasing cost pressure. In many cases, you will just succeed in producing competitive and innovative products by combining and coupling of different procedures to an independent (hybrid) technology. The use of hybrid procedures for metal joining and heat treatment of metallic materials finds more and more industrial fields of application. Modern vacuum lines with integrated pressurized gas quenching are considered high-performance and flexible means of production for brazing and heat treatment tasks as well in the turbine industry as in the mould making and tool manufacturing industry. In doing so, the heat treatment is coupled with the brazing cycle in a combined process so that the brazing temperatures and soak times are adapted to the necessary temperatures and times for solution heat treatment and austeniting. This user-oriented article describes on the one hand examples of brazing of turbine components, but above all the practical experience from the plastics processing industry, where the requirement for a high-efficient cooling of injection moulding dies gains more and more importance.The combined procedure "Vacuum Brazing and Hardening" offers plenty of possibilities to produce mould inserts with an efficient tempering system in an economic way.

  19. Joining mechanism of Ti/Al dissimilar alloys during laser welding-brazing process

    International Nuclear Information System (INIS)

    Research highlights: → The microstructures of interfacial zones were confirmed in detail by transmission electron microscope (TEM). Interfacial reaction layers of brazing joint were composed of α-Ti, nanosize granular Ti7Al5Si12 and serration-shaped TiAl3. For the first time, obvious stacking fault structure in intermetallic phase TiAl3 was found when the thickness of the reaction layer was very thin (approximately below 1 μm). → Metallurgical characteristics for laser welding-brazing process in the environment of far from equilibrium was expounded by microstructures of the joints, the characteristics of thermal process and element diffusion behavior. - Abstract: Joining mechanism of Ti/Al dissimilar alloys was investigated during laser welding-brazing process with automated wire feed. The microstructures of fusion welding and brazing zones were analysed in details by transmission electron microscope (TEM). It was found that microstructures of fusion welding zone consist of α-Al grains and ternary near-eutectic structure with α-Al, Si and Mg2Si. Interfacial reaction layers of brazing joint were composed of α-Ti, nanosize granular Ti7Al5Si12 and serration-shaped TiAl3. For the first time, apparent stacking fault structure in intermetallic phase TiAl3 was found when the thickness of the reaction layer was very thin (approximately less than 1 μm). Furthermore, crystallization behavior of fusion zone and mechanism of interfacial reaction were discussed in details.

  20. The metallographic investigation of brazed joints in nickel base alloys using various techniques for the production of contrast

    International Nuclear Information System (INIS)

    Brazing with high melting point nickel base brazing alloys permits distortion-free, high strength joints to be produced in high temperature, high alloy steel and nickel alloys which cannot easily be welded. This method is used for gas turbine parts subject to high thermal stresses and in nuclear engineering. (orig.)

  1. 75 FR 52037 - Welding, Cutting and Brazing Standard; Extension of the Office of Management and Budget's (OMB...

    Science.gov (United States)

    2010-08-24

    ... Order No. 5-2007 (67 FR 31160). Signed at Washington, DC, on August 16, 2010. David Michaels, Assistant... Occupational Safety and Health Administration Welding, Cutting and Brazing Standard; Extension of the Office of... the information collection requirements contained in the Welding, Cutting and Brazing Standard (29...

  2. Microstructure evolution and mechanical properties of vacuum-brazed C/C composite with AgCuTi foil

    International Nuclear Information System (INIS)

    The microstructure and bonding strength of vacuum-brazed C/C composite and C/C composite with AgCuTi foil are studied. The interface structure of the brazed joint is C/C composite–TiC–eutectic structure of AgCu–TiC–C/C composite. The maximum shear strength of the joint is about 20 MPa and TiC formed at the edge of C/C composite plays a key role in the brazing process. It improves the wettability of the C/C composite and inhibits diffusion of the Ag and Cu atoms in the filler metal and C atoms in the C/C composite. The fracture mode of the brazing joint is brittle. The interface evolution in the brazing process and associated mechanism are discussed

  3. Dissimilar laser brazing of h-BN and WC-Co alloy in Ar atmosphere without evacuation process

    Science.gov (United States)

    Sechi, Y.; Nagatsuka, K.; Nakata, K.

    2012-08-01

    Laser brazing with Ti as an active element in Ag-Cu alloy braze metal has been successfully applied to dissimilar joining of h-BN and WC-Co alloy in Ar (99.999% purity) gas flow atmosphere without any evacuation process. Good wettability of the braze metal with h-BN and WC-Co alloy were confirmed by the observation and structural analysis of the interface by electron probe micro-analysis and scanning acoustic microscopy. The oxidation of titanium was not observed and this showed that the laser brazing with titanium as an active element in braze metal could be performed even in an Ar gas flow atmosphere without an evacuation process using a high-vacuum furnace.

  4. Interfacial structure and joint strengthening in arc brazed galvanized steels with copper based filler

    Institute of Scientific and Technical Information of China (English)

    LI Rui-feng; YU Zhi-shui; QI Kai

    2006-01-01

    Galvanized steel sheets were joined by tungsten inert gas(TIG) and metal inert gas(MIG) brazing process using copper based filler. The results show that the joint zone hardness is higher than that of the base material or copper filler from the microhardness tests of TIG brazing specimens, and the fracture spot is at the base materials zone from the tensile tests of MIG brazing specimens. Examination using energy dispersive X-ray analysis reveals the presence of intermetallic compound Fe5Si3(Cu) in the joint. The dispersal of fine Fe5Si3(Cu) particles is the main strengthening factor for the joint. The Fe5Si3(Cu) particles are determined to arise from three sources, namely, spot micro-melt, whisker-like fragmentation and dissolve-separation actions.

  5. Design and construction of a 33 GHz brazed accelerator waveguide for high gradient operation

    International Nuclear Information System (INIS)

    This paper discusses design and construction features of a precision machined and brazed traveling wave structure for use as a high gradient 33.3 GHz electron linear accelerator test section in a Two Beam Accelerator. Design emphasis was directed at meeting an RF filling time requirement of 12F<16ns, and at fabricating a test structure that would provide guidelines for demonstrating average accelerating fields of approximately 300 MV/m (maximum surface fields of 650 MV/m). Microwave measurement data, obtained during construction, are described and include a phase dispersion simple cold test technique for accurately predicting the structure filling time. A companion paper discusses plans for high power testing of both this brazed structure and a hybrid brazed/electroformed structure, using the Electron Laser Facility ELF at LLNL

  6. Effects of Different Braze Materials and Composite Substrates on Composite/Ti Joints

    Science.gov (United States)

    Morscher, Gregory N.; Singh, Mrityunjay; Asthana, Rajiv; Shpargel, Tarah

    2007-01-01

    An ever increasing number of applications require robust joining technologies of dissimilar materials. In this study, three types of ceramic composites (C-C, C-SiC, and SiC-SiC) were vacuum brazed to commercially pure Ti using the Cusil-ABA (63 Ag - 35.5 Cu - 1.75 Ti) active metal braze alloy. The study also compared composite specimens as-fabricated and after surface grinding/polishing. A butt-strap tensile shear strength test was used to evaluate the joined structures at room temperature, 270 and 500 C. The elevated temperatures represent possible use temperatures for some heat rejection type applications. Joint strength will be discussed in light of braze wetting and spreading properties, composite properties, and test temperature.

  7. Nondestructive test of brazed cooling tubes of prototype bolometer camera housing using active infrared thermography.

    Science.gov (United States)

    Tahiliani, Kumudni; Pandya, Santosh P; Pandya, Shwetang; Jha, Ratneshwar; Govindarajan, J

    2011-01-01

    The active infrared thermography technique is used for assessing the brazing quality of an actively cooled bolometer camera housing developed for steady state superconducting tokamak. The housing is a circular pipe, which has circular tubes vacuum brazed on the periphery. A unique method was adopted to monitor the temperature distribution on the internal surface of the pipe. A stainless steel mirror was placed inside the pipe and the reflected IR radiations were viewed using an IR camera. The heat stimulus was given by passing hot water through the tubes and the temperature distribution was monitored during the transient phase. The thermographs showed a significant nonuniformity in the brazing with a contact area of around 51%. The thermography results were compared with the x-ray radiographs and a good match between the two was observed. Benefits of thermography over x-ray radiography testing are emphasized. PMID:21280850

  8. Basic principles of creating a new generation of high- temperature brazing filler alloys

    Science.gov (United States)

    Kalin, B. A.; Suchkov, A. N.

    2016-04-01

    The development of new materials is based on the formation of a structural-phase state providing the desired properties by selecting the base and the complex of alloying elements. The development of amorphous filler alloys for a high-temperature brazing has its own features that are due to the limited life cycle and the production method of brazing filler alloys. The work presents a cycle of analytical and experimental materials science investigations including justification of the composition of a new amorphous filler alloy for brazing the products from zirconium alloys at the temperature of no more than 800 °C and at the unbrazing temperature of permanent joints of more than 1200 °C. The experimental alloys have been used for manufacture of amorphous ribbons by rapid quenching, of which the certification has been made by X-ray investigations and a differential-thermal analysis. These ribbons were used to obtain permanent joints from the spacer grid cells (made from the alloy Zr-1% Nb) of fuel assemblies of the thermal nuclear reactor VVER-440. The brazed samples in the form of a pair of cells have been exposed to corrosion tests in autoclaves in superheated water at a temperature of 350 °C, a pressure of 160 MPa and duration of up to 6,000 h. They have been also exposed to destructive tests using a tensile machine. The experimental results obtained have made it possible to propose and patent a brazing filler alloy of the following composition: Zr-5.5Fe-(2.5-3.5)Be-1Nb-(5-8)Cu-2Sn-0.4Cr-(0.5-1.0)Ge. Its melting point is 780 °C and the recommended brazing temperature is 800°C.

  9. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    OpenAIRE

    Jean S. Pimenta; Augusto J. A. Buschinelli; Rubens M. do Nascimento; Augusto E. Martinelli; Joseph Remmel

    2013-01-01

    Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the c...

  10. THERMAL FIELD MODELING IN THE MIG / MAG - CMT BRAZE-WELDING PROCESS OF GALVANIZED SHEETS

    Directory of Open Access Journals (Sweden)

    GHEORGHE SIMA

    2013-10-01

    Full Text Available This paper deals with some technical aspects of the optimization process braze-welding of galvanized steel sheet with a thickness of 0.7-1.5 mm. The braze-welding process is presented systemic, highlighting the input and output variables (of the zinc layer and intermetallic layer characteristics. It is presented the test for statistical analysis performed on a four-level factorial experiment aimed at studying the influence of the main simultaneously welding parameters of the welding technology CMT (Cold Metal Transfer: determining an optimal welding current IS, welding speed vS, boos current Ina and arc length correction factor l0.

  11. Laser hybrid brazing of oxide ceramics for high temperature gas sensing applications in (V)HTRS

    International Nuclear Information System (INIS)

    It has been shown that the use of halogen lamps to assist laser brazing reduces total energy and joining time. For parts with specific geometries not suitable for a rotation process, an assistive heating with halogen lamps might be even more beneficial, to alleviate temperature gradients and transients. Forsterite-based ceramics are highly suitable as a joining partner for ZrO2, especially in a laser brazing process based on volume heating. By adding Fe2O3 to the raw powder mixture, the absorptivity of the forsterite ceramic can be tuned with an optimum at 0.1 wt.% Fe, reducing the necessary laser energy input even more. (orig.)

  12. Ultrasonic inspection of the brazed joint and explosive welds used to repair the PFR evaporators

    International Nuclear Information System (INIS)

    A small number of in-service failures associated with the steam-tube to tube-plate welds of the PFR evaporators led to the decision to protect the welds by sleeving. The philosophy was to insert a sleeve through the tube-plate and into the steam tube, thus bridging the existing weld. The top portion of the sleeve was to be explosively welded to the zone adjacent to the top face of the tube-plate and the lower portion brazed into the steam tube. This paper deals with the development and use of ultrasonics to test both the brazed and explosively welded joints

  13. Compound characterization of laser brazed SiC-steel joints using tungsten reinforced SnAgTi-alloys

    Science.gov (United States)

    Südmeyer, I.; Rohde, M.; Fürst, T.

    2010-02-01

    With the help of a CO2-laser (λ = 10.64 μm) Silicon carbide (Trade name: Ekasic-F, Comp: ESK Ceramics) has been brazed to commercial steel (C45E, Matnr. 1.1191) using SnAgTi-filler alloys. The braze pellets were dry pressed based on commercially available powders and polished to a thickness of 300 μm. The SnAgTi-fractions were varied with the objective of improving the compound strength. Furthermore, tungsten reinforced SnAgTi-fillers were examined with regard to the shear strength of the ceramic/steel joints. Polished microsections of SnAgTi-pellets were investigated before brazing in order to evaluate the particle distribution and to detect potential porosities using optical microscopy. The brazing temperature and the influence of the reinforcing particles on the active braze filler were determined by measurements with a differential scanning calorimeter (DSC). After brazing. the ceramic-steel joints were characterized by scanning electron micrographs and EDX-analysis. Finally the mechanical strength of the braze-joints was determined by shear tests.

  14. Assessing braze quality in the actively cooled Tore Supra Phase III outboard pump limiter

    International Nuclear Information System (INIS)

    The quality of brazing of pyrolytic graphite armor brazed to copper tubes in Tore Supra's Phase III Outboard Pump Limiter was assessed through pre-service qualification testing of individual copper/tile assemblies. The evaluation used non-destructive, hot water transient heating tests performed in the high-temperature, high-pressure flow loop at Sandia's Plasma Materials Test Facility. Surface temperatures of tiles were monitored with an infrared camera as water at 120 degrees C at about 2.07 MPa (300 psi) passed through a tube assembly initially at 30 degrees C. For tiles with braze voids or cracks, the surface temperatures tagged behind those of adjacent well-bonded tiles. Temperature tags were correlated with flaw sizes observed during repairs based upon a detailed 2-D heat transfer analyses. open-quotes Badclose quotes tiles, i.e., temperature tags of 10-20 degrees C depending upon tile's size, were easy to detect and, when removed, revealed braze voids of roughly 50% of the joint area. Eleven of the 14 tubes were rebrazed after bad tiles were detected and removed. Three tubes were rebrazed twice

  15. Gaseous Shielding Gas Additives as Flux Substitute for TIG Arc Brazing

    Directory of Open Access Journals (Sweden)

    Uwe Reisgen

    2015-09-01

    Full Text Available Abstract Brazing is one of the key technologies in the field of joining of metal components. To improve the wetting of brazing material and work-piece surface, it is often required to fall back on the use of flux. The application of these substances requires accuracy and is often connected with considerable expenditure and it is, just as the removal of flux residues, often an additional working step which has to be carried out manually. Within the framework of a DFG research project it has been investigated to which degree gaseous substances as addition to the shielding gas may replace conventional flux in TIG arc brazing. To this end, investigations have been carried out using different combinations of base and filler materials. Mainly monosilane as a gaseous flux substitute has been added in low concentrations to the shielding gas volume flow. The resulting brazed joints have been quantified with regard to their geometry, their fusion conditions and their chemical compositions. These qualities were then correlated and evaluated with the provided quantity of monosilane in order to identify dependencies.

  16. Non destructive determination of the mechanical strength of a brazed joint with electrical potential measurements

    International Nuclear Information System (INIS)

    A method is described which allows the evaluation of the mechanical strength of a brazed joint by measuring the surface voltage when a current runs through the joint. The results are discussed and compared with those obtained from traditionnal destructive tests

  17. Active vacuum brazing of CNT films to metal substrates for superior electron field emission performance

    International Nuclear Information System (INIS)

    The joining of macroscopic films of vertically aligned multiwalled carbon nanotubes (CNTs) to titanium substrates is demonstrated by active vacuum brazing at 820 °C with a Ag–Cu–Ti alloy and at 880 °C with a Cu–Sn–Ti–Zr alloy. The brazing methodology was elaborated in order to enable the production of highly electrically and thermally conductive CNT/metal substrate contacts. The interfacial electrical resistances of the joints were measured to be as low as 0.35 Ω. The improved interfacial transport properties in the brazed films lead to superior electron field-emission properties when compared to the as-grown films. An emission current of 150 μA was drawn from the brazed nanotubes at an applied electric field of 0.6 V μm−1. The improvement in electron field-emission is mainly attributed to the reduction of the contact resistance between the nanotubes and the substrate. The joints have high re-melting temperatures up to the solidus temperatures of the alloys; far greater than what is achievable with standard solders, thus expanding the application potential of CNT films to high-current and high-power applications where substantial frictional or resistive heating is expected. (paper)

  18. Bonding of Al2O3 ceramic and Nb using transient liquid phase brazing

    Institute of Scientific and Technical Information of China (English)

    于治水; 梁超; 李瑞峰; 吴铭方; 祁凯

    2004-01-01

    The brazing of Al2O3 to Nb was achieved by the method of transient liquid phase (TLP) bonding. Ti foil and Ni-5V alloy foil were used as interlayers for the bonding. The base materials were brazed at 1 423 - 1 573 K for 1-120 min. The results show that the shear strength of the joint first increases and then decreases with increasing holding time and brazing temperature. The joint interface microstructure and elements distribution were investigated. It can be concluded that a composite structure, in which the base metals are solid solution Nb(V) and Nb(Ti)reinforced by Ni2Ti, is formed when the brazing temperature is 1 473 K and holding time 15 min, and a satisfactory joint strength can be achieved. The interaction of Ti foil and Ni-5V foil leads to the formation of liquid eutectic phase with low melting point, at the same time the combination of Ti come from the interlayer with O atoms from Al2O3 results in the bonding of Al2 O3 and Nb.

  19. Penetrating behavior of eutectic liquid during Al/Cu contact reactive brazing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The behavior of eutectic liquid penetrating into the Al base during Al/Cu contact reactive brazing process was studied. Analysis results show that the eutectic liquid prefers to expand along the grain boundary in the depth direction. Meanwhile, dissolution of solid Al and Cu into the eutectic liquid promotes the eutectic reaction and the continuously formed eutectic liquid leads to the reactive penetrating.

  20. 49 CFR 178.51 - Specification 4BA welded or brazed steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... not exceed 1/8 inch per minute during yield strength determination. (k) Elongation. Physical test... other side. Strength of longitudinal seam: Copper brazed longitudinal seam must have strength at least 3/2 times the strength of the steel wall. (2) Welding procedures and operators must be qualified...

  1. Effect of holding time on vacuum brazing for a stainless steel plate-fin structure

    International Nuclear Information System (INIS)

    This paper presents a vacuum brazing of 304 stainless steel plate-fin structures with nickel-based BNi-2 filler metal. The effect of brazing holding time on tensile strength and microstructure has been investigated, aiming to obtain the optimal brazing holding time. The microstructure in brazing joint consists of diffusion-affected zone (DAZ), interface reaction zone (IRZ), isothermally solidified zone (ISZ) and athermally solidified zone (ASZ). The structure in the fillet is composed of solid solution, nickel silicon, nickel boron compound and a mixture with nickel silicon and nickel boron. The tensile strength increases along with the increase of holding time, but decreases when the holding time is over 25 min. A maximum tensile strength of 65.1 MPa is obtained with 25 min holding time. Too short holding time will make boron diffuse insufficiently and generate a great deal of brittle boride components, and too long holding time will make the base metal dissolve into the filler metal excessively and creates more corrosion voids.

  2. Micro-nano filler metal foil on vacuum brazing of SiCp/Al composites

    Science.gov (United States)

    Wang, Peng; Gao, Zeng; Niu, Jitai

    2016-06-01

    Using micro-nano (Al-5.25Si-26.7Cu)- xTi (wt%, x = 1.0, 1.5, 2.0, 2.5 and 3.0) foils as filler metal, the research obtained high-performance joints of aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process and Ti content on joint properties was investigated, respectively. The experimental results indicate that void free dense interface between SiC particle and metallic brazed seam with C-Al-Si-Ti product was readily obtained, and the joint shear strength enhanced with increasing brazing temperature from 560 to 580 °C or prolonging soaking time from 10 to 90 min. Sound joints with maximum shear strength of 112.5 MPa was achieved at 580 °C for soaking time of 90 min with (Al-5.25Si-26.7Cu)-2Ti filler, where Ti(AlSi)3 intermetallic is in situ strengthening phase dispersed in the joint and fracture occured in the filler metal layer. In this research, the beneficial effect of Ti addition into filler metal on improving wettability between SiC particle and metallic brazed seam was demonstrated, and capable welding parameters were broadened for SiCp/Al-MMCs with high SiC particle content.

  3. Characteristics of dissimilar laser-brazed joints of isotropic graphite to WC–Co alloy

    International Nuclear Information System (INIS)

    Highlights: ► Ti was required in the filler metal for brazing graphite to WC–Co alloy. ► The shear strength of the joint increased with Ti content up to 1.7 mass%. ► Ti concentrated at the interface of graphite/filler metal. ► TiC was formed at the interface of graphite/filler metal. - Abstract: The effect of Ti serving as an activator in a eutectic Ag–Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC–Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC–Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC–Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.

  4. Active Brazing of C/C Composite to Copper by AgCuTi Filler Metal

    Science.gov (United States)

    Zhang, Kexiang; Xia, Lihong; Zhang, Fuqin; He, Lianlong

    2016-05-01

    Brazing between the carbon-fiber-reinforced carbon composite (C/C composite) and copper has gained increasing interest because of its important application in thermal management systems in nuclear fusion reactors and in the aerospace industry. In order to examine the "interfacial shape effect" on the mechanical properties of the joint, straight and conical interfacial configurations were designed and machined on the surface of C/C composites before joining to copper using an Ag-68.8Cu-4.5Ti (wt pct) alloy. The microstructure and interfacial microchemistry of C/C composite/AgCuTi/Cu brazed joints were comprehensively investigated by using high-resolution transmission electron microscopy. The results indicate that the joint region of both straight and conical joints can be described as a bilayer. Reaction products of Cu3Ti3O and γ-TiO were formed near the copper side in a conical interface joint, while no reaction products were found in the straight case. The effect of Ag on the interfacial reaction was discussed, and the formation mechanism of the joints during brazing was proposed. On the basis of the detailed microstructure presented, the mechanical performance of the brazed joints was discussed in terms of reaction and morphology across the joint.

  5. Joining Strength and Microstructure of Sintered SiC/SiC Joints Prepared by Active Brazing Process

    OpenAIRE

    LIU Yan,HUANG Zheng-Ren,LIU Xue-Jian,YUAN Ming

    2009-01-01

    Sintered SiC ceramics were brazed with itself by ternary Ag-Cu-Ti filler metal foil. Effects of brazing parameters such as temperature, holding time on joining strength, together with interface microstructure and reaction products were investigated. Experimental results indicate that joining strength has peak value with the increasing of brazing temperature and holding time, and the max fourª²point bending strength of SiC/SiC joints reaches 342MPa. The joining strength increases first with th...

  6. Experimental investigation on both low cycle fatigue and fracture behavior of DZ125 base metal and the brazed joint at elevated temperature

    International Nuclear Information System (INIS)

    Highlights: → Mechanical properties of DZ125 base metal and brazed joint were investigated at 850 deg. C. → The brazed joint has the obvious softening phenomenon at stress range above 640 MPa. → The brazed joint shows lower fatigue life compared with the base metal. → All the brazed joints are fractured in the brazing seam. → The differences of fracture phenomena between two types of specimens were observed. - Abstract: Due to the different low cycle fatigue (LCF) properties and fatigue fracture behavior between DZ125 base metal and the brazed joint, the LCF tests are carried out systematically using tension cycling under stress amplitude control conditions (stress ratio R = 0) at elevated temperature in laboratory air. The present paper sets out to investigate the cyclic deformation response of DZ125 base metal and the brazed joint in two aspects, i.e. fatigue life and fatigue fracture behavior, with the comparative method. Furthermore, the comparative method on the typical fatigue fracture surface features (including fatigue source zone, crack propagation zone and fatigue fracture zone) of DZ125 base metal and the brazed joint cycled to failure is conducted in detail. Based on both the macro mechanical behavior and macro and micro fracture observations, experimental results show that: (1) for the brazed joint, the softening is not obvious at lower stress ranges. But from 640 to 720 MPa, it is very significant; (2) under the same test condition, the brazed joint shows lower fatigue life compared with DZ125 base metal and all brazed joints are fractured in the brazing seam observed by the Scanning Electron Microscope (SEM); and (3) there are many distinctive differences of the fracture phenomena between DZ125 base metal and the brazed joint as follows: (1) the crack initiation mode; (2) the crack propagation behavior; and (3) the morphology of dimple pattern at the fatigue fracture zone.

  7. Effect of the joint clearance in the welding properties of austenitic stainless steel brazed at high temperature

    International Nuclear Information System (INIS)

    By metallographic, microhardening and tension tests, the effects of joint clearance in the precipitation of fragile phases, and its relation with the mechanical properties of the brazed joints at the temperature of 10100C, are investigated. (E.G.)

  8. Pre-qualification of brazed plasma facing components of divertor target elements for ITER like tokamak application

    Energy Technology Data Exchange (ETDEWEB)

    Singh, K.P., E-mail: kpsingh@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India); Pandya, Santosh P.; Khirwadkar, S.S.; Patel, Alpesh; Patil, Y.; Buch, J.J.U.; Khan, M.S.; Tripathi, Sudhir; Pandya, Shwetang; Govindrajan, J. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat (India); Jaman, P.M.; Rathore, Devendra; Rangaraj, L.; Divakar, C. [Materials Science Division, National Aerospace Laboratories, CSIR, Bangalore, Karnataka (India)

    2011-10-15

    Qualification of tungsten (W) and graphite (C) based brazed plasma facing components (PFCs) is an important R and D area in fusion research. Pre-qualification tests for brazed joints between W-CuCrZr and C-CuCrZr using NDT (IR thermography and ultrasonic test) and thermal fatigue test are attempted. Mockups having good quality brazed joints of W and C based PFCs were identified using NDT. Subsequently, thermal fatigue test was performed on the identified mockups. All brazed tiles of W based PFC mockups could withstand thermal fatigue test, however, few tiles of C based PFC mockup were found detached. Thermal analyses of mockups are performed using finite element analysis (ANSYS) software to simulate the thermal hydraulic condition with 10 MW/m{sup 2} uniform heat flux. Details about experimental and computational work are presented here.

  9. Interfacial reaction product and mechanical properties of the electron beam brazed K465 Ni-based superalloy joints

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Zhang Binggang; He Jingshan; Feng Jicai; Wu Yingjie

    2008-01-01

    Ni-based superalloy K465 is brazed with BNi-2 filler metal by vacuum electron beam brazing (VEBB). In process of VEBB, effects of processing primary parameters on shear strength of joints are investigated. Microstructure of the brazed joint with BNi-2 filler metal is studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the structure of brazed seam consists of a large amount of Ni-based γ solid solution, Ni3Al (γ′), Ni3B, WB, CrB, and a small quantity of WC, NbC. The maximum shear strength of the joint is 398 MPa when the beam current of welding is 2.6 mA, heating time is 480 s and focused current is 1 800 mA.

  10. Microstructure and Strength of Brazed Joints of Ti3Al Base Alloy with Cu-P Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Peng HE; Jicai FENG; Heng ZHOU

    2005-01-01

    Brazing of Ti3Al alloys with the filler metal Cu-P was carried out at 1173~1273 K for 60~1800 s. When products are brazed, the optimum brazing parameters are as follows: brazing temperature is 1215~1225 K; brazing time is 250~300 s. Four kinds of reaction products were observed during the brazing of Ti3Al alloys with the filler metal Cu-P, i.e., Ti3Al phase with a small quantity of Cu (Ti3Al(Cu)) formed close to the Ti3Al alloy; the TiCu intermetallic compounds layer and the Cu3P intermetallic compounds layer formed between Ti3Al(Cu) and the filler metal, and a Cu-base solid solution formed with the dispersed Cu3P in the middle of the joint. The interfacial structure of brazed Ti3Al alloys joints with the filler metal Cu-P is Ti3Al/Ti3Al(Cu)/TiCu/Cu3P/Cu solid solution (Cu3P)/Cu3P/TiCu/Ti3Al(Cu)/Ti3Al, and this structure will not change with brazing time once it forms. The thickness of TiCu+Cu3P intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity K0 of reaction layer TiCu+Cu3P in the brazed joints of Ti3Al alloys with the filler metal Cu-P are 286 k J/mol and 0.0821 m2/s, respectively, and growth formula was y2=0.0821exp(-34421.59/T)t.Careful control of the growth for the reaction layer TiCu+Cu3P can influence the final joint strength. The formation of the intermetallic compounds TiCu+Cu3P results in embrittlement of the joint and poor joint properties. The Cu-P filler metal is not fit for obtaining a high-quality joint of Ti3Al brazed.

  11. 焊料在电子器件中的应用%Application of the Brazing Materials for Electronic Devices

    Institute of Scientific and Technical Information of China (English)

    王恭年; 高陇桥

    2001-01-01

    The compositions and properties of commonly used brazing materials for electonic devices are reviewed in this paper.The problems of the brazing materials at present and its research and development direction are also proposed.%综述了目前在电子器件中常用焊料的组分和性能,指出了该类焊料存在的问题及其今后的研究、发展方向。

  12. WETTING AND REACTIVE AIR BRAZING OF BSCF FOR OXYGEN SEPARATION DEVICES

    Energy Technology Data Exchange (ETDEWEB)

    LaDouceur, Richard M.; Meier, Alan; Joshi, Vineet V.

    2014-10-13

    Reactive air brazes Ag-CuO and Ag-V2O5 were evaluated for brazing Ba0.5Sr0.5Co0.8Fe0.2O(3-δ) (BSCF). BSCF has been determined in previous work to have the highest potential mixed ionic/electronic conducting (MIEC) ceramic material based on the design and oxygen flux requirements of an oxy-fuel plant such as an integrated gasification combined cycle (IGCC) used to facilitate high-efficiency carbon capture. Apparent contact angles were observed for Ag-CuO and Ag-V2O5 mixtures at 1000 °C for isothermal hold times of 0, 10, 30, and 60 minutes. Wetting apparent contact angles (θ<90°) were obtained for 1%, 2%, and 5% Ag-CuO and Ag-V2O5 mixtures, with the apparent contact angles between 74° and 78° for all compositions and furnace dwell times. Preliminary microstructural analysis indicates that two different interfacial reactions are occurring: Ag-CuO interfacial microstructures revealed the same dissolution of copper oxide into the BSCF matrix to form copper-cobalt-oxygen rich dissolution products along the BSCF grain boundaries and Ag-V2O5 interfacial microstructures revealed the infiltration and replacement of cobalt and iron with vanadium and silver filling pores in the BSCF microstructure. The Ag-V2O5 interfacial reaction product layer was measured to be significantly thinner than the Ag-CuO reaction product layer. Using a fully articulated four point flexural bend test fixture, the flexural fracture strength for BSCF was determined to be 95 ± 33 MPa. The fracture strength will be used to ascertain the success of the reactive air braze alloys. Based on these results, brazes were fabricated and mechanically tested to begin to optimize the brazing parameters for this system. Ag-2.5% CuO braze alloy with a 2.5 minute thermal cycle achieved a hermetic seal with a joint flexural strength of 34 ± 15 MPa and Ag-1% V2O5 with a 30 minute thermal cycle had a joint flexural strength of 20 ± 15 MPa.

  13. Development of Ag-Cu-Zn-Sn brazing filler metals with a 1 0 weight-% reduction of silver and same liquidus temperature

    Institute of Scientific and Technical Information of China (English)

    Daniel Schnee; Gunther Wiehl; Sebastian Starck; Chen Kevin

    2014-01-01

    With BrazeTec BlueBraze the manufacturers in HVACR industry have an alternative filler metal with 10 weight-%less silver but same brazing temperatures.The performance of these new alloys has been evaluated in several tests.The evaluation included wetting investigations,metallographic examinations,joint strength at different temperatures and pulsation and corrosion resistance.The results ofthese tests will be presented in this paper.

  14. Mechanical and microstructural behavior of brazed aluminum / stainless steel mixed joints

    Science.gov (United States)

    Fedorov, V.; Weis, S.; Wagner, G.

    2016-03-01

    There is a requirement to combine different materials such as aluminum and stainless steel in industrial applications like automotive heat exchangers. Brazing offers the possibility to reduce the joining temperature in comparison to welding due to the lower liquidus temperature of the fillers. In the present work, the mechanical and microstructural behavior of aluminum / stainless steel mixed joints is investigated. The specimens are produced by induction brazing using an AlSi10filler and a non-corrosive flux. To evaluate the mechanical properties of the joints, tensile tests at elevated temperatures are carried out. Additionally, long-term thermal exposure experiments are done in order to investigate the changes in the microstructure.

  15. Topological dependence of mechanical responses of solidification microstructures in aluminum brazed joints

    Institute of Scientific and Technical Information of China (English)

    GAO Feng(高峰); QIAN Yi-yu(钱乙余); D.P.Sekulic; MA Xin(马鑫); F.Yoshida

    2003-01-01

    The main objective is to provide an evidence of spatial dependence of mechanical responses of a heterogeneous aluminum brazed joint re-solidified clad,and to confirm a sufficient sensitivity of a nano-indentation--load curve method for identifying the dependence.Topological features of a network of solidification microstructures(αphase and eutectic),formed during quench in a brazing process of aluminum alloy,influence significantly dynamic mechanical responses of resulting heterogeneous material.Nano/micro indentation depth vs load characteristics of differing phases suggest a spatially sensitive mechanical response of a re-solidified fillet in the joint zone.Hence,a spatial distribution,pattern formations and other morphological characteristics of microstructures have a direct impact on an ultimate joint integrity.Topology-induced variations of indentation-load curves was presented.A hypothesis involving microstructures'spatial distribution vs mechanical response was formulated.

  16. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    OpenAIRE

    Sérgio Ivan dos Santos; Carlos Alberto Medeiros Casanova; Cleiton Rodrigues Teixeira; Naira Maria Balzaretti; João Alziro Herz da Jornada

    2004-01-01

    The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness). The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a ...

  17. Novel high chromium containing braze filler metals for heat exchanger applications

    Energy Technology Data Exchange (ETDEWEB)

    Rangaswamy, S.; Fortuna, D. [Sulzer Metco, Troy (United States)

    2007-07-01

    A new family of boron-free, high chromium containing braze filler metal compositions were developed (Amdry 105, Amdry 108, Amdry 805). Filler metal properties including metallurgical phases, melting range, flow, corrosion resistance and high temperature oxidation resistance are reported. Additionally, the technical and economical advantages of using these new filler metals in fabricating flat plate type of heat exchangers and metallic catalytic converters is discussed. (orig.)

  18. Oil Circulation Effects on Evaporation Heat Transfer in Brazed Plate Heat Exchanger using R134A

    OpenAIRE

    Jang, Jaekyoo; Chang, Youngsoo; Kang, Byungha

    2012-01-01

    Experimental study was performed for oil circulation effects on evaporation heat transfer in the brazed type plate heat exchangers using R134A. In this study, distribution device was installed to ensure uniform flow distribution in the refrigerant flow passage, which enhances heat transfer performance of plate type heat exchanger. Tests were conducted for three evaporation temperature; 33℃, 37℃, and 41℃ and several oil circulation conditions. The nominal conditions of refrigerant are as follo...

  19. Characteristics of dissimilar laser-brazed joints of isotropic graphite to WC-Co alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nagatsuka, Kimiaki, E-mail: nagatuka@jwri.osaka-u.ac.jp [Graduate School of Engineering, Osaka University, Joining and Welding Research Institute, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Sechi, Yoshihisa, E-mail: sechi@kagoshima-it.go.jp [Kagoshima Prefectural Institute of Industrial Technology, 1445-1 Oda, Hayato-cho, Kirishima, Kagoshima 899-5105 (Japan); Miyamoto, Yoshinari, E-mail: y_miyamoto@toyotanso.co.jp [Toyo Tanso Co., Ltd., 5-7-12 Takeshima, Nishiyodgawa-ku, Osaka 555-0011 (Japan); Nakata, Kazuhiro, E-mail: nakata@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, 11-1, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2012-04-25

    Highlights: Black-Right-Pointing-Pointer Ti was required in the filler metal for brazing graphite to WC-Co alloy. Black-Right-Pointing-Pointer The shear strength of the joint increased with Ti content up to 1.7 mass%. Black-Right-Pointing-Pointer Ti concentrated at the interface of graphite/filler metal. Black-Right-Pointing-Pointer TiC was formed at the interface of graphite/filler metal. - Abstract: The effect of Ti serving as an activator in a eutectic Ag-Cu alloy filler metal in dissimilar laser-brazed joints of isotropic graphite and a WC-Co alloy on the joint strength and the interface structure of the joint is investigated in this study. To evaluate the joint characteristics, the Ti content in the filler metal was increased from 0 to 2.8 mass%. The laser brazing was carried out by irradiating a laser beam selectively on the WC-Co alloy plate in Ar atmosphere. The threshold content of Ti required to join isotropic graphite to WC-Co alloy was 0.4 mass%. The shear strength at the brazed joint increased rapidly with increasing Ti content up to 1.7 mass%, and a higher Ti content was found to be likely to saturate the shear strength to a constant value of about 14 MPa. The isotropic graphite blocks also fractured at this content. The concentration of Ti observed at the interface between isotropic graphite and the filler metal indicates the formation of an intermetallic layer of TiC.

  20. Improving interfacial reaction nonhomogeneity during laser welding-brazing aluminum to titanium

    International Nuclear Information System (INIS)

    Highlights: → Interfacial reaction nonhomogeneity of laser welding-brazing was improved. → The process window was extended by rectangular spot combined with V-shaped groove. → Mechanical property and its stability of Ti/Al dissimilar joint were enhanced. -- Abstract: Heterogeneous interfacial reactions were easily found along the Ti/Al interface due to high temperature gradient during laser welding-brazing of Ti/Al dissimilar alloys. To improve the nonhomogeneity, relative uniform energy distribution of laser beam and appropriate groove were attempted. The effects of these attempts on the nonhomogeneity of interfacial reactions were investigated by finite element method (FEM) numerical simulation and experimental validation. The results indicate that the V-shaped groove can make the interface roughly parallel to the isotherm of the temperature field. Moreover, the rectangular spot laser can further improve homogenization of the interfacial reaction along the interface in comparison with circular spot laser. Tensile test results show that the combination of rectangular spot laser welding-brazing and V-shaped groove can effectively control the fracture of Ti/Al joints in the seam in a wide processing parameters window, and the average tensile strength reaches 278 MPa.

  1. Preparation of W/CuCrZr monoblock test mock-up using vacuum brazing technique

    International Nuclear Information System (INIS)

    Development of the joining for W/CuCrZr monoblock PFC test mock-up is an interest area in Fusion R and D. W/Cu bimetallic material has prepared using OFHC copper casting approach on the radial surface of W monoblock tile surface. The W/Cu bimetallic material has been joined with CuCrZr tube (heat sink) material with the vacuum brazing route. Vacuum brazing of W/Cu-CuCrZr has been performed @ 970 °C for 10 mins using NiCuMn-37 filler material under deep vacuum environment (10-6 mbar). Graphite fixtures were used for OFHC copper casting and vacuum brazing experiments. The joint integrity of W/Cu-CuCrZr monoblock mock-up on W/Cu and Cu-CuCrZr has been checked using ultrasonic immersion technique. Micro-structural examination and Spot-wise elemental analysis have been carried out using HR-SEM and EDAX. The results of the experimental work will be discussed in the paper. (author)

  2. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  3. Residual Stress in Brazing of Submicron Al2O3 to WC-Co

    Science.gov (United States)

    Grunder, T.; Piquerez, A.; Bach, M.; Mille, P.

    2016-07-01

    This study evaluated the residual stresses induced by brazing and grinding submicron Al2O3, using different methods. Energy dispersive x-ray spectrometry analysis (EDX) of 72Ag-Cu filler and filler/WC-Co interface showed evidence of atomic diffusion and possible formation of titanium oxide layers between the joint and the bonding materials. An analytical model supported by the finite element method (FEM) based on strain determination due to the difference in variation of thermal expansion was used to assess the stress distribution at the coupling interface and in bulk materials. The model took into account the evolution of the Young's modulus and of the thermal expansion with temperature. The model could be used to follow strain and stress evolutions of the bonded materials during the cooling cycle. The maximum stress rose above -300 MPa at the center of the 100 × 100 × 3 mm ceramic plates. The residual stresses on the external surface of ceramic were investigated by x-ray diffraction (XRD) and indentation fracture method (IFM). After brazing and grinding the plate, the principal stresses were 128.1 and 94.9 MPa, and the shear stress was -20.1 MPa. Microscopic examination revealed grain pull-out promoted by the global residual stresses induced by the brazing and grinding processes. The surface stresses evaluated by the different methods were reasonably correlated.

  4. Residual Stress in Brazing of Submicron Al2O3 to WC-Co

    Science.gov (United States)

    Grunder, T.; Piquerez, A.; Bach, M.; Mille, P.

    2016-06-01

    This study evaluated the residual stresses induced by brazing and grinding submicron Al2O3, using different methods. Energy dispersive x-ray spectrometry analysis (EDX) of 72Ag-Cu filler and filler/WC-Co interface showed evidence of atomic diffusion and possible formation of titanium oxide layers between the joint and the bonding materials. An analytical model supported by the finite element method (FEM) based on strain determination due to the difference in variation of thermal expansion was used to assess the stress distribution at the coupling interface and in bulk materials. The model took into account the evolution of the Young's modulus and of the thermal expansion with temperature. The model could be used to follow strain and stress evolutions of the bonded materials during the cooling cycle. The maximum stress rose above -300 MPa at the center of the 100 × 100 × 3 mm ceramic plates. The residual stresses on the external surface of ceramic were investigated by x-ray diffraction (XRD) and indentation fracture method (IFM). After brazing and grinding the plate, the principal stresses were 128.1 and 94.9 MPa, and the shear stress was -20.1 MPa. Microscopic examination revealed grain pull-out promoted by the global residual stresses induced by the brazing and grinding processes. The surface stresses evaluated by the different methods were reasonably correlated.

  5. Fabrication and Characterization of Brazed Joints for SiC-Metallic Systems Utilizing Refractory Metals

    Science.gov (United States)

    Coddington, Bryan; Asthana, Rajiv; Halbig, Michael C.; Singh, M.

    2011-01-01

    Metal to ceramic joining plays a key role for the integration of ceramics into many nuclear, ground and aero based technologies. In order to facilitate these technologies, the active metal brazing of silicon carbide (CVD beta-SiC, 1.1 mm thick, and hot-pressed alpha-SiC, 3 mm thick) to the refractory metals molybdenum and tungsten using active braze alloys was studied. The joint microstructure, composition, and microhardness were evaluated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and Knoop hardness testing. The braze alloys, Cusil-ABA, Ticusil and Copper-ABA, all formed sound joints with excellent wetting and chemical bonding with the SiC substrate. Despite the close thermal expansion match between the metal substrates and SiC, hairline cracks formed in alpha-SiC while beta-SiC showed no signs of residual stress cracking. The use of ductile interlayers to reduce the effect from residual stresses was investigated and joints formed with copper as an interlayer produced crack free systems utilizing both CVD and hot-pressed SiC.

  6. Nickel-coated Steel Stud to Aluminum Alloy Joints Made by High Frequency Induction Brazing

    Institute of Scientific and Technical Information of China (English)

    GE Jiaqi; WANG Kehong; ZHANG Deku; WANG Jian

    2015-01-01

    Nickel-coated 45 steel studs and 6061 aluminum alloy with 4047 Al alloy foil asfi ller metal were joined by using high frequency induction brazing. The microstructure of Fe/Al brazed joint was studied by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD). Results showed that 45 steel stud and 6061 aluminum alloy could be successfully joined by high frequency induction brazing with proper processing parameters. The bonding strength of the joint was of the order of 88 MPa. Ni coating on steel stud successfully avoided the generation of Fe-Al intermetallic compound which is brittle by blocking the contact between Al and Fe. Intermetallic compounds, i e,Al3Ni2, Al1.1Ni0.9 and Al0.3Fe3Si0.7 presented in Al side, FeNi and Fe-Al-Ni ternary eutectic structure were formed in Fe side. The micro-hardness in intermetallic compound layer was 313 HV. The joint was brittle fractured in the intermetallic compounds layer of Al side, where plenty of Al3Ni2 intermetallic compounds were distributed continuously.

  7. Brazing ZrO2 ceramic to Ti–6Al–4V alloy using NiCrSiB amorphous filler foil: Interfacial microstructure and joint properties

    International Nuclear Information System (INIS)

    Reliable brazing of ZrO2 ceramic and Ti–6Al–4V alloy was achieved using NiCrSiB amorphous filler foil. The interfacial microstructure of ZrO2/Ti–6Al–4V joints was characterized by scanning electron microscope, energy dispersive spectrometer and micro-focused X-ray diffractometer. The effects of brazing temperature on the interfacial microstructure and joining properties of brazed joints were investigated in detail. Active Ti of Ti–6Al–4V alloy dissolved into molten filler metal and reacted with ZrO2 ceramic to form a continuous TiO reaction layer, which played an important role in brazing. Various reaction phases including Ti2Ni, Ti5Si3 and β-Ti were formed in brazed joints. With an increasing of brazing temperature, the TiO layer thickened gradually while the Ti2Ni amount reduced. Shear test indicated that brazed joints tend to fracture at the interface between ZrO2 ceramic and brazing seam or Ti2Ni intermetallic layer. The maximum average shear strength reached 284.6 MPa when brazed at 1025 °C for 10 min. - Graphical Abstract: Interfacial microstructure of ZrO2/TC4 joint brazed using NiCrSiB amorphous filler foil was: ZrO2/TiO/Ti2Ni + β-Ti + Ti5Si3/β-Ti/Widmanstätten structure/TC4. - Highlights: • Brazing of ZrO2 ceramic and Ti-6Al-4V alloy was achieved. • Interfacial microstructure was TiO/Ti2Ni + β + Ti5Si3/β/Widmanstätten structure. • The formation of TiO produced the darkening effect of ZrO2 ceramic. • The highest joining strength of 284.6MPa was obtained

  8. Synthesis and characterization of Ni-Mo filler brazing alloy for Mo-W joining for microwave tube technology

    Directory of Open Access Journals (Sweden)

    Frank Ferrer Sene

    2013-04-01

    Full Text Available A brazing process based on Ni-Mo alloy was developed to join porous tungsten cathode bottom and dense molybdenum cathode body for microwave tubes manufacture. The Ni-Mo alloy was obtained by mixing and milling powders in the eutectic composition, and applied on the surface of the components. The brazing was made at 1400 °C by using induction heating in hydrogen for 5 minutes. Alumina surfaces were coated with the binder and analyzed by Energy Dispersive X-rays Fluorescence. The brazed samples were analyzed by Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy. Stress-strain tests were performed to determine the mechanical behavior of the joining. The quality of the brazing was evaluated by assuring the presence of a "meniscus" formed by the Ni-Mo alloy on the border of the tungsten and molybdenum joint, the absence of microstructural defects in the interface between the tungsten and molybdenum alloys, and the adhesion of the brazed components.

  9. A New Vacuum Brazing Route for Niobium-316L Stainless Steel Transition Joints for Superconducting RF Cavities

    Science.gov (United States)

    Kumar, Abhay; Ganesh, P.; Kaul, R.; Bhatnagar, V. K.; Yedle, K.; Ram Sankar, P.; Sindal, B. K.; Kumar, K. V. A. N. P. S.; Singh, M. K.; Rai, S. K.; Bose, A.; Veerbhadraiah, T.; Ramteke, S.; Sridhar, R.; Mundra, G.; Joshi, S. C.; Kukreja, L. M.

    2015-02-01

    The paper describes a new approach for vacuum brazing of niobium-316L stainless steel transition joints for application in superconducting radiofrequency cavities. The study exploited good wettability of titanium-activated silver-base brazing alloy (CuSil-ABA®), along with nickel as a diffusion barrier, to suppress brittle Fe-Nb intermetallic formation, which is well reported during the established vacuum brazing practice using pure copper filler. The brazed specimens displayed no brittle intermetallic layers on any of its interfaces, but instead carried well-distributed intermetallic particles in the ductile matrix. The transition joints displayed room temperature tensile and shear strengths of 122-143 MPa and 80-113 MPa, respectively. The joints not only exhibited required hermeticity (helium leak rate ultra-high vacuum but also withstood twelve hour degassing heat treatment at 873 K (suppresses Q-disease in niobium cavities), without any noticeable degradation in the microstructure and the hermeticity. The joints retained their leak tightness even after undergoing ten thermal cycles between the room temperature and the liquid nitrogen temperature, thereby establishing their ability to withstand service-induced low cycle fatigue conditions. The study proposes a new lower temperature brazing route to form niobium-316L stainless steel transition joints, with improved microstructural characteristics and acceptable hermeticity and mechanical properties.

  10. Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

    Science.gov (United States)

    Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

    2016-04-01

    Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

  11. An Ag based brazing system with a tunable thermal expansion for the use as sealant for solid oxide cells

    Science.gov (United States)

    Kiebach, Ragnar; Engelbrecht, Kurt; Grahl-Madsen, Laila; Sieborg, Bertil; Chen, Ming; Hjelm, Johan; Norrman, Kion; Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2016-05-01

    An Ag-Al2TiO5 composite braze was developed and successfully tested as seal for solid oxide cells. The thermo-mechanical properties of the Ag-Al2TiO5 system and the chemical compatibility between this composite braze and relevant materials used in stacks were characterized and the leak rates as a function of the operation temperature were measured. The thermal expansion coefficient in the Ag-Al2TiO5 system can be tailored by varying the amount of the ceramic filler. The brazing process can be carried out in air, the joining partners showed a good chemical stability and sufficient low leak rates were demonstrated. Furthermore, the long-term stability of the Ag-Al2TiO5 composite braze was studied under relevant SOFC and SOEC conditions. The stability of brazed Crofer/Ag-Al2TiO5/NiO-YSZ assemblies in reducing atmosphere and in pure oxygen was investigated over 500 h at 850 °C. Additionally, a cell component test was performed to investigate the durability of the Ag-Al2TiO5 seal when exposed to dual atmosphere. The seals performed well over 900 h under electrolysis operation conditions (-0.5 A cm2, 850 °C), and no cell degradation related to the Ag-Al2TiO5 sealing was found, indicating that the developed braze system is applicable for the use in SOFC/SOEC stacks.

  12. Potential and limitations of microanalysis SEM techniques to characterize borides in brazed Ni-based superalloys

    International Nuclear Information System (INIS)

    Brazed Ni-based superalloys containing complex phases of different Boron contents remain difficult to characterize at the micrometer scale. Indeed Boron is a light element difficult to measure precisely. The state-of-the-art microanalysis systems have been tested on a single crystal MC2 based metal brazed with BNi-2 alloy to identify boride precipitates. Effort has been made to evaluate the accuracy in Boron quantitation. Energy-dispersive and wavelength-dispersive X-ray spectroscopy attached to a Scanning Electron Microscope have first been used to determine the elemental composition of Boron-free phases, and then applied to various types of borides. Results have been compared to the ones obtained using a dedicated electron probe microanalysis, considered here as the reference technique. The most accurate method to quantify Boron using EDS is definitely by composition difference. A precision of 5 at.% could be achieved with optimized data acquisition and post-processing schemes. Attempts that aimed at directly quantifying Boron with various standards using EDS or coupled EDS/WDS gave less accurate results. Ultimately, Electron Backscatter Diffraction combined with localized EDS analysis has proved invaluable in conclusively identifying micrometer sized boride precipitates; thus further improving the characterization of brazed Ni-based superalloys. - Highlights: • We attempt to accurately identify Boron-rich phases in Ni-based superalloys. • EDS, WDS, EBSD systems are tested for accurate identification of these borides. • Results are compared with those obtained by electron probe microanalysis. • Boron was measured with EDS by composition difference with a precision of 5 at. %. • Additional EBSD in phase identification mode conclusively identifies the borides

  13. Adhesive bonding and brazing of nanocrystalline diamond foil onto different substrate materials

    Science.gov (United States)

    Lodes, Matthias A.; Sailer, Stefan; Rosiwal, Stefan M.; Singer, Robert F.

    2013-10-01

    Diamond coatings are used in heavily stressed industrial applications to reduce friction and wear. Hot-filament chemical vapour deposition (HFCVD) is the favourable coating method, as it allows a coating of large surface areas with high homogeneity. Due to the high temperatures occurring in this CVD-process, the selection of substrate materials is limited. With the desire to coat light materials, steels and polymers a new approach has been developed. First, by using temperature-stable templates in the HFCVD and stripping off the diamond layer afterwards, a flexible, up to 150 μm thick and free standing nanocrystalline diamond foil (NCDF) can be produced. Afterwards, these NCDF can be applied on technical components through bonding and brazing, allowing any material as substrate. This two-step process offers the possibility to join a diamond layer on any desired surface. With a modified scratch test and Rockwell indentation testing the adhesion strength of NCDF on aluminium and steel is analysed. The results show that sufficient adhesion strength is reached both on steel and aluminium. The thermal stress in the substrates is very low and if failure occurs, cracks grow undercritically. Adhesion strength is even higher for the brazed samples, but here crack growth is critical, delaminating the diamond layer to some extent. In comparison to a sample directly coated with diamond, using a high-temperature CVD interlayer, the brazed as well as the adhesively bonded samples show very good performance, proving their competitiveness. A high support of the bonding layer could be identified as crucial, though in some cases a lower stiffness of the latter might be acceptable considering the possibility to completely avoid thermal stresses which occur during joining at higher temperatures.

  14. Reactive air brazing for sealing mixed ionic electronic conducting hollow fibre membranes

    International Nuclear Information System (INIS)

    Mixed ionic–electronic conducting (MIEC) ceramic membranes and high-temperature alloys are candidate materials for applications in high-temperature gas separation systems and solid oxide fuel cells (SOFCs). Ensuring a gas-tight seal between the components is of paramount importance in the operation of such devices. This paper investigates the wettability and joining of representative ceramic-to-ceramic and ceramic-to-metal components by reactive air brazing (RAB) using Ag–Cu alloys. The correlation of the interfacial reaction (including wettability) to the hermeticity of the joints has been demonstrated by elemental mapping using Electron Probe Micro-Analysis with wavelength dispersive spectrometry (EPMA-WDS). The wettability studies described herein demonstrate that RAB is a reliable method to achieve strong, gas-tight bonding between the dissimilar materials. These are the first reported results of successful air-brazed joints between La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) and BaCo0.4Fe0.4Zr0.2O3-δ (BCFZ) hollow fibre membranes to FeCrAlloy components using a 4 mol.% Cu in Ag filler metal composition which delivered an impressive runtime of up to 2000 h (for LSCF). It has been demonstrated that these RAB joints are hermetic and resistant to thermal ageing, making them suitable for membrane-based gas-separation applications. Post-operation EPMA-WDS analysis of the microstructures and compositional distribution of the brazed seals has revealed that their performance is largely dependent upon a reaction zone and an interfacial oxide layer adherent to the FeCrAlloy surface

  15. Brazing of Sealing for Instrumentation Feed through of high Pressure Vessel

    International Nuclear Information System (INIS)

    Fuel Test Loop(FTL) is a facility which could conduct a fuel irradiation test at HANARO(High-flux Advanced Neutron Application Reactor). FTL simulates commercial NPP's operating conditions such as the pressure, temperature and neutron flux levels to conduct the irradiation and thermo-hydraulic tests. It is composed of an In-Pile test Section(IPS) and an Out- Pile System(OPS). The OPS contains a pressurizer, cooler, pump, heater and purification system which are necessary to maintain the proper fluid conditions. In addition, the OPS contains engineered safety systems that could safely shutdown both HANARO and FTL if an accident occurs. The IPS accommodating fuel pins has loaded IP-1 hole in HANARO has a double pressure vessel for the design conditions of 350 .deg. C, 17.5MPa and is composed of outer assembly and inner assembly. It has instruments such as a thermocouple, LVDT and SPND to measure the fuel performances during the test. FTL coolant is supplied to the IPS at the core of commercial nuclear power plants and the same temperature, pressure and flow conditions. Sensors installed on the inside of IPS to send a signal transmission MI-Cables to the outside for instrumentation is through the pressure boundary. Therefore, pressure boundary should be maintained in the sealing performance. Brazing is typically lower than the melting point of material without melting the material almost would be like welding when it is necessary to use. It is commonly used to use BAg(ASME II SFA-5.8 UNS-P07563) filler metal, but corrosion occurs containing a large quantity of copper in Bag, and when contact with the coolant, the coolant water quality is influenced. Therefore, using BNi-2(ASME II SFA-5.8 UNS-N99620) filler metal is considered. Brazing at the Sealing Plug in the top of IPS was considered for Mi-cable's integrity and to maintain the pressure boundary. After brazing is performed, brazing the Mi-cable integrity and pressure boundary sealing performance was tested

  16. Phase analysis of fume during arc weld brazing of steel sheets with protective coatings

    Directory of Open Access Journals (Sweden)

    J. Matusiak

    2016-04-01

    Full Text Available The article presents the results of research of the phase identification and of the quantitative phase analysis of fume generated during Cold Metal Transfer (CMT, ColdArc and Metal Inert Gas / Metal Active Gas (MIG / MAG weld brazing. Investigations were conducted for hot - dip coated steel sheets with zinc (Zn and zinc-iron (Zn - Fe alloy coatings. Arc shielding gases applied during the research-related tests were Ar + O2, Ar + CO2, Ar + H2 and Ar + CO2 + H2 gas mixtures. The analysis of the results covers the influence of the chemical composition of shielding gas on the chemical composition of welding fume.

  17. Effect of interlayer on the mechanical properties of YG8 hard carbide/40Cr steel brazed joints

    Institute of Scientific and Technical Information of China (English)

    Wu Mingfang; Pu Juan; Chen Jian

    2009-01-01

    The effects of Cu foil and Ni foil on the mechanical properties of YG8 hard carbide/4OCr steel brazed joints were investigated. The results show that both Cu foil and Ni foil were beneficial to decrease the residual stress and enhance the joint strength. Moreover, Ni foil exhibited the better impact on enhancing the joint strength relative to Cu foil. When Cu foil was used as interlayer material, the key factor to restrain the joint strength was the massive and quick dissolution of Cu. Therefore, in order to prevent the excessive dissolution of Cu foil, the process parameter should be controlled strictly in the brazing process.

  18. Phase constitution in the interfacial region of laser penetration brazed magnesium–steel joints

    International Nuclear Information System (INIS)

    The phase constitution in the interfacial region of laser penetration brazed magnesium–steel joints was investigated using electron microscopy. From the distribution of elements, the transition zone was mainly composed of elements Mg and Fe along with some Al and O. Furthermore, the transition layer consisted mainly of intermetallic compounds and metal oxides. The compounds were identified as Al-rich phases, such as Mg17Al12, Mg2Al3, FeAl and Fe4Al13. More noteworthy was that the thickness of the transition layer was determined by Fe–Al compounds. The presence of FeAl and Fe4Al13 was a result of the complex processes that were associated with the interfacial reaction of solid steel and liquid Mg–Al alloy. - Highlights: • A technology of laser penetration brazed Mg alloy and steel has been developed. • The interface of Mg/Fe dissimilar joints was investigated using electron microscopy. • The transition layer consisted of intermetallic compounds and metal oxides. • Moreover, the thickness of transition layer was determined by Fe/Al compounds. • The presence of FeAl and Fe4Al13 was associated with the interfacial reaction

  19. Phase constitution in the interfacial region of laser penetration brazed magnesium–steel joints

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Yugang; Han, Duanfeng, E-mail: handuanfeng@gmail.com; Xu, Xiangfang; Wu, Bintao

    2014-07-01

    The phase constitution in the interfacial region of laser penetration brazed magnesium–steel joints was investigated using electron microscopy. From the distribution of elements, the transition zone was mainly composed of elements Mg and Fe along with some Al and O. Furthermore, the transition layer consisted mainly of intermetallic compounds and metal oxides. The compounds were identified as Al-rich phases, such as Mg{sub 17}Al{sub 12}, Mg{sub 2}Al{sub 3}, FeAl and Fe{sub 4}Al{sub 13}. More noteworthy was that the thickness of the transition layer was determined by Fe–Al compounds. The presence of FeAl and Fe{sub 4}Al{sub 13} was a result of the complex processes that were associated with the interfacial reaction of solid steel and liquid Mg–Al alloy. - Highlights: • A technology of laser penetration brazed Mg alloy and steel has been developed. • The interface of Mg/Fe dissimilar joints was investigated using electron microscopy. • The transition layer consisted of intermetallic compounds and metal oxides. • Moreover, the thickness of transition layer was determined by Fe/Al compounds. • The presence of FeAl and Fe{sub 4}Al{sub 13} was associated with the interfacial reaction.

  20. Quality evaluations of the fuel bundle welds and brazed joints by acoustic microscopy

    International Nuclear Information System (INIS)

    For more than 20 years, the quality control of the end-cap, end-plates welds and of the brazed appendage joints is made by destructive methods (metallographic examinations or mechanical tests) on specimens sampled from production. Having a very limited statistics, these destructive methods are useful only to indicate 'trends' of the production quality, not for detecting infrequent single defect events. It is recognized that nondestructive examination techniques are required to achieve sufficient evidence of the production quality, at a statistically significant sampling rate. For this reason, the INR-Ultraacoustics R and D Lab has develop a family of equipments for high resolution ultrasonic imaging, at performances close to the Acoustic Microscopy domain. The paper make a presentation of the examination methods and of the experimental results obtained on characteristic welds and brazed joints samples. Detailed off-line evaluations of the C-scan and B-scan ultrasonic images are made and comparative analyses with metallography are performed. Also, in the case of end-cap welds, numerical stress analysis are made, in order to establish the influence of flaws on the weld strength. (author)

  1. Melting Point Depression and Fast Diffusion in Nanostructured Brazing Fillers Confined Between Barrier Nanolayers

    Science.gov (United States)

    Kaptay, G.; Janczak-Rusch, J.; Jeurgens, L. P. H.

    2016-05-01

    Successful brazing using Cu-based nanostructured brazing fillers at temperatures much below the bulk melting temperature of Cu was recently demonstrated (Lehmert et al. in, Mater Trans 56:1015-1018, 2015). The Cu-based nano-fillers are composed of alternating nanolayers of Cu and a permeable, non-wetted AlN barrier. In this study, a thermodynamic model is derived to estimate the melting point depression (MPD) in such Cu/AlN nano-multilayers (NMLs) as function of the Cu nanolayer thickness. Depending on the melting route, the model predicts a MPD range of 238-609 K for Cu10nm/AlN10nm NMLs, which suggests a heterogeneous pre-melting temperature range of 750-1147 K (476-874 °C), which is consistent with experimental observations. As suggested by basic kinetic considerations, the observed Cu outflow to the NML surface at the temperatures of 723-1023 K (450-750 °C) can also be partially rationalized by fast solid-state diffusion of Cu along internal interfaces, especially for the higher temperatures.

  2. Brazing characteristics of a Zr–Ti–Cu–Fe eutectic alloy filler metal for Zircaloy-4

    International Nuclear Information System (INIS)

    A Zr–Ti–Cu–Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr58Ti16Cu10Fe16 (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr–Cu–Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr2Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min

  3. Brazing characteristics of a Zr–Ti–Cu–Fe eutectic alloy filler metal for Zircaloy-4

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung G.; Lim, C.H. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Kim, K.H. [University of Science and Technology, Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Park, S.S. [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Lee, M.K., E-mail: leeminku@kaeri.re.kr [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of); Rhee, C.K. [Nuclear Materials Development Division, Korea Atomic Energy Research Institute (KAERI), Yuseong, Daejeon 305-353 (Korea, Republic of)

    2013-10-15

    A Zr–Ti–Cu–Fe quaternary eutectic alloy was employed as a new Be-free brazing filler metal for Zircaloy-4 to supersede physically vapor-deposited Be coatings used conventionally with several disadvantages. The quaternary eutectic composition of Zr{sub 58}Ti{sub 16}Cu{sub 10}Fe{sub 16} (at.%) showing a low melting temperature range from 832 °C to 853 °C was designed by a partial substitution of Zr with Ti based on a Zr–Cu–Fe ternary eutectic system. By applying an alloy ribbon with the determined composition, a highly reliable joint was obtained with a homogeneous formation of predominantly grown α-Zr phases owing to a complete isothermal solidification, exhibiting strength higher than that of Zircaloy-4. The homogenization of the joint was rate-controlled by the diffusion of the filler elements (Ti, Cu, and Fe) into the Zircaloy-4 base metal, and the detrimental segregation of the Zr{sub 2}Fe phase in the central zone was completely eliminated by an isothermal holding at a brazing temperature of 920 °C for 10 min.

  4. Mechanical characterization and modeling of brazed tungsten and Cu–Cr–Zr alloy using stress relief interlayers

    International Nuclear Information System (INIS)

    A rapidly solidified foil-type Ti–Zr based amorphous filler with a melting temperature of 850 °C was used to braze tungsten to Cu–Cr–Zr alloy for water cooled divertors and plasma facing components application. Brazed joints of dissimilar materials suffer from a mismatch in coefficients of thermal expansion. In order to release the residual stress caused by the mismatch, brazed joints of tungsten and Cu–Cr–Zr alloy using different interlayers were studied. The shear strength tests of brazed W/Cu joints show that the average strength of the joint with a W70Cu30 composite plate interlayer reached 119.8 MPa, and the average strength of the joint with oxygen free high conductivity copper (OFHC Cu)/Mo multi-interlayers reached 140.8 MPa, while the joint without interlayer was only 16.6 MPa. Finite element method (FEM) has been performed to investigate the stress distribution and effect of stress relief interlayers. FEM results show that the maximum von Mises stress occurs in the tungsten/filler interface and that the filler suffers the peak residual stresses and becomes the weakest zone. And the use of OFHC Cu/Mo multi-interlayers can reduce the residual stress significantly, which agrees with the mechanical experiment data

  5. Compressive Strength Evaluation in Brazed ZrO2/Ti6Al4V Joints Using Finite Element Analysis

    Science.gov (United States)

    Sharma, Ashutosh; Kee, Se Ho; Jung, Flora; Heo, Yongku; Jung, Jae Pil

    2016-04-01

    This study aims to synthesize and evaluate the compressive strength of the ZrO2/Ti-6Al-4V joint brazed using an active metal filler Ag-Cu-Sn-Ti, and its application to dental implants assuring its reliability to resist the compressive failure in the actual oral environment. The brazing was performed at a temperature of 750 °C for 30 min in a vacuum furnace under 5 × 10-6 Torr atmosphere. The microstructure of the brazed joint showed the presence of an Ag-rich matrix and a Cu-rich phase, and Cu-Ti intermetallic compounds were observed along the Ti-6Al-4V bonded interface. The compressive strength of the brazed ZrO2/Ti-6Al-4V joint was measured by EN ISO 14801 standard test method. The measured compressive strength of the joint was ~1477 MPa—a value almost five times that of existing dental cements. Finite element analysis also confirmed the high von Mises stress values. The compressive strains in the samples were found concentrated near the Ti-6Al-4V position, matching with the position of the real fractured sample. These results suggest extremely significant compressive strength in ZrO2/Ti-6Al-4V joints using the Ag-Cu-Sn-Ti filler. It is believed that a highly reliable dental implant can be processed and designed using the results of this study.

  6. 78 FR 53159 - Standard for Welding, Cutting, and Brazing; Extension of the Office of Management and Budget's...

    Science.gov (United States)

    2013-08-28

    ... Paperwork Reduction Act of 1995 (44 U.S.C. 3506 et seq.) and Secretary of Labor's Order No. 1-2012 (77 FR... Occupational Safety and Health Administration Standard for Welding, Cutting, and Brazing; Extension of the... Budget's (OMB) approval of the information collection requirements contained in the Standard for...

  7. Compressive Strength Evaluation in Brazed ZrO2/Ti6Al4V Joints Using Finite Element Analysis

    Science.gov (United States)

    Sharma, Ashutosh; Kee, Se Ho; Jung, Flora; Heo, Yongku; Jung, Jae Pil

    2016-05-01

    This study aims to synthesize and evaluate the compressive strength of the ZrO2/Ti-6Al-4V joint brazed using an active metal filler Ag-Cu-Sn-Ti, and its application to dental implants assuring its reliability to resist the compressive failure in the actual oral environment. The brazing was performed at a temperature of 750 °C for 30 min in a vacuum furnace under 5 × 10-6 Torr atmosphere. The microstructure of the brazed joint showed the presence of an Ag-rich matrix and a Cu-rich phase, and Cu-Ti intermetallic compounds were observed along the Ti-6Al-4V bonded interface. The compressive strength of the brazed ZrO2/Ti-6Al-4V joint was measured by EN ISO 14801 standard test method. The measured compressive strength of the joint was ~1477 MPa—a value almost five times that of existing dental cements. Finite element analysis also confirmed the high von Mises stress values. The compressive strains in the samples were found concentrated near the Ti-6Al-4V position, matching with the position of the real fractured sample. These results suggest extremely significant compressive strength in ZrO2/Ti-6Al-4V joints using the Ag-Cu-Sn-Ti filler. It is believed that a highly reliable dental implant can be processed and designed using the results of this study.

  8. Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

    Science.gov (United States)

    Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

    2016-04-01

    Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

  9. Active brazing of carbon fiber reinforced SiC composite and 304 stainless steel with Ti–Zr–Be

    International Nuclear Information System (INIS)

    Carbon fiber reinforced SiC (Cf/SiC) was successfully joined to 304 stainless steel with Ti–Zr–Be filler metal by vacuum brazing. The interfacial microstructure was investigated by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), auger electron energy spectroscopy (AES) and X-diffraction (XRD). The mechanical properties of the brazed joints were measured by a mechanical testing machine. The results show that Ti and Zr elements in the interlayer can react with the brazed materials, the brazed joint mainly consists of Ti5Si3, TiSi, TiBe, TiFe and Zr(s,s) reaction products. The 304 stainless steel constantly dissolved and Ti, Be diffused into 304 stainless steel, which formed the diffusion layers between interlayer and 304 stainless steel. Ti and Be elements have an effect on promoting the formation of α-Fe layer. The maximum shear strength of 109.13±2.55 MPa is obtained at 950 °C with 60 min holding time

  10. Microstructural and Mechanical Evaluation of a Cu-Based Active Braze Alloy to Join Silicon Nitride Ceramics

    Science.gov (United States)

    Singh, M.; Asthana, Rajiv; Varela, F. M.; Martinez-Fernandez, J.

    2010-01-01

    Self-joining of St. Gobain Si3N4 (NT-154) using a ductile Cu-Al-Si-Ti active braze (Cu-ABA) was demonstrated. A reaction zone approx.2.5-3.5 microns thick) developed at the interface after 30 min brazing at 1317 K. The interface was enriched in Ti and Si. The room temperature compressive shear strengths of Si3N4/Si3N4 and Inconel/Inconel joints (the latter created to access baseline data for use with the proposed Si3N4/Inconel joints) were 140+/-49MPa and 207+/-12MPa, respectively. High-temperature shear tests were performed at 1023K and 1073 K, and the strength of the Si3N4/Si3N4 and Inconel/Inconel joints were determined. The joints were metallurgically well-bonded for temperatures above 2/3 of the braze solidus. Scanning and transmission electron microscopy studies revealed a fine grain microstructure in the reaction layer, and large grains in the inner part of the joint with interfaces being crack-free. The observed formation of Ti5Si3 and AlN at the joint interface during brazing is discussed.

  11. Joining of CBN abrasive grains to medium carbon steel with Ag-Cu/Ti powder mixture as active brazing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ding, W.F. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)]. E-mail: dingwf2000@vip.163.com; Xu, J.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Shen, M. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Su, H.H. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Fu, Y.C. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Xiao, B. [College of Mechanical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2006-08-25

    In order to develop new generation brazed CBN grinding wheels, the joining experiments of CBN abrasive grains and medium carbon steel using the powder mixture of Ag-Cu alloy and pure Ti as active brazing alloy are carried out at elevated temperature under high vacuum condition. The relevant characteristics of the special powder mixture, the microstructure of the interfacial region, which are both the key factors for determining the joining behavior among the CBN grains, the filler layer and the steel substrate, are investigated extensively by means of differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis. The results show that, similar to Ag-Cu-Ti filler alloy, Ag-Cu/Ti powder mixture exhibits good soakage capability to CBN grains during brazing. Moreover, Ti in the powder mixture concentrates preferentially on the surface of the grains to form a layer of needlelike Ti-N and Ti-B compounds by chemical metallurgic interaction between Ti, N and B at high temperature. Additionally, based on the experimental results, the brazing and joining mechanism is deeply discussed in a view of thermodynamic criterion and phase diagram of Ti-B-N ternary system.

  12. Influence of laser energy input mode on joint interface characteristics in laser brazing with Cu-base filler metal

    Institute of Scientific and Technical Information of China (English)

    LI Li-qun; FENG Xiao-song; CHEN Yan-bin

    2008-01-01

    The flange butt joints of 1 mm-thick galvanized steel sheets were brazed with CuSi3 as filler metal at different laser heating modes. The microstructures and element distributions of joint interface were investigated by SEM and EDS. The results show that there is no obvious interface layer with the circular individual beam heating and lamellar Fe-Si intermetallic compound layer is found with dual-beam laser spot heating. With the irradiation of rectangular laser spot, the joint interface layer is also formed. The layer thickness is larger than that of dual-beam brazing and the layer shape is fiat so that intermetallic compounds trend to grow into cellular crystals. Moreover, the interface layer shape also depends on its position in the joint. Under the high heat input, dendritic or granular intermetallic compounds dispersively distribute in brazing seam adjacent to the interface, which is caused by the melting or dissolving of the base metal. According to the results, the brazing quality can be controlled by laser heating mode and processing parameters.

  13. Development and heat load experiments of graphite brazed to stainless steel for the first wall structure of FER

    International Nuclear Information System (INIS)

    A guard limiter concept with graphite brazed to a stainless steel base plate has been proposed in FER. The bonding of graphite and stainless steel was successfully done by vacuum brazing with an interlayer material of Mo or Cu. Mechanical strengths were measured by tensile and shear tests. Fatigue test up to approximately 107 cycles were done. Heat load experiments were performed with electron beam equipment. Brazed materials with a Mo interlayer were subjected to a heat load up to 60 MJ/m2 (6 kJ/cm2). No complete failures were observed in every condition, but cracks were generated by heat loads greater than 40 MJ/m2 (4 kJ/cm2). The failures were generated in graphite near to the interface. Mechanical strength and thermal shock resistance were improved by the change from 1 to 3 mm in thickness of Mo interlayer. Residual stresses due to brazing and cool-down were analyzed with an FEM code, and the results were compared with strain measurements on the test specimen. A comparison study on interlayer materials is continuing, and heat load cycle tests are now underway for 10 MJ/m2 (1 kJ/cm2), which is a target value based on the FER design. (orig.)

  14. Induction brazing of 6063/3 A21 aluminum alloy%6063和3A21铝合金的感应钎焊应用研究

    Institute of Scientific and Technical Information of China (English)

    杨林

    2013-01-01

    介绍了感应钎焊技术在雷达产品常用钎焊铝合金上的应用,通过对铝合金感应加热的感应器优化设计技术和精密温控技术的研究,实现了铝合金感应钎焊的精密控温,进行了管与管、管与法兰异型接头的感应器设计,开展了铝合金的感应硬钎焊工艺研究,分析了铝合金感应钎焊工件的钎焊缝和钎焊圆角、尺寸变形精度、表面氧化和微观组织等.文中实现了铝合金复杂结构的感应钎焊,并应用于铝合金6063法兰和3A21方型波导管接头的钎焊,为此类结构提供一种新的焊接方法.%The application of induction brazing to aluminum alloy composite in radar was introduced. The induction brazing temperature was precisely controlled by the optimization of induction coil and the research on temperature - control technology. The induction coil used in brazing tube/tube or tube/flange joint was design, and the induction brazing process was also studied. The brazed joint, brazing deformation, surface oxidation, and microstructure of the aluminum alloy were analyzed. This study realizes the induction brazing of aluminum alloy composite with complicate structure, and this technology was applied to braze 6063 aluminum alloy flange and 3A21 aluminum alloy rectangle wave guide, which provided a new method to braze aluminum alloy composite with similar structure.

  15. A combined electron probe micro analysis and scanning Kelvin probe force microscopy study of a modified AA4xxx/AA3xxx aluminium brazing sheet

    International Nuclear Information System (INIS)

    Highlights: • SKPFM and FE-EPMA for a modified aluminium brazing sheet were performed. • Cross-sectional electrochemical properties of the material were measured. • Cross-sectional variation of microstructural chemistry was investigated. • The electrochemical responses were correlated to the microstructural features. • A solution for corrosion protection enhancement of the material was proposed. -- Abstract: The electrochemical and microstructural properties of the clad and core from a modified AA3xxx/AA4xxx brazing sheet were investigated before and after brazing. For this, scanning Kelvin probe force microscopy (SKPFM) and field emission electron probe micro analysis (FE-EPMA) were used. The Volta potential difference (VPD) was measured as a function of depth for the brazed and non-brazed sheets. This was correlated with the cross-sectional variation of chemistry and microstructure that result from brazing. Furthermore, potentiodynamic polarization experiments and subsequent microscopic analysis of the corroded samples were used to explore the corrosion mechanism of the modified brazed sheet. The investigation revealed that the major consequences of brazing for the microstructure are: an increase in the Si content of the matrix in the heat affected zone (HAZ); a non-uniform distribution of Cu in the HAZ; an accumulation of Cu in Al–Si eutectics and around the grain boundaries, including α-Al(Mn,Fe)Si and Al2Cu intermetallics; the presence of some continuous grain boundaries in both the clad and core of the sheet; and the non-uniform precipitation of intermetallics at Al–Si eutectic phases. The impact of these microstructural changes on the corrosion behaviour of the brazed sheet was: to increase the VPD of the re-solidified clad matrix; to introduce localized corrosion susceptibility on the brazed clad and core structures; and to reduce the cathodic protection power of the re-solidified clad material. As a result of the correlation between

  16. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  17. Scanning Kelvin probe force microscopy as a means of predicting the electrochemical characteristics of the surface of a modified AA4xxx/AA3xxx (Al alloys) brazing sheet

    International Nuclear Information System (INIS)

    Highlights: ► Macro- and micro-electrochemical surface properties of an aluminium brazing sheet were investigated. ► Electrochemical surface properties before and after brazing were studied and compared. ► Scanning Kelvin probe force microscopy and potentiodynamic polarization measurements were performed. ► The electrochemical responses were correlated to the pre- and post-brazing treatment microstructure. -- Abstract: Macro- and micro-electrochemical properties of clad and core surfaces of a modified AA4xxx/AA3xxx brazing sheet material, before and after brazing, have been evaluated and compared. By scanning Kelvin probe force microscopy (SKPFM), the Volta potential distribution over the brazed and non-brazed clad surfaces was measured. The changes in the Volta potential maps were correlated to the macro-electrochemical responses of the surfaces and the microstructural features that evolve as a result of brazing. By performing potentiodynamic polarization experiments and microscopic analysis of the corroded surfaces and cross sections, the suitability of SKPFM analysis for corrosion performance prediction of the aluminium brazing sheet material in a sea water acidified accelerated test (SWAAT) environment was confirmed. Considering the purity of Si phase in the structures of both brazed and non-brazed material, it is suggested that Si can be applied as a reliable local reference in both structures to compare the changes in Volta potential differences as the result of different heat treatments of aluminium brazing sheet. Increasing the copper content of the re-solidified clad material as a result of brazing treatment was found to increase the Volta potential of the matrix which in turn reduces the cathodic protection power of the re-solidified clad material towards the core material

  18. ON FABRICATION AND BRAZING OF 15A, 120 keV CONTINUOUS DUTY ACCELERATOR GRID ASSEMBLIES

    Energy Technology Data Exchange (ETDEWEB)

    Biagi, L.A.; Koehler, G.W.; Paterson, J.A.

    1980-05-01

    The development of high intensity neutral beam injectors at the Lawrence Berkeley Laboratory has progressed from relatively low duty cycle, low energy devices to the next generation of continuous duty high energy units. The earlier pulsed versions were designed with edge cooled grid structures described ·in a previous publication. The prerequisites set by the higher duty cycle devices no longer allow the edge cooling methods to be employed. Hollow molybdenum grid rails with deionized cooling water flowing at pressures of approximately 1.73 x 10{sup 6}Pa (250 PSI) at from 1.135 to 1.89 liters per minute (.3 to .5 GPM) are brazed to Type 304L stainless steel rail holders.

  19. Electrochemical depth profiling of multilayer metallic structures: An aluminum brazing sheet

    DEFF Research Database (Denmark)

    Afshar, F. Norouzi; Ambat, R.; Kwakernaak, C.;

    2012-01-01

    Combinatory localized electrochemical cell and glow discharge optical emission spectrometry (GDOES) measurements were performed to obtain a thorough in depth electrochemical characterization of an aluminum brazing sheet. By defining electrochemical criteria i.e. breakdown potential, corrosion...... potential, cathodic and anodic reactivities, and tracking their changes as a function of depth, the evolution of electrochemical responses through out the material thickness were analyzed and correlated to the corresponding microstructural features. Polarization curves in 1wt% NaCl solution at pH 2.8 were...... susceptible to localized attack. Consistent with this, optical microscopy and scanning electron microscope analysis revealed a relatively high density of fine intermetallic and silicon particles at these areas. The corrosion mechanism of the top layers was identified to be intergranular and pitting corrosion...

  20. Nonlinear thermal and structural analysis of a brazed solar-central-receiver panel

    Energy Technology Data Exchange (ETDEWEB)

    Napolitano, L.M. Jr.; Kanouff, M.P.

    1981-07-01

    One part of the evaluation program for a molten sodium central receiver was to be a test of a reduced-scale panel at Sandia's Central Receiver Test Facility in Albuquerque. The panel incorporates a new way of joining tubes - brazing to intermediate filler strips - which can affect the panel's lifetime. To calculate the stresses and strains for the worst-case section of the experimental panel, we have done a nonlinear elastic-plastic analysis with the MARC finite element computer code, which takes the temperature dependence of the material properties into account. From the results, tube design lifetimes are predicted. The analysis shows that concerns for cracking and reduction in lifetime are warranted, but a more detailed fracture analysis is necessary to determine whether there is a stable-crack-growth problem.

  1. Ion-irradiation hardening of brazed joints of tungsten and oxide dispersion strengthened (ODS) ferritic steel

    International Nuclear Information System (INIS)

    Irradiation hardening and microstructural change of the brazed-joint of W and oxide dispersion strengthened ferritic steel (ODS-FS) was investigated by nano-indentation hardness test and transmission electron microscopy after ion irradiation with 6.4 MeV Fe3+ ions at 500°C up to 10 dpa. Dual-beam irradiation of Fe3+ ions and energy-degraded 1 MeV He+ ion was also carried out. A considerable irradiation hardening occurred in the W base metal where dislocation loops and nano-scaled voids or He-bubbles were observed. Dual-beam irradiation enhanced the hardening. No significant hardening was observed in ODS-FS. The hardness of insert material was reduced after irradiation, which is due to the recovery of dislocations generated during joining process. (author)

  2. Microstructure and mechanical properties of MoSi2–MoSi2 joints brazed by Ag–Cu–Zr interlayer

    International Nuclear Information System (INIS)

    Highlights: ► Brazing of MoSi2–MoSi2 using Ag–Cu–Zr interlayer at different temperatures. ► Investigation of shear strength and microstructure of the joint by SEM and XRD. ► Formation of Ag-rich solid solution and various Cu–Zr–Si intermetallic compounds. ► Maximum shear strength for the sample with 830 °C brazing temperature. ► Various fracture path and morphology at different brazing temperatures. - Abstract: The present work investigates joining of two MoSi2 parts through Cusil/Zr/Cusil interlayer with Cusil being a commercial eutectic of Cu–Ag alloy. The joining operation was implemented in an inert gas tube furnace by brazing. The brazing temperature ranged from 800 to 930 °C while the operation lasted for 60 min. Evaluation of joints strength through shear loading identified the maximum strength 60.31 MPa for the brazed sample at 830 °C. Interfacial microstructure was studied by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) techniques. Applying the temperature of 830 °C was led to a uniform dense joint consisting of various phases with excellent bonding within the interfaces. XRD and EDS results revealed different phases such as Mo5Si3, Ag-rich solid solution and Cu10Zr7 at the interface. At higher brazing temperatures the amount of intemetallic compounds and residual stresses increased and therefore, mechanical properties of the joint degraded. The fracture analysis by SEM revealed various fracture path and morphology for different brazing temperatures

  3. Effects of processing parameters on microstructure and mechanical behavior of SiO2/Ti-6Al-4V joint brazed with AgCu/Ni interlayer

    International Nuclear Information System (INIS)

    SiO2 glass ceramic has been successfully joined to Ti-6Al-4V alloy with AgCu/Ni composite interlayer. The brazing temperature varies from 950 deg. C to 980 deg. C, with the holding time ranging from 1 min to 45 min. AgCu eutectic foil melted first, followed by the Ti-Cu-Ni ternary eutectic reaction, then Ti reacted to SiO2 glass ceramic. All of Ti atoms came from Ti-6Al-4V alloy but not from braze alloy. The effects of brazing temperature and dwelling time on interface structure and joint strength were investigated in the present work. The largest shear strength of brazed joint could reach 110 MPa when the brazing temperature was 970 deg. C, holding time was 10 min, and fracture occurred in the SiO2 glass ceramic part. While the thin reaction layer at SiO2 side is the weak part of the joint when the brazing parameter is not appropriate.

  4. Interlayer design to control interfacial microstructure and improve mechanical properties of active brazed Invar/SiO2–BN joint

    International Nuclear Information System (INIS)

    Ag–Cu/Cu/Ag–Cu–Ti composite interlayer was successfully designed to braze Invar alloy and SiO2–BN ceramic. The effect of Cu-foil thickness on the microstructure and mechanical properties of the brazed joints was investigated. The results showed that, compared with single Ag–Cu–Ti brazing foil, the formation of brittle Fe2Ti and Ni3Ti compounds detrimental to the joint strength was greatly inhibited by using composite interlayer. The active Ti atoms in the liquid filler reacted with SiO2–BN ceramic to form a TiN–TiB2 fine-grain layer. The desired interfacial microstructure composed of layered Ag- and Cu-based solid solutions was obtained, which was beneficial for the joint strength. The shear strength of brazed joints was 207% higher than the joints brazed with single Ag–Cu–Ti foil when a 100 μm thick Cu interlayer was used. The inhibition of brittle compounds formation was attributed to the control of reaction sequences during brazing and to the addition of Cu barrier layer

  5. Interface Behavior of Mg alloy Eutectic Brazing%镁合金共晶钎焊界面行为

    Institute of Scientific and Technical Information of China (English)

    白莉

    2012-01-01

    Magnesium alloy was bonded by eutectic contacting reaction brazing using pure silver interlayer, and the microstructure, interface diffusion behavior of elements of the welded joint was studied. The results from the experiment show that the eutectic contacting reaction brazing can achieve effective connection of magnesium alloy, and the interface has relatively higher content of silver, which has the obvious trend of diffusion for both sides of magnesium alloy.%采用纯银做中间层共晶钎焊工艺对镁合金进行连接,研究了接头微观组织及界面元素扩散行为.结果表明,采用共晶钎焊可以实现镁合金的有效连接,结合界面银元素相对含量较高,有着明显的向两边镁合金扩散的趋势.

  6. Brazing of 14-5 PH steel and Fe - TiC composite using AWS BNi2 filler metal

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2007-01-01

    Full Text Available Purpose: Purpose of this paper is description of influence of the parameters of the 14-5 PH steel and cermets - PMFe-TiC composite plates brazing using nickel based brazing filler metal BNi2 structure and properties of joints.Design/methodology/approach: Brazing was done in vacuum according to a special thermal cycle programme.Metallographic, X Ray analysis, microanalysis, hardness and tensile strength, as well quality investigations ofproduced joints have been done.Findings: It was shown that The joint has a eutectic multilayer structure with a zone of intermetallic compoundsin the steel – soldier and soldier – PM Fe-TiC composite - Ferro – Titanit plates boundary. Intermetalliccompounds zone differ clearly on account of a chemical composition, microstructure, and hardness from abrazing filler metal matrix.Research limitations/implications: It was shown that the diffusive zone from the PM Fe-TiC composite side isrich in titanium, molybdenum and iron, in the joint axis there is a zone rich in silicon, and in a boundary fillermetal – steel rich in iron and nickel. In the rich in nickel and iron filler metal matrix, there are intermetallicphases rich in chromium, which consist several percent of nickel, iron and molybdenum. The diffusive zonesare characterized by hardness higher than the filler metal matrix.Practical implications: As a result of conducted experiments a production of spinning nozzle of a die forpolyethylene granulation with a vacuum-brazed with a PM Fe-TiC composite plates cutting surface have beenworked out and applied in industry.Originality/value: An original value of the paper is to prove the propensity of concentration gradients ofalloying components and intermetallic phases creation.

  7. Cold metal transfer welding–brazing of pure titanium TA2 to magnesium alloy AZ31B

    Energy Technology Data Exchange (ETDEWEB)

    Cao, R., E-mail: caorui@lut.cn; Wang, T.; Wang, C.; Feng, Z.; Lin, Q.; Chen, J.H.

    2014-08-25

    Highlights: • Mg–Ti joints can be successfully performed at suitable welding variables by CMT. • Typical brazing–welding joints can be formed for Mg–Ti joint and Ti–Mg joint. • The brazing interface is mainly composed of Ti{sub 3}Al, Mg{sub 17}Al{sub 12} and Mg{sub 0.97}Zn{sub 0.03}. • Elements Al and Zn are crucial to join successfully Mg and Ti base metals. - Abstract: Pure titanium TA2 was joined to Mg AZ31B by cold metal transfer (CMT) welding–brazing method in the form of two lap-shear joints (Mg–Ti joint and Ti–Mg joint) with Mg AZ61 wire. The microstructure of Ti/Mg CMT joints was identified and characterized by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The mechanical properties of various welding parameters were compared and analyzed. Desired Ti/Mg CMT joints with satisfied weld appearances and mechanical properties were achieved at suitable welding variables. The Ti/Mg CMT joints had dual characteristics of a welding joint at the Mg side and a brazing joint at the Ti side. Moreover, for two joints, the brazing interfaces were composed of an intermetallic compounds (IMCs) layer including Ti{sub 3}Al, Mg{sub 17}Al{sub 12} and Mg{sub 0.97}Zn{sub 0.03} phases. Mg–Ti joint had the higher tensile load of 2.10 kN, and Ti–Mg joint had the tensile load of 1.83 kN.

  8. Cold metal transfer welding–brazing of pure titanium TA2 to magnesium alloy AZ31B

    International Nuclear Information System (INIS)

    Highlights: • Mg–Ti joints can be successfully performed at suitable welding variables by CMT. • Typical brazing–welding joints can be formed for Mg–Ti joint and Ti–Mg joint. • The brazing interface is mainly composed of Ti3Al, Mg17Al12 and Mg0.97Zn0.03. • Elements Al and Zn are crucial to join successfully Mg and Ti base metals. - Abstract: Pure titanium TA2 was joined to Mg AZ31B by cold metal transfer (CMT) welding–brazing method in the form of two lap-shear joints (Mg–Ti joint and Ti–Mg joint) with Mg AZ61 wire. The microstructure of Ti/Mg CMT joints was identified and characterized by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The mechanical properties of various welding parameters were compared and analyzed. Desired Ti/Mg CMT joints with satisfied weld appearances and mechanical properties were achieved at suitable welding variables. The Ti/Mg CMT joints had dual characteristics of a welding joint at the Mg side and a brazing joint at the Ti side. Moreover, for two joints, the brazing interfaces were composed of an intermetallic compounds (IMCs) layer including Ti3Al, Mg17Al12 and Mg0.97Zn0.03 phases. Mg–Ti joint had the higher tensile load of 2.10 kN, and Ti–Mg joint had the tensile load of 1.83 kN

  9. Two-beam Laser Brazing of Thin Sheet Steel for Automotive Industry Using Cu-base Filler Material

    Science.gov (United States)

    Mittelstädt, C.; Seefeld, T.; Reitemeyer, D.; Vollertsen, F.

    This work shows the potential of two-beam laser brazing for joining both Zn-coated steel and 22MnB5. Brazing of Zn-coated steel sheets using Cu-Si filler wire is already state of the art in car manufacturing. New press-hardened steels like 22MnB5 are more and more used in automotive industry, offering high potential to save costs and improve structural properties (reduced weight / higher stiffness). However, for joining of these ultra-high strength steels investigations are mandatory. In this paper, a novel approach using a two-beam laser brazing process and Cu-base filler material is presented. The use of Cu-base filler material leads to a reduced heat input, compared to currently applied welding processes, which may result in benefits concerning distortion, post processing and tensile strength of the joint. Reliable processing at desired high speeds is attained by means of laser-preheating. High feed rates prevent significant diffusion of copper into the base material.

  10. Reduced-Temperature Transient-Liquid-Phase Bonding of AluminaUsing a Ag-Cu-Based Brazing Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Moo; Glaeser, Andreas M.

    2005-12-19

    The mechanical properties and microstructural evolution ofmetal-ceramic bonds produced using a transient liquid phase (TLP) aredescribed. Alumina (Al2O3) was joined at 500 degrees C, 600 degrees C,and 700 degrees C using a multilayer In/Cusil-ABA (R) (commercialcopper-silver eutectic brazing alloy)/In interlayer. The introduction ofthin In cladding layers allows the system to bond at much lowertemperatures than those typically used for brazing with Cusil-ABA (R),thereby protecting temperature-sensitive components. After chemicalhomogenization, the interlayers retain an operating temperature rangesimilar to that of the brazed joints. TLP bonds made at 500 degrees C,600 degrees C, and 700 degrees C with holding times ranging from as lowas 1.5 h to 24 h had average fracture strengths above 220 MPa. Theeffects of bonding temperature and time on fracture strength aredescribed. Preliminary analysis of the interlayers shows that the Ag-Inor Cu-In intermetallic phases do not form. Considerations unique tosystems with two-phase core layers are discussed. Experiments usingsingle-crystal sapphire indicate rapid formation of a reaction layer at700 degrees C, suggesting the possibility of making strong bonds usinglower temperatures and/or shorter processing times.

  11. Microstructure and properties of diffusion bonded Ti-6Al-4V parts using brazing-assisted hot isostatic pressing

    International Nuclear Information System (INIS)

    Highlights: → A low cost method of diffusion bonding has been developed for complex-shaped components of Ti6Al4V. → Vacuum brazing has been used to seal the periphery to allow encapsulation-free HIPping. → The tensile properties of the bonds are comparable with those of the bulk material, but the fatigue life was slightly reduced. - Abstract: Ti-6Al-4V couples have been diffusion bonded by hot isostatic pressing (HIPping) after vacuum brazing was used to seal the periphery of the bonding samples so that no encapsulation was required during HIPping. Analytical scanning electron microscopy was used to assess the microstructure of the HIPped interface and tensile and fatigue properties of bonded samples were compared with those of the bulk starting material. The tensile properties of the bonds were shown to be comparable with those of the bulk material, but the fatigue life was slightly downgraded. The fatigue fractures were initiated by inclusions on the bonding interface, caused by contamination before bonding, but the fatigue cracks did not propagate along the bonding interface indicating a strong bond. It is concluded that this technique of vacuum brazing plus HIPping could be used for encapsulation-free HIPping to produce complex-shaped components.

  12. Critical Issues for Producing UHTC-Brazed Joints: Wetting and Reactivity

    Science.gov (United States)

    Passerone, A.; Muolo, M. L.; Valenza, F.

    2016-03-01

    A brief survey is presented of the most important interaction phenomena occurring at the solid-liquid interfaces in metal-ceramic systems at high temperatures, with special attention to the most recent developments concerning wetting and joining transition metals diborides. These phenomena are described and discussed from both the experimental and theoretical points of view in relation to joining ceramic and metal-ceramic systems by means of processes in the presence of a liquid phase (brazing, TLPB etc.). It is shown that wetting and the formation of interfacial dissolution regions are the results of the competition between different phenomena: dissolution of the ceramic in the liquid phase, reaction and formation of new phases at the solid-liquid interface, and drop spreading along the substrate surface. We emphasize the role of phase diagrams to support both the design of the experiments and the choice of active alloying elements, and to interpret the evolution of the system in relation to temperature and composition. In this respect, the sessile-drop technique has been shown to be helpful in assessing critical points of newly calculated phase diagrams. These studies are essential for the design of joining processes, for the creation of composite materials, and are of a particular relevance when applied to UHTC materials.

  13. Vacuum brazing of OFE Copper-316L stainless steel transition joints without electroplating stainless steel part for application in particle accelerators

    International Nuclear Information System (INIS)

    Brazed transition Joints between OFE copper and type 316L austenitic stainless steel (SS) find extensive applications in particle accelerators all over the world. In contrast to excellent wettability of OFE copper, austenitic SS is well known for its poor wettability for BVAg-8 (72Ag/28Cu; melting point: 1052 K) braze filler metal (BFM). High surface wettability is believed to be necessary to drag molten BFM into the capillary gap between mating metallic surfaces. Therefore, the widely accepted practice for vacuum brazing of such transition joints involves electroplating of SS parts with nickel or copper to enhance its wettability. A recently concluded in-house study, involving Nb to Ni-plated 316L SS brazing, has demonstrated that satisfactory ingress of BFM into a capillary joint between two dissimilar metals is possible if the poor wettability of one of the mating surfaces is compensated by good wettability of its counterpart. In the light of these observations, the present study was undertaken to explicitly evaluate the requirement of electroplating the SS part for establishment of sound OFE copper-316L SS brazed joints suitable for service in ultra-high vacuum (UHV) of particle accelerators

  14. Effects of Al2O3 Particulates on the Thickness of Reaction Layer of Al2O3 Joints Brazed with Al2O3-Particulate-Contained Composite Filler Materials

    Institute of Scientific and Technical Information of China (English)

    Jianguo YANG; Jingwei WU; Hongyuan FANG

    2003-01-01

    In order to understand the rate-controlling process for the interfacial layer growth of brazing joints brazed with activecomposite filler materials, the thickness of brazing joints brazed with conventional active filler metal and activecomposite filler materials with different volume fraction of Al2O3 particulate was studied. The experimental resultsindicate although there are Al2O3 particulates added into active filler metals, the time dependence of interfacial layergrowth is t2 as described by Fickian law for the joints brazed with conventional active filler metal. It also shows thatthe key factor affecting the interfacial layer growth is the volume fraction of alumina in the composite filler materialcompared with the titanium weight fraction in the filler material.

  15. Silicon high vacuum brazing study and microstructural analysis of the joint formation; Estudo da brasagem de silicio em alto vacuo e analise microestructural da juncao

    Energy Technology Data Exchange (ETDEWEB)

    Santana, E.C.A. [Universidade Estadual Paulista - UNESP, Campus de Guaratingueta, SP (Brazil); Francisco, F.R.; Bagnato, O.R. [Laboratorio Nacional de Luz Sincrotron - LNLS, Campinas, SP (Brazil)], e-mail: erika.santana@lnls.br

    2010-07-01

    On the project of Synchrotron Light Source, silicon-crystal are often used as monochromator and mirrors, to reflect the electrons beam. Silicon is known as a very fragile material, and its optical elements must be designed carefully. Usually, it is bonded in a cooling support made by copper. Thermal contact between the crystal plate and cooling support is made of In-Ga liquid alloy. Due to the difficult of this bonding, brazing tests are being taken with Fe-Ni alloy, in order to improve the silicon mirrors application and performance. Wet ability tests were performed between the silicon plate and commercial fillers. A brazing test was made of silicon and Al12Si, as filler, with Fe-Ni, as base material. Results of microstructure analysis indicated that the braze of a silicon plate is quite promissory. (author)

  16. Brazing of Mo to a CuZr alloy for the production of bimetallic raw materials for the CLIC accelerating structures

    CERN Document Server

    Salvo, M; Heikkinen, Samuli; Salvo, Milena; Casalegno, Valentina; Sgobba, Stefano; Rizzo, Stefano; Izquierdo, Gonzalo Arnau; Taborelli, Mauro

    2010-01-01

    Future linear accelerators, as CLIC (Compact Linear Collider), are extremely demanding in terms of material properties. Traditionally accelerating structure is made of brazed OFE copper parts. For the high conducting regions submitted to mechanical fatigue, CuZr would represent an improved selection than pure copper while for regions where the highest electric field is applied a refractory metal, i.e. Mo, could result in a better performance. The feasibility of joining such materials, namely CuZr (UNS C15000) and pure Mo has been investigated. The joining method developed and investigated here consists in a vacuum brazing process exploiting a Cu-based brazing filler applied under appropriate vacuum conditions. Apparent shear strength (adapted from ASTM B898) on the joined samples was about 200 MPa. (C) 2010 Elsevier B.V. All rights reserved.

  17. Application of Be-free Zr-based amorphous sputter coatings as a brazing filler metal in CANDU fuel bundle manufacture

    International Nuclear Information System (INIS)

    Amorphous sputter coatings of Be-free multi-component Zr-based alloys were applied as a novel brazing filler metal for Zircaloy-4 brazing. By applying the homogeneous and amorphous-structured layers coated by sputtering the crystalline targets, the highly reliable joints were obtained with the formation of predominantly grown α-Zr grains owing to a complete isothermal solidification, exhibiting high tensile and fatigue strengths as well as excellent corrosion resistance, which were comparable to those of Zircaloy-4 base metal. The present investigation showed that Be-free and Zr-based multi-component amorphous sputter coatings can offer great potential for brazing Zr alloys and manufacturing fuel rods in CANDU fuel bundle system. (author)

  18. Response to high heat fluxes and metallurgical examination of a brazed carbon-fiber-composite/refractory-metal divertor mock-up

    International Nuclear Information System (INIS)

    As a feasibility-study an actively cooled divertor mock-up has been subjected to high heat flux loading in electron beam simulation. The divertor design concept is based on a carbon-fiber-composite material (Aerolor 05) brazed onto a TZM/Mo41Re heat sink. The plasma facing carbon armor is divided in seven tiles to allow variable loading parameters - and repeated destructive tests. The mock-up has survived high heat flux loading up to about 12 MW/m2 surface heat flux in steady-state conditions. One armor tile showed no change in the thermal response even after 500 s at ∝14 MW/m2. To estimate the general thermal response of the mock-up design, numerical methods were applied. The predicted behavior was confirmed by the experimental results. The loading experiments were followed by a detailed metallurgical investigation of the loaded sample regions and the braze joints. The typical damages after high heat flux testing and cycling were failure (i.e. detachment) in the Zr brazed carbon/TZM joint, and failure in the CuPd bonded TZM/TZM joint due to an excess of the melting temperature of the brazes. The microstructural changes in the braze regions and the recrystallization behavior of the refractory alloys are discussed. Only in one case the loaded surface of the carbon armor shows considerable erosion, caused by a partial detachment along a braze joint and thus loss of the good thermal contact during the last applied loading shots. The thermal analyses and high heat flux performance of the Aerolor-05 armored mock-up are compared to the thermal response of a previously tested mock-up of corresponding geometry with armor tiles of isotropic graphite. (orig.)

  19. Design, fabrication, and performance of brazed, graphite electrode, multistage depressed collectors with 500-W, continuous wave, 4.8- to 9.6-GHz traveling-wave tubes

    Science.gov (United States)

    Ramins, Peter; Ebihara, Ben

    1989-01-01

    A small, isotropic graphite electrode, multistage depressed collector (MDC) was designed, fabricated, and evaluated in conjunction with a 500-W, continuous wave (CW), 4.8- to 9.6-GHz traveling-wave tube (TWT). The carbon electrode surfaces were used to improve the TWT overall efficiency by minimizing the secondary electron emission losses in the MDC. The design and fabrication of the brazed graphite MDC assembly are described. The brazing technique, which used copper braze filler metal, is compatible with both vacuum and the more commonly available hydrogen atmosphere brazing furnaces. The TWT and graphite electrode MCC bakeout, processing, and outgassing characteristics were evaluated and found to be comparable to TWT's equipped with copper electrode MDC's. The TWT and MDC performance was optimized for broadband CW operation at saturation. The average radiofrequency (RF), overall, and MDC efficiencies were 14.9, 46.4, and 83.6 percent, respectively, across the octave operating band. A 1500-hr CW test, conducted without the use of an appendage ion pump, showed no gas buildup and excellent stability of the electrode surfaces.

  20. Brazing of aluminium assemblies under nitrogen convection in a charge furnace; Brasage d'assemblages en aluminium sous convection d'azote dans un four a charge

    Energy Technology Data Exchange (ETDEWEB)

    Faure, D.; Perez, G. [BMI Fours Industriels, 38 - Saint Quentin Fallavier (France)

    2006-03-15

    The research of a weight saving has led to the use of aluminium in the automotive industry, which has been innovation instigator for a lot of industries. The brazing under vacuum of aluminium, even if it presents a lot of advantages, is inadequate to the mass production because it is too difficult for the quality of the preliminary assembly to the brazing. It is rather reserved to the advance technology industries such as the aeronautics or the power electronics. A lot of aluminium heat exchangers are mass manufactured and brazed by the Nocolok process. (O.M.)

  1. 中国古青铜器表面富锡铜鎏镀及鎏焊的工艺探索第三部分——鎏焊%Technological study on amalgam coating and brazing of tin-rich copper on surface of bronze wares of ancient China——Part Ⅲ.Amalgam brazing

    Institute of Scientific and Technical Information of China (English)

    吴元康; 储荣邦

    2012-01-01

    Amalgam brazing is derived from amalgam coating. The definition, characteristics, application, and significance of amalgam brazing were expatiated. A process of amalgam brazing for producing combined bronze wares was developed. The compositions of brazing material and flux were given. The operations of pretreatment, mercury removal by heating, and post-treatment were described. The implementation of amalgam coating and brazing processes was introduced taking the Western Han Dynasty's bronze cowry container with tribute-paying figures excavated in Yunnan as an example. The method for distinguishing whether an antique bronze ware is produced by cast welding after lost-wax casting or by copper brazing with separated small cast parts was presented.%鎏焊是从鎏镀衍生而来的.阐述了鎏焊的定义、特点、应用和意义.设计了用于制作组合青铜器的鎏焊工艺,给出了焊料、焊剂配方,说明了前处理、加热驱汞及后处理的操作方法.以西汉云南纳贡场面青铜贮贝器为例,介绍了鎏镀与鎏焊工艺的具体实施过程.提出了鉴别古青铜器是由失蜡铸造后铸焊而成还是由分铸小件铜焊而成的方法.

  2. 多元平行流式冷凝器炉中钎焊工艺研究%Study on Brazing Process for Condenser in Controlled Atmosphere Brazing Furnace

    Institute of Scientific and Technical Information of China (English)

    郭艳; 凌泽民; 李金阁

    2011-01-01

    The optimum technological parameters of brazing condenser in controlled atmosphere brazing(CAB) furnace were obtained by simulating 3-D temperature distribution of micro-joint between fin and flat tube of the condenser using ANSYS software. The process experiment, temperature measurement and properties testing were carried out. The results show that the real thermal cycle curve fits well with the initial simulation one. The morphology of the welded joint has no defects and the microstructure is dense and mainly a(Al)+Al-Si. The leaking has no slightly leaking. It can be obtained that it is a meaningful method to put FEM employ into the process design.%采用ANSYS软件,通过对温度场的模拟,确定了较佳的工艺参数,并进行了工艺实验、温度检测及相关性能测试.温度检测结果表明,模拟曲线与实测曲线吻合较好,说明模拟的温度场是正确的.通过对钎焊接头显微组织分析表明,接头无缺陷,组织致密,显微组织主要以a(Al)+Al-Si共晶组织为主;相关性能测试表明,接头无微漏,达到了使用要求.说明采用有限元软件进行工艺指导是可行的.

  3. An Ag based brazing system with a tunable thermal expansion for the use as sealant for solid oxide cells

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Engelbrecht, Kurt; Grahl-Madsen, Laila;

    2016-01-01

    as a function of the operation temperature were measured. The thermal expansion coefficient in the Ag-Al2TiO5 system can be tailored by varying the amount of the ceramic filler. The brazing process can be carried out in air, the joining partners showed a good chemical stability and sufficient low leak rates......, a cell component test was performed to investigate the durability of the Ag-Al2TiO5 seal when exposed to dual atmosphere. The seals performed well over 900 h under electrolysis operation conditions (−0.5 A cm2, 850 °C), and no cell degradation related to the Ag-Al2TiO5 sealing was found, indicating...

  4. Interface microstructure of the brazed zirconia and Ti-6Al-4V using Ti-based amorphous filler

    OpenAIRE

    Liu Y; Hu J; Zhang Y; Guo Z

    2013-01-01

    The polycrystalline ZrO2−3mol.%Y2O3 was brazed to Ti-6Al-4V using a Ti47Zr28Cu14Ni11 (at.%) amorphous ribbon at 1123 K in a high vacuum. The microstructure of the interface and evolution mechanism of the joint was investigated. The experimental result showed that the typical interfacial microstructures of the joints consisted of ZrO2/TiO+TiO2+Cu2Ti4O+Ni2Ti4O/α-Ti+(Ti,Zr)2(Cu,Ni) eutectic/(Ti,Zr)2(Cu,Ni)/acicular Widmanstäten structure/Ti-6Al-4V alloy. ...

  5. Numerical Simulation of Brazing TiC Cermet to Iron with TiZrNiCu Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Lixia ZHANG; Jicai FENG

    2004-01-01

    The maximum thermal stress and stress concentration zones of iron/TiC cermet joint during cooling were studied in this paper. The results showed that the shear stress on iron/TiC cermet joint concentrates on the interface tip and the maximum shear stress appears on the left tip of iron/TiZrNiCu interlace. Positive tensile stress on TiC cermet undersurface concentrates on both sides of TiC cermet and its value decreases during cooling. Negative tensile stress on TiC cermet undersurface concentrates on the center of TiC cermet and its value increases during cooling. Brazing temperature has little effect on the development and maximum thermal stress.

  6. Pre-Brazed Casting and Hot Radial Pressing: A Reliable Process for the Manufacturing of CFC and W Monoblock Mockups

    International Nuclear Information System (INIS)

    ENEA association is involved in the European International Thermonuclear Experimental Reactor (ITER) R-and-D activities and in particular for the manufacturing of high heat flux plasma-facing components (HHFC), such as the divertor targets, the baffles and the limiters: During the last years ENEA has manufactured actively cooled mock-ups by using different technologies, namely brazing, diffusion bonding and hot isostatic pressing (HIPping). A new manufacturing process has been set up and tested. It was successfully applied for the manufacturing of W armoured monoblock mockups. This technique is the HRP (Hot Radial Pressing) based on performing a radial diffusion bonding between the cooling tube and the armour tile by pressurizing only the internal tube and by keeping the joining zone in vacuum and at the required bonding temperature. The heating is obtained by a standard air furnace. The next step was to apply the HRP technique for the manufacturing of CFC armoured monoblock components. For this purpose some issues have to be solved like as the low CFC tensile strength, the pure copper interlayer between the heat sink and the armour necessary to mitigate the stress at the joint interface and the low wettability of the pure copper on the CFC matrix. This paper reports the research path followed to manufacture a medium scale vertical target CFC and W armoured mockup by HRP. An ad hoc rig able to maintain the CFC in a compressive constant condition was also designed and tested. The casting of a soft copper interlayer between the tube and the tile was performed by a new technique: the Pre-Brazed Casting (PBC, ENEA patent). Some mock-ups with three NB31 CFC tiles were successfully manufactured and tested to thermal fatigue using electron beam facilities. They all reached at least 1000 cycles at 20 MW/m2 without suffering any damage. The manufactured medium scale vertical target mock-up is now under testing at the FE2000 (France) facility. (author)

  7. In situ synthesis of TiB whisker reinforcements in the joints of Al2O3/TC4 during brazing

    International Nuclear Information System (INIS)

    Research highlights: → Al2O3 ceramic and TC4 alloy were successfully brazed by Ag-Cu-Ti-B mixed powder. → TiBw was in situ synthesized during the brazing process. → TiBw not only refined the microstructure of the joint but also alleviated the joint stress. → The effect of the volume fraction of in situ TiBw on the microstructure of joints was studied. → The effect of the volume fraction of in situ TiBw on the shear strength of joints was researched. - Abstract: Al2O3 ceramic has been successfully joined to Ti-6Al-4V alloy with Ag-Cu-Ti-B mixed powder. The TiB whiskers in the brazing layer were in situ synthesized during brazing. The effects of B content in reactant on the phase composition, microstructure and shear strength of the joints were investigated using SEM, EDS, and shear test. Results indicate that B content in the filler has a great impact upon the microstructure of the joints via exerting an influence on the volume fraction of in situ synthesized TiB whiskers. When the TiB content is 40 vol.%, the shear strength reaches the maximum value of 77.9 MPa. The higher content of TiB (≥40 vol.%) depresses the shear strength of the joints due to the interfacial thermal stress cannot be relaxed. Reaction phases (Ti3Cu2AlO, Ti2Cu, Ti2(Cu, Al), Ti(Cu, Al) and Ti3Al) appear in the joint, moreover, as the volume fraction of TiB increase, Ag (s.s) and Ti(Cu, Al) distribute more uniform and fine in the brazing layer, as well as TiB whiskers mainly distribute in them. Eventually, Ti3Cu2AlO, TiB and TiB2 firstly generate based on the thermodynamic analysis, and in excessive Ti circumstances, TiB whiskers remain in the brazing alloy.

  8. High-temperature brazing of X5CrNi18 10 and NiCr20TiAl using the atmospherically plasma-sprayed L-Ni2 filler metal

    International Nuclear Information System (INIS)

    The hybrid-technological combination of the atmospheric plasma spraying for the application of a high-temperature filler metal followed by a brazing process was analyzed in terms of structure and mechanical properties of X5CrNi18 10 and NiCr20TiAl brazing joints. The thickness of the filler metal layer was minimized at <50μm by optimization of the atmospheric plasma spraying process. The brazing seam is hence partly free from brittle phases and yields a increased ultimate tensile strength of brazed and heat-treated joints at different temperatures (room temperature, 500degC and 700degC). Additional information concerning the mechanical properties of the brazing joints was derived from the results of the fractographic examinations of the fracture surfaces and from the characteristic strength values of the long-period creep tests. It was also attempted to apply the results of inductively brazed, cylindrical samples to complex (overlapping joints) and large-surface components produced under practical conditions in the vacuum furnace. (orig.)

  9. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag–Cu eutectic alloy filler and Ag interlayer

    International Nuclear Information System (INIS)

    The electrochemical corrosion properties of Ti–STS dissimilar joints brazed by a 72Ag–28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag–Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance

  10. Phase-dependent corrosion of titanium-to-stainless steel joints brazed by Ag–Cu eutectic alloy filler and Ag interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M.K.; Park, J.J.; Lee, J.G., E-mail: jglee88@kaeri.re.kr; Rhee, C.K.

    2013-08-15

    The electrochemical corrosion properties of Ti–STS dissimilar joints brazed by a 72Ag–28Cu alloy filler and an Ag interlayer were studied in a 3.5% NaCl solution using potentiodynamic polarization and ac impedance spectroscopy. For a joint with a layered structure of Ti(base)/TiAg/Ag solid solution/Ag–Cu eutectic/STS(base), galvanic corrosion mostly occurred in the TiAg phase with a severe material loss, indicating that the TiAg layer acted as an anode in the galvanic couple in the layered joint. The Ag-rich solid solution layer was also corroded to a certain extent, but the corrosion in this layer was dominated by the selective pitting corrosion of the eutectic Cu-rich phase. With an increase in the brazing temperature, the Cu-rich phases disappeared owing to the enhanced isothermal solidification effect, leading to an improvement of the corrosion resistance.

  11. Effect of bonding time on joint properties of vacuum brazed WC - Co hard metal/carbon steel using stacked Cu and Ni alloy as insert metal

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.B.; Jung, S.B. [Sungkyunkwan Univ., Dept. of Advanced Materials Engineering, Suwon, Kyounggi-do (Korea); Kwon, B.D. [Seoul Technical High School, Dept. of Metallurgy, Seoul (Korea)

    2004-11-15

    Hard metal WC - Co and carbon steel were successfully joined using double layered Cu alloy and amorphous Ni alloy as inert metal and an oil cooling method after brazing. Defects such as cracks and voids were not formed near the bonded zone. This result means that double layered insert metals and oil cooling minimised the residual stress near the bonded zone after brazing. The shear strength of the joints decreased with increasing bond time. The reasons why the shear strength decreased as bond time increased could be many, including shape of the interface, formation and growth of brittle intermetallic compounds, and coarsening of WC particles near the bond zone. The maximum shear strength of the joints was 310 MPa under conditions 0.6 ks bond time and 8 wt-%Co content in the WC hard alloy. (Author)

  12. Evaluation of hardness of the interfacial reaction products at the alumina-stainless steel brazed interface by modeling of nanoindentation results

    International Nuclear Information System (INIS)

    We have analyzed the 304 stainless steel (SS)-(Ag-Cu-Ti)-alumina brazed interface using scanning electron microscopy, electron probe microanalysis and nanoindentation. The SS interface exhibits increased bond strength and a larger diffusion zone compared to the alumina interface. In order to explain the nature of variation in hardness, we have fitted a second-degree Hermite polynomial-based model to the experimental observations of the nanoindentation results, across the reaction product zone of both interfaces

  13. Evaluation of hardness of the interfacial reaction products at the alumina-stainless steel brazed interface by modeling of nanoindentation results

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Abhijit [Material Science and Technology Division, National Metallurgical Laboratory (CSIR), Jamshedpur 831 007 (India); Department of Chemistry, Jadavpur University, Kolkata 700032 (India)], E-mail: chatrak130@yahoo.co.in; Chaudhuri, Sanjay [Department of Statistics and Applied Probability, National University of Singapore, Singapore 117546 (Singapore); Sen, Pratik K. [Department of Chemistry, Jadavpur University, Kolkata 700032 (India); Ray, Ajoy Kumar [Material Science and Technology Division, National Metallurgical Laboratory (CSIR), Jamshedpur 831 007 (India)

    2007-11-15

    We have analyzed the 304 stainless steel (SS)-(Ag-Cu-Ti)-alumina brazed interface using scanning electron microscopy, electron probe microanalysis and nanoindentation. The SS interface exhibits increased bond strength and a larger diffusion zone compared to the alumina interface. In order to explain the nature of variation in hardness, we have fitted a second-degree Hermite polynomial-based model to the experimental observations of the nanoindentation results, across the reaction product zone of both interfaces.

  14. Fatigue properties of laser-brazed joints of Dual Phase and TRansformation Induced Plasticity steel with a copper-aluminium consumable

    International Nuclear Information System (INIS)

    High strength steels combine good formability with excellent mechanical properties and have developed continuously in recent years. Joining these materials is however increasingly difficult as fusion joining processes destroy the carefully constructed microstructure. To counteract this problem, joining processes which require less heat input have been investigated. Laser brazing is a relatively new technique and a potential candidate which has found application in the automotive industry. In this paper the fatigue lifetime properties of laser-brazed Dual Phase (DP600) and TRansformation Induced Plasticity (TRIP700) steel joints made with a copper-aluminium consumable are reported. Joints created with DP600 steel showed fracture through the steel due to a brass present in the stress concentration region at the edge of the reinforcement. TRIP700 steels show similar results if the applied maximum stress is in excess of 280 MPa. However, at maximum stresses of 230 MPa, failure occurred across the interface between the braze metal and the steel. A basic fatigue crack path model is presented for the two competing failure mechanisms.

  15. Dissimilar Laser Welding/Brazing of 5754 Aluminum Alloy to DP 980 Steel: Mechanical Properties and Interfacial Microstructure

    Science.gov (United States)

    Yang, Jin; Li, Yulong; Zhang, Hua; Guo, Wei; Weckman, David; Zhou, Norman

    2015-11-01

    A diode laser welding/brazing technique was used for lap joining of 5754 aluminum alloy to DP 980 steel with Al-Si filler metal. The correlation between joint interfacial microstructure, wettability of filler metal, and mechanical properties was systematically investigated. At low laser power (1.4 kW), a layer of intermetallic compounds, composed of θ-Fe(Al,Si)3 and τ 5 -Al7.2Fe1.8Si, was observed at the interface between fusion zone and steel. Because of the poor wettability of filler metal on the steel substrate, the joint strength was very low and the joint failed at the FZ/steel interface. When medium laser power (2.0 kW) was applied, the wettability of filler metal was enhanced, which improved the joint strength and led to FZ failure. With further increase of laser power to 2.6 kW, apart from θ and τ 5, a new hard and brittle η-Fe2(Al,Si)5 IMC with microcracks was generated at the FZ/steel interface. The formation of η significantly degraded the joint strength. The failure mode changed back to interfacial failure.

  16. Analysis on interfacial layer of aluminum alloy and non-coated stainless steel joint made by TIG welding-brazing

    Institute of Scientific and Technical Information of China (English)

    Song Jiaaling; Lin Sanbao; Yang Chunli; Ma Guangchao; Wang Yinjie

    2009-01-01

    Dissimilar metals TIG welding-brazing of aluminum alloy and non-coated stainless steel was investigated. The resultant joint was characterized in order to identify the phases and the brittle intermetaUic compounds (IMCs) in the interfacial layer by optical metalloscope (OM), wanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the cracked joint was analyzed in order to understand the cracking mechanism of the joint. The results show that the microfusion of the stainless steel can improve the wetting and spreading of liquid aluminum base filler metal on the steel surface and the melted steel accelerates the formation of mass of brittle IMCs in the interracial layer, which causes the joint cracking badly. The whole interfacial layer is 5 - 7 μm thick and comprises approximately 5 μm-thickness reaction layer in aluminum side and about 2 μm-thickness diffusion layer in steel side. The stable Al-rich IMCs are formed in the interfaciallayer and the phases transfer from (Al + FeAl3) in aluminum side to (FeAl3+ Fe2Al5) and (α-Fe + FeAl) in steel side.

  17. The Study Of The Impact Of Surface Preparation Methods Of Inconel 625 And 718 Nickel-Base Alloys On Wettability By BNi-2 And BNi-3 Brazing Filler Metals

    Directory of Open Access Journals (Sweden)

    Lankiewicz K.

    2015-06-01

    Full Text Available The article discusses the impact of surface preparation method of Inconel 625 and 718 nickel-base alloys in the form of sheets on wettability of the surface. The results of the investigations of surface preparation method (such as nicro-blasting, nickel plating, etching, degreasing, abrasive blasting with grit 120 and 220 and manually grinding with grit 120 and 240 on spreading of BNi-2 and BNi-3 brazing filler metals, widely used in the aerospace industry in high temperature vacuum brazing processes, are presented. Technological parameters of vacuum brazing process are shown. The macro- and microscopic analysis have shown that nicro-blasting does not bring any benefits of wettability of the alloys investigated.

  18. Microstructural evolution and characterisation of interfacial phases in Al2O3/Ag–Cu–Ti/Al2O3 braze joints

    International Nuclear Information System (INIS)

    Alumina ceramics with different levels of purity have been joined to themselves using an active braze alloy (ABA) Ag–35.3Cu–1.8Ti wt.% and brazing cycles that peak at temperatures between 815 °C and 875 °C for 2 to 300 min. The microstructures of the joints have been studied using scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray spectroscopy. A limited number of joints prepared with the ABA Ag–26.7Cu–4.5Ti wt.% have also been studied. In terms of characterising the interfacial phases, efforts were made to understand the interfacial reactions, and to determine the influence of various brazing parameters, such as the peak temperature (Tp) and time at Tp (τ), on the microstructure. In addition, the extent to which impurities in the alumina affect the interfacial microstructure has been determined. Ti3Cu3O has been identified as the main product of the reactions at the ABA/alumina interfaces. At the shortest joining time used, this phase was observed in the form of a micron-size continuous layer in contact with the ABA, alongside a nanometre-size layer on the alumina that was mostly composed of γ-TiO grains. Occasionally, single grains of Ti3O2 were observed in the thin layer on alumina. In the joints prepared with Ag–35.3Cu–1.8Ti wt.%, the interfacial structure evolved considerably with joining time, eventually leading to a high degree of inhomogeneity across the length of the joint at the highest Tp. The level of purity of alumina was not found to affect the overall interfacial microstructure, which is attributed to the formation of various solid solutions. It is suggested that Ti3Cu3O forms initially on the alumina. Diffusion of Ti occurs subsequently to form titanium oxide at the Ti3Cu3O/alumina interface

  19. A contribution to the study of metal-ceramic bonding by direct vacuum brazing with reactive metals

    International Nuclear Information System (INIS)

    Wettability and bonding tests were utilized to evaluate the behaviour of various specials alloys, for work at high temperature under vacuum, for the inter-bonding of silicon carbide, alumina ceramic, graphite (for electrical applications) and petroleum coke and their joining with themselves as the metals titanium, molybdenum, nickel and copper. The joints exhibiting effective bonding were investigated by means of optical microscopy, scanning electron microscopy and X-rays diffraction. Elemental mapping of the constituents and quantitative chemical microanalysis were also undertaken, via the energy dispersive analysis of X-rays (SEM/EDS). On the basis of the results the possible mechanisms of bond-formation have been discussed. It was verified that: a) of the filler metals studied, those which exhibited effective wettability on all the above materials were: 49Cu-49Ti-2Be, Zircaloy4-5Be and a commercial alloy Ticusil, which consisted of a Cu-Ag eutectic with a small addition of pure Ti, of nominal composition 26.7Cu-68.8Ag-4.5Ti; b) the alloys with high levels of reactive metals such as Ti and Zr tended to form low ductility bonds due to the formation of hard, brittle phases; c) the copper suffered pronounced erosion when in direct contact with alloys of high Ti and Zr contents, due to the formation of phases whose melting points were below the brazing temperature of those materials; e) the compounds detected as reaction products were identified as, TiC in the samples rich in carbon, such as the SiC ceramic and graphite joints, or the oxides Cu2Ti2O5 and Cu3TiO4 in the bonding of alumina to alloys including Ti in their composition or in that of the filler metal, proving that the effectiveness of the bond is dependent upon an initial and indispensable chemical bonding. (author)

  20. Mechanical properties of SiC/BraSiC/SiC brazed assemblies and design criterion for failure

    International Nuclear Information System (INIS)

    Silicon carbide (SiC) based structures are widely used in space industry and energy conversion thanks to mechanical and thermal properties of this material and to its chemical stability. Brazing currently seems the most appropriate to allow the production of very large elements. The procedure called BraSiC uses SiC combined with a metal component, the bonding is made at high temperature, impregnation is achieved by gravity/capillarity. In a first step, the elastic properties and the toughness of the various constituents (substrates and solder) were characterized using ultrasonic methods and micro and nano-indentation. An extensive 4-point bending test campaign on bars assembled end-to-end was conducted to obtain measurements of the tensile strength. It led to analyze the role of different parameters: thickness of the butt joint (20 to 200 μm), temperature (from -196 to 1000 C), atmosphere (air, helium). Some additional tests have been initiated to understand the effect of a pre-existing notch or a lack of solder. This experimental work was accompanied by a theoretical model based on the use of a failure mixed criterion. This approach was used initially to assess the feasibility of an axisymmetric bending test on a disk-disk. It was then exploited to highlight the role of the thickness of the solder joint in tests on bars, resulting in a very simple formula, in perfect agreement with the experimental results: the most important parameter is the inverse of the square root of the solder joint thickness. (author)

  1. Brazing of Ti- Ni Coated Diamonds%复合镀覆Ti-Ni金刚石的钎焊应用

    Institute of Scientific and Technical Information of China (English)

    王艳辉; 臧建兵; 王明智

    2001-01-01

    Latest developments of coating technology show that, when diamond crystal or PCD is coated with Ti or W by vacuum slow vapor deposition process, it can be further coated with Ni, Co or Cr by electroless plating or electroplating so as to form a composite coating on its surface. Due to the strong metallurgical adhesion between diamond and coating, diamond is easily brazed onto different metal substrate. Composite-coated diamond is mainly used for making surface-set tool to obrain high protrusion height of diamond grit and strong interface adhesion. Thus tool's lifetime and efficiency are improved greatly.%镀覆技术的研究进展表明:经过真空微蒸发镀钛、钨的金刚石单晶或聚晶,可以采用化学镀或电镀的方法在钛或钨镀层上进一步镀覆镍、钴、铬等金属,这种复合镀层与金刚石界面强力冶金结合,并且可以采用各种钎焊方法实现金刚石与多种金属基体的焊接。复合镀覆的金刚石可用于各类表镶工具的制造,获得高出刃、高磨粒结合强度,使金刚石表镶工具的使用寿命和加工效率大幅度提高。

  2. The effect of different crystal conditions of filler metal on vacuum brazing of TiAl alloy and 42CrMo

    Institute of Scientific and Technical Information of China (English)

    Zhu Ying; Zhang Mo; Wang Guojian; Li Wenyi; Kang Hui; Qu Ping

    2007-01-01

    Ti-based filler metals made by transient solidification and normal crystallization were selected for the vacuum brazing of the TiAl alloy and 42CrMo under different processing parameters. The results show that the tensile strength of the joint of transient solidified filler metal is higher than that of normal crystallized filler metal under the same processing parameters. By the analysis of scanning electron microscope(SEM) and X-ray diffracting (XRD) , it is found that the higher strength maybe caused by the generating of TiAl , TiNi and TiCu at the interface of joint made by transient solidified filler metal.

  3. The quality evaluation of the end-plate welds and brazed joints for CANDU nuclear fuel by an ultrasonic imaging method

    International Nuclear Information System (INIS)

    This paper describes a method for the quality evaluation of spot welds and brazed joints by analysing ultrasonic images (C-scan). A present, the quality control for these joints is made by destructive methods. The authors present the most frequent types of flaw met in their investigations. They have attempted to obtain a dependence of torsion moment, measured by a destructive method against the polar inertia moment, obtained from parameters measured on ultrasound images. The ultrasonic images were analysed off-line using a dedicated software. (author)

  4. Research on Treatment of Diamond Surface by Film Deposition and Induction Brazing%金刚石表面的膜层沉积处理及其感应钎焊的研究

    Institute of Scientific and Technical Information of China (English)

    马伯江; 蔡啸; 于庆先

    2012-01-01

    Diamond grits were deposited by hot filament chemical vapor deposition (HFCVD) and they were used to fabricate the brazed diamond tools by induction brazing. The gas ratio (H2/CH4) used was 100 : 1.5(standard cubic--centimetres per minute), the total gas pressure was maintained at about 2.0 kPa, and the substrate temperature was heated to 700℃ for 45 minutes during HFCVD. As a result, amorphous carbon film is deposited on the diamond surface. The diamond edges exposed out of the filler alloy keeps good sharpness after induction brazing of HFCVD deposited diamond. Chro- mium- carbides with uniform porosity and irregular shapes were formed on the diamond grits im mersed into the brazing filler alloy. The liquid brazing filler metal filled in porosity can enhance the bonding strength between the brazing filler metal and the diamond grits. The heavy--load grinding tests of the brazed diamond wheels fabricated by three kinds of diamond grits show that there is a low percentage of pullout from matrix and whole grain fracture for the deposited diamond grits brazed by induction heating.%将热丝化学气相沉积(HFCVD)处理的金刚石作为磨料感应钎焊制作金刚石工具。HFCVD处理试验中,混合气为H2和CH4(体积流量比为100∶1.5),炉内压力为2.0kPa,700℃下处理45min后,在金刚石表面沉积了一层非晶碳膜。感应钎焊HFCVD处理的金刚石显示,出露部分的金刚石棱边能保持良好的锋利性;浸没在钎料层下面的金刚石表面形成了有均匀孔隙且形状不规则的铬碳化合物,液态钎料充填这些化合物孔隙之间,能够增强钎料对金刚石的把持强度。3种金刚石磨料感应钎焊制作的金刚石磨盘的高效重负荷石材磨削试验显示,HFCVD处理的金刚石的整体破碎率和脱落率最低。

  5. Ni-Cr-B-Si+Cu-P-Sn复合钎料真空钎焊金刚石%Vacuum brazing diamond with Ni-Cr-B-Si+Cu-P-Sn composite filler metal

    Institute of Scientific and Technical Information of China (English)

    卢金斌; 贺亚勋; 张旺玺; 刘磊; 李华

    2016-01-01

    采用在镍基钎料中分别添加3%、5%和7%(质量分数)Cu-P-Sn组成新型复合钎料,并进行金刚石磨粒的钎焊实验,利用SEM、EDS和XRD对金刚石焊后的界面碳化物形貌及钎料组织进行测试分析。结果表明:添加5%Cu-P-Sn的复合钎料进行金刚石钎焊时,钎焊温度有所下降,金刚石表面碳化物较规整,并且数量有所下降,降低金刚石的热损伤。新型钎料中形成树枝晶α-Ni基固溶体和枝晶间Ni 31 Si 12、Cr 7 C 3等化合物的组织,不同含量Cu-P-Sn与Ni-Cr-B-Si合金可以较大程度互溶,可以实现钎料性能的调控,降低金刚石的热损伤。%A series of new composite brazing fillers metal were got by adding 3%, 5% or 7% (mass fraction) Cu-P-Sn in the primary brazing filler metal Ni-Cr-B-Si, respectively, then, they were used to braze diamond particles. The interface morphology of diamond carbide and the microstructure of brazing filler metal were tested by SEM, EDS and XRD. The results show that, when the composite brazing filler metal containing 5% Cu-P-Sn alloy, the carbide on the surface of the diamond is more regular and less with brazing temperature decreases, which decreases the thermal damage to the diamond. In the brazing filler alloy, the microstructures, such as dentrite included solid solution of Ni with some carbides like Ni31Si12 and Cr7C3, are formed. As the added component, Cu-P-Sn at different proportions can be dissolved into the primary brazing filler Ni-Cr-B-Si in large degree, which can adjust the properties of the filler and reduce the heat damage to the diamond.

  6. Active brazing of ceramic inlays for the application in wear critical areas of forging dies; Aktivloeten von keramischen Segmenten fuer den Einsatz in verschleisskritischen Bereichen von Schmiedegesenken

    Energy Technology Data Exchange (ETDEWEB)

    Bach, Fr.W.; Doege, E.; Kutlu, I.; Huskic, A. [Institut fuer Umformtechnik und Umformmaschinen, Universitaet Hannover, Welfengarten 1A, 30167 Hannover (Germany)

    2002-11-01

    The use of reinforcing ceramic segments in forging tools is investigated and has been successfully tested with model of dies recently. With reinforcing ceramic segments, however, the thermal widening of the steel tool is a major problem for forging dies. Further, only rotationally symmetrical ceramic inserts can be used as reinforcements which restricts the shape capabilities in tool design significantly. A considerably greater design flexibility is possible if the ceramic segments are brazed into the die body material. To this end, reactively brazed ceramic-metal composites are to be developed and tested for feasibility in the forging process. (Abstract Copyright [2002], Wiley Periodicals, Inc.) [German] Der Einsatz durch thermisches Schrumpfen gefuegter keramischer Segmente in Schmiedewerkzeugen wird seit einiger Zeit untersucht und erfolgreich an Modellgesenken erprobt. Hier zeigt sich die Gefahr der thermischen Aufweitung des Schrumpfverbandes als Hauptproblem bei Schmiedegesenken mit eingeschrumpften keramischen Segmenten. Weiterhin lassen sich nur rotationssymmetrische keramische Segmente einschrumpfen, was eine erhebliche Einschraenkung der Gestaltungsmoeglichkeiten in der Werkzeugkonstruktion bedeutet. Deutlich groessere Gestaltungsmoeglichkeiten bietet das Aktivloeten keramischer Segmente in Gesenkgrundkoerper. Hierfuer sollen aktivgeloetete Keramik-Metall-Verbunde entwickelt und auf Einsatzfaehigkeit im Schmiedeprozess ueberprueft werden. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  7. Vacuum brazing of TiAl48Cr2Nb2 casting alloys based on TiAl (γ intermetallic compound

    Directory of Open Access Journals (Sweden)

    Z. Mirski

    2010-01-01

    Full Text Available A growing interest in modern engineering materials characterised by increasingly better operational parameters combined with a necessity to obtain joints of such materials representing good operation properties create important research and technological problems of today. These issues include also titanium joints or joints of titanium alloys based on intermetallic compounds. Brazing is one of the basic and sometimes even the only available welding method used for joining the aforesaid materials in production of various systems, heat exchangers and, in case of titanium alloys based on intermetallic compounds, turbine elements and space shuttle plating etc. This article presents the basic physical and chemical properties as well as the brazability of alloys based on intermetallic compounds. The work also describes the principle and mechanisms of diffusion-brazed joint formation as well as reveals the results of metallographic and strength tests involving diffusion-welded joints of TiAl48Cr3Nb2 casting alloy based on TiAl (γ phase with the use of sandwich-type layers of silver-based parent metal (grade B- Ag72Cu-780 (AG 401 and copper (grade CF032A. Structural examination was performed by means of light microscopy, scanning electron microscope (SEM and energy dispersion spectrometer (EDS. Furthermore, the article reveals the results of shear strength tests involving the aforementioned joints.

  8. Study of Process on Brazing Diamond/CBN Grinding Wheel Matrix Technology%钎焊金刚石/CBN砂轮基体工艺方法初探

    Institute of Scientific and Technical Information of China (English)

    袁建新; 王永强; 马家稑

    2012-01-01

    According to several process methods on manufacturing the brazing diamond/CBN grinding wheel in the domestic market currently, the advantages and disadvantages of these methods are analyzed. In accordance with the actual problem occurred during factory tests: the welding temperature affects severely hardness of the grinding wheel matrix, and accordingly affects the accuracy consistency, a method for finding out a suitable matrix material is presented in this thesis, and thus a better sample is offered to solve the effect problem of the high - temperature brazing on the matrix. The conclusion is; to meet the dynamic performance requirements of CBN/diamond grinding wheel matrix, the 40Mn2 material is recommended for a grinding wheel matrix, its hardness can reach around HRC38 after temper at a temperature of around 700℃ , and thus can meet the requirements of high - speed grinding and high - precision grinding.%针对目前国内制作钎焊金刚石/CBN砂轮的几种工艺方法,分析了存在的优缺点.根据工厂试验中出现的实际问题,指出了寻找到合适基体材料的方法,为解决高温钎焊对基体的影响提供了一个较好的样本.为了满足CBN/金刚石砂轮基体的力学性能需要,建议砂轮基体采用40Mn2这种材料,在700℃左右回火,其硬度可以达到38HRC左右,能够满足高速磨削和高精度磨削的要求.

  9. Comparison of Microstructure and Mechanical Properties of Induction and Vacuume Brazed Joint of Titanium Via Copper and Ag-Cu Eutectic Filler Metal / Mikrostruktura I Właściwości Mechaniczne Połączeń Tytanu Lutowanych Indukcyjnie I Próżniowo Z Użyciem Spoiwa Miedzianego I Eutektycznego Ag-Cu

    Directory of Open Access Journals (Sweden)

    Różański M.

    2015-12-01

    Full Text Available This study presents the basic physico-chemical properties and describes the brazeability of titanium. The work contains the results of macro and microscopic metallographic examination as well as the results of strength-related tests of vacuum and induction brazed joints made of Grade 2 technical titanium using the Cu 0.99 and Ag 272 filler metal interlayers and F60T flux intended for titanium brazing in the air atmosphere.

  10. 铝制冷却器真空钎焊接头界面结构及断口分析%Interface Structure and Fracture Analysis of Aluminum Cooler Vacuum Brazing Joint

    Institute of Scientific and Technical Information of China (English)

    许敬年; 曹秀丽; 冯涛

    2012-01-01

    采用真空钎焊技术研制了一种用于高级轿车的铝制冷却器.采用LT-3铝复合板材进行了焊接试验,分析了钎焊接头的组织,并对所试制的铝制板翅式冷却器进行了水压试验及其断口分析.结果表明,钎焊接头中生成了网状共晶组织,接头中生成了金属间化合物.焊接完成的板翅式冷却器水压试验压力可达到15 kg/cm2以上,钎焊接头断口属于混合断裂,断口表面分布有二次裂纹、韧窝、解理面、沿晶断裂等断裂特征.%A kind of aluminum cooler used for advanced car by adopting vacuum brazing technology was developed. Welding test was conducted by Utilizing LT-3 aluminum composite plate. The structure of brazing joint was analyzed, and hydrostatic test and fracture analysis on fin type cooler of trial produced aluminum composite plate were carried out. The results showed that there are some reticular eutectic structures and intermetallic compound in the brazing joint. The hydrostatic test pressure of fine type cooler can reach more than 15 kg/cm2, the fracture type of the brazing joint is mixed fracture, and secondary cracks, dimples, cleavage planes and intergranular fracture etc. distribute on the surface of the fracture.

  11. Review Article: recent advances in metal-ceramic brazing Artigo Revisão: avanços recentes em brasagem metal-cerâmica

    Directory of Open Access Journals (Sweden)

    R. M. do Nascimento

    2003-12-01

    Full Text Available Metal-ceramic joining has slowly but steadily become an important manufacturing step. The evolution of joining processes has allowed ceramics to be used in combination with metals in a number of hybrid devices from traditional light bulbs and seals to improved cutting tools and modern monitoring and measuring electronic devices. New joining methods and newer approaches to conventional methods have been developed aiming at joints characterized by improved reliability, and interfaces capable of withstanding high-temperature resistance with minimum residual stresses. A summary of recent improvements on alternative approaches to ceramic-metal joining as well as new developments on brazing are presented herein. The present review also focuses on recent advances towards brazing metallized ceramics and the selection of filler alloys, since in a scenario that includes joining by laser and direct bonding with liquid transient phases, brazing continues to be by far the most widely used approach to joining as a result of its low-cost and possibility to join intricate geometries for large-scale production. Finally, methods to evaluate the mechanical strength and residual thermal stresses are presented in addition to alternative approaches to minimize residual stresses and, consequently, improve joint reliability.O interesse no estudo de métodos de junção-cerâmica para aplicações industriais tem crescido gradativamente ao longo dos anos. A evolução dos processos de união tem permitido a utilização de cerâmicas em conjunto com metais na fabricação de diversos componentes híbridos incluindo lâmpadas tradicionais, juntas para vácuo, ferramentas de corte de alto desempenho e modernos dispositivos eletrônicos de medição e monitoramento. Novos métodos de união e aprimoramentos de métodos convencionais têm sido estudados com o intuito de produzir-se juntas com alta confiabilidade e interfaces capazes de suportar altas temperaturas de

  12. Condensation heat transfer and pressure drop of R-134a saturated vapour inside a brazed compact plate fin heat exchanger with serrated fin

    Science.gov (United States)

    Ramana Murthy, K. V.; Ranganayakulu, C.; Ashok Babu, T. P.

    2016-05-01

    This paper presents the experimental heat transfer coefficient and pressure drop measured during R-134a saturated vapour condensation inside a small brazed compact plate fin heat exchanger with serrated fin surface. The effects of saturation temperature (pressure), refrigerant mass flux, refrigerant heat flux, effect of fin surface characteristics and fluid properties are investigated. The average condensation heat transfer coefficients and frictional pressure drops were determined experimentally for refrigerant R-134a at five different saturated temperatures (34, 38, 40, 42 and 44 °C). A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 22 kg/m2s. In the forced convection condensation region, the heat transfer coefficients show a three times increase and 1.5 times increase in frictional pressure drop for a doubling of the refrigerant mass flux. The heat transfer coefficients show weak sensitivity to saturation temperature (Pressure) and great sensitivity to refrigerant mass flux and fluid properties. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. Correlations are provided for the measured heat transfer coefficients and frictional pressure drops.

  13. Development of a brazing process for the production of water- cooled bipolar plates made of chromium-coated metal foils for PEM fuel cells

    Science.gov (United States)

    Mueller, M.; Hoehlich, D.; Scharf, I.; Lampke, T.; Hollaender, U.; Maier, H. J.

    2016-03-01

    Beside lithium batteries, PEM fuel cells are the most promising strategy as a power source to achieve the targets for introducing and increasing the usage of electric vehicles. Due to limited space and weight problems, water cooled, metallic bipolar plates in a fuel cell metal stack are preferred in motor vehicles. These plates are stamped metal sheets with a complex structure, interconnected media-tight. To meet the multiple tasks and requirements in use, complex and expensive combinations of materials are currently in use (carbon fiber composites, graphite, gold-plated nickel, stainless and acid resistant steel). The production of such plates is expensive as it is connected with considerable effort or the usage of precious metals. As an alternative, metalloid nitrides (CrN, VN, W2N, etc.) show a high chemical resistance, hardness and a good conductivity. So this material category meets the basic requirements of a top layer. However, the standard methods for their production (PVD, CVD) are expensive and have a slow deposition rate and a lower layer thicknesses. Because of these limitations, a full functionality over the life cycle of a bipolar plate is not guaranteed. The contribution shows the development and quantification of an alternative production process for bipolar plates. The expectation is to get significant advantages from the combination of chromium electrodeposition and thermochemical treatment to form chromium nitrides. Both processes are well researched and suitable for series production. The thermochemical treatment of the chromium layer also enables a process-integrated brazing.

  14. Mg/Cu异种材料共晶反应钎焊连接研究%Dissimilar Metals Between Copper and Magnesium Alloy in Eutectic Contacting Reaction Brazing

    Institute of Scientific and Technical Information of China (English)

    王怀建; 袁苗达; 白莉

    2012-01-01

    Magnesium alloy (AZ31B) and Copper (T2) were bonded by eutectic contacting reaction brazing. The microstructural features and mechanical properties of the welded joint was studied by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS). The results show that when the welding process is at 500 °C for 5 min, under the pressure of 2MPa, the tensile strength of the welded joint reaches 42MPa.%采用共晶钎焊工艺对Mg/Cu异种材料进行连接,焊后利用扫描电镜和EDS对焊接接头的微观组织及元素扩散行为进行了研究.在焊接温度为500℃,焊接时间为5min,焊接压力为2MPa的工艺下,焊接接头最高抗拉强度为42 MPa.

  15. Interfacial microstructure and strength of diffusion brazed joint between Al2O3–TiC and 9Cr1MoV steel

    Indian Academy of Sciences (India)

    Wang Juan; Li Yajiang; S A Gerasimov

    2007-08-01

    Joining of composite, Al2O3–TiC, with heat-resistant 9Cr1MoV steel, was carried out by diffusion brazing technology, using a combination of Ti, Cu and Ti as multi-interlayer. The interfacial strength was measured by shear testing and the result was explained by the fracture morphology. Microstructural characterization of the Al2O3–TiC/9Cr1MoV joint was investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM) with energy-dispersion spectroscopy (EDS). The results indicate that a Al2O3–TiC/9Cr1MoV joint with a shear strength of 122 MPa can be obtained by controlling heating temperature at 1130°C for 60 min with a pressure of 12 MPa. Multi-interlayer Ti/Cu/Ti was fused fully and diffusion occurred to produce interfacial layer between Al2O3–TiC and 9Cr1MoV steel. The total thickness of the interfacial layer is about 100 m and Ti3AlC2, TiC, Cu and Fe2Ti are found to occur in the interface layer.

  16. Microstructure characteristic of SS304/BNi-2/SS304 butt joint by high temperature brazing%SS304/BNi-2/SS304高温钎焊对接接头微观结构特征

    Institute of Scientific and Technical Information of China (English)

    竺国荣; 陈虎; 祝金丹; 巩建鸣

    2011-01-01

    通过试验手段研究了SS304/BNi-2/SS304钎焊对接接头微观结构特征,使用能谱分析结合合金三元相图研究了接头区域典型的微观结构形貌和特征相变化规律,讨论了降熔元素在接头等温凝固连接过程中所起的关键作用。结果表明,在钎焊温度时,B从液相钎料向固相母材的快速扩散控制了接头的等温凝固过程,也因此决定了接头的微观结构相特征;钎焊接头通常会存在4种典型的相特征区域;钎角质量对于整个钎焊接头性能有重要影响。%The microstructure characteristic of SS304/Bni -2/SS304 butt joint was analyzed by high temperature brazing through the experimental research. Some typical microstructural morphologies and phase transition feature of the butt joint were studied by using ternary phase diagrams and EDS analysis. The critical effect of element diffusion on isothermal solidification of brazed joint was also discussed by analyzing the microstructural evolution. The results showed that the quick diffusing of boron from the liquid filler alloy into solid base metal controlled the isothermal solidification process as well as the joint microstructure. Four typical characteristic zones could be observed for the whole brazed joint. The fillet quality played a very important role in the whole joint performance.

  17. Research of Electrochemical Corrosive Characteristics of Zn-Al Solders for Cu/Al Brazing%铜/铝钎焊用Zn-Al钎料的电化学腐蚀性能研究

    Institute of Scientific and Technical Information of China (English)

    王凯; 刘正林; 杨凯珍

    2011-01-01

    Zn-Al solders used for Cu/Al brazing were prepared by ingot metallurgy method in high frequency induction furnace. The anti-corrosive properties of Zn-Al solders added with Mg were evaluated and analyzed by immersion tests, electrochemical corrosion measurements, and the corrosive mechanism was discussed. The results show that the electrode potential of the solders substrates can be significantly improved by the addition of Mg to greatly improve the anti-corrosive properties of solders, while it will not significantly reduce the shear strength of welding joint. Using the Zn-Al solder added with Mg and CsF-AlF3 flux, Al and Cu tubes can be brazed by high frequency brazing method without air leaking at high air pressure even after immersion tests.%采用铸锭冶金法,在高频感应炉中制备了铜/铝钎焊用Zn-22Al钎料,通过浸泡腐蚀试验、电化学腐蚀试验对添加Mg元素的钎料的耐蚀性能进行了评价分析,并探讨了其腐蚀机理.研究结果表明,添加Mg元素可显著提高钎料基体的电极电位,从而显著提高钎料本身的耐腐蚀性能,并不会显著降低铜/铝接头的强度.加入Mg元素的Zn-22Al钎料,配合CsF-AlF3无腐蚀中温钎剂,采用高频感应加热钎焊连接铜/铝管,通过浸泡腐蚀试验后,仍可获得高剪切强度的接头.

  18. Effect of ZrO2 Nanoparticles on the Microstructure of Al-Si-Cu Filler for Low-Temperature Al Brazing Applications

    Science.gov (United States)

    Sharma, Ashutosh; Roh, Myung-Hwan; Jung, Do-Hyun; Jung, Jae-Pil

    2016-01-01

    In this study, the effect of ZrO2 nanoparticles on Al-12Si-20Cu alloy has been studied as a filler metal for aluminum brazing. The microstructural and thermal characterizations are performed using X-ray diffraction (XRD), scanning electron microscope (SEM), and differential thermal analysis (DTA). The intermetallic compound (IMC) phases are identified by the energy-dispersive spectroscopy analysis coupled with the SEM. The filler spreading test is performed according to JIS-Z-3197 standard. XRD and SEM analyses confirm the presence of Si particles, the CuAl2 ( θ) intermetallic, and the eutectic structures of Al-Si, Al-Cu, and Al-Si-Cu in the Al matrix in the monolithic and composite samples. It is observed that when the ZrO2 is added in the alloy, the CuAl2 IMCs and Si particles are found to be dispersed uniformly in the Al matrix up to 0.05 wt pct ZrO2. DTA results show that the liquidus temperature of Al-12Si-20Cu filler metal is dropped from ~806.78 K to 804.6 K (533.78 °C to 531.6 °C) with a lowering of 2 K (2 °C) in liquidus temperature, when the amount of ZrO2 is increased up to 0.05 wt pct. It is also shown that the presence of ZrO2 nanoparticles in the filler metal has no deleterious effect on wettability up to 0.05 wt pct of ZrO2. The ultimate tensile strength and elongation percentage are also found to improve with the addition of ZrO2 nanoparticles in the Al-12Si-20Cu alloy.

  19. 高硅铝合金真空钎焊接头组织与性能测试研究%Microstructure and Properties" Testing of Hypereutectic Si-A1 Alloy Vacuum Brazed Joint

    Institute of Scientific and Technical Information of China (English)

    陈潇潇; 侯玲; 徐道荣

    2012-01-01

    选用Cu箔、Zn及BA188SiMg片状钎料作为填充金属,采用真空加热方法进行高硅铝合金的钎焊连接,并对接头进行光学金相、显微硬度、扫描电子显微等测试、分析、研究。结果表明:3种钎料钎焊高硅铝合金,通过凝固、结晶等过程形成冶金结合,生成共晶体和固溶体组织,形成可靠的连接接头,外观良好。%Hypereutectic Si A1 Alloys were connected by vacuum soldering with the filler of BAI88SiMg, pure copper and zinc, and the joints of brazing were analyzed and researched by optical microscope,Vickers and scanning electron microscopy. The results show that hypereutectic Si-A1 alloys can be connected hard with the solid solution and eutectic by the process of solidification and crystallization with three brazing filler metals, and reliable joints with good surface are formed.

  20. 不锈钢真空钎焊管板连接微观特征及残余应力有限元分析%Microstructure Characteristics and Finite Element Analysis for Welding Residual Stress of Vacuum Brazed of Stainless Steel Tube Sheet Joint

    Institute of Scientific and Technical Information of China (English)

    吕彪; 熊缨

    2011-01-01

    采用拉伸试验机对304不锈钢管板结构真空钎焊强度进行了试验,运用金相和EDS方法分析了钎焊接头的微观组织特征.运用有限元ANSYS软件对微小尺寸不锈钢管板结构在真空钎焊过程中产生的残余应力进行了模拟.结果表明,应力集中出现在管板连接钎焊接头处,有限元分析获得了该处的残余应力分布规律.%The intensity of vacuum brazed of 304 stainless steel tube sheet structure has been tested with the tensile testing machine. This paper presented the microstructure characters of brazed joint with metallographic analysis and EDS analysis,studied the residual stress of vacuum brazed of the small size stainless steel tube sheet structure with finite element software ANSYS. The experimental results show that the stress concentration occurs at the joint of the brazed tube sheet, finite element analysis obtains the distribution of the residual stress. [ Ch,7 fig. 4 tab. 10 ref.

  1. 保温时间对Mg/Cu共晶反应钎焊连接的影响%Effects of Holding Time on Eutectic Contacting Reaction Brazing of Mg/Cu

    Institute of Scientific and Technical Information of China (English)

    王怀建; 白莉

    2012-01-01

    Magnesium alloy and copper were bonded by eutectic contacting reaction brazing, and the effects of holding time on the microstructure and tensile properties were studied. The results from the experiment show that when the welding process is 500℃ keeping for 30 min, welding pressure is 2MPa, the tensile strength can reach 54MPa.%采用共晶钎焊工艺对Mg/Cu异种材料进行连接,研究了不同保温时间对接头微观组织及力学性能的影响.结果表明,在焊接温度为500℃、保温时间为30 min、焊接压力为2MPa的工艺下,焊接接头最高抗拉强度为54 MPa.

  2. Wetting evaluation of silver based braze alloys onto zirconia metalized with reactive elements for application in oil well drill bots; Avaliacao do molhamento de ligas de adicao a base de prata sobre zirconia polida e metalizada com elementos ativos para aplicacao em brocas de perfuracao de pocos de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, J.C.; Silva, J.M.; Santos, P.R.F.; Nascimento, R.M.; Martinelli, A.E. [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Dept. de Engenharia de Materiais], Email: jocabuzo@gmail.com; Pimenta, J.S. [Universidade Federal de Santa Catarina (UFSC), Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Drill bits with hard ceramic inserts are often used on drilling operations. The cutting and crushing action of rocks will produce failures in the tricone bits, which are related to wear; total or partial rupture of the drill bit body or even the inserts; thermal shock and corrosion. The research of better drill bits with ceramic inserts thermally more stable and mechanically stronger, will lead to an increase of their lifetime, and so reducing costs of substitution and maintenance. In the present work, some silver based braze alloys were melted onto zirconia YSZ substrates metallized or not with active metals. inside a furnace with vacuum of 10{sup -5} mbar to evaluate the wetting behavior. The system with AgCuTi and the non metallized YSZ ceramic, showed low contact angles and stable interfaces, which may be appropriate for brazing metal/ceramic parts. (author)

  3. Multiple-unit implant frames: one-piece casting vs. laser welding and brazing Sobre estruturas de implantes múltiplos: fundição em monobloco versus soldagem a laser e brasagem

    Directory of Open Access Journals (Sweden)

    Elza Maria Valadares da Costa

    2004-09-01

    Full Text Available The linear distortion of prostheses over implants, one-piece casting and cast in sections followed by laser welding by laser and brazing was evaluated in an edentulous mandibular model with five parallel abutments, with a distance of 10mm from center to center. Seventy five gold cylinders were tightened with screws on the abutments with 10Ncm torque. The cylinder/analogue assemblies were measured by microscopic examination (0.001mm accuracy and the obtained results were compared with the GC (control group. Fifteen metal frames were waxed and cast in a gold alloy (Stabilor, Degussa Hulls, Brazil and divided into three groups with five elements each, as followed: GM (one-piece casting, GB (section and brazing and GL (section and laser welding. In all groups, measurements were taken at the right, left, buccal and lingual sides of the cylinder/analogue interface and the results were submitted to analysis of variance (ANOVA and to the Tukey test (5%. The smallest amount of distortion was seen in the laser group (GL with a mean value of 13.58, followed by the brazing group (GB with a mean value of 24.33 and one-piece (GM with a mean value of 40.00. The greatest distortion was found in the one-piece group (GM.A distorção linear das próteses sobre implantes, fundidas em monobloco e fundidas em secções e soldadas a laser e por brasagem foi avaliada em um modelo de uma mandíbula edêntula com cinco análogos de pilares de implantes, paralelos entre si com distância de 10mm medidos de centro a centro. Sobre estes foram parafusados novos cilindros de ouro, com torque de 10N/cm. Então foram executadas 15 sobre-estruturas metálicas que foram divididas: GC - Adaptação passiva dos cilindros de ouro; GM - monobloco, GB - segmentos soldados por brasagem e, GL - segmentos soldados a laser. Observaram-se as estruturas fixadas com parafusos novos sob microscópio de mensuração. A medição foi realizada na vestibular direita e esquerda e da mesma forma

  4. MIG Arc Brazing of Dissimilar Metals between Pure Aluminum and Zinc-Coated Steel%纯铝与镀锌钢板MIG熔-钎焊工艺研究

    Institute of Scientific and Technical Information of China (English)

    国旭明; 汪建梅; 徐荣正

    2013-01-01

    MIG arc brazing of dissimilar metals between pure aluminum and zinc-coated steel in a lap joint was investigated using Al-Mg,Al-Si filler wires.The interface structure and the mechanical properties of the fusion-brazing joint were characterized.The results show that the high quality welded joint is successfully achieved with Al-Mg,Al-Si filler wire in the suitable welding parameters.The intermetallic compound layer (IMC) is composed of θ-Al3Fe,η-Al5Fe2 and AlFeSi phases by using Al-Si filler wire.It is thinner and denser than that obtained by using Al-Mg filler wire.The growth of IMC layer is suppressed due to the addition of Si element.The shear strength of welded joint nearly reaches that of pure aluminum.The cracking position occurs in weld zone.%采用Al-Mg,Al-Si两种填充焊丝,研究了纯铝与镀锌钢板异种金属材料的MIG熔-钎焊工艺,分析了焊接接头的界面结构特征及其力学性能.研究结果表明:在合适的焊接参数下,选用两种填充焊丝可以实现纯铝板(1060)与镀锌钢板的MIG熔-钎焊.与添加Al-Mg焊丝相比,填充Al-Si焊丝,界面反应层由θ-Al3 Fe,η-Al5 Fe2和AlFeSi相组成,且反应层较薄,焊缝中加入Si元素有效地抑制了金属间化合物层的生长,此时所获得的拉剪强度较大,接近纯铝板(1060)的抗拉强度,接头断裂发生在焊缝位置.

  5. Advantages of reduced heat input during ChopArc-welding and brazing for coated and combined metals for light weight vehicles; Vorteile des waermearmen ChopArc-Schweissens und - Loetens bei beschichteten und artverschiedenen Blechen fuer Leichtfahrzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Dorn, L.; Goecke, S.F. [Inst. fuer Werkzeugmaschinen und Fabrikbetrieb, TU-Berlin (Germany)

    2001-07-01

    In conventional MAG-short-arc-welding the arc burns after ignition non-defined with continuously energy input until the next short circuit. Thereby, stochastically process fluctuations are caused by the non controlled melting of the electrode tip. In the recently developed ChopArc process, after a defined extinguishing a non arcing phase follows without any energy input until the next short circuiting on the controlled melting of the electrode tip. Hence, with the ChopArc it is possible to realize a sticky melt for thin sheet, root pass and out-of-position welding, as well as a low melt viscosity for sufficient capillary effect in MAG-brazing. (orig.) [German] Beim herkoemmlichen MAG-Kurzlichtbogen-Schweissen brennt der Lichtbogen nach seiner Zuendung bis zum naechsten Kurzschluss undefiniert mit einem kontinuierlichen Energieeintrag weiter. Aus dem dabei unkontrollierten Aufschmelzen der Elektrodenspitze resultieren stochastische Prozessschwankungen. Dagegen folgt beim neuen ChopArc-Verfahren einem gesteuerten Aufschmelzen des Elektrodendrahtes in der Brennphase mit definierter Abschaltung des Lichtbogens eine Unterbrechungsphase ohne Energieeintrag bis zum naechsten Kurzschlusseintritt. Mit dem ChopArc ist es nun moeglich, sowohl eine zaehe Schmelze fuer Duennblech-, Wurzel- oder Zwangslagenschweissen, als auch eine niedrige Schmelzbadviskositaet fuer eine gute Kapillarwirkung des Lotes beim MAG-Loeten zu erzielen. (orig.)

  6. Mg/Cu共晶反应钎焊微观组织及力学特性分析%Microstructure and properties of welded joints of Mg/Cu by eutectic reaction brazing

    Institute of Scientific and Technical Information of China (English)

    王怀建; 白莉

    2013-01-01

    Magnesium alloy (AZ31B) and copper (T2) were bonded by eutectic reaction brazing technology, and effects of temperature on microstructures, tensile properties were studied. The microstructures of joints were investigated using scanning electron microscopy (SEM). And tensile strength test was performed on universal tensile testing machine. Results from the experiment show that when the welding temperature is 500 °C , its tensile strength can reach the maximum of 54 MPa, and the joint shows. brittle fracture.%采用共晶反应钎焊连接工艺对Mg/Cu异种材料进行连接,研究不同温度对接头微观组织及力学特性的影响.采用扫描电镜对焊接接头的微观组织进行研究,采用拉伸试验机研究接头的力学特性.研究表明:在焊接温度为500℃,焊接接头强度最高,最高抗拉强度为54 MPa,断口呈现脆性断裂特性.

  7. 单层钎焊CBN成型砂轮磨削钛合金的温度研究%Temperature research of profile grinding on titanium alloy by monolayer brazed CBN forming grinding wheels

    Institute of Scientific and Technical Information of China (English)

    白永明; 童圣亭

    2014-01-01

    Because of its special properties , titanium alloy has been widely used in the aerospace field , but how to efficiently process is a difficult problem in current research .Designed a monolayer brazing CBN forming grinding wheel , and using it in straight groove grinding of titanium alloy TC 4 material .Through a series of temperature tests by different grinding conditions ,stud-ying the grinding characteristics of the wheel in grinding TC 4 titanium alloy materials .%钛合金因其具备的特殊性能而使其在航空航天领域得到了广泛的应用,但是钛合金的高效加工一直是当前研究的难点。设计一种单层钎焊CBN成型砂轮,用于TC4钛合金材料的直槽磨削加工。通过开展一系列不同磨削条件下的温度试验,研究所设计的砂轮磨削TC4钛合金材料的磨削性能。

  8. Study of No Corrosion Aluminum Fluxes on Brazing Aluminum Heat Exchanger%钎焊铝制热交换器用无腐蚀铝钎剂的研究

    Institute of Scientific and Technical Information of China (English)

    刘宏江; 曾燕; 蔡志红; 蔡沛沛; 贺军四; 胡泽宇; 李世婕; 黄烨

    2014-01-01

    Based on the AlF3 -KF eutectic compound fluxes, under the circumstances of not changing the non-corrosive nature, by adding additives, the eutectic compound fluxes are modified. By adding inorganic additives, the abilities of removing the oxide film and solderability are improved;And through adding organic additives, the settling property in water is improved, the purpose of efficient use in brazing aluminum heat exchanger is achieved.%以AlF3-KF共晶化合物钎剂为基础,在不改变其无腐蚀性质的情况下,通过添加助剂,对其进行改性。添加无机助剂,提高了钎剂的去膜能力和助焊性;添加有机助剂,提高了钎剂在水中的抗沉降性能,从而达到能高效应用于钎焊铝制热交换器的目的。

  9. Brasagem da zircônia metalizada com titânio à liga Ti-6Al-4V Brazing of metalized zirconia with titanium to Ti-6Al-4V alloy

    Directory of Open Access Journals (Sweden)

    J. S. Pimenta

    2012-06-01

    Full Text Available Zircônia tetragonal estabilizada com ítria foi mecanicamente metalizada com titânio e a condição de molhamento avaliada com as ligas convencionais Ag-28Cu e Au-18Ni. Estas dissolveram o revestimento de titânio para uma completa distribuição deste metal ativo na superfície cerâmica, gerando uma liga ativa in situ e possibilitando adequadas ligações químicas ao metal base na temperatura de união. Os melhores resultados de molhamento foram selecionados para brasagem indireta em forno de alto-vácuo nas juntas ZrO2/Ti-6Al-4V. Testes de detecção de vazamento de gás hélio foram realizados na interface de união das juntas; amostras removidas na seção transversal de juntas estanques foram examinadas por técnicas de análise microestrutural. Formou-se uma camada escura adjacente à cerâmica metalizada, responsável pelo molhamento ocasionado pela liga Ag-28Cu. Entretanto, o uso da liga Au-18Ni resultou em precipitação de intermetálicos e microtrincamento interfacial. Perfis de microdureza através da interface resultante até onde a zircônia mostrou típico escurecimento não indicaram alternância significativa entre medições consecutivas; os resultados dos ensaios de resistência mecânica à flexão-3p foram considerados satisfatórios.Yttria tetragonal zirconia polycrystal was mechanically metallized with titanium and the wetting behavior on the ceramic surface was analyzed using the conventional fillers Ag-28Cu and Au-18Ni. These alloys had dissolved the active metal coating, which acts to zirconia reduction on its surface and promoting suitable chemical bonding to the metallic member. Better wetting results were selected for indirect brazing in a high-vacuum furnace for ZrO2/Ti-6Al-4V simple butt joints. Helium gas leak detection was made at the joints interface; samples were removed from the tight joints cross-section and examined by microstructural analysis techniques and EDX analysis. There was formation of a dark

  10. 金刚石/铜基钎料粉末注射成型工艺参数的优化%Optimization of Parameters in Diamonds/Copper Based Brazing Filler Metal Powders Injection Molding Process

    Institute of Scientific and Technical Information of China (English)

    伍俏平; 邓朝晖; 潘占; 张荣辉; 张正

    2012-01-01

    通过正交试验对金刚石/铜基钎料粉末小型薄壁件的注射成型工艺参数进行了优化。结果表明:当模具温度为40℃,注射压力为12MPa,注射温度为150℃,注射流量为20cm^3·S^-1,为最佳工艺参数组合,能获得表面光整、组织均匀的注射生坯;随着注射压力的增大,注射生坯密度增大;注射温度升高,生坯密度降低;注射流量增大,生坯密度先升后降。%Optimization of parameters in the injection molding process of diamonds/copper based brazing niter metal powders was investigated by orthogonal experiments. Results indicate that the optimized combination of parameters was given as following: the mould temperature was 40 ℃; injection pressure was 12 MPa; injection temperature was 150 ℃ and injection flow rate was 20 cm^3 . s 1. And a molded specimen with a smooth surface, uniform microstructure could be achieved under the optimized condition. The density of molded specimens increased with increase of injection pressure, but decreased with increase of injection temperature, and the density increased first and decreased afterwards when the iniection flow rate increased.

  11. Experimental Investigation on Induction Brazing of Monolayer Diamond Grinding Wheel with Ni-CrAlloy under vacuum Atmosphere%真空感应钎焊单层金刚石砂轮的实验研究

    Institute of Scientific and Technical Information of China (English)

    武志斌; 肖冰; 徐鸿钧

    2001-01-01

    An experimental investigation is made on induction brazing ofmonolayer diamond grinding wheel with Ni-Cr alloy as solder under vacuum atmosphere.As a result,the strong bonding between diamond and steel is obtained,while the filled intermediate layer material is reactive Ni-Cr alloy slice.With the observation by scanning microscope,the composition analysis by X-ray energy spectrum and the structure analysis by X-ray diffractometer,it is shown that it is the continuous stable chromium carbide film formed on the interface between the diamond and the filled intermediate layer,and the (FexCry) C layer on the interface between steel surface and the filled intermediate layer that cause the better bonding strength.Finally,a grinding test proves the correctness of the investigation result.%在真空条件下用Ni-Cr合金做钎料进行了钎焊单层金刚石砂轮的实验研究,实现了金刚石与钢基体间的牢固化学冶金结合。通过扫描电镜X射线能谱,结合X射线衍射结构分析,发现Ni-Cr合金中的Cr原子与金刚石表面的碳原子反应生成稳定连续的Cr3C2膜,在钢基体结合界面上生成(FexCry)C,这是实现合金层与金刚石及钢基体之间都有较高结合强度的主要因素。通过磨削实验验证了金刚石确实有较高的把持强度。

  12. How braze flaws affect the thermal-hydraulic performance of the Tore Supra Phase-III outboard pump limiter. A case study of the effects of nonuniform thermal resistance on the peak heat flux to the coolant for tubes with one-sided heating

    International Nuclear Information System (INIS)

    The phase-III Outboard Pump Limiter is a heat sink made of pyrolytic graphite armor brazed to water-cooled copper tubes. Around the inner wall of the tube wall, some of the water can be in the subcooled boiling regime. The central issue analyzed here is how the heat flow in the tube changes when the thermal resistance along the heated portion of the tube is redistributed. Cracks or braze flaws in the joint between the tile and tube cause this redistribution. Severe cracks or flaws reduce the power-handling capability of this assembly because the local peak heat fluxes increase and, for a given critical heat flux (CHF), the safety margin decreases. There were some surprises. The increase in local peak heat flux for the most common type of flaw encountered in the fabrication of this limiter was negligible up to a flaw size of nearly 50%. The examples presented are intended as a case study that illuminates the more general problem of how correlations for heat transfer and for CHF developed for uniform circumferential heating are applied to a case of one-sided heating. 17 refs., 19 figs., 1 tab

  13. Effect of grit spacing on hole diameter precision and hole wall roughness of CFRP laminate drilled with brazed diamond core drill%钎焊金刚石套料钻磨粒间距对碳纤维增强树脂基复合材料(CFRP)制孔直径和孔壁粗糙度的影响

    Institute of Scientific and Technical Information of China (English)

    王伟锋; 陈燕; 徐九华; 牟娟

    2012-01-01

    Carbon fiber reinforced plastics ( CFRP) laminate was drilled with brazed diamond core drill under no cooling condition. The effect of grit spacing of diamond on hole diameter precision and hole wall roughness in drilling CFRP at different feed speed was studied. A heat affected simulation model of CFRP hole diameter drilled with brazed diamond core drill was established. The results indicated that expanding factor oi hole diameter decreased with the increase of grit spacing and feed speed, and grit spacing had a relatively larger effect on expanding factor. The surface roughness of hole wall increased with the increase of grit spacing and feed speed. When grit spacing of brazed diamond core drill was 1. 6 mm and feed speed was 150 mm/min, the hole quality of CFRP laminate was perfect.%在无冷却润滑条件下,采用钎焊金刚石套料钻对CFRP层合板进行钻削加工试验,研究了不同进给速度条件下钎焊金刚石套料钻的磨粒间距对CFRP层合板制孔直径精度和孔壁粗糙度的影响,建立了钎焊金刚石套料钻钻削CFRP的温度场仿真模型.研究结果表明:制孔直径的扩孔因子随着磨粒间距和进给速度的增加而减小,磨粒间距对扩孔因子的影响程度较大;孔壁相同位置处的粗糙度随着磨粒间距和进给速度的增加而增加;采用磨粒间距为1.6 mm的80/100金刚石磨粒的套料钻,在进给速度为150mm/min时钻削CFRP层合板制孔效果好.

  14. 铝/镀锌钢薄板异种金属CMT熔钎焊接头组织与力学性能%Microstructure and Mechanical Properties of CMT Welding-brazing Joint for Dissimilar Materials between Aluminums and Galvanized Steels

    Institute of Scientific and Technical Information of China (English)

    余刚; 曹睿; 陈剑虹

    2012-01-01

    The dissimilar materials, aluminum alloys and galvanized steels were joined by CMT welding -brazing method. Analyzing the macro feature of cross -section, microstructure, the defects and mechanical properties of welding-brazing joints with SEM, EDAX, tension text, it is shown that the lap joints with better properties and better weld appearance are formed between the aluminum alloys and galvanized steels. From the microstructure and formation of weld metal, the cross-section of the joint can be divided into four zones; weld metal, middle interface, transitional interface and zinc - rich zone. There is a continuous and compact inter -metallic compound layers with a thickness of 3~4μm, which is formed in the brazing interface zone between the weld metal and the galvanized steel sheet. The main components of the layer are Fe3 Al, FeAl2, Fe2 Al5 and FeAl3,then, the zinc-rich zone is mainly composed of aluminum -rich solid solution and residue of Zn. Tensile strength tests show that the joint is fractured in the aluminum heat affect zone, and the joint strength with 204MPa is obtained.%采用冷金属过渡方法对铝合金和镀锌钢板进行了熔钎焊连接,使用扫描电镜、能谱分析和拉伸试验分析了接头的截面形貌、组织特征、焊接缺陷及力学性能.试验结果表明,铝合金和镀锌钢能得到成形美观、性能良好的搭接接头.对焊缝金属的组织特征分析表明,焊接接头由熔化区、中心界面区、过渡界面区和富锌区组成,在焊缝金属和镀锌板的界面区形成厚度为3~4μm的金属间化合物层(主要成分为Fe3Al、FeAl2、Fe2Al5和FeAl3),富锌区由富铝的固溶体和残留的锌组成.在进行拉伸试验时,断裂发生在热影响区,接头强度为204MPa.

  15. Step brazing a multi-target TRAX

    International Nuclear Information System (INIS)

    Fabrication of a target holder for a multi-target transmission anode x-ray tube (TRAX) involved joining of five different materials. The TRAX will generate a nearly mono-energetic x-ray beam useful for instrument calibration and dosimetry studies. Each of three different targets will provide a different energy. The design will allow the experimenter to place a different target in front of the electron beam without breaking vacuum each time. The procedure is described for attaching three 12.7 mm (1/2 in.) diameter targets - made of tungsten, gold and uranium 238 (D-38) - to an OFHC copper support bar. The joining of the copper bar to a welded stainless steel bellows and flange is also described

  16. 超声时间和预留间隙对超声波辅助钎焊镁合金钎料填缝性能的影响%Influence of ultrasonic time and pre-clearance on gap-filling behavior of filler metal during ultrasonic-assisted brazing of magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    李红; 耿园月; 闫久春; 栗卓新

    2013-01-01

    In order to investigate the influence of ultrasonic on flow behavior of filler metal when the filler metal propagates on the solid/liquid surface in brazing process, the gap-filling behavior of the molten filler metal during ultrasonic-assisted brazing of magnesium alloy was in-situ observed by high-speed video camera. Besides, the gap-filling behavior in unparalleled gaps and brazed joint properties were investigated. When the filler metal fills the gap in the direction parallel to the ultrasonic energy propagation, the dynamic curve of filling-gap distance appears linear relation with the ultrasonic time. And it shows that at the same ultrasonic time, good pre-clearance results in low filling velocity. Along the filler flow direction, the thickness of brazed joint decreases gradually. The filling-gap distance decreases as ultrasonic time increases when filler metal is placed at large gap side. The compactness of the joint is general. The filling-gap distance increases firstly and then decreases with the ultrasonic time increasing when the filler metal is placed at small gap side. In this case, the defects appear in the whole joint. The analysis indicates that the flow behavior of filler metal in unparalleled clearance is influenced by the combined effect of ultrasonic induced gap-filling action and capillary action.%采用高速摄影对超声波辅助钎焊镁合金过程熔态钎料的填缝行为进行了实时观察,并研究了不等间隙中钎料的填缝行为及接头性能.结果表明,超声波在钎焊固/液界面传播对钎料填缝行为有显著的影响.钎料在平行于超声波能量传播方向上填缝,填缝长度和超声时间的动力学曲线呈直线型.超声时间相同时,预留间隙越大,钎料的填缝速度越低.在大间隙端加钎料,随超声时间增加,填缝长度减小,钎缝致密性较好;小间隙端加钎料,随超声时间增加,填缝长度先增大后减小,整个钎缝均存在缺陷.认为钎料在不等

  17. 石墨自润滑钎焊CBN砂轮磨削镍基高温合金温度的试验研究%Experimental study on grinding temperature of nickel-based superalloy with graphite self-lubrication brazed CBN wheel

    Institute of Scientific and Technical Information of China (English)

    黄加林; 傅玉灿; 赵立; 陈路; 陈珍珍

    2012-01-01

    Grinding comparative experiments of nickel-based superalloy GH4169 with both graphite self-lubrication brazed CBN wheel and vitrified CBN counterpart were carried out. Grinding temperatures of the workpiece surface were measured with semi-manual thermocouple method. The morphology of the grains on the surface of the wheel and the distribution of element were detected using scanning electron microscope ( SEM) and energy dispersion spectrometer (EDS). The results showed that the grinding temperature of graphite self-lubrication brazed CBN wheel was 100 ℃ lower than that of vitrified CBN wheel under the same grinding parameters. Moreover, a layer of graphite film was formed on the surface of the CBN grits after grinding, which indicated that the lubricant graphite could spread over the wheel surface during the grinding process and decreased the friction between the grinding wheel and the workpiece in contact zone, thus decreased the grinding temperature.%利用石墨自润滑钎焊CBN砂轮和陶瓷CBN砂轮进行了高温合金GH4169磨削对比试验,采用夹丝半人工热电偶方法测量工件表面磨削温度,并运用扫描电镜、能谱仪对砂轮表面磨粒的微观形貌及元素分布情况进行分析.结果表明:在相同磨削条件下,多层自润滑钎焊CBN砂轮磨削GH4169高温合金的磨削温度比陶瓷结合剂CBN砂轮低100℃左右;砂轮表层的磨粒表面形成一层石墨薄膜,有助于减小摩擦,从而降低磨削温度.

  18. Inert Welding/Brazing Gas Filters and Dryers

    Science.gov (United States)

    Goudy, Jerry

    2009-01-01

    The use of hybridized carbon/silicon carbide (C/SiC) fabric to reinforce ceramic matrix composite face sheets and the integration of such face sheets with a foam core creates a sandwich structure capable of withstanding high-heat-flux environments (150 W/sq cm) in which the core provides a temperature drop of 1,000 C between the surface and the back face without cracking or delamination of the structure. The composite face sheet exhibits a bilinear response, which results from the SiC matrix not being cracked on fabrication. In addition, the structure exhibits damage tolerance under impact with projectiles, showing no penetration to the back face sheet. These attributes make the composite ideal for leading-edge structures and control surfaces in aerospace vehicles, as well as for acreage thermal protection systems and in high-temperature, lightweight stiffened structures. By tailoring the coefficient of thermal expansion (CTE) of a carbon fiber containing ceramic matrix composite (CMC) face sheet to match that of a ceramic foam core, the face sheet and the core can be integrally fabricated without any delamination. Carbon and SiC are woven together in the reinforcing fabric. Integral densification of the CMC and the foam core is accomplished with chemical vapor deposition, eliminating the need for bond-line adhesive. This means there is no need to separately fabricate the core and the face sheet, or to bond the two elements together, risking edge delamination during use. Fibers of two or more types are woven together on a loom. The carbon and ceramic fibers are pulled into the same "pick" location during the weaving process. Tow spacing may be varied to accommodate the increased volume of the combined fiber tows while maintaining a target fiber volume fraction in the composite. Foam pore size, strut thickness, and ratio of face sheet to core thickness can be used to tailor thermal and mechanical properties. The anticipated CTE for the hybridized composite is managed by the choice of constituents, varying fiber tow sizes and constituent part ratios. This structural concept provides high strength and stiffness at low density 1.06 g/cu cm in panels tested. Varieties of face sheet constructions are possible, including variations in fiber type and weave geometry. The integrated structures possible with this composite could eliminate the need for non-load-bearing thermal protection systems on top of a structural component. The back sheet can readily be integrated to substructures through the incorporation of ribs. This would eliminate weight and cost for aerospace missions.

  19. Development of brazed connections stable in thermal cycling for materials with different coefficients of thermal expansion

    International Nuclear Information System (INIS)

    The need for temperature change resestance (in the region of 50 to 10000C) of joints between different materials, especially soldered joints between pipes consisting of materials having very different thermal expansion coefficients, gives rise to great engineering problems. If these joints are stressed by temperature changing processes, such high tensions can occur in the joint zone, mainly tensile stress, that the joint may be destroyed and thus of no use. A new construction was developed as auxiliary measure in which the tensile stress in reduced to a great extent. In this construction, both pipe ends which are inserted into are another to be joined, have several axial slits in the region of the depth of insertion. The assembly of this construction and its testing are described. Application tips to create this kind of joints between non-metallic materials are given. (orig.)

  20. Joining titanium materials with tungsten inert gas welding, laser welding, and infrared brazing.

    Science.gov (United States)

    Wang, R R; Welsch, G E

    1995-11-01

    Titanium has a number of desirable properties for dental applications that include low density, excellent biocompatibility, and corrosion resistance. However, joining titanium is one of the practical problems with the use of titanium prostheses. Dissolved oxygen and hydrogen may cause severe embrittlement in titanium materials. Therefore the conventional dental soldering methods that use oxygen flame or air torch are not indicated for joining titanium materials. This study compared laser, tungsten inert gas, and infrared radiation heating methods for joining both pure titanium and Ti-6Al-4V alloy. Original rods that were not subjected to joining procedures were used as a control method. Mechanical tests and microstructure analysis were used to evaluate joined samples. Mechanical tests included Vickers microhardness and uniaxial tensile testing of the strength of the joints and percentage elongation. Two-way analysis of variance and Duncan's multiple range test were used to compare mean values of tensile strength and elongation for significant differences (p < or = 0.05). Tensile rupture occurred in the joint region of all specimens by cohesive failure. Ti-6Al-4V samples exhibited significantly greater tensile strength than pure titanium samples. Samples prepared by the three joining methods had markedly lower tensile elongation than the control titanium and Ti-6Al-4V rods. The changes in microstructure and microhardness were studied in the heat-affected and unaffected zones. Microhardness values increased in the heat-affected zone for all the specimens tested. PMID:8809260

  1. On the effect of brazing thermal cycle on the properties of niobium and its alloys

    International Nuclear Information System (INIS)

    The effect of the main parameters of the soldering thermal cycle on the properties of Nb and its alloys was studied by heating the samples under modelled conditions of soldering. The studies were made on commercial VN-niobium, alloys of the Nb-Mo-Zr system VN2A, VN2AEHM) and alloys of the Nb-Mo-Zr-C system (VN5AEH,VN5A). The degree of a preliminary plastic deformation of samples 0.3 to 0.8 mm thick made up 60 to 80%. The heating was made in vacuum (10-4 to 5x10-5 mm Hg) or in argon by passing the electric current across the samples. After heating a metallographic study and X-ray electron-probe analysis were made. The studies have shown that the changes in the heating rate result in a proportional change in the recrystallization initiation temperature. At a heating rate 300 deg C/s the recrystallization initiation temperature of commercial Nb is 930 to 960 deg as soon as the heating rate increases up to 900 deg/c the recrystallization initiation temperature rises up to about 1200 deg C. The heating temperature effect on the mechanical characteristics of commercial Nb and alloys VN2, VN2AEH and VN5AEH is shown. It is found that soldered joints of Nb and its alloys could be made of good quality when observing the thermal cycles ensuring the minimum softening of the base material. The main factors affecting the properties of Nb and alloy-VN2 are the heating temperature and the extent of a preliminary cold deformation. In a more deformed material the annealing results in the activation of the recrystallization processes. The production of high-strength soldered joints of commercial Nb is possible at the soldering temperature equal to 1100 deg C, but of Nb-Mo-Zr alloys-at 1200 to 1300 deg C and hold-up periods not exceeding one hour. A heterophase structure of alloys of the Nb-Mo-Zr-C system and the presence of Mo- and Zr-carbide phases in them result in a considerable hardening of the alloys and the increase in their recrystallization temperature. The usage of alloys with carbon additions permits to produce structures with soldered high-strength joints exhibiting workability at 1500 deg C

  2. Ultrasonic C-scan inspection of brazed joint in thin panel honeycomb structure

    Institute of Scientific and Technical Information of China (English)

    刘斌; 刚铁

    2014-01-01

    The non-destructive testing ofbrazed joint in honeycomb structure with thin panel(thickness:0.2 mm)was studied by ultrasonic C-scan method.Samples with different types ofartificial defect were designed;the characteristic signal and the main parameters ofthe test were determined by the pre-experiment,and then parameters were optimized by orthogonal design, finally the optimum process was verified by a single panel sample. The multiple reflection echoes were chosen as the characteristic signal.The optimal C-scan results were achieved when the 20 MHz focus probe was used,and the pass band range for received signal were selected as 8-17.5 MHz.The defects such as incomplete penetration and core damage can be detected with ultrasonic C-scan,and the detection accuracy can reach to 1 mm.

  3. Brazing of SiC Ceramics Using Ag-Cu-In-Ti Filler Metal

    OpenAIRE

    LIU Yan,HUANG Zheng-Ren,LIU Xue-Jian,YUAN Ming

    2009-01-01

    Sintered silicon carbide was jointed with itself using Ag-Cu-In-Ti filler metal successfully. Interfacial microstructure was investigated by electron probe microanalysis (EPMA) and transmission electron microscope (TEM). Joining strength of SiC/SiC joints was measured by four-point flexural strength. The experimental results indicate that joining strength has a peak value with the joining temperature increasing, and the max flexural strength reaches 234MPa, however joining strength decreases ...

  4. 49 CFR 178.50 - Specification 4B welded or brazed steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... calculated shear strength at least 10 times the test pressure of the cylinder; gaskets required, adequate to... as the finished cylinder. (k) Physical test. A physical test must be conducted to determine yield strength, tensile strength, elongation, and reduction of area of material as follows: (1) The test...

  5. 49 CFR 178.55 - Specification 4B240ET welded or brazed cylinders.

    Science.gov (United States)

    2010-10-01

    ... tight fit and calculated shear strength at least 10 times the test pressure of the cylinder; gaskets... between knife edges, wedge shaped, 60° angle, rounded to 1/2 inch radius. (k) Physical test. A physical test must be conducted to determine yield strength, tensile strength, elongation, and reduction of...

  6. Low-Temperature Interface Reaction between Titanium and the Eutectic Silver-Copper Brazing Alloy

    OpenAIRE

    Andrieux, J; Dezellus, Olivier; Bosselet, F.; Viala, J.C.

    2009-01-01

    Reaction zones formed at 790 °C between solid titanium and liquid Ag-Cu eutectic alloys (pure and Ti-saturated) have been characterized. When pure Ag-Cu eutectic alloy with 40 at.% Cu is used, the interface reaction layer sequence is: alpha-Ti / Ti2Cu / TiCu / Ti3Cu4 / TiCu4 / L. Because of the fast dissolution rate of Ti in the alloy, the reaction zone remains very thin (3-6 µm) whatever the reaction time. When the Ag-Cu eutectic alloy is saturated in titanium, dissolution no longer proceeds...

  7. The influence of brazing materials on the strain formation of intenally water-cooled x-ray optics

    Czech Academy of Sciences Publication Activity Database

    Oberta, Peter; Kittler, Martin; Áč, V.; Hrdý, Jaromír; Iragashi, N.; Scheinost, A.C.; Uchida, Y.

    2015-01-01

    Roč. 22, Mar (2015), 342-347. ISSN 0909-0495 Institutional support: RVO:68378271 Keywords : X-ray optics * high heat load * internal cooling * crystal bonding Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.736, year: 2014

  8. Corrosion behaviour of Ti/Al2O3 interfaces produced by an active metal brazing methodology

    OpenAIRE

    Ariza, E.; Rocha, L. A.; Paiva, O. C.

    2004-01-01

    Metal/ceramic joints are used in a broad range of applications in biomedicine, such as the encapsulation of implantable telemetric devices, the fabrication of crowns and bridges for dental restoration, or the production of drug delivery systems, biomedical sensors and electrodes. Apart of other characteristics, the corrosion resistance of metal/ceramic interfaces is of prime importance when biomedical applications are considered. Most of metal/ceramic joints are produced by the active meta...

  9. Numerical simulation of iron/TiC ceramic tappet brazed with TiZrNiCu filler metal

    Institute of Scientific and Technical Information of China (English)

    张丽霞; 冯吉才; 李卓然

    2003-01-01

    Maximum value of thermal stress and stress concentration zones of iron/TiC ceramic tappet during cooling were studied.The results show that when the temperature is 300 K,the maximum values of shear stress and tensile stress on iron/TiC ceramic interface both appear on the tip of TiZrNiCu/iron interface,so cracks always originate from TiZrNiCu/iron interface.Positive tensile stress on iron undersurface relaxes to the inner of iron and negative tensile stress on iron undersurface concentrates on the side of iron as the temperature declines,which leads to the origination of cracks on iron undersurface because of the alternation between positive and negative tensile stress.

  10. Microstructures characteristics and properties of solidified aluminum alloy brazed joint%铝合金钎焊凝固接头的组织特征和性能

    Institute of Scientific and Technical Information of China (English)

    高峰; 钱乙余; D.P.Sekulic; 马鑫; F.Yoshida

    2003-01-01

    研究了钎焊温度对钎焊接头微观组织的影响, 并利用图像软件Image-Pro Plus确定了不同初始凝固温度下α-(Al)相在钎焊接头中的体积分数. 结果表明: 随着初始凝固温度增加, α-(Al)相所占的比例增大. 通过成分分析(EPMA)和硬度测试, 分析了硅扩散层的特征. 压痕法测试结果表明: 不同初始凝固温度下获得的同种组织, 其力学和物理等综合性能不同, 从而造成整个钎焊接头力学性能的差异.

  11. Sputter target

    Science.gov (United States)

    Gates, Willard G.; Hale, Gerald J.

    1980-01-01

    The disclosure relates to an improved sputter target for use in the deposition of hard coatings. An exemplary target is given wherein titanium diboride is brazed to a tantalum backing plate using a gold-palladium-nickel braze alloy.

  12. Thermal cycling tests of actively cooled beryllium copper joints

    International Nuclear Information System (INIS)

    Screening tests (steady state heating) and thermal fatigue tests with several kinds of beryllium-copper joints have been performed in an electron beam facility. Joining techniques under investigation were brazing with silver containing and silver-free braze materials, hot isostatic pressing (HIP) and diffusion bonding (hot pressing). Best thermal fatigue performance was found for the brazed samples. (author)

  13. Thermal cycling tests of actively cooled beryllium copper joints

    Energy Technology Data Exchange (ETDEWEB)

    Roedig, M.; Duwe, R.; Linke, J.; Schuster, A.; Wiechers, B. [Forschungszentrum Juelich GmbH (Germany)

    1998-01-01

    Screening tests (steady state heating) and thermal fatigue tests with several kinds of beryllium-copper joints have been performed in an electron beam facility. Joining techniques under investigation were brazing with silver containing and silver-free braze materials, hot isostatic pressing (HIP) and diffusion bonding (hot pressing). Best thermal fatigue performance was found for the brazed samples. (author)

  14. 78 FR 75947 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding...

    Science.gov (United States)

    2013-12-13

    ...; Welding, Cutting, and Brazing Standard ACTION: Notice. SUMMARY: The Department of Labor (DOL) is... (ICR) titled, ``Welding, Cutting, and Brazing Standard,'' to the Office of Management and Budget (OMB... the Welding, Cutting, and Brazing Standard, regulations 29 CFR part 1910, subpart Q. More...

  15. Modélisation numérique avec apport de matière du soudo-brasage des assemblages hétérogènes acier/aluminium

    OpenAIRE

    Optasanu, Virgil; Sallamand, Pierre; Martin, Bruno; Montesin, Tony

    2007-01-01

    This study deals with the numerical simulation of heterogeneous brazing of steel / aluminium alloy sheets by CMT process. The difference between the linear expansion coefficients of these materials generates high deformations and residual stress. The addiction of brazing material is simulated. A validation the model is made in the simplest case of a sheet of aluminium alloy with a brazing bead. Comparisons are made between numerical and experimental results on out-of-plane displacements of st...

  16. Multilayered interface in Ti/macor machinable glass-ceramic joints

    OpenAIRE

    Guedes, A.; A.M.P. Pinto; Vieira, M. F.; Viana, Filomena

    2001-01-01

    Macor® machinable glass-ceramic and commercially pure (cp.) titanium were joined by active metal brazing, using a 64Ag–34.5Cu–1.5Ti (wt.%) filler alloy. The influence of the brazing temperature and holding stage on the microstructure and hardness profile of the interface, as well as on the shear strength of the joint, were assessed. Brazing was performed in a high vacuum furnace at 850, 890 and 930°C for 10 and 30 min. The reaction between the braze alloy and both materials led to t...

  17. 46 CFR 56.75-30 - Pipe joining details.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Pipe joining details. 56.75-30 Section 56.75-30 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Brazing § 56.75-30 Pipe joining details. (a) Silver brazing. (1) Circumferential pipe joints...

  18. 46 CFR 56.75-25 - Detail requirements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Detail requirements. 56.75-25 Section 56.75-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Brazing § 56.75-25 Detail requirements. (a) Pipe may be fabricated by brazing when the...

  19. 46 CFR 57.05-3 - Limited space qualifications.

    Science.gov (United States)

    2010-10-01

    ... Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING.... EC01FE91.028 Figure 57.05-3(a)—Limited space restriction for pipe welding performance qualification EC01FE91.029 Figure 57.05-3(b)—Limited space restriction for pipe brazing performance qualification...

  20. Broadband, High-Temperature Ultrasonic Transducer

    Science.gov (United States)

    Parker, F. Raymond; Winfree, William P.; Barrows, Danny A.

    1995-01-01

    Materials chosen for endurance at high temperatures and acoustic coupling and damping. Acoustic transducer designed to exhibit broad frequency response and to survive temperatures close to melting points of brazing alloys. Attached directly and continuously to hot object monitored ultrasonically: for example, it can be attached to relatively cool spot on workpiece during brazing for taking ultrasonic quality-control measurements.

  1. Method of joining metals of significantly different expansion rates

    Science.gov (United States)

    Caler, W.; La Salle, F.; Traylor, J.

    1971-01-01

    To join a refractory metal to a dissimilar high-temperature metal, braze a section of high elasticity, high ductility metal /such as columbium or columbium alloy/ between the metals to be joined, using a fork-type joint to hold the braze and transition member in place during expansion.

  2. 75 FR 74083 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding...

    Science.gov (United States)

    2010-11-30

    ... ] additional information, see the related notice published in the Federal Register on August 24, 2010 (75 FR...; Welding, Cutting and Brazing ACTION: Notice. SUMMARY: The Department of Labor (DOL) hereby announces the... request (ICR) titled, ``Welding, Cutting and Brazing,'' to the Office of Management and Budget (OMB)...

  3. Mechanical Properties of 17-4PH Stainless Steel Foam Panels

    Science.gov (United States)

    Raj, S. V.; Ghosn, L. J.; Lerch, B. a.; Hebsur, M.; Cosgriff, L. M.; Fedor, J.

    2007-01-01

    Rectangular 17-4PH stainless steel sandwiched foam panels were fabricated using a commercial manufacturing technique by brazing two sheets to a foam core. Microstructural observations and ultrasonic nondestructive evaluation of the panels revealed large variations in the quality of the brazed areas from one panel to the next as well as within the same panel. Shear tests conducted on specimens machined from the panels exhibited failures either in the brazed region or in the foam core for the poorly brazed and well-brazed samples, respectively. Compression tests were conducted on the foam cores to evaluate their elastic and plastic deformation behavior. These data were compared with published data on polymeric and metallic foams, and with theoretical deformation models proposed for open cell foams.

  4. The accelerator driven transmutation technology - A study on the linac for proton accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bum Soo; Joh, Ki Hun; Kim, Sung Myun; Park, Heung Gyu; Park, Jong Pil; Kang, Bo Sun [Samsung Heavy Industries, Taejon (Korea)

    1999-04-01

    The purpose of this study is to investigate the manufacturing technology of proton accelerators, and to find the adequate manufacturing technique for construction of such proton accelerators. Review of manufacturing technology for RFQ has been carried out - RFQ machine of other country has been reviewed on the aspects of manufacturing, - Machining of engineering mock-up has been performed based on the designed data, - Brazing technology for RFQ, and brazing test and analysis of Copper specimen. Adequate brazing conditions for RFQ - 1st brazing (vane to section, 950 deg C), Filler metal composition: Cu-20Sn, Brazing conditions: peak temp. 950 deg C (holding time 20min, rising rate 7 deg C/min), Atmosphere: H{sub 2}. - 2nd brazing (section to section, 850 deg C or less), Filler metal: Cu-Sn4%-P7.5%-Ag6%, Brazing conditions: peak temp. 750 deg C (holding time 20min, rising rate 7 deg C/min), Atmosphere: H{sub 2}. 8 refs., (author). 31 figs., 6 tabs.

  5. Ultrasonic testing technology development for pressure retaining Ti alloy-stainless steel dissimilar metal joint of SMART steam generator

    International Nuclear Information System (INIS)

    The steam generator for the Integral reactor SMART has module feed water (FW) pipe and module steam pipe which consist of Ti-alloy and STS321 called dissimilar metal joint. These brazed joints are classified as a class 1 boundary component being needed inservice inspection according to ASME Sec. XI. But inspecting the thread part of brazed joint is really difficult due to geometrical condition. For this reason, various NDT methods have been investigated. In this paper, the ultrasonic inspection was recommended to evaluate the integrity of brazed dissimilar metal joint, and representative UT results of specimens are presented

  6. Analysis of Poor Factor for Brazed Car Condenser by 434-0 Aluminium Alloy Composite Plate%434-O铝合金复合板制成汽车冷凝器真空钎焊不良因素分析

    Institute of Scientific and Technical Information of China (English)

    陈丽君

    2010-01-01

    铝合金汽车冷凝器真空钎焊打压试验后出现起鼓、鼓暴现象,对零件中434复合板材料做了成分、热差、金相分析系统的对比试验.结果表明,冷凝器钎焊良好和钎焊不良中434复合板材成分、晶粒度、熔化温度等均无明显差异.打压起鼓、鼓暴现象应与冷凝器装配、翅片强度等因素有关,并提出了相应的工艺措施.

  7. Analysis of Poor Factor for Brazed Car Condenser by 434-O Aluminum Alloy Composite Plate%434-O铝合金复合板制成汽车冷凝器真空钎焊不良因素分析(续)

    Institute of Scientific and Technical Information of China (English)

    陈丽君

    2010-01-01

    @@ 由表1、表2显示:原始复合板材1#、2#两个试样芯层3003、皮层4004合金化学成分均合格,符合GB/T3190-2008的要求. 2.2 热差分析 制备热差分析试样,利用综合热差分析仪测定434-O合金的熔化温度,1#、2#两批试样热差分析结果见图3所示.

  8. An investigation on the effects of phase change material on material components used for high temperature thermal energy storage system

    Science.gov (United States)

    Kim, Taeil; Singh, Dileep; Zhao, Weihuan; Yua, Wenhua; France, David M.

    2016-05-01

    The latent heat thermal energy storage (LHTES) systems for concentrated solar power (CSP) plants with advanced power cycle require high temperature phase change materials (PCMs), Graphite foams with high thermal conductivity to enhance the poor thermal conductivity of PCMs. Brazing of the graphite foams to the structural metals of the LHTES system could be a method to assemble the system and a method to protect the structural metals from the molten salts. In the present study, the LHTES prototype capsules using MgCl2-graphite foam composites were assembled by brazing and welding, and tested to investigate the corrosion attack of the PCM salt on the BNi-4 braze. The microstructural analysis showed that the BNi-4 braze alloy can be used not only for the joining of structure alloy to graphite foams but also for the protecting of structure alloy from the corrosion by PCM.

  9. Research Activities at IPT, DTU on Resistance Projection Welding

    DEFF Research Database (Denmark)

    Bay, Niels

    Resistance welding processes and among these especially the resistance projection welding is considered an industrially strategic process with increasing applications as alternative to other welding processes, soldering, brazing and mechanical assembling. This is due to increasing requirements as...

  10. LIFE CYCLE DESIGN OF AIR INTAKE MANIFOLDS; PHASE I: 2.0 L FORD CONTOUR AIR INTAKE MANIFOLD

    Science.gov (United States)

    The project team applied the life cycle design methodology to the design analysis of three alternative air intake manifolds: a sand cast aluminum, brazed aluminum tubular, and nylon composite. The design analysis included a life cycle inventory analysis, environmental regulatory...

  11. Bonding of Cf/SiC composite to Invar alloy using an active cement, Ag-Cu eutectic and Cu interlayer

    Science.gov (United States)

    Lei, Zhao; Xiaohong, Li; Jinbao, Hou; Qiang, Sun; Fuli, Zhang

    2012-10-01

    The interfacial microstructures and mechanical properties of the joints formed by active cement added brazing in vacuum of Cf/SiC composite to Invar alloy, using Ag-Cu eutectic alloy and pure copper foil as braze alloy and interlayer respectively, were investigated. CuTi, Cu4Ti3, Fe2Ti and the reaction layer of TiC and Si were the predominant components at the joint interface. The maximum shear strength of the joint was 77 MPa for brazing at 850 °C for 15 min. The results show that active cement added brazing in vacuum using Ag-Cu eutectic alloy and Cu interlayer can be used successfully for joining Cf/SiC composites to Invar alloy.

  12. Development of High Temperature Dissimilar Joint Technology for Fission Surface Power Systems

    Science.gov (United States)

    Locci, Ivan E.; Bowman, Cheryl L.; Gabb, Timothy P.

    2009-01-01

    NASA is developing fission surface power (FSP) system technology as a potential option for use on the surface of the moon or Mars. The goal is to design a robust system that takes full advantage of existing materials data bases. One of the key components of the power conversion system is the hot-side Heat Exchanger (HX). One possible design for this heat exchanger requires a joint of the dissimilar metals 316L stainless steel and Inconel 718, which must sustain extended operation at high temperatures. This study compares two joining techniques, brazing and diffusion bonding, in the context of forming the requisite stainless steel to superalloy joint. The microstructures produced by brazing and diffusion bonding, the effect of brazing cycle on the mechanical tensile properties of the alloys, and the strength of several brazed joints will be discussed.

  13. The evolution of interface microstructure in a ZrO2/Ag-Cu-Al-Ti system

    International Nuclear Information System (INIS)

    Among ceramic/metal (C/M) joining technologies, the active filler metal method has been studied extensively due to the simple brazing process and excellent joint strength. Active metal elements, typically Ti, are intentionally added to braze alloys to enhance the formation of reaction products between the ceramic and the braze metal at the C/M interface. In the brazing of Al2O3 with the Ag-Cu-Ti filler metal, reaction products such as γ-TiO, Cu2(Ti, Al)4O, Ti3(Cu0.76Al0.18Sn0.06)3O were found, while products such as Ti5Si3 and TiN formed in the brazing of Si3N4. The presence of reaction layers at the C/M interface influences the interface strength in a complex way. In Cu/Al2O3, Co/Al2O3, Ni/Al2O3, and Cu/diamond systems, maxima of joint strength were observed at some intermediate Ti addition, while the flexural strength decreased substantially with the thickening of the TiO layer in a ZrO2/Ag-Cu-Sn-Ti system. Thus, composition of the braze alloy (particularly, the content of the active metal), process conditions such as brazing temperature and time, microstructure and mechanical properties of reaction products at the C/M interfaces, interfacial chemistry, and residual stress are primary factors to be studied in order to understand the strengths of the C/M interfaces systematically. In the present and the following papers, evolutions of interfacial microstructures at various brazing conditions, and corresponding interface strengths are reported, respectively, for a ZrO2/Ag-Cu-Al-Ti system

  14. A reliable repair solution; Betriebssichere Instandsetzungsloesung

    Energy Technology Data Exchange (ETDEWEB)

    Masannek, E. [KWG-Kraftwerksgesellschaft Stassfurt mbH (Germany); [KWG-Kraftwerksgesellschaft Stassfurt mbH (Germany); Ebi, G. [Sensoplan AG, Hohentengen (Germany); [Sensoplan AG, Hohentengen (Germany)

    2006-07-01

    A ground fault of the generator rotor caused a forced outage of the steam turbine generator at the Stassfurt industrial power plant on April 18, 2004. The subsequent root cause analysis identified the fatigue fracture of a coil connector of the rotor winding as failure origin. An improved design of the brazed copper strands and an optimized induction brazing procedure eliminating the risk of hydrogen embrittlement served to establish a mechanically robust repair solution. (orig.)

  15. Investigation into the joining of MoSi{sub 2} to 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Vaidya, R.U.; Bartlett, A.H.; Conzone, S.D.; Butt, D.P.

    1996-10-01

    Partial transient liquid phase joining and low temperature brazing were applied in joining MoSi{sub 2} to 316L ss. Exploratory studies were carried out on various interlayer materials. Mechanical, physical, and chemical compatibilities between various interlayers, brazing material, and substrate materials were investigated. Effect of thermal expansion mismatch between various components of the joint on the overall joint integrity was also studied. Preliminary findings are outlined.

  16. A Study of Deposition Coatings Formed by Electroformed Metallic Materials

    OpenAIRE

    Hayashi, Shoji; Sugiyama, Shuta; Shimura, Kojiro; Tobayama, Go; Togashi, Toshio

    2016-01-01

    Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface ...

  17. 46 CFR 56.75-5 - Filler metal.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Filler metal. 56.75-5 Section 56.75-5 Shipping COAST... Brazing § 56.75-5 Filler metal. (a) The filler metal used in brazing must be a nonferrous metal or alloy having a melting point above 1,000 °F. and below that of the metal being joined. The filler metal...

  18. Improved method for the preparation of TiN-coated WC-Co-based samples for cross-sectional AEM investigation.

    Science.gov (United States)

    Hefter, J; Ostreicher, K; Sung, C

    1992-11-01

    An improved method for the preparation of cross-sectional thin foils of coated WC-Co samples for studies by analytical electron microscopy is described. A braze alloy is used to join the sections of the sample together and the resulting sample is stable during subsequent grinding, dimpling, and milling operations. Cross-sectional micrographs provide examples of the efficacy of this method. No microstructural alteration associated with the brazing operation was observed. PMID:1472751

  19. Improved Blackbody Temperature Sensors for a Vacuum Furnace

    Science.gov (United States)

    Farmer, Jeff; Coppens, Chris; O'Dell, J. Scott; McKechnie, Timothy N.; Schofield, Elizabeth

    2009-01-01

    Some improvements have been made in the design and fabrication of blackbody sensors (BBSs) used to measure the temperature of a heater core in a vacuum furnace. Each BBS consists of a ring of thermally conductive, high-melting-temperature material with two tantalum-sheathed thermocouples attached at diametrically opposite points. The name "blackbody sensor" reflects the basic principle of operation. Heat is transferred between the ring and the furnace heater core primarily by blackbody radiation, heat is conducted through the ring to the thermocouples, and the temperature of the ring (and, hence, the temperature of the heater core) is measured by use of the thermocouples. Two main requirements have guided the development of these BBSs: (1) The rings should have as high an emissivity as possible in order to maximize the heat-transfer rate and thereby maximize temperature-monitoring performance and (2) the thermocouples must be joined to the rings in such a way as to ensure long-term, reliable intimate thermal contact. The problem of fabricating a BBS to satisfy these requirements is complicated by an application-specific prohibition against overheating and thereby damaging nearby instrumentation leads through the use of conventional furnace brazing or any other technique that involves heating the entire BBS and its surroundings. The problem is further complicated by another application-specific prohibition against damaging the thin tantalum thermocouple sheaths through the use of conventional welding to join the thermocouples to the ring. The first BBS rings were made of graphite. The tantalum-sheathed thermocouples were attached to the graphite rings by use of high-temperature graphite cements. The ring/thermocouple bonds thus formed were found to be weak and unreliable, and so graphite rings and graphite cements were abandoned. Now, each BBS ring is made from one of two materials: either tantalum or a molybdenum/titanium/zirconium alloy. The tantalum

  20. Fabrication of High-Temperature Heat Exchangers by Plasma Spraying Exterior Skins on Nickel Foams

    Science.gov (United States)

    Hafeez, P.; Yugeswaran, S.; Chandra, S.; Mostaghimi, J.; Coyle, T. W.

    2016-06-01

    Thermal-sprayed heat exchangers were tested at high temperatures (750 °C), and their performances were compared to the foam heat exchangers made by brazing Inconel sheets to their surface. Nickel foil was brazed to the exterior surface of 10-mm-thick layers of 10 and 40 PPI nickel foam. A plasma torch was used to spray an Inconel coating on the surface of the foil. A burner test rig was built to produce hot combustion gases that flowed over exposed face of the heat exchanger. Cooling air flowed through the foam heat exchanger at rates of up to 200 SLPM. Surface temperature and air inlet/exit temperature were measured. Heat transfer to air flowing through the foam was significantly higher for the thermally sprayed heat exchangers than for the brazed heat exchangers. On an average, thermally sprayed heat exchangers show 36% higher heat transfer than conventionally brazed foam heat exchangers. At low flow rates, the convective resistance is large (~4 × 10-2 m2 K/W), and the effect of thermal contact resistance is negligible. At higher flow rates, the convective resistance decreases (~2 × 10-3 m2 K/W), and the lower contact resistance of the thermally sprayed heat exchanger provides better performance than the brazed heat exchangers.

  1. NEW HIGH STRENGTH AND FASTER DRILLING TSP DIAMOND CUTTERS

    Energy Technology Data Exchange (ETDEWEB)

    Robert Radtke

    2006-01-31

    The manufacture of thermally stable diamond (TSP) cutters for drill bits used in petroleum drilling requires the brazing of two dissimilar materials--TSP diamond and tungsten carbide. The ENDURUS{trademark} thermally stable diamond cutter developed by Technology International, Inc. exhibits (1) high attachment (shear) strength, exceeding 345 MPa (50,000 psi), (2) TSP diamond impact strength increased by 36%, (3) prevents TSP fracture when drilling hard rock, and (4) maintains a sharp edge when drilling hard and abrasive rock. A novel microwave brazing (MWB) method for joining dissimilar materials has been developed. A conventional braze filler metal is combined with microwave heating which minimizes thermal residual stress between materials with dissimilar coefficients of thermal expansion. The process results in preferential heating of the lower thermal expansion diamond material, thus providing the ability to match the thermal expansion of the dissimilar material pair. Methods for brazing with both conventional and exothermic braze filler metals have been developed. Finite element modeling (FEM) assisted in the fabrication of TSP cutters controllable thermal residual stress and high shear attachment strength. Further, a unique cutter design for absorbing shock, the densification of otherwise porous TSP diamond for increased mechanical strength, and diamond ion implantation for increased diamond fracture resistance resulted in successful drill bit tests.

  2. Suppression of Boride Formation in Transient Liquid Phase Bonding of Pairings of Parent Superalloy Materials with Different Compositions and Grain Structures and Resulting Mechanical Properties

    Science.gov (United States)

    Steuer, Susanne; Singer, Robert F.

    2014-07-01

    Two Ni-based superalloys, columnar grained Alloy 247 and single-crystal PWA1483, are joined by transient liquid phase bonding using an amorphous brazing foil containing boron as a melting point depressant. At lower brazing temperatures, two different morphologies of borides develop in both base materials: plate-like and globular ones. Their ratio to each other is temperature dependent. With very high brazing temperatures, the deleterious boride formation in Alloy 247 can be totally avoided, probably because the three-phase-field moves to higher alloying element contents. For the superalloy PWA1483, the formation of borides cannot be completely avoided at high brazing temperatures as incipient melting occurs. During subsequent solidification of these areas, Chinese-script-like borides precipitate. The mechanical properties (tensile tests at room and elevated temperatures and short-term creep rupture tests at elevated temperatures) for brazed samples without boride precipitation are very promising. Tensile strengths and creep times to 1 pct strain are comparable, respectively, higher than the ones of the weaker parent material for all tested temperatures and creep conditions (from 90 to 100 pct rsp. 175 to 250 pct).

  3. 汽车空调压缩机吸入管钎焊工艺设计%Design of soldering process for suction pipe in automobile air conditioning compressor

    Institute of Scientific and Technical Information of China (English)

    王红宾; 白钢; 付春坤

    2012-01-01

    吸入管与压缩机连接处的制冷剂泄漏是汽车空调系统的常见问题,制冷剂泄漏严重影响压缩机效率,并增加能耗、污染环境.在现有钎焊工艺的基础上,结合生产实际,设计和优化钎焊工艺参数,改善钎焊接头性能,提高焊接质量,解决汽车空调压缩机吸入管的泄漏问题.利用UG三维软件设计效率更高、更便捷的钎焊工装夹具,以提高生产效率.%The leakage of refrigerants which seriously impact on the compressor efficiency and increase energy consumption and environmental pollution is the common problems of automotive air conditioning system in the place that the suction pipe and compressor connection.Based on the existing brazing process,combining with practices,this paper designs and optimizes brazing process parameters to improve the performance of brazing joint and brazing quality and solve problems that the suction pipe of automobile air-conditioner compressor leaks.Using UG 3D software,designs brazing jig that is more efficient and convenient to improve production efficiency.

  4. Thermal response and material degradation of tungsten-coated carbon divertor mock-ups by high heat flux

    International Nuclear Information System (INIS)

    Carbon/carbon composite (CX-2002U) and isotropic grain graphite (IG-430U) coated by VSP-W (Vacuum Plasma Splay-tungsten) were developed as a lightweight high-Z plasma-facing material. After brazing them on OFHC (Oxygen Free High Conductivity) blocks using a titanium foil and silver based materials, their thermal response and thermal fatigue properties were examined. The targets were actively cooled under steady state high heat flux. Heat load resistance of the VPS-W coated CX-2002U/OFHC was much better than that of the VSP-W coated IG-430U/OFHC due to the high thermal conductivity of CX-2002U (350 W/mK). Neither cracks nor exfoliation were observed on the W surface and the braze interface even after 160 cycles of heat load for 20 s at 10 MW/m2 in the case of Ti brazing. This result indicates that the Ti-brazing is a promising alternative to Ag-brazing for joining carbon to Cu and it is a potential candidate for a high heat resistance armor material on plasma facing components. (author)

  5. 中国古青铜器表面富锡铜鎏镀及鎏焊的工艺探索第二部分——鎏镀的原理及工艺设计%Technological study on amalgam coating and brazing of tin-rich copper on surface of bronze wares of ancient China—Part Ⅱ.Principle and process design of amalgam coating

    Institute of Scientific and Technical Information of China (English)

    吴元康; 储荣邦

    2012-01-01

    The major roles of Cu, Sn, Pd, and Hg in amalgam coating material, the principle of metallurgical reactions between the elements, and the phase transformation involved in the process of removing mercury by heating were described. Three formulations of Sn-rich copper powder for amalgam coating were designed to reproduce antique bronze mirrors. The pretreatment of bronze wares, the preparation of amalgam coating material and its coating method, and the operation procedure of mercury removal by heating were introduced. The reasons why the Sn-rich coatings on ancient bronze wares are produced by amalgam coating of Sn-rich copper were presented.%阐述了鎏镀料中铜、锡、铅、汞的主要作用,以及加热驱汞时各元素之间冶金反应的原理和物相变化.以仿古青铜镜为例,设计了3种鎏镀用富锡铜粉的配方,介绍了青铜件的镀前处理,汞齐涂料配制和涂抹的方法,以及加热驱汞的操作步骤.指出了古青铜器表面富锡镀层为鎏镀富锡铜的依据.

  6. 中国古青铜器表面富锡铜鎏镀及鎏焊的工艺探索 第一部分——富锡铜鎏镀在古青铜器中的应用%Technological study on amalgam coating and brazing of tin-rich copper on surface of bronze wares of ancient China—Part Ⅰ.Application of amalgam coating of tin-rich copper in ancient bronze wares

    Institute of Scientific and Technical Information of China (English)

    吴元康; 储荣邦

    2012-01-01

    The ancient bronze wares with Sn-rich copper coatings on their surfaces were introduced based on the archaeological findings in China. The definition and classification of amalgam coating were described. It is pointed out that most ancient bronze wares were treated by amalgam coating of Sn-rich copper, not by hot-dip plating or other processes. The removal of Hg by heating after amalgam coating and the decomposition of Sn7-9Hg in soil lead to the fact that Hg is undetectable on the surface of ancient bronze wares.%根据出土文物的情况,介绍了表面具有富锡铜层的古青铜器.阐述了鎏镀的定义及分类.指出古青铜器大多经过富锡铜鎏镀工艺处理,而不是热浸镀或其他工艺.认为鎏镀后加热驱汞及Sn7-9Hg在土壤环境中分解,是导致古青铜器表面测不出汞的原因.

  7. Manufacturing of indigenous RF cavity for Indus-2

    International Nuclear Information System (INIS)

    At present four, 505.8 MHz, imported copper RF cavities are being used in Indus-2 synchrotron radiation source. These cavities are used to impart energy to the electron beam to attain the required energy level and also maintain it. From first stage of accelerator i.e booster synchrotron the electron beam is injected into Indus-2 ring where the beam energy is increased from 550 MeV to 2.5 GeV using these cavities. Indigenous developmental work is initiated to fabricate RF cavities using in-house manufacturing facilities. For fabrication of this cavity various innovative tasks were executed which includes, development of forming tools, optimization of machining parameters, development of cutting tools, various brazing trials, brazing procedure qualification, design and development of machining and brazing fixtures, optimization of chemical cleaning procedure etc. The paper also discusses about specifications of the cavity, its vacuum testing and RF testing results. (author)

  8. Effect of La2O3 Nanoparticles on the Brazeability, Microstructure, and Mechanical Properties of Al-11Si-20Cu Alloy

    Science.gov (United States)

    Sharma, Ashutosh; Roh, Myung Hwan; Jung, Jae Pil

    2016-06-01

    The Al-11Si-20Cu brazing alloy and its ex situ composite with the content ranging from 0.01 to 0.05 wt.% of La2O3 are produced by electromagnetic induction-cum-casting route. The brazeability of the alloy and composite samples are tested using the spreading technique according to JIS Z-3197 standard. The mechanical properties such as filler microhardness, tensile shear strength, and elongation of the brazed joints are evaluated in the as-brazed condition. It is reported that incorporation of an optimal amount of 0.05 wt.% of hard La2O3 nanoparticles in the Al-Si-Cu matrix inhibits the growth of the large CuAl2 intermetallic compounds (IMCs) and Si particles. As a consequence, the composite filler brazeability, microhardness, joint tensile shear strength, and elongation are improved significantly compared to those of monolithic Al-11Si-20Cu alloy.

  9. Electrochemical profiling of multi-clad aluminium sheets used in automotive heat exchangers

    DEFF Research Database (Denmark)

    Bordo, Kirill; Ambat, Rajan; Peguet, Lionel;

    2014-01-01

    The objective of the present study is to understand the mechanisms of corrosion propagation across the multi-clad structure of Al alloys sheets as a function of local alloy composition and microstructure, with and without brazing treatment. Electro-chemical behaviour at different depths...... was profiled using a combination of glow dis-charge optical emission spectroscopy (GDOES) sputtering, localized potentiodynam-ic polarization and zero resistance ammetry (ZRA) measurements. Multi-clad struc-ture used was a four layer sandwich consisting of a copper-containing AA3xxx long-life core alloy, AA......4343 brazing clad on both sides and a copper-free AA3xxx interlay-er on the air-side of the sandwich sheet. The polarization behaviour of both as-rolled and brazed materials (i.e. corrosion potential, pitting potential, cathodic and anodic reactivities) was determined as a function of depth using...

  10. Development of beryllium bonds for plasma-facing components

    International Nuclear Information System (INIS)

    This study concerns the techniques of bonding beryllium to both structural material (AISI 316 SS) and heat sink material (copper and DS-copper) plates, and the characterization of the bonding material obtained. Conventional bonding techniques for joining Be to SS and copper using brazing alloys were first investigated. The best result was obtained using a silver-copper eutetic alloy as a brazing alloy. However, the high-temperature capability of the materials prepared by this method is limited by the performance of brazing alloys at the operating temperature. To avoid this problem, we are developing a joining process known as solid-state reaction bonding that improves the capability at the operating temperature. (orig.)

  11. Ultrasonic Spectroscopy of Stainless Steel Sandwich Panels

    Science.gov (United States)

    Cosgriff, Laura M.; Lerch, Bradley A.; Hebsur, Mohan G.; Baaklini, George Y.; Ghosn, Louis J.

    2003-01-01

    Enhanced, lightweight material systems, such as 17-4PH stainless steel sandwich panels are being developed for use as fan blades and fan containment material systems for next generation engines. In order to improve the production for these systems, nondestructive evaluation (NDE) techniques, such as ultrasonic spectroscopy, are being utilized to evaluate the brazing quality between the 17-4PH stainless steel face plates and the 17-4PH stainless steel foam core. Based on NDE data, shear tests are performed on sections representing various levels of brazing quality from an initial batch of these sandwich structures. Metallographic characterization of brazing is done to corroborate NDE findings and the observed shear failure mechanisms.

  12. Material studies in the frame of CLIC Accelerating structures production conducted within the Mechanics program together with Metso Oy

    CERN Document Server

    Nurminen, Janne

    2012-01-01

    MeChanICs (Marie Curie Linking Industry to CERN) is an Industry to Academia Partnership and Pathways (IAPP) platform for precision manufacturing knowledge exchange bringing together five Finnish manufacturing companies with Helsinki Insitute of Physics (HIP) and CERN. The scientific objective of MeChanICs project is to contribute to the manufacturing RTD of CLIC enabling technologies. The focus is on the design, materials, machining, brazing and assembly of A CLIC accelerating structure. This study deals with the materials work package of the program and wants to explore the following items: 1) producing copper accelerating structures for CLIC from raw copper powder by near net shape hot isostatic pressing (HIP). 2) The feasibility to use HIP diffusion bonding of the accelerator structures as a function of surface quality and applied temperature and pressure. 3) Brazing for CLIC AS auxiliary systems, like water cooling or damping manifolds, to the disc stack by coating one of the brazing partners with an enab...

  13. Development of laser welded appendages to Zircaloy-4 fuel tubing (sheath/cladding)

    International Nuclear Information System (INIS)

    Highlights: • Examines feasibility of laser welding appendages to Zr-4 tubing. • Laser welding minimizes the HAZ and removes toxic Be. • Mechanical properties of laser welds appear competitive with induction brazed joints. • Work appears promising and lays the foundation for further investigations. - Abstract: Laser welding is a potential alternative to the induction brazing process commonly used for appendage attachment in CANDU® fuel fabrication that uses toxic Be as a filler metal, and creates multiple large heat affected zones in the sheath. For this work, several appendages were laser welded to tubing using different laser heat input settings and then examined with a variety of techniques: visual examination, metallography, shear strength testing, impact testing, and fracture surface analysis. Where possible, the examination results are contrasted against production induction brazed joints. The work to date looks promising for laser welded appendages. Further work on joint optimization, corrosion testing, irradiation testing, and post-irradiation examination will be performed in the future

  14. Metal-ceramic joining; Proceedings of the Symposium, TMS Fall Meeting, Detroit, MI, Oct. 8, 9, 1990

    International Nuclear Information System (INIS)

    Topics discussed in this book are in the areas of high temperature applications, joining processes, and electronic applications in metal ceramic joining. Papers are presented on the reactive diffusion bonding of Si3N4 to MA6000, the material factors affecting joining of silicon nitride ceramics, an overview of techniques and recent advances in ceramic-metal joining and metallization, a residual stress analysis and microstructural observations of ceramic-to-metal brazed joints, and the peel adhesion bond strength of direct bonded copper-alumina as affected by alumina sintering aids. Attention is also given to joining of partially stabilized zirconia to nodular cast iron, the silicate brazing of alumina ceramics using calcium aluminosilicate interlayers, graded metal-ceramic microjoints in parallel, the reactive metal brazing of aluminum nitride, and the effect of substrate surface on the bonding of Cu-AlN by active metal thin film and gas-metal eutectic methods

  15. Joining of Zirconium Diboride-Based Ceramic Composites to Metallic Systems for High-Temperature Applications

    Science.gov (United States)

    Asthana, R.; Singh, M.

    2008-01-01

    Three types of hot-pressed zirconium diboride (ZrB2)-based ultra-high-temperature ceramic composites (UHTCC), ZrB2-SiC (ZS), ZrB2-SiC-C (ZSC), and ZrB2-SCS9-SiC (ZSS), were joined to Cu-clad-Mo using two Ag-Cu brazes (Cusil-ABA and Ticusil, T(sub L) approx.1073-1173 K) and two Pd-base brazes (Palco and Palni, T(sub L) approx.1493-1513 K). Scanning Electron Microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) revealed greater chemical interaction in joints made using Pd-base brazes than in joints made using Ag-Cu based active brazes. The degree of densification achieved in hot pressed composites influenced the Knoop hardness of the UHTCC and the hardness distribution across the braze interlayer. The braze region in Pd-base system displayed higher hardness in joints made using fully-dense ZS composites than in joints made using partially-dense ZSS composites and the carbon-containing ZSC composites. Calculations indicate a small negative elastic strain energy and an increase in the UHTCC's fracture stress up to a critical clad layer thickness . Above this critical thickness, strain energy in the UHTCC is positive, and it increases with increasing clad layer thickness. Empirical projections show a reduction in the effective thermal resistance of the joints and highlight the potential benefits of joining the UHTCC to Cu-clad-Mo.

  16. Discipline report on thermal analyses of M551, M552, and M553 experiments. [on gravity and heat conduction

    Science.gov (United States)

    Muraki, T.; Masubuchi, K.

    1974-01-01

    Reduced gravity does not significantly affect the thermal histories in the M551 specimen, even if molten metal flow pattern is different from that in terrestrial conditions. Thermal histories corresponding to terrestrial experimental conditions were calculated by use of the computer programs. Heat conduction through brazing alloy (M552 experiment) is improved in the Skylab conditions, because of the increased extent, rate and uniformity of braze spreading in space. Effects of reduced gravity on heat flow in the M553 specimen are insignificant, because convection effects appear instantaneously and conduction is a governing factor on the heat flow.

  17. Assessing the influence of heat treatments on γ-TiAl joints

    OpenAIRE

    Guedes, A.; Pinto, A. M. P.; Vieira, M F; Viana, Filomena

    2006-01-01

    The heat treatment of γ-TiAl alloy (Ti-47Al-2Cr-2Nb (at.%)) diffusion brazed joints was investigated. Joining was performed using a Ti/Ni/Ti clad-laminated braze alloy foil at 1050 and 1150ºC with a dwell time of 10 minutes. The joints were subsequently heat treated at 1250 and 1350ºC for 240 and 30 minutes, respectively. The microstructure and the chemical composition of the interfaces were analysed by scanning electron microscopy (SEM) and by energy dispersive X-ray spectroscopy (EDS), r...

  18. Development of high intensity ECR ion source for ADS

    International Nuclear Information System (INIS)

    Electron cyclotron resonance principle based ion source consists of plasma chamber, five electrode ion extraction system and high voltage ceramic insulation system. Five electrodes have complex geometry with water cooling arrangement and bimetallic joints. Beam diagnostic and beam dump system are inherent part of it to measure beam quality and current. This paper describes mechanical design and manufacturing features of plasma chamber, electrodes and faraday cup of proton source. Various joining techniques like braze welding, brazing, electron beam welding and diffusion bonding are used to manufacture electrodes and plasma chamber. Beam diagnostic chamber and beam dump chamber are designed, manufactured and helium leak tested at CDM, BARC. (author)

  19. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Directory of Open Access Journals (Sweden)

    L. Quintino

    2013-09-01

    Full Text Available Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic NiTi and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to assess the type of fracture and the capability of achieving bonding and involved mechanisms are discussed.

  20. Joining of ceramic Ba0.5Sr0.5Co0.8Fe0.2O3 membranes for oxygen production to high temperature alloys

    DEFF Research Database (Denmark)

    Kiebach, Wolff-Ragnar; Engelbrecht, Kurt; Kwok, Kawai;

    2016-01-01

    The possibility of joining dense ceramic BCSF tubular membranes to metal alloys using a silver braze was investigated. Four different alloys (Crofer 22 APU (R), Kanthal APM (R), Haynes 214 (R) and EN 1.4841) were considered and the influence of their oxide scale stability/reactivity and their the......The possibility of joining dense ceramic BCSF tubular membranes to metal alloys using a silver braze was investigated. Four different alloys (Crofer 22 APU (R), Kanthal APM (R), Haynes 214 (R) and EN 1.4841) were considered and the influence of their oxide scale stability...

  1. Bonding and Integration of C-C Composite to Cu-Clad-Molybdenum for Thermal Management Applications

    Science.gov (United States)

    Asthana, R.; Singh, M.; Shpargel, T.P.

    2008-01-01

    Two- and three-dimensional carbon-carbon composites with either resin-derived matrix or CVI matrix were joined to Cu-clad-Mo using active Ag-Cu braze alloys for thermal management applications. The joint microstructure and composition were examined using Field-Emission Scanning Electron Microscopy and Energy-Dispersive Spectroscopy, and the joint hardness was characterized using the Knoop microhardness testing. Observations on the infiltration of the composite with molten braze, dissolution of metal substrate, and solute segregation at the C-C surface have been discussed. The thermal response of the integrated assembly is also briefly discussed.

  2. BNL 56 MHz HOM Damper Prototype Fabrication at JLab

    Energy Technology Data Exchange (ETDEWEB)

    Huque, Naeem A. [Jefferson Lab., Newport News, VA (United States); Daly, Edward F. [Jefferson Lab., Newport News, VA (United States); Clemens, William A. [Jefferson Lab., Newport News, VA (United States); McIntyre, Gary T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Wu, Qiong [Brookhaven National Lab. (BNL), Upton, NY (United States); Seberg, Scott [Brookhaven National Lab. (BNL), Upton, NY (United States); Bellavia, Steve [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-09-01

    A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider's (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

  3. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Quintino, L., E-mail: lquirino@ist.utl.pt [Universidade Tecnica de Lisboa (IST/UTL) (Portugal). Instituto Superior Tecnico. Dept. de Engenharia Mecanica; Liu, L., E-mail: ray.plasma@gmail.com [Tsinghua Univ., Beijing (China). Dept. of Mechanical Engineering; Hu, A.; Zhou, Y., E-mail: anming.hu@uwaterloo.ca, E-mail: nzhou@uwaterloo.ca [University of Waterloo, Ontario (Canada). Dept. of Mechanical Engineering; Miranda, R.M., E-mail: rmiranda@fct.unl.pt [Universidade Nova de Lisboa (UNIDEMI), Caparica (Portugal). Dept. de Engenharia Mecanica e Industrial

    2013-07-15

    Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic Ni Ti and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to asses the type of fracture and the capability of achieving bonding and involved mechanisms are discussed. (author)

  4. Tensile, Fatigue and Creep Properties of Aluminum Heat Exhanger Tube Alloys for Temperatures from 293 K to 573 K (20°C to 300°C)

    OpenAIRE

    Kahl, Sören; Ekström, Hans-Erik; Mendoza, Jesus

    2014-01-01

    Since automotive heat exchangers are operated at varying temperatures and under varying pressures, both static and dynamic mechanical properties should be known at different temperatures. Tubes are the most critical part of the most heat exchangers made from aluminum brazing sheet. We present tensile test, stress amplitude-fatigue life, and creep–rupture data of six AA3XXX series tube alloys after simulated brazing for temperatures ranging from 293 K to 573 K (20 °C to 300 °C). While correlat...

  5. BNL 56 MHz HOM damper prototype fabrication at JLAB

    Energy Technology Data Exchange (ETDEWEB)

    Huque, N.; McIntyre, G.; Daly, E. F.; Clemens, W.; Wu, Q.; Seberg, S.; Bellavia, S.

    2015-05-03

    A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider’s (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

  6. Fracture analysis of Ag nanobrazing of NiTi to Ti alloy

    International Nuclear Information System (INIS)

    Dissimilar joining of shape memory alloys to Ti alloys has long been attempted by several research groups due to the foreseen potential industrial applications. However, the very dissimilar thermo-physical properties of both materials place several difficulties. Brazing can be a solution since the base materials are subjected to a less sharp thermal cycle. In the present study brazed overlap joints of 1 mm thick plates of equiatomic Ni Ti and Ti6Al4V were produced using nano silver based filler materials. Surfaces were analyzed to asses the type of fracture and the capability of achieving bonding and involved mechanisms are discussed. (author)

  7. Ceramic Technology Project database: March 1990 summary report. DOE/ORNL Ceramic Technology Project

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.L.P.

    1992-07-01

    This report is the fifth in a series of semiannual data summary reports on information being stored in the Ceramic Technology Project (CTP) database. The overall system status as of March 31, 1990, is summarized, and the latest additions of ceramic mechanical properties data are given for zirconia, silicon carbide, and silicon nitride ceramic mechanical properties data, including some properties on brazed specimens.

  8. Ceramic Technology Project database: March 1990 summary report

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.L.P.

    1992-07-01

    This report is the fifth in a series of semiannual data summary reports on information being stored in the Ceramic Technology Project (CTP) database. The overall system status as of March 31, 1990, is summarized, and the latest additions of ceramic mechanical properties data are given for zirconia, silicon carbide, and silicon nitride ceramic mechanical properties data, including some properties on brazed specimens.

  9. Bibliography of the technical literature of the Materials Joining Group, 1951--1991

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Goodwin, G.M.; Gardner, K. [comps.

    1991-12-01

    This document contains a listing of the written scientific information originating in the Materials Joining (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1991. This registry of documents is as much as possible, in the order of issue date.

  10. 46 CFR 57.03-1 - General requirements.

    Science.gov (United States)

    2010-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING... procedure qualification thickness ranges Thickness, “t” of test plate or pipe as welded (inches) Range of thickness of materials qualified by test plate or pipe (inches) Minimum Maximum 1/16 to 3/8, inclusive...

  11. Preparing for CLIC tests

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    The Canon 5 undergoes first brazing for preparation in the CLIC study at the CLIC Test Facility 2 (CTF2). This will test injection for a proposed linear collider that will further explore discoveries made at the LHC. Electric fields in the canon will boost electrons into the acceleration fields of the collider.

  12. Transient thermal behavior of multilayer media: Modeling and application to stratified moulds

    Science.gov (United States)

    Lazard, M.

    2006-07-01

    Transient and steady-state heat transfer in multilayer media is investigated by the thermal quadrupole method. A semi-analytical solution is proposed for the cases of layers parallel or orthogonal to the main heat-flux direction. The principal application is the study of the effect of the brazing metal used in stratified steel moulds.

  13. Half-yearly report on the 1-10-1967

    International Nuclear Information System (INIS)

    This document gathers several reports of studies. The first part contains studies related to heat exchange problems: non destructive testing in the fabrication of nuclear exchangers; welding of heat exchangers; leakage detection during operation on the tubes of a heat exchanger of a boiling heavy water reactor; realisation of reliability device of thermocouples; tests of thermal insulators; study of decompression strength of irradiated insulating materials by dust rate measurement). The second part contains studies related to various technologies: study of the behaviour of different brazed joints in Be-Be(Zr-1,6Cu), (Zr-1,6Cu) and Be(Zr-1,6Cu); study of brazing of alumina-metal and alumina-alumina assemblies; fixation by brazing of wires on the inner faces of an hexagonal tube (brazing of a turbulence wire on Rapsodie needle sheath), welding tests on AG3; non-destructive testing of Zy-stainless steel diffused junctions; fabrication of pressure tubes for Aida loop; realisation of fatigue cracks by ultrasounds; application of electrolytic coatings to fretting of stainless steels, first results; silastene irradiation

  14. High-strength alloy with resistance to hydrogen-environment embrittlement

    Science.gov (United States)

    Mcnamara, T. G.

    1975-01-01

    Alloy is precipitation-hardened, high-strength, and low-thermal-expansion materials. It is iron-based and contains nickel and chromium at lower levels than high-strength alloys. It is readily welded and brazed and has good oxidation resistance. Tests indicated there was no reduction of notched or smooth strength.

  15. Fabrication and characterization of tungsten and graphite based PFC for divertor target elements of ITER like tokamak application

    Energy Technology Data Exchange (ETDEWEB)

    Khirwadkar, S.S., E-mail: sameer@ipr.res.in [Institute For Plasma Research, Bhat, Gandhinagar, Gujarat (India); Singh, K.P.; Patil, Y.; Khan, M.S.; Buch, J.J.U.; Patel, Alpesh; Tripathi, Sudhir [Institute For Plasma Research, Bhat, Gandhinagar, Gujarat (India); Jaman, P.M.; Rangaraj, L.; Divakar, C. [Materials Science Division, National Aerospace Laboratories, CSIR, Bangalore, Karnataka (India)

    2011-10-15

    The development of the fabrication technology of macro-brush configuration of tungsten (W) and carbon (graphite and CFC) plasma facing components (PFCs) for ITER like tokamak application is presented. The fabrication of qualified joint of PFC is a requirement for fusion tokamak. Vacuum brazing method has been employed for joining of W/CuCrZr and C/CuCrZr. Oxygen free high conductivity (OFHC) copper casting on W tiles was performed followed by machining, polishing and ultrasonic cleaning of the samples prior to vacuum brazing. The W/CuCrZr and graphite/CuCrZr based test mockups were vacuum brazed using silver free alloys. The mechanical shear and tensile strengths were evaluated for the W/CuCrZr and graphite/CuCrZr brazed joint samples. The micro-structural examination of the joints showed smooth interface. The details of fabrication and characterization procedure for macro-brush tungsten and carbon based PFC test mockups are presented.

  16. Improved Air-Treatment Canister

    Science.gov (United States)

    Boehm, A. M.

    1982-01-01

    Proposed air-treatment canister integrates a heater-in-tube water evaporator into canister header. Improved design prevents water from condensing and contaminating chemicals that regenerate the air. Heater is evenly spiraled about the inlet header on the canister. Evaporator is brazed to the header.

  17. Progress in Joining Ceramics to Metals

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The research and development of joining methods of ceramics to metals, especially brazing, diffusion bonding and partial transition liquid phase bonding, were introduced. Some opinions were put forward. For new composites emerging, it is necessary to develop new joining methods, particularly in the field of high temperature technique for joining ceramics to superalloys.

  18. Energy absorption of andwiched honeycombs with facesheets under in-plane crushing

    NARCIS (Netherlands)

    Atli-Veltin, B.; Gandhi, F.

    2013-01-01

    The in-plane crushing and energy absorption of sandwiched honeycomb cores with facesheets are examined through finite element simulations. Assuming no debonding between the facesheet and honeycomb core (which would be the case if manufacturing techniques such as brazing are used to produce very stro

  19. Methods for batch fabrication of cold cathode vacuum switch tubes

    Science.gov (United States)

    Walker, Charles A.; Trowbridge, Frank R.

    2011-05-10

    Methods are disclosed for batch fabrication of vacuum switch tubes that reduce manufacturing costs and improve tube to tube uniformity. The disclosed methods comprise creating a stacked assembly of layers containing a plurality of adjacently spaced switch tube sub-assemblies aligned and registered through common layers. The layers include trigger electrode layer, cathode layer including a metallic support/contact with graphite cathode inserts, trigger probe sub-assembly layer, ceramic (e.g. tube body) insulator layer, and metallic anode sub-assembly layer. Braze alloy layers are incorporated into the stacked assembly of layers, and can include active metal braze alloys or direct braze alloys, to eliminate costs associated with traditional metallization of the ceramic insulator layers. The entire stacked assembly is then heated to braze/join/bond the stack-up into a cohesive body, after which individual switch tubes are singulated by methods such as sawing. The inventive methods provide for simultaneously fabricating a plurality of devices as opposed to traditional methods that rely on skilled craftsman to essentially hand build individual devices.

  20. The Apparent Contact Angle and Wetted Area of Active Alloys on Silicon Carbide as a Function of the Temperature and the Surface Roughness: A Multivariate Approach

    Science.gov (United States)

    Tillmann, Wolfgang; Pfeiffer, Jan; Wojarski, Lukas

    2015-08-01

    Despite the broad field of applications for active filler alloys for brazing ceramics, as well as intense research work on the wetting and spreading behavior of these alloys on ceramic surfaces within the last decades, the manufactured joints still exhibit significant variations in their properties due to the high sensitivity of the alloys to changing brazing conditions. This increases the need for investigations of the wetting and spreading behavior of filler alloys with regard to the dominating influences combined with their interdependencies, instead of solely focusing on single parameter investigations. In this regard, measurements of the wetting angle and area were conducted at solidified AgCuTi and CuSnTi alloys on SiC substrates. Based on these measurements, a regression model was generated, illustrating the influence of the brazing temperature, the roughness of the faying surfaces, the furnace atmosphere, and their interdependencies on the wetting and spreading behavior of the filler alloys. It was revealed that the behavior of the melts was significantly influenced by the varied brazing parameters, as well as by their interdependencies. This result was also predicted by the developed model and showed a high accuracy.

  1. Bibliography of the technical literature of the Materials Joining Group, Metals and Ceramics Division, 1951 through June 1987

    International Nuclear Information System (INIS)

    This document contains a listing of the written scientific information originating in the Materials Joining Group (formerly the Welding and Brazing Group), Metals and Ceramics Division, Oak Ridge National Laboratory during 1951 through June 1987. It is a registry of about 400 documents as nearly as possible in the order in which they were issued

  2. Standard marking system for valves, fittings, flanges and unions

    International Nuclear Information System (INIS)

    The marking system described applies to valves, fittings, flanges and unions used in piping connections which include flanged, soldered, brazed, threaded or welded joints. These specified markings serve to identify the manufacturer, rating designation, materials of construction, and special service limitations imposed by the manufacturer

  3. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ2 and Cr2N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  4. 76 FR 45655 - Airworthiness Directives; Superior Air Parts and Lycoming Engines (Formerly Textron Lycoming...

    Science.gov (United States)

    2011-08-01

    ... Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will not affect intrastate aviation in Alaska...). Diaphragms produced from specific lot numbers could have stud threads that don't meet design, incomplete braze between the stud and hub, and studs made from lower temper material. Diaphragms from these...

  5. 46 CFR 56.75-10 - Joint clearance.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Joint clearance. 56.75-10 Section 56.75-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Brazing § 56.75-10 Joint clearance. (a) The clearance between surfaces to be joined shall be no larger than is necessary to insure...

  6. 49 CFR 178.65 - Specification 39 non-reusable (non-refillable) cylinders.

    Science.gov (United States)

    2010-10-01

    ... which will not be detrimental to the integrity of the cylinder. Welding or brazing of attachments to the cylinder must be completed prior to all pressure tests. (4) Welding procedures and operators must be... head has adequate thickness, each opening must be reinforced by a securely attached fitting, boss,...

  7. CW RFQ fabrication and engineering

    International Nuclear Information System (INIS)

    The design and fabrication of a four-vane RFQ to deliver a 100 mA CW proton beam at 6.7 MeV is described. This linac is an Oxygen-Free Electrolytic (OFE) copper structure 8 m in length and was fabricated using hydrogen furnace brazing as the joining technology

  8. 46 CFR 57.01-1 - Qualifications and production tests.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Qualifications and production tests. 57.01-1 Section 57.01-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Scope § 57.01-1 Qualifications and production tests. (a) (Replaces QW 101 and QB 101.) The regulations in this part shall apply to...

  9. 46 CFR 57.06-4 - Production testing specimen requirements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Production testing specimen requirements. 57.06-4 Section 57.06-4 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Production Tests § 57.06-4 Production testing specimen requirements. (a) For test plates three-fourths inch or less in thickness...

  10. 46 CFR 57.06-3 - Method of performing production testing.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Method of performing production testing. 57.06-3 Section 57.06-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Production Tests § 57.06-3 Method of performing production testing. (a) Except as otherwise specified in this section a test plate...

  11. 46 CFR 57.06-5 - Production toughness testing.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Production toughness testing. 57.06-5 Section 57.06-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Production Tests § 57.06-5 Production toughness testing. (a) In addition to the test specimens required by § 57.06-4(a), production toughness...

  12. 46 CFR 57.06-1 - Production test plate requirements.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Production test plate requirements. 57.06-1 Section 57.06-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Production Tests § 57.06-1 Production test plate requirements. (a) Production test plates shall be provided for Class I, Class I-L, Class...

  13. 46 CFR 57.06-2 - Production test plate interval of testing.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Production test plate interval of testing. 57.06-2 Section 57.06-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Production Tests § 57.06-2 Production test plate interval of testing. (a) At least one set of production test plates shall be...

  14. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  15. 29 CFR 1910.255 - Resistance welding.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Resistance welding. 1910.255 Section 1910.255 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.255 Resistance welding. (a.... Ignitron tubes used in resistance welding equipment shall be equipped with a thermal protection switch....

  16. 46 CFR 57.05-5 - Low temperature application.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Low temperature application. 57.05-5 Section 57.05-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING WELDING AND BRAZING Performance Qualifications § 57.05-5 Low temperature application. For low temperature application, each...

  17. 化学镀

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    3D Stacked Packages With Bumpless Interconnect Technology;?AActive brazing alloy produced by electroless plating technique; Additional effect of electroless plating fihn (damping capacity improvelnent; Adsorbates formed on non-conducting substrates by two-step catalyzation pretreatment for electroless plating;Deposition of Through-Hole Metal Fihn Oll Glass with Electroless Plating

  18. Energy and technology review

    International Nuclear Information System (INIS)

    Research programs at LLNL are reviewed. This issue discusses validation of the pulsed-power design for FXR, the NOVA plasma shutter, thermal control of the MFTF superconducting magnet, a low-energy x-ray spectrometer for pulsed-source diagnostics, micromachining, the electronics engineer's design station, and brazing with a laser microtorch

  19. Titanium honeycomb structure. [for supersonic aircraft wing structure

    Science.gov (United States)

    Davis, R. A.; Elrod, S. D.; Lovell, D. T.

    1972-01-01

    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.

  20. Preparation and characterization of segmented p-type Ti0.3Zr0.35Hf0.35CoSb0.8Sn0.2/Ca3Co4O9

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Han, Li; Stamate, Eugen; Pham, Hoang Ngan; Balke, Benjamin; Linderoth, Søren; Van Nong, Ngo; Pryds, Nini

    HH using an electrically conductive adhesive and brazing joining technique. The thermoelectric properties of the component materials as well as the interfacial resistance at high temperatures were characterized as a function of temperature up to 1100 K, and the results are discussed in details....

  1. Joining techniques for core flow test loop fuel rod simulators

    International Nuclear Information System (INIS)

    Laser welding and furnace brazing techniques have been developed to join subassemblies for fuel rod simulators (FRSs) that have survived up to 1000-h steady-state operation at 700 to 11000C cladding temperatures and over 5000 thermal transients, ranging from 10 to 500C/s. A pulsed-laser welding procedure uses small diameter filler wire to join one end of a resistance heating element to a tubular conductor. The other end of the heating element is laser welded to an end plug, which in turn is welded to a central conductor. Before these welding operations, the intermediate material conductors (either tubular or rod) are vacuum brazed to matching copper leads. On room temperature tensile testing, 10 of 11 brazements between copper and nickel rods failed in the copper rather than the brazement. The thin walls and ductility of the copper and nickel tubular conductors caused joint machining and fitup problems. Accordingly, it has not been possible to consistently produce tensile test samples of brazed dissimilar metal tubular conductors that will fail outside the joint area. A unique tubular electrode carrier has also been developed for gas tungsten arc welding FRSs to the tubesheet of a test assembly. Two seven-rod mockups of the simulator-to-tubesheet joint area were welded and successfully cycled 500 times from 3700C (6980F) down to 1000C (2120F) with an internal pressure of 11.72 MPa (1700 psi). No leakage was detected by helium mass spectrometry, either before or after testing. Modified versions of the electrode carrier were developed for brazing electrical leads to the upper ends of the FRSs. Satisfactory brazes have been made on both single-rod mockups and arrays of simulators

  2. Status of the beryllium replacement project

    International Nuclear Information System (INIS)

    Currently, beryllium (Be) is used as the filler metal for brazing appendages on the sheaths of CANDU® fuel elements. Because of its toxicity, occupational exposure limits for Be are being reduced to very low levels, resulting in significant challenges to CANDU® fuel fabricators. The CANDU® Owners Group (COG) initiated a test program to identify a filler material to replace Be and confirm that the brazed joints meet the established technical requirements for CANDU® fuel. Together with eliminating health risks associated with the use of Be, the industry needs to be assured that continuation of fuel supply remains unaffected and that fuel fabrication processes continue to comply with health and safety standards. A literature survey of studies on brazing and joining of Zircaloy identified potential filler materials that can meet or exceed existing design requirements of the brazed joint, including the required mechanical, microstructural, corrosion resistance, and irradiation properties equivalent to those obtained with Be as braze material. Candidate materials were evaluated against several criteria, including manufacturability, melting point, wettability, mechanical properties, corrosion resistance, effect on neutron economy, potential activation products, and interaction with fuel channels and other related disciplines. This exercise resulted in a list of promising candidate materials that were recommended for the first phase of testing. These materials include stainless steel (304 or 316), Al-Si, Ni-P, and Zr-Mn alloys. To allow a CANDU® utility have sufficient confidence in considering implementation of a different braze filler material, a Be Replacement Test Program, involving out-reactor and in-reactor tests, is being undertaken as a collaborative endeavour by the Canadian nuclear industry. The out-reactor tests consist of: a constructability assessment to determine the material’s suitability with current fuel manufacturing methods; evaluation of

  3. Observations on the post-mortem investigation of electron beam welds and other micro-structural features of JET Hypervapotrons

    International Nuclear Information System (INIS)

    A metallurgical post-mortem investigation has been carried out on Mark 1 Hypervapotron elements from the Joint European Tokamak (JET), with the aim of aiding engineers in improving the future design of such high heat flux (HHF) component. Optical and electron microscopy and X-ray techniques have been utilised. Work has predominately focused on the electron beam (EB) welded and vacuum brazed joints of the Hypervapotron. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) has been used to assess the chemical composition while micro and nano indentation testing has been used to study the hardness profiles of these joints. Poor quality control of the vacuum brazing process resulted in nickel based filler material, contaminating internal surfaces. Variable penetration and entrapped voids in the EB welds suggested weld spiking occurred during the joining process. Details of these findings and a critical assessment of the potential implications are given where appropriate.

  4. Use of vanadium in the production of cryostats and ovens for neutro-crystallographic experiments

    International Nuclear Information System (INIS)

    The scattering of neutrons by vanadium is incoherent, and thus this metal is of great interest in the construction of cryostats and ovens. As no diffusion peak is expected at finite angles, the use of vanadium prevents the difference techniques to be used with other materials. Thin vanadium tubes have been manufactured at Saclay which can be soldered or brazed on other metals or alloys. Several techniques of soldering, brazing, etc..., are registered, with which we have obtained non brittle and leak free joints. Description of a cryostat designed to operate at 4 deg. K and of an oven operating between 50 deg. C and 1000 deg. C with very low thermal gradient is given at full length. (authors)

  5. Joining SI3N4 for Advanced Turbomachinery Applications

    Energy Technology Data Exchange (ETDEWEB)

    GLASS, S. JILL; LOEHMAN, RONALD E.; HOSKING, F. MICHAEL; STEPHENS JR., JOHN J.; VIANCO, PAUL T.; NEILSEN, MICHAEL K.; WALKER, CHARLES A.; POLLINGER, J.P.; MAHONEY, F.M.; QUILLEN, B.G.

    2000-07-01

    The main objective of this project was to develop reliable, low-cost techniques for joining silicon nitride (Si{sub 3}N{sub 4}) to itself and to metals. For Si{sub 3}N{sub 4} to be widely used in advanced turbomachinery applications, joining techniques must be developed that are reliable, cost-effective, and manufacturable. This project addressed those needs by developing and testing two Si{sub 3}N{sub 4} joining systems; oxynitride glass joining materials and high temperature braze alloys. Extensive measurements were also made of the mechanical properties and oxidation resistance of the braze materials. Finite element models were used to predict the magnitudes and positions of the stresses in the ceramic regions of ceramic-to-metal joints sleeve and butt joints, similar to the geometries used for stator assemblies.

  6. The jointing stress analysis of one-shot seal-off high-voltage vacuum interrupters

    Institute of Scientific and Technical Information of China (English)

    Zhao Zhizhong; Zou Jiyan; Cong Jiyuan; Wen Huabin; Sun Hui

    2006-01-01

    The free shrinkage of ceramic or metal is restricted due to solidification of the solder. Hence the shrinkage stress arises and the jointing strength is reduced during the brazing of high-voltage vacuum interrupters ( HVVIs ) . The solder bound contour was gained by solved energy bound equation. The finite element model of weld beads was established with Surface Evolver software. Then the stress in two different cooling techniques ( natural cooling and force cooling) was calculated with ANSYS. Comparing the stress, a better cooling technique was selected for HVVIs. Its cooling time is shortened by 3 hours while the jointing stress doesn' t increase and the tensile strength of ceramic to metal seal is not decreased. The stress-rupture tests have validated the calculated results. More important, a method is found, by which the brazing technique could be improved in advance instead of blind experiments.

  7. Development and fabrication of 12 Tesla Nb3Sn superconductors

    International Nuclear Information System (INIS)

    Fabrication techniques for large pool boiling conductors for the High Field Test Facility (HFTF), the General Dynamics-Airco 12 T model coil, or a Fusion Engineering Device (FED) are presented. These conductors are manufactured as follows: long continuous segments of a high-current core are fabricated by compacting a cable of small stands in a continuously seam welded copper tube. The operating current of the HFTF conductor is 5000 amp at 12 T. To provide additional wetted surface areas for cooling, the reacted compacted monolith is continuously soldered to embossed copper strips. Bond quality is continuously monitored with ultrasonic testing techniques. The operating current of the General Dynamics-Airco 12 T model coils 12.5 ka at 12 T and the compacted monolithic core is joined to a large aspect ratio copper stabilizer by brazing or diffusion bonding. Properties of brazed joints are reported. 5 refs

  8. Thermal cycling tests of RG-Ti/Mo monoblock divertor modules

    International Nuclear Information System (INIS)

    Test results for actively cooled, graphite RG-Ti type brazed to molybdenum tube divertor mock-ups are presented. Particular attention was paid to finding a reliable, non-destructive method of investigating brazed joints. The mock-ups were ultrasonically tested and the results correlated with the microstructure of the joints. Two types of tests were carried out: screening tests with a stepped increase of the surface heat flux from shot to shot and thermal cycling tests at a fixed power density level. The heat loads were varied in the range from 6 MW/m2 to 12 MW/m2. About 150 cycles of heat loads with a power density of 10 MW/m2 were realized and no macrodamage was found. The heat flux experiments were accompanied by detailed metallographic investigations. ((orig.))

  9. Design and development of high efficiency 140W space TWT with graphite collector

    International Nuclear Information System (INIS)

    4-stage graphite collector assembly has been designed and developed for a 140W Ku-band space TWT to achieve the collector efficiency more than 80%. The UHV compatible, high density, copper impregnated POCO graphite (DFP-1C) was used to fabricate the four collector electrodes of the 4-stage depressed collector. Copper impregnated graphite material is used for the collector electrodes because of its low secondary electron emission coefficient, high thermal and electrical conductivities, easy machining and brazing, low thermal expansion coefficient and low weight. The graphite material was characterized for the UHV compatibility. The collector electrodes were precisely fabricated by careful machining, and technology was developed for brazing of graphite electrodes with high voltage alumina insulators. Complete TWT with four-stage graphite collector was developed and 140W output power at gain more than 55 dB was achieved. The TWT was pumped from both the gun and the collector ends

  10. Determination of traces of light elements in gold artifacts using nuclear reactions

    Science.gov (United States)

    Demortier, Guy; Gilson, André

    Nuclear reaction analysis (NRA) has been developed to achieve a sufficient sensitivity for the determination of low Z elements in narrow regions (around 1 mm 2) of a matrix rich in high Z elements (gold, silver, copper). Traces of sulphur and silicon are specially useful for the understanding of the antique brazing procedures of archaeological gold artifacts. Proton spectra from (d,p) reactions on thick targets for the analysis of Si and S, and incidentally Mg, Al, P, Cl, K, have been investigated in order to determine the most useful deuteron energy for sensitive and interference free determinations. Applications to brazing alloys obtained by dissolution of cadmium ores in melted gol (as done in antiquity) and to artifacts of Byzantine times (IXth century A.D.) are presented.

  11. An experimental study of natural convection in open-cell aluminum foam

    Science.gov (United States)

    De Jaeger, P.; Reynders, R.; De Schampheleire, S.; T'Joen, C.; Huisseune, H.; Amee, B.; De Paepe, M.

    2012-11-01

    Natural convecton n air-saturated alumnum foam has been measured. A carefully designed experimental setup is built for his ask. The calibraton is done by comparing he results of a flat plate wh literature data, revealing excellent agreement. The nvestigated foams have a pore densiy of 10 and 20 PPI. The bondng of the foam is performed via brazing, or by applying a single epoxy which is enriched wh highly conductve alumna particles. The Rayleigh number is varied between 2500 and 6000, wh he rato of he surface area o he perimeter of he substrate as characteristc length. The foam height is varied between 12 and 25.4 mm. A major difference between both he bondng methods is observed. The brazed samples showed a beter heat ransfer n all cases. Furthermore, when ncreasing he foam height, a clear augmentaton of he heat ransfer is observed. Based on hese results, a correlaton is presented.

  12. Use of Silicon Carbide as Beam Intercepting Device Material: Tests, Issues and Numerical Simulations

    CERN Document Server

    Delonca, M; Gil Costa, M; Vacca, A

    2014-01-01

    Silicon Carbide (SiC) stands as one of the most promising ceramic material with respect to its thermal shock resistance and mechanical strengths. It has hence been considered as candidate material for the development of higher performance beam intercepting devices at CERN. Its brazing with a metal counterpart has been tested and characterized by means of microstructural and ultrasound techniques. Despite the positive results, its use has to be evaluated with care, due to the strong evidence in literature of large and permanent volumetric expansion, called swelling, under the effect of neutron and ion irradiation. This may cause premature and sudden failure, and can be mitigated to some extent by operating at high temperature. For this reason limited information is available for irradiation below 100°C, which is the typical temperature of interest for beam intercepting devices like dumps or collimators. This paper describes the brazing campaign carried out at CERN, the results, and the theoretical and numeric...

  13. Fabrication of PWR fuel assembly and CANDU fuel bundle

    International Nuclear Information System (INIS)

    For the project of localization of nuclear fuel fabrication, the R and D to establish the fabrication technology of CANDU fuel bundle as well as PWR fuel assembly was carried out. The suitable boss height and the prober Beryllium coating thickness to get good brazing condition of appendage were studied in the fabrication process of CANDU fuel rod. Basic Studies on CANLUB coating method also were performed. Problems in each fabrication process step and process flow between steps were reviewed and modified. The welding conditions for top and bottom nozzles, guide tube, seal and thimble screw pin were established in the fabrication processes of PWR fuel assembly. Additionally, some researches for a part of PWR grid brazing problems are also carried out

  14. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2014-06-01

    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  15. Crack analysis, glass-ceramic insulator of vacuum tube

    International Nuclear Information System (INIS)

    The high voltage glass-ceramic insulators from ten vacuum tubes that had failed a bubble leak test were analyzed to determine the cause. All insulators exhibited a similar crack pattern. It appeared that the primary crack initiated at a point near the top of the insulator and resulted in a fracture that radiated from the inner sleeve of the tube to the outer frame. These cracks were duplicated on subassemblies by applying heat to the inner sleeve near the top surface of the insulator. It was determined that the cracks resulted from heating problems associated with the source closure braze. It was determined that misalignment of the radio-frequency braze coil caused cracking of assemblies

  16. Development of High-Temperature and Low-Oxygen Atmosphere Controlled Furnace and Its Application to Metal Jointing Technology

    Science.gov (United States)

    Kanda, Kiichi; Hashimoto, Hiromu

    Metal joining by brazing or diffusion bonding is typically performed at temperatures around 1573K. At such temperatures, atmosphere or vacuum furnaces are required to avoid metal oxidation while heating. The drawbacks of atmosphere furnaces are their use of explosive gases such as hydrogen and the inability of using metal conveyor belts above 1423K. In this study, a non-oxidizing continuous furnace that uses only inert gas atmospheres was developed to work in conjunction with a carbon/carbon composite conveyor belt that can be used up to 2873K, and was used in metal joining processes. The development of the furnace, its working principle and features, and its application in brazing and diffusion bonding of stainless steel are reported with supporting experimental data.

  17. Current state-of-the-art manufacturing technology for He-cooled divertor finger

    International Nuclear Information System (INIS)

    A divertor concept for DEMO has been investigated at Karlsruhe Institute of Technology (KIT) which has to withstand a heat flux of 10 MW/m2. The design utilizes small finger module composed of a small tungsten tile brazed on a thimble made from tungsten alloy. The divertor finger is cooled by helium jet impingement at 10 MPa and 600 deg. C. The subject of this paper is technological studies on machining and braze joining the divertor components. Goal of this task, which is considered an important R and D issue, is to find out appropriate manufacturing methods to ensure high functionality and high reliability of the divertor as well as to meet the economic aspect. One of the major requirements for manufacturing is micro-crack-free surface of tungsten parts, since crack propagations in tungsten were observed in the previous high-heat-flux tests at Efremov. Different manufacturing methods and the corresponding results are discussed in the following report.

  18. Development of techniques for joining fuel rod simulators to test assemblies

    International Nuclear Information System (INIS)

    A unique tubular electrode carrier is described for gas tungsten-arc welding small-diameter nuclear fuel rod simulators to the tubesheet of a test assembly. Both the close-packed geometry of the array of simulators and the extension of coaxial electrical conductors from each simulator hindered access to the weld joint. Consequently, a conventional gas tungsten-arc torch could not be used. Two seven-rod assemblies that were mockups of the simulator-to-tubesheet joint area were welded and successfully tested. Modified versions of the electrode carrier for brazing electrical leads to the upper ends of the fuel pin simulators are also described. Satisfactory brazes have been made on both single-rod mockups and an array of 25 simulators by using the modified electrode carrier and a filler metal with a composition of 71.5 Ag-28 Cu-0.5 Ni

  19. Neutron diffraction stress determination in W-laminates for structural divertor applications

    Directory of Open Access Journals (Sweden)

    R. Coppola

    2015-07-01

    Full Text Available Neutron diffraction measurements have been carried out to develop a non-destructive experimental tool for characterizing the crystallographic structure and the internal stress field in W foil laminates for structural divertor applications in future fusion reactors. The model sample selected for this study had been prepared by brazing, at 1085 °C, 13 W foils with 12 Cu foils. A complete strain distribution measurement through the brazed multilayered specimen and determination of the corresponding stresses has been obtained, assuming zero stress in the through-thickness direction. The average stress determined from the technique across the specimen (over both ‘phases’ of W and Cu is close to zero at −17 ± 32 MPa, in accordance with the expectations.

  20. Brazeability of a 3003 Aluminum alloy with Al-Si-Cu-based filler metals

    Science.gov (United States)

    Tsao, L. C.; Weng, W. P.; Cheng, M. D.; Tsao, C. W.; Chuang, T. H.

    2002-08-01

    Al-Si-Cu-based filler metals have been used successfully for brazing 6061 aluminum alloy as reported in the authors’ previous studies. For application in heat exchangers during manufacturing, the brazeability of 3003 aluminum alloy with these filler metals is herein further evaluated. Experimental results show that even at such a low temperature as 550 °C, the 3003 alloys can be brazed with the Al-Si-Cu fillers and display bonding strengths that are higher than 77 MPa as well. An optimized 3003 joint is attained in the brazements with the innovative Al-7Si-20Cu-2Sn-1Mg filler metal at 575 °C for 30 min, which reveals a bonding strength capping the 3003 Al matrix.

  1. Zircaloy-sheathed element rods fitted with thermo-couples

    International Nuclear Information System (INIS)

    In order to carry out thermal conductivity measurements on UO2 in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors)

  2. Development of technology and properties investigation of steel/bronze joints proposed for ITER HHF components manufacturing

    International Nuclear Information System (INIS)

    Full text of publication follows: During the development of ITER HHF components manufacturing it is necessary to provide reliable joints between heat sink material made of CuCrZr bronze and the supporting construction made of austenitic steel. Four different methods have been tried out: - Hot Isostatic Pressing (HIP), - HIP assisted brazing, - furnace assisted brazing, - Casting. The investigation of structure and properties of joints show that HIP and casting provide the better results than the other technologies. However, HIP is relatively expensive technology, and big size HIP furnace is required for the full scale components manufacturing that are not available n RF now. Therefore, casting was selected as a reference manufacturing technology for the primary wall of ITER modules n RF. The paper summarizes the results of bronze/steel joints manufacturing and investigation of their properties. (authors)

  3. Design of Accelerated Fatigue Tests for Flame Free Refrigeration Fittings

    OpenAIRE

    Wilson, Michael; Bowers, Chad D.

    2014-01-01

    Refrigerant leakage from failed braze joints is a multi-billion dollar problem for the global HVAC&R industry. Leaks are typically caused due to mechanical fatigue from extreme pressure cycling, temperature cycling including exposure to freeze/thaw cycles, or vibrational wear induced from rotating electrical machinery. Three tests to accelerate mechanical fatigue were devised to simulate real world extreme conditions to determine possible failure modes of refrigerant components. The first tes...

  4. Thermal fatigue resistance of W-Cu divertor plates for fusion reactors

    International Nuclear Information System (INIS)

    The results of thermal cycling tests of W-Cu pseudo-alloy as a candidate material for fusion reactor divertor plates showed that the material resisted without any damages to radiation and thermal shock effects of cyclic electron beam of 6, 8 and 10 MW/m2 power density when a good thermal sink was provided. Practically ideal thermal contact between thermally loaded sample and cooled substrate was shown can be obtained using various spelters vacuum brazing. 2 refs.; 4 figs

  5. Numerical Modelling of Indution Heating - Fundamentals

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    Induction heating is extensively used for brazing and heat treatment of materials to produce consumer and industrial products; structural assemblies; electrical and electronic products; mining, machine, and hand tools; ordnance equipment; and aerospace assemblies. It is often applied when rapid and...... localised heating is required in order to avoid distortions and to combine complex metal combinations and geometries. The process time is usually in the range of seconds. It is therefore very advantageous when large numbers of parts are handled automatically....

  6. A Study of the Surface Quality of High Purity Copper after Heat Treatment

    CERN Document Server

    Aicheler, M; Atieh, S; Calatroni, S; Riddone, G; Lebet, S; Samoshkin, A

    2011-01-01

    Themanufacturing flow of accelerating structures for the compact linear collider, based on diamond-machined high purity copper components, include several thermal cycles (diffusion bonding, brazing of cooling circuits, baking in vacuum, etc.). The high temperature cycles may be carried out following different schedules and environments (vacuum, reducing hydrogen atmosphere, argon, etc.) and develop peculiar surface topographies which have been the object of extended observations. This study presents and discusses the results of scanning electron microscopy (SEM) and optical microscopy investigations.

  7. Experimental evaluation of a R134a/CO2 cascade refrigeration plant

    OpenAIRE

    Sanz Kock, Carlos; Llopis Doménech, Rodrigo; Sánchez García-Vacas, Daniel; Cabello López, Ramón; Torrella Alcaraz, Enrique

    2014-01-01

    We present the experimental evaluation of a R134a/CO2 cascade refrigeration plant designed for low evaporation temperature in commercial refrigeration applications. The test bench incorporates two single- stage vapour compression cycles driven by semi hermetic compressors coupled thermally through two brazed plate cascade heat exchangers working in parallel and controlled by electronic expansion valves. The experimental evaluation (45 steady-states) covers evaporating temperatures from -40 to...

  8. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material

    Directory of Open Access Journals (Sweden)

    Jens Johannes Bock

    2008-10-01

    Full Text Available The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005. Data were analyzed by ANOVA (p=0.05 and Bonferroni post hoc test (p=0.05. In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N. Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N. Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test. In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  9. Joining ceramics to metals using metallic foam

    OpenAIRE

    Shirzadi, A. A.; Zhu, Y.; Bhadeshia, H. K. D. H.

    2008-01-01

    A general method for brazing ceramics to metals using a compliant metallic foam as a buffer layer has been developed. Using stainless steel foams, bonds between alumina and 316 stainless steel with shear strengths up to 33 MPa have been achieved. The resultant ductility enhances the resistance of the joint to thermal cycling; AlN-Inconel 600 bonds exhibited good thermal shock resistance. Alumina - stainless steel bonds withstood more that 60 thermal cycles between 200 and 800°C in air.

  10. Bonding between Carbon Fiver/Carbon composite and copper alloy

    International Nuclear Information System (INIS)

    In order to develop material for Divertor of Nuclear Fusion Reactor, we investigated bonding method between C-C material (Carbon Fiber/Carbon composite) and three kinds of heat sink materials, the microstructure of the bonding layer, shearing strength, thermal shock resistance temperature and analysis of thermal stress. C-C material was manufactured with carbon fiber oriented in one direction. Thermal conductivity of C-C is 570 W/m·k along this orientation. For heat sink material, three kinds of material, Cu, Cr-Cu alloy and W-Cu alloy were used. Results are summarized below; (1) As a brazing filler metal for bonding between C-C and copper alloy, ten kinds of brazing filler metals were investigated. As a result 2Ti-AgCu paste filler metal was selected. The brazing filler metal is excellent in wettability and as high shearing strength as a bonding layer. (2) Shearing strengths of the C-C/copper and copper alloy joints with 2Ti-AgCu paste brazing filler metal decrease in the order of C-C/Cu, C-C/Cr-Cu, C-C/W-Cu. Hardness of the bonding layer decrease in the order of C-C/W-Cu, C-C/Cr-Cu and C-C/Cu. Therefore, the shearing strength of the bonding layer increase with decreasing hardness. (3) By using a copper plate of 2-5 mm in thickness as a bonding layer between of C-C/Cr-Cu and C-C/W-Cu joints, shearing strength and thermal shock resistance temperature are improved to those of the C-C/Cu joint. Through thermal stress analysis, the thermal stress relief of the copper plate was confirmed. (author)

  11. Electrochemical profiling of multi-clad aluminium sheets used in automotive heat exchangers

    OpenAIRE

    Bordo, Kirill; Ambat, Rajan; Peguet, Lionel; Afseth, Andreas

    2014-01-01

    The objective of the present study is to understand the mechanisms of corrosion propagation across the multi-clad structure of Al alloys sheets as a function of local alloy composition and microstructure, with and without brazing treatment. Electro-chemical behaviour at different depths was profiled using a combination of glow dis-charge optical emission spectroscopy (GDOES) sputtering, localized potentiodynam-ic polarization and zero resistance ammetry (ZRA) measurements. Multi-clad struc-tu...

  12. Fuel Manifold Resists Embrittlement by Hydrogen

    Science.gov (United States)

    Adams, T.

    1986-01-01

    Completely-cast hydrogen-compatible alloy preferable to protective plating. Complexity of plating, welding, and brazing unnecessary if hydrogen-compatible alloy used for entire casting instead of protective overlay. Parts exposed to high-pressure hydrogen made immune to hydrogen embrittlement if fabricated from new alloy, Incoly 903 (or equivalent). Material strong and compatible with hydrogen at all temperatures and adapted for outlet manifold of Space Shuttle main combustion chamber.

  13. Evaluation of corrosion resistance of multi-layered Ti/gass-ceramic interfaces by electrochemical impedance spectroscopy

    OpenAIRE

    Ariza, E.; Rocha, L. A.

    2005-01-01

    Practical applications of metal/ceramic joints can be found in the biomedical field regarding the encapsulation of implantable telemetric devices, the fabrication of crowns and bridges for dental restoration, or in the production of drug delivery systems, biomedical sensors and electrodes. Most of metal/ceramic joints are produced by the active metal brazing technique, which originates a multi-layered interface which should be able of accommodating the abrupt electronic, crystallographic, ...

  14. Bridge Coupler for APT

    OpenAIRE

    Greninger, Paul T.; Rodarte, Henry J.

    2000-01-01

    The Coupled Cavity Drift Tube Linac (CCDTL) used in the Accelerator for the Production of Tritium (APT) is fully described elsewhere [1]. The modules are composed of several machined and brazed segments that must account for the accumulation of dimensional tolerances in the build up of the stack. In addition, space requirements dictate that power fed to the accelerator cannot be through the accelerating cavities. As well, we would like to remove a single segment of the accelerator without rem...

  15. Final report: Joining of dissimilar materials for fusion reactor applications

    International Nuclear Information System (INIS)

    The research activities in this project include the following: investigation into the microstructure evolution and structure-property relationship of vanadium alloys under simulated joining conditions, development and characterization of vanadium/stainless steel brazed joints, and studies of fracture and failure behaviors of vanadium/stainless steel dissimilar joints. In addition, both short term training and education towards advanced degrees for six students have been accomplished in this project

  16. Selected advances in materials research

    International Nuclear Information System (INIS)

    Several findings emanating from materials research that should have a beneficial impact on technological advancement in the future are described. The report deals with the GRAPHNOL, a new class of high-temperature brazing alloy for joining refractory components, gel-sphere-pac process for manufacture of nuclear fuel, and noble-metal fuel cladding for service in radioisotope thermoelectric generators designed to provide auxiliary power aboard spacecraft for planetary exploration

  17. Neutron irradiation test of copper alloy/stainless steel joint materials

    OpenAIRE

    山田 弘一; 河村 弘

    2006-01-01

    As a study about the joint technology of copper alloy and stainless steel for utilization as cooling piping in International Thermonuclear Experimental Reactor (ITER), Al2O3-dispersed strengthened copper or CuCrZr was joined to stainless steel by three kinds of joint methods (casting joint, brazing joint and friction welding method) for the evaluation of the neutron irradiation effect on joints. A neutron irradiation test was performed to three types of joints and each copper alloy. The avera...

  18. Thermal effect on the thermomechanical behavior of contacts in a Traveling Wave Tube (TWT)

    OpenAIRE

    Chbiki, M; Da Silva Botelho, T; Bauzin, J. G.; Laraqi, N.; Jarno, J.-F

    2015-01-01

    International audience A new thermo-elasto-plastic study of the contact between the helix and the rods of the delay line of Traveling Waves Tubes (TWT) was realized. Our study is focused on the analysis of the hot lines shrinking phenomenon. In the studied case, unlike brazed configuration, the contact areas are not perfect, resulting in a diminution of the heat transfer process. In order to maximize the contact area and to homogenize the contact pressure, a soft thermal conductive materia...

  19. Waveguide diamond vacuum windows with HELICOFLEXR seals

    International Nuclear Information System (INIS)

    Since brazing to diamond can be difficult, time-consuming and expensive, we have designed windows sealed for high vacuum by two HelicoflexR metal seals on opposing faces of a diamond disk. To prevent excessive stress on the diamond, the seals must be well aligned and external forces on the window assembly must not be transmitted to the diamond. We describe the main features of these windows. Calculations of the temperature rises and stresses in the diamond are presented. (author)

  20. Environmentally friendly joining of tubes by their ends

    DEFF Research Database (Denmark)

    Silva, Carlos M.A.; Nielsen, Chris Valentin; Alves, Luis M.;

    2015-01-01

    This paper proposes an environmentally friendly joining process for connecting tubes by their ends that has the potential to replace current solutions based on fastened, crimped, welded, brazed or adhesive bonded joints. The process is based on a new type of tubular lap joint produced by local...... with a better performance than current environmentally friendly alternatives based on tubular butt joints produced by plastic deformation. © 2014 Elsevier Ltd. All rights reserved....

  1. Anodic Activation of Aluminum by Trace Element Tin

    OpenAIRE

    Tan, Juan

    2011-01-01

    Anodic activation of commercial and model aluminum alloys in chloride solution became of practical importance in connection with filiform corrosion of painted aluminum sheet in architectural application and aluminum components of brazed heat exchangers. Activation in chloride solution manifests itself in the form of a significant negative shift in the pitting potential relative to pure aluminum and a significant increase in the anodic current output at potentials where aluminum is normally ex...

  2. Charge distribution in a 5 kW heat pump using propane as working fluid : Part II: Modelling of liquid hold-up

    OpenAIRE

    Samoteeva, Oxana; Fernando, Primal; Palm, Björn; Lundqvist, Per

    2001-01-01

    A theoretical model for prediction of the amount of refrigerant in condenser and evaporator of a 5kW capacity heat pump is developed. Condenser and evaporator of the experimental test rig are SWEP Brazed Plate Heat Exchangers (BPHE). Plate heat exchangers are widely used in refrigeration and heat pump applications today. However, the mechanisms of boiling and condensation in BPHE represent a difficult issue, for which only few models are developed and presented in published literature. The mo...

  3. Fuzzy Logic Controller based on geothermal recirculating aquaculture system

    OpenAIRE

    Hanaa M. Farghally; Doaa M. Atia; Hanaa T. El-madany; Faten H. Fahmy

    2014-01-01

    One of the most common uses of geothermal heat is in recirculation aquaculture systems (RAS) where the water temperature is accurately controlled for optimum growing conditions for sustainable and intensive rearing of marine and freshwater fish. This paper presents a design for RAS rearing tank and brazed heat exchanger to be used with geothermal energy as a source of heating water. The heat losses from the RAS tank are calculated using Geo Heat Center Software. Then a plate type heat exchang...

  4. Present and possible application of neutron radiography in aviation in the Netherlands

    International Nuclear Information System (INIS)

    The literature on neutron radiography, its principles and its applications especially as conducted by the Energieonderzoek Centrum Nederland ECN on behalf of the National Aerospace Laboratory NLR, is reviewed. It is concluded that neutron radiography already is a valuable inspection tool and in addition to that it offers bright possibilities for the future, probably especially in the field of corrosion detection in aluminium and inspection of brazed joints

  5. Joining of yttria-tetragonal zirconia polycrystal with an aluminum-zirconium alloy

    International Nuclear Information System (INIS)

    Specimens of yttria-tetragonal zirconia polycrystal (Y-TZP) have been joined with an Al-5.8 wt% Zr alloy at temperatures of 900 degrees C and above. The braze alloy contained large needlelike precipitates of the intermetallic phase Al3Sr. It is shown that these large precipitates can aid in strengthening of the joint, especially if they are close to the interface. With decreasing layer thickness, the strengths increased with values as high as 420 MPa

  6. Analytical and experimental evaluation of joining silicon nitride to metal and silicon carbide to metal for advanced heat engine applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.; Selverian, J.H.; O`Neil, D.; Kim, H. [GTE Labs., Inc., Waltham, MA (US); Kim, K. [Brown Univ., Providence, RI (US). Div. of Engineering

    1993-05-01

    This report summarizes the results of Phase 2 of Analytical and Experimental Evaluation of Joining Silicon Nitride to Metal and Silicon Carbide to Metal for Advanced Heat Engine Applications. A general methodology was developed to optimize the joint geometry and material systems for 650{degrees}C applications. Failure criteria were derived to predict the fracture of the braze and ceramic. Extensive finite element analyses (FEA) were performed to examine various joint geometries and to evaluate the affect of different interlayers on the residual stress state. Also, material systems composed of coating materials, interlayers, and braze alloys were developed for the program based on the chemical stability and strength of the joints during processing, and service. The FEA results were compared with experiments using two methods: (1) an idealized strength relationship of the ceramic, and (2) a probabilistic analysis of the ceramic strength (NASA CARES). The results showed that the measured strength of the joint reached 30--80% of the strength predicted by FEA. Also, potential high-temperature braze alloys were developed and evaluated for the high-temperature application of ceramic-metal joints. 38 tabs, 29 figs, 20 refs.

  7. Thermal and mechanical analysis of the Faraday shield for the Compact Ignition Tokamak

    International Nuclear Information System (INIS)

    The antenna for the ion cyclotron resonance heating (ICRH) system of the Compact Ignition Tokamak (CIT) is protected from the plasma environment by a Faraday shield, an array of gas-cooled metallic tubes. The plasma side of the tubes is armored with graphite tiles, which can be either brazed or mechanically attached to the tube. The Faraday shield has been analyzed using finite element codes to model thermal and mechanical responses to typical CIT heating and disruption loads. Four representative materials (Inconel 718, tantalum-10 tungsten, copper alloy C17510, and molybdenum alloy TZM) and several combinations of tube and armor thicknesses were used in the thermal analysis, which revealed that maximum allowable temperatures were not exceeded for any of the four materials considered. The two-dimensional thermal stress analysis indicated Von Mises stresses greater than twice the yield stress for a tube constructed of Inconel 718 (the original design material) for the brazed-graphite design. Analysis of stresses caused by plasma disruption (/rvec J/ /times/ /rvec B/) loads eliminated the copper and molybdenum alloys as candidate tube materials. Of the four materials considered, tantalum-10 tungsten performed the best for a brazed graphite design, showing acceptable thermal stresses (69% of yield) and disruption stresses (42% of yield). A preliminary thermal analysis of the mechanically attached graphite scheme predicts minimal thermal stresses in the tube. The survivability of the graphite tubes in this scheme is yet to be analyzed. 8 refs., 19 figs., 2 tabs

  8. Development of laser welded appendages to Zircaloy-4 fuel tubing (sheath/cladding)

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, S., E-mail: steve.livingstone@cnl.ca [Canadian Nuclear Laboratories Limited, Chalk River, ON, Canada K0J 1J0 (Canada); Xiao, L. [Canadian Nuclear Laboratories Limited, Chalk River, ON, Canada K0J 1J0 (Canada); Corcoran, E.C.; Ferrier, G.A.; Potter, K.N. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, Canada K7K 7B4 (Canada)

    2015-04-01

    Highlights: • Examines feasibility of laser welding appendages to Zr-4 tubing. • Laser welding minimizes the HAZ and removes toxic Be. • Mechanical properties of laser welds appear competitive with induction brazed joints. • Work appears promising and lays the foundation for further investigations. - Abstract: Laser welding is a potential alternative to the induction brazing process commonly used for appendage attachment in CANDU{sup ®} fuel fabrication that uses toxic Be as a filler metal, and creates multiple large heat affected zones in the sheath. For this work, several appendages were laser welded to tubing using different laser heat input settings and then examined with a variety of techniques: visual examination, metallography, shear strength testing, impact testing, and fracture surface analysis. Where possible, the examination results are contrasted against production induction brazed joints. The work to date looks promising for laser welded appendages. Further work on joint optimization, corrosion testing, irradiation testing, and post-irradiation examination will be performed in the future.

  9. Technical Consultation of the International Space Station (ISS) Internal Active Thermal Control System (IATCS) Cooling Water Chemistry

    Science.gov (United States)

    Gentz, Steven J.; Rotter, Hank A.; Easton, Myriam; Lince, Jeffrey; Park, Woonsup; Stewart, Thomas; Speckman, Donna; Dexter, Stephen; Kelly, Robert

    2005-01-01

    The Internal Active Thermal Control System (IATCS) coolant exhibited unexpected chemical changes during the first year of on-orbit operation following the launch and activation in February 2001. The coolant pH dropped from 9.3 to below the minimum specification limit of 9.0, and re-equilibrated between 8.3 and 8.5. This drop in coolant pH was shown to be the result of permeation of CO2 from the cabin into the coolant via Teflon flexible hoses which created carbonic acid in the fluid. This unexpected diffusion was the result of having a cabin CO2 partial pressure higher than the ground partial pressure (average 4.0 mmHg vs. less than 0.2 mmHg). This drop in pH was followed by a concurrent increasing coolant nickel concentration. No other metal ions were observed in the coolant and based on previous tests, the source of nickel ion was thought to be the boron nickel (BNi) braze intermetallics used in the construction of HXs and cold plates. Specifically, BNi2 braze alloy was used for the IATCS IFHX and BNi3 braze alloy was used for the IATCS Airlock Servicing and Performance Checkout Unit (SPCU) HX and cold plates. Given the failure criticality of the HXs, a Corrosion Team was established by the IATCS CWG to determine the impact of the nickel corrosion on hardware performance life.

  10. Integration Science and Technology of Silicon-Based Ceramics and Composites:Technical Challenges and Opportunities

    Science.gov (United States)

    Singh, M.

    2013-01-01

    Ceramic integration technologies enable hierarchical design and manufacturing of intricate ceramic and composite parts starting with geometrically simpler units that are subsequently joined to themselves and/or to metals to create components with progressively higher levels of complexity and functionality. However, for the development of robust and reliable integrated systems with optimum performance for high temperature applications, detailed understanding of various thermochemical and thermomechanical factors is critical. Different technical approaches are required for the integration of ceramic to ceramic and ceramic to metal systems. Active metal brazing, in particular, is a simple and cost-effective method to integrate ceramic to metallic components. Active braze alloys usually contain a reactive filler metal (e.g., Ti, Cr, V, Hf etc) that promotes wettability and spreading by inducing chemical reactions with the ceramics and composites. In this presentation, various examples of brazing of silicon nitride to themselves and to metallic systems are presented. Other examples of joining of ceramic composites (C/SiC and SiC/SiC) using ceramic interlayers and the resulting microstructures are also presented. Thermomechanical characterization of joints is presented for both types of systems. In addition, various challenges and opportunities in design, fabrication, and testing of integrated similar (ceramic-ceramic) and dissimilar (ceramic-metal) material systems will be discussed. Potential opportunities and need for the development of innovative design philosophies, approaches, and integrated system testing under simulated application conditions will also be presented.

  11. Sixteen silver wires to assemble 350 kg of copper

    CERN Multimedia

    Alizée Dauvergne

    2010-01-01

    Assembly of the first radiofrequency quadrupole (RFQ) module for the future LINAC4 linear accelerator has just been completed by CERN's Assembly and Forming section (EN) using a technique called vacuum brazing which involves furnace-baking at 800°C and micron precision, leaving absolutely nothing to chance. Serge Mathot (EN/MME) and his team used the vacuum brazing technique to assemble the first RFQ module for the future LINAC4. The future LINAC4 will use four types of accelerating structures, each playing a different role in increasing the energy of the beam. The first of these are the radiofrequency quadrupole modules (RFQ, see box) which accelerate and focus the beam from the start. "The modules are complex items. Each had to be produced in 4 parts, corresponding to the 4 electrodes," explains physicist Serge Mathot, a vacuum brazing specialist in the Engineering (EN) Department. "To work properly, these modules must be aligned to a precision of a few microns. It...

  12. A comparison between finite element modeling and various thermographic non-destructive testing techniques for the quantification of the thermal integrity of macro-brush plasma facing components used in a tokamak.

    Science.gov (United States)

    Pandya, Santosh P; Pandya, Shwetang N; Patil, Yashashri V; Krishnan, Deepu S; Murugesan, Menaka; Sharath, D; Singh, K Premjit; Khan, Md Shoaib; Arafat, M; Biju, N; Khirwadkar, Samir S; Govidarajan, Jagannathan; Venkatraman, B; Balasubramaniam, Krishnan

    2016-02-01

    The plasma facing components (PFCs) inside a tokamak are typically exposed to extremely high heat flux of the order of MW/m(2). The brazing quality between the plasma facing materials (PFMs) and the heat sink will determine the structural integrity and hence the effective service life of these PFCs. Suitable non-destructive testing (NDT) techniques for the pre-qualification of these components are thus essential to evaluate their structural integrity at various stages of their service life. Macro-brush type mockups of prototype PFCs with graphite as PFM have been inspected for their brazing quality using different active Infrared (IR)-thermographic NDT techniques. The results obtained from these techniques are compared and discussed. The brazing quality was quantified by establishing a comparison between the experimental results and the results from Finite Element Analysis (FEA). The percentage of contact between the PFM and the substrate was varied in FEA. FEA results when compared with experiments shows that tiles have different amounts of contact with the substrate ranging between 10% and 80%. PMID:26931878

  13. Design modification of the in-pile test section for increase of sealing capability

    International Nuclear Information System (INIS)

    Since KAERI established the fuel test loop (FTL) at HANARO in 2009, KAERI has carried out several experiments to verify the performances of the equipment. Based on the experiments, the design modification of the In-Pile test Section (IPS) has been processed to improve some difficulties such as difficulty in ejecting the inner assembly of the IPS from the pressure vessel, difficulty of the sealing process of the cooling water, etc. At first, because the cooling water of HANARO in KAERI consists of an open-pool type, if a certain shock is generated during the disassembly process, the cooling water can be spattered out of the pool. Therefore, two jacking bolts will be added on the top flange part of the inner assembly to decrease the shock. Second, at the pressure boundary of the IPS where MI-cables go through, the brazing process has been used to seal out the cooling water. However, because the length of the IPS is up to 5.5 meters, it is too difficult and time consuming to carry out the brazing process at the end part of the IPS. Therefore, the brazing process will be replaced with the mechanical sealing structure to simplify the assembly process. (author)

  14. Irradiation-induced softening of Ni3P and (Ni, Fe, Cr)3P alloys

    International Nuclear Information System (INIS)

    Production of amorphous alloys by solid state reactions (SSR) has attracted much interest during the last few years. One of the methods to induce such a reaction is the irradiation of suitable crystalline alloys by fast particles. Examination of this kind of SSR in M3P type of brazing alloys (M: Metal) is attractive because of the following reason: In brazed joints of candidate structural materials like 316L stainless steel for applications in fusion reactors, crystalline intermetallic phases have been detected which are unstable relative to the amorphous state when irradiated at moderate temperatures with fast particles. It is expected that the transition to the amorphous state is accompanied by changes of the mechanical properties, which are of fundamental interest in this context. Until now, only a few studies on the evolution of mechanical properties during amorphization have been performed. Measurements of microhardness of the crystalline and the corresponding amorphous phase do not exist to the authors knowledge. In this communication, the authors present results on changes of microhardness, due to amorphization by fast ions. The measurements have been performed on a model alloy Ni3P and on the brazed joint of stainless steel 316L, containing M3P (M: Ni, Fe, Cr) as one of the phases. Though microhardness is not a fundamental property of materials, it is a manifestation of several related properties, such as yield stress, ductility, work-hardening, elastic modulus and residual stress states. It represents a resistance for indentation and is, therefore, appropriate for comparative purposes

  15. Joining and Testing Composite Plates to Ti Tubes

    Science.gov (United States)

    Morscher, Gregory N.; Singh, Mrityunjay; Shpargei, Tarah; Asthana, Rajiv

    2005-01-01

    The joining of metal tubes to composite plates is required for heat-rejection components in several space applications. Currently a number of different braze compositions are being evaluated as to their effectiveness. Such tube-plate configurations cannot be represented by traditional methods of testing, e.g., lap joints. The joined region is not between two flat surfaces, but rather between a flat surface and a curved surface. Therefore, several tests have been employed to ascertain the effectiveness of the different braze approaches in tension that are both simple and representative of the actual system and relatively straightforward in analysis. The results of these "tube-tests" will be discussed for the three different braze compositions, Cu-ABA, Ti-Cu-Sil, and Ti-Cu-Ni. In addition, fracture analysis of the failed joints was performed and offers insights into the cause of joint failure and the distinctions which need to be made between the "strength" of a joint versus the "load carrying ability" of a joint.

  16. High temperature grain growth and oxidation of Fe-29Ni-17Co (Kovar{trademark}) alloy leads

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, J.J.; Greulich, F.A.; Beavis, L.C.

    1993-12-31

    One important application for the Fe-29Ni-17Co (Kovar{trademark}) alloy in wire form is in brazed feed through assemblies which are integral parts of vacuum electronic devices. Since Cu metal brazes are performed at process temperatures of about 1100{degrees}C, there is opportunity for significant grain growth to occur during the brazing operation. Additional high temperature exposure includes decarburization of the Fe-29Ni-17Co alloy wire in wet hydrogen for 30 min. at 1000{degrees}C prior to the Cu brazing operation. Two approaches have been used to characterize grain growth in two lots of Fe-29Ni-17Co alloy: (1) a once-through processing study to study the effect of one-time-only device thermal processing on the resulting grain size, and (2) an isothermal grain growth study involving various times at 800--1100{degrees}C. The results of the once-through processing study indicate that acceptable grain sizes are obtained from both cold worked and mill-annealed wire lots following Cu brazing. The isothermal grain growth study indicates that the linear intercept distance for Fe-29Ni-17Co can be described with a power law function of time, and that thermal exposure must be controlled at temperatures in excess of 900{degrees}C in order to avoid excessive grain growth. A second study has characterized the oxidation kinetics of Fe-29Ni-17Co alloy wire in air at temperatures ranging from 550--700{degrees}C. This study indicates the parabolic growth law applies for this material, and between 550 and 700{degrees}C, oxidation in this alloy occurs at an activation energy of 27.9 kcal/mole. Other oxidation studies at higher temperatures ({ge}750{degrees}C) indicate an activation energy of 52.2 kcal/mole for oxidation of Fe-29Ni-17Co alloy at temperatures greater than 790{degrees}C. Quantitative point analyses of the oxide scale formed at 600{degrees}C suggest that a significant fraction of the scale is close to the stoichiometry of the Fe{sub 2}O{sub 3}-type oxide.

  17. Design for fabrication of 325 MHz RFQ structure

    International Nuclear Information System (INIS)

    RRCAT has taken up a program on R and D activities for a 1 GeV, high intensity superconducting H-ion/proton linac for spallation neutron source programme. Front end of the linac will consist H-ion source, LEBT and 3 MeV Radio Frequency Quadrupole (RFQ). Design for fabrication is an important activity in the development of RFQ structure. Based on the physics design of new RFQ, the structure will be 3.5 m long and it will be fabricated by machining and joining of three segments of lengths ∼ 1150 mm each. Each segment of RFQ structure will be made by machining of rectangular OFE Copper bars. The assembly of each segment will be made by joining of vanes of T and W shapes. Fabrication drawings have been developed to ensure the required geometrical tolerances. Vane modulation data from the PARMTEQ- M has been used for preparation of solid models of modulated vanes which will be used in computer controlled machining of RFQ vanes. Machining of all the parts would be carried out using a high precision CNC milling machine. A portable arm CMM will be used to carry out dimensional inspection of parts during machining. The final inspection will be carried out using a high accuracy CMM. Fixtures required for machining, handling and assembly are being developed. Individual parts of RFQ segments will be vacuum brazed to form a closed geometry. Brazing trials to simulate RFQ joint is in progress. Joining of brazed segments will be made by using demountable RF seals. Paper will describe details about the processes being planned for successful development of RFQ structure. (author)

  18. NaK pool-boiler solar receiver durability bench test. Volume 2: Metallurgical analysis

    Science.gov (United States)

    Goods, S. H.; Bradshaw, R. W.

    1995-01-01

    The principal materials used in the construction of a NaK based pool-boiler were analyzed. The device, operated for 7500 hours, accumulated 1000 thermal cycles to a peak temperature of 750 C. Haynes 230, used to fabricate the pool-boiler vessel, was found to perform satisfactorily. Air-side corrosion of the pool-boiler vessel was insignificant. Internal surface of the alloy exhibited some NaK-induced elemental dissolution; this dissolution was somewhat more extensive where the alloy was exposed to the liquid metal compared to regions exposed only to NaK vapor; however, the corresponding metal loss in all regions was inconsequential, never exceeding more than a few microns. Autogenous seam welds of the alloy responded in a similar fashion, exhibiting only minimal metal loss over the course of the experiment. While there was 50% loss in ductility of the alloy there remained adequate ductility for the anticipated operating environment. An enhanced boiling nucleation surface comprised of stainless steel powder brazed to the vessel ID showed no change in its structure. It remained intact, showing no cracking after repeated thermal cycling. Other materials used in the experiment showed more extensive degradation after exposure to the NaK. IN 600, used to fabricate thermowells, exhibited extensive surface and intergranular dissolution. Grain boundary dissolution was sufficiently severe in one of the thermowells to cause an air leak, resulting in experiment termination. BNi-3, a brazing alloy used to join the pool-boiler vessel, endcaps and thermowells, showed some dissolution where it was exposed to the NaK as well as thermal aging effects. However, all brazes remained structurally sound. A nickel metal ribbon showed catastrophic dissolution, resulting in the formation of deep (greater than 30 (mu)m) pits and cavities. A zirconium metal foil used to getter oxygen from the NaK became extremely brittle.

  19. Fabrication of metallic honeycomb panels for reusable TPS - structures

    International Nuclear Information System (INIS)

    The manufacturing technology with specific regard to high temperature brazing was developed to fabricate a honeycomb panel consisting of a thin-sectioned PM 2000 core material sandwiched on both sides with PM 1000 face sheets. For brazing the PM 1000 / PM 2000 panel the braze alloy PdNi was selected due to the best oxidation behavior while good mechanical properties and wetting behavior compared with other tested filler alloys. To examine the concept of a hybrid PM 1000/2000 panel as a stiffened skin panel a number of engineering test samples of sub-scale and two full-size panels were fabricated at Plansee AG and supplied to Fokker Space for testing under representative in-service conditions. Engineering tests showed that the test samples were rather insensitive to temperature gradients even at temperature differences between the face sheets of 550 oC. The engineering test samples exhibited no plastic deformation after testing at different heating rates ranging from 5 to 40 oC/s and at temperature profiles representative for two flights. The requirement for the designed application regarding impact properties at low as well as high speed were met. Impact at low speed with an energy of 8 J did not cause any cracks. Hail tests where ice bullets were fired with speeds to 208 m/s at different angles from 25 o to 90 oC against the test piece showed no damage at 25o and caused slight indentation at 45o and cracks at 90o, which demonstrated a good performance for the fly through a hail cloud without any problems. In tests to determine the response of a full-size panel to a number of simulated thermo-mechanical flight load cycles the panel passed 50 cycles successfully without damage. (author)

  20. Design and construction of the photocathode electron gun cavity

    International Nuclear Information System (INIS)

    A 1300-MHz, two-cell rf accelerator cavity has been constructed for the high-brightness photocathode electron source program. Each cell has an rf drive. Cell 1 has a replacement photocathode plug on the back wall and has a shape designed for linear radial fields. Cell two has a more standard high-shunt-impedance shape. SUPERFISH values for shunt impedances are, respectively, 29.5 and 45.8 MΩ/m. Peak surface field maximums are 58.9 and 32.1 MV/m for an electron acceleration of 0.9 and 1.0 MeV. Drive coupling is matched for 55 and 86% beam loading at 1-A average current. The system has vacuum pumping ports, into both cells and is baked at 300 degree C. Typical operating pressures are in the low 10-10-torr range. Cell frequencies are fine tuned by a combination of operating temperature and cell nose pulling. Cell-to-cell coupling was intended to be low (K = 0.0002); however, because of the high Qs (13,300 and 20,000), substantial coupling effects are seen. Cutting the vacuum-port slots shifted the frequencies by 1.5 MHz and gave an apparent 10% increase in the cavity Qs. Construction of the cavity required a series of four brazes with several annealing cycles. All joints are flat, and the sequence is such that each joint is brazed horizontally; as a result, all joints were successfully brazed on the first attempt. The latest experiment measurements are given in another paper at this conference. 2 refs., 3 figs

  1. Proceso de unión de insertos de carburo tungsteno en la fabricación de herramientas de corte individualizadas

    OpenAIRE

    Estupiñán Camargo, John Alexánder

    2013-01-01

    En la fabricación de herramientas de corte para mecanizar materiales en condiciones adversas de corte se requiere que el sistema de sujeción del inserto de carburo de tungsteno mantenga la integridad y robustez durante el corte. El proceso de unión por soldadura fuerte (brazing) permite la unión de insertos de carburo de tungsteno con portaherramientas del acero al medio carbono debido a que estos no compartan las mismas propiedades físico-químicas; esta unión de materiales cerámicos co...

  2. Progress report

    International Nuclear Information System (INIS)

    This 2000 issue of the activity report of the CEREM (CEA) gives a general overview of the CEREM organization, activities and human resources with some budgetary information. The main activities described concern the materials fabrication for the nuclear industry and for the medical field, the powder metallurgy, the surface treatments, the joining (by electron beam welding, laser welding, brazing), the electrochemical storage of the energy (SOFC, PEMFC, lithium batteries), the robots for nuclear, automotive and aeronautic industries, the mechanical properties and the cracks, the corrosion and physico-chemistry of fluids, the non-destructive testing and the applications and metrology of ionizing radiations. (O.M.)

  3. Composite magnetostrictive materials for advanced automotive magnetomechanical sensors

    International Nuclear Information System (INIS)

    In this paper we present the development of a composite magnetostrictive material for automotive applications. The material is based on cobalt ferrite, CoO centre dot Fe2O3, and contains a small fraction of metallic matrix phase that serves both as a liquid phase sintering aid during processing and enhances the mechanical properties over those of a simple sintered ferrite ceramic. In addition the metal matrix makes it possible to braze the material making the assembly of a sensor relatively simple. The material exhibits good sensitivity and should have high corrosion resistance while at the same time it is low cost

  4. Development of laser welding system for attachment of bearing pads of nuclear fuel element

    International Nuclear Information System (INIS)

    In CANDU nuclear fuel manufacturing the brazing technology has been adopted conventionally to attach the bearing pads of nuclear fuel elements. However, in order to meet good performance of nuclear fuel and improved working efficiency, we started developing the laser welding technology for attachments of the bearing pads. Since the YAG laser can be suitable for small parts and transmit the beam through the optical fiber, the process is corresponding to mass-production with working shops. Making the most of this feature, we have developed the laser welding system for attachment of the bearing pads on nuclear fuel elements, and has carried out basic welding experiments

  5. Investigation on laser welding characteristics for appendage of bearing pads of nuclear fuel element

    International Nuclear Information System (INIS)

    In CANDU nuclear fuel manufacturing the brazing technology has been adopted conventionally to attach the bearing pads of nuclear fuel elements. However, in order to meet good performance of nuclear fuel and improved working efficiency, we started developing the laser welding technology for attachments of the bearing pads. Since the YAG laser can be suitable for small parts and transmit the beam through the optical fiber, the process is corresponding to mass-production with working shops. Making the most of this feature, we have developed the laser welding for appendage of the bearing pads of nuclear fuel elements, and has studied on the laser welding characterisitcs of appendages for nuclear fuel element

  6. Fabrication of a tantalum neutral source heat exchanger

    International Nuclear Information System (INIS)

    The fabrication and testing of the Neutral Source Heat Exchanger (NSHE), a device required for a plutonium isotope separation pilot plant are described. The unit is a circular water-cooled tantalum plate which will have plutonium cast onto it. After the plutonium is cast and machined to final shape, the assembly will serve as a sputtering substrate for the separation process. The cooling water flow path is unique (adjacent logarithmic spirals terminating 180 degress apart) and created several fabrication and testing challenges. A photograph of the lower plate, showing the water channel geometry and brazing filler material, is shown

  7. Design of a self-focusing linear electron accelerator

    International Nuclear Information System (INIS)

    In this report we tackle the principal physical and technical problems related to the design of a self-focusing linear electron accelerator. The study of the dynamic phenomena occurring at the entrance to the first resonant cell allows us, by an adequate choice of the longitudinal height of this cell, to avoid the use of an external magnetic focusing coil. Optimization of the ultra high frequency properties of the resonant structure has been achieved by polishing the internal surfaces of the cavities, by adapting a new brazing technique and optimizing the geometry of the cells. A simulation code has been adapted to an interactive use on microcomputer

  8. Safety handbook

    International Nuclear Information System (INIS)

    The purpose of the Australian Nuclear Science and Technology Organization's Safety Handbook is to outline simply the fundamental procedures and safety precautions which provide an appropriate framework for safe working with any potential hazards, such as fire and explosion, welding, cutting, brazing and soldering, compressed gases, cryogenic liquids, chemicals, ionizing radiations, non-ionising radiations, sound and vibration, as well as safety in the office. It also specifies the organisation for safety at the Lucas Heights Research Laboratories and the responsibilities of individuals and committees. It also defines the procedures for the scrutiny and review of all operations and the resultant setting of safety rules for them. ills

  9. Sensors for use in nuclear reactor cores

    International Nuclear Information System (INIS)

    A neutron sensor is described for use in nuclear reactor cores which does not require external power but merely an emitter, a collector and an insulator material between the two to generate an electric current that is indicative of the intensity of the radiation. The sensor is manufactured in such a way that brazed joints or spices are avoided and the insulation material used may be of relatively low density of compaction and will center the emitter and the lead wire with respect to the outer sheath or tube without deformation or varying geometry of the center wire or emitter. (UK)

  10. Transient-Liquid-Phase and Liquid-Film-Assisted Joining ofCeramics

    Energy Technology Data Exchange (ETDEWEB)

    Sugar, Joshua D.; McKeown, Joseph T.; Akashi, Takaya; Hong, SungM.; Nakashima, Kunihiko; Glaeser, Andreas M.

    2005-02-09

    Two joining methods, transient-liquid-phase (TLP) joining and liquid-film-assisted joining (LFAJ), have been used to bond alumina ceramics. Both methods rely on multilayer metallic interlayers designed to form thin liquid films at reduced temperatures. The liquid films either disappear by interdiffusion (TLP) or promote ceramic/metal interface formation and concurrent dewetting of the liquid film (LFAJ). Progress on extending the TLP method to lower temperatures by combining low-melting-point (<450 C) liquids and commercial reactive-metal brazes is described. Recent LFAJ work on joining alumina to niobium using copper films is presented.

  11. Application of titanium materials to vacuum chambers and components

    International Nuclear Information System (INIS)

    This paper describes the outgassing properties of titanium materials, and development of vacuum chambers and components for practical UHV/XHV systems. The mechano-chemically polished and the chemically polished titanium materials have a smooth surface and a thin (≤ 10 nm) oxide surface layer, which showed extremely low outgassing rate below 10-12 Pams-1 after baking process. In order to fabricate practical vacuum systems welding, metallizing and brazing processes were optimized, and complex shaped vacuum chambers and various vacuum components such as a bellows, valve, electric feedthrough and ceramic duct with titanium sleeve were fabricated. Sufficient mechanical properties and durability were obtained for practical use

  12. A review of the US joining technologies for plasma facing components in the ITER fusion reactor

    International Nuclear Information System (INIS)

    This paper is a review of the current joining technologies for plasma facing components in the US for the International Thermonuclear Experimental Reactor (ITER) project. Many facilities are involved in this project. Many unique and innovative joining techniques are being considered in the quest to join two candidate armor plate materials (beryllium and tungsten) to a copper base alloy heat sink (CuNiBe, OD copper, CuCrZr). These techniques include brazing and diffusion bonding, compliant layers at the bond interface, and the use of diffusion barrier coatings and diffusion enhancing coatings at the bond interfaces. The development and status of these joining techniques will be detailed in this report

  13. Performances of PIXE and nuclear microprobes for the study of gold soldering processes

    International Nuclear Information System (INIS)

    Our work undertaken ten years ago in order to understand the procedures used in antiquity to realize tiny solders on gold jewellery artefacts has been extended to the rediscovery, in laboratory, of possible antique recipes and their improvements for modern purposes. We are now able to put forward economical processes to solder pieces of gold at low temperatures using bulk brazing materials and diffusion bonding processes by local diffusion of cadmium or rapid diffusion of silicon along grain boundaries. The performances of PIXE and nuclear microprobes to investigate materials and solders are discussed. (orig.)

  14. Laser-welded Dissimilar Steel-aluminum Seams for Automotive Lightweight Construction

    Science.gov (United States)

    Schimek, M.; Springer, A.; Kaierle, S.; Kracht, D.; Wesling, V.

    By reducing vehicle weight, a significant increase in fuel efficiency and consequently a reduction in CO 2 emissions can be achieved. Currently a high interest in the production of hybrid weld seams between steel and aluminum exists. Previous methods as laser brazing are possible only by using fluxes and additional materials. Laser welding can be used to join steel and aluminum without the use of additives. With a low penetration depth increases in tensile strength can be achieved. Recent results from laser welded overlap seams show that there is no compromise in strength by decreasing penetration depth in the aluminum.

  15. Metals and Ceramics Division annual progress report, October 1, 1978-June 30, 1979

    International Nuclear Information System (INIS)

    Research is reported concerning: (1) engineering materials including materials compatibility, mechanical properties, nondestructive testing, pressure vessel technology, and welding and brazing; (2) fuels and processes consisting of ceramic technology, fuel cycle technology, fuels evaluation, fuels fabrication and metals processing; and (3) materials science which includes, ceramic studies, physical metallurgy and properties, radiation effects and microstructural analysis, metastable and superconducting materials, structure and properties of surfaces, theoretical research, and x-ray research and applications. Highlights of the work of the metallographic group and the current status of the High-Temperature Materials Laboratory (HTML) and the Materials and Structures Technology Management Center (MSTMC) are presented

  16. A new RFQ linac fabrication technique

    International Nuclear Information System (INIS)

    The use of hydrogen furnace brazing has been applied as a joining technology to the fabrication of a Radio-Frequency-Quadrupole (RFQ) linac for the Los Alamos Accelerator Performance Demonstration Facility (APDF). The design concept provides a monolithic cavity with no longitudinal rf, vacuum, or mechanical joints. A 530 MHz, 0.46 meter long engineering model RFQ has been fabricated and tested at the Los Alamos National Laboratory as a technical demonstration of this concept. It is planned that two funneled RFQ's for the APDF (7 MeV, 350 MHz, 100 mAmp CW, each eight meters in length) will be manufactured by this method

  17. Quality approach and professional regulations; Demarche qualite et regles professionnelles

    Energy Technology Data Exchange (ETDEWEB)

    Bernier, J. [Association Francaise de Froid (AFF), 75 - Paris (France)

    1997-12-31

    After a review of the main performance and environmental issues related to the utilization of alternative refrigerant fluids in refrigerating systems, the thermo-pump concept is proposed for space heating and air conditioning. Performances of reverse heat pumps have been greatly enhanced through the use of scroll and screw compressors, electronic reducing valves and brazed plate exchangers. Installation regulations have been developed in order to ensure optimal operating conditions for residential systems with a power range inferior to 30 kW: information is given on radiating floors with hot and cooled water, the hydraulic network in individual houses, the implementation of underground collectors, and the operation of thermo-pumps

  18. RF Loads for Energy Recovery

    CERN Document Server

    Federmann, S; Caspers, F

    2012-01-01

    Different conceptional designs for RF high power loads are presented. One concept implies the use of solid state rectifier modules for direct RF to DC conversion with efficiencies beyond 80%. In addition, robust metallic low-Q resonant structures, capable of operating at high temperatures (>150 ◦C) are discussed. Another design deals with a very high temperature (up to 800 ◦C) air cooled load using a ceramic foam block inside a metal enclosure. This porous ceramic block is the microwave absorber and is not brazed to the metallic enclosure.

  19. Development of high-temperature ultrasonic transducers for under-sodium viewing applications

    International Nuclear Information System (INIS)

    PZT type immersion transducers, bonded using pure lead, can be manufactured and operated satisfactorily in sodium at temperatures up to 2800C. A satisfactory technique of braze bonding lithium niobate Z-cut crystal to stainless steel diaphragms has been developed. The bonded diaphragms can be assembled into transducers which are then capable of operation at temperatures up to 6000C. Sealed transducers which had been pre-oxidised, maintained sensitivity for about 70 days when operated at temperatures between 3000C and 5000C. There was subsequently a slow fall in sensitivity with time at temperature. (Author)

  20. High Temperature Ultrasonic Transducer for Real-time Inspection

    Science.gov (United States)

    Amini, Mohammad Hossein; Sinclair, Anthony N.; Coyle, Thomas W.

    A broadband ultrasonic transducer with a novel porous ceramic backing layer is introduced to operate at 700 °C. 36° Y-cut lithium niobate (LiNbO3) single crystal was selected for the piezoelectric element. By appropriate choice of constituent materials, porosity and pore size, the acoustic impedance and attenuation of a zirconia-based backing layer were optimized. An active brazing alloy with high temperature and chemical stability was selected to bond the transducer layers together. Prototype transducers have been tested at temperatures up to 700 °C. The experiments confirmed that transducer integrity was maintained.

  1. FIRE PERMIT NOW ON EDH!

    CERN Multimedia

    TIS General Safety Group or

    2001-01-01

    The electronic version of the Fire Permit form is now active. The aim of the Fire Permit procedure is to reduce the risk of fire or explosion. It is mandatory when performing 'hot work' (mainly activities which involve the use of naked flames or other heat sources - e.g. welding, brazing, cutting, grinding, etc.). Its use is explained in the CERN Fire Protection Code E. (Fire Protection) The new electronic form, which is substantially unchanged from the previous authorizing procedure, will be available on the Electronic Document Handling system (https://edh.cern.ch/) as of 1st September 2001. From this date use of the paper version should be discontinued.

  2. Characteristics of deformation joining of aluminum-stainless steel composite sheet

    Institute of Scientific and Technical Information of China (English)

    李培武; 孙康宁; 李爱民; 李中友; 刘秀忠; 栾新民; 徐秀丽

    2003-01-01

    In order to study the characteristics of deformation joining of aluminum-stainless steel composite sheet,an applied example of this composite sheet was given.The conditions of the composite sheet were discussed,the optical micrographs and scanning electron micrographs were examined by contrast ways of deformation joining and braze joining.Simultaneously the analysis of energy spectrum was also conducted.The results indicate that the deformation joining composite sheet possesses high bonding strength,good corrosion resistance,less inclusions and less microcracks.

  3. Vacuum Chamber for the Measurement System of the Beam Energy

    Science.gov (United States)

    Abakumova, E.; Achasov, M.; Dong, HaiYi; Qu, HuaMin; Krasnov, A.; Kosarev, A.; Muchnoi, N.; Pyata, E.; Xiao, Qiong; Mo, XiaoHu; Wang, YiFang; Zhukov, A.

    Vacuum chamber for the beam energy measurement system based on the Compton backscattering method is presented. The main elements of the chamber are GaAs entrance viewport and a copper mirror. The viewport design provides baking out of the vacuum chamber up to 250 °C. To produce the viewport, an original technology based on brazing GaAs plate by lead has been developed. The vacuum chambers were installed at the BEPC-II and VEPP-4 M colliders. After installation the residual gas pressure is about 10-10 Torr.

  4. Development of X-band accelerating structures for high gradients

    Institute of Scientific and Technical Information of China (English)

    S. Bini; M. G. Grimaldi; L. Romano; F. Ruffino; R. Parodi; V. Chimenti; A. Marcelli; L. Palumbo; B. Spataro; V. A. Dolgashev; S. Tantawi; A.D. Yeremian; Y. Higashi

    2012-01-01

    Short copper standing wave (SW) structures operating at an X-band frequency have been recently designed and manufactured at the Laboratori Nazionali di Frascati of the Istituto Nazionale di Fisica Nucleare (INFN) using the vacuum brazing technique.High power tests of the structures have been performed at the SLAC National Accelerator Laboratory.In this manuscript we report the results of these tests and the activity in progress to enhance the high gradient performance of the next generation of structures,particularly the technological characterization of high performance coatings obtained via molybdenum sputtering.

  5. Copper-to-silicon-carbide joints development for Future CLIC Hom Dampers

    CERN Document Server

    Gil Costa, Miguel

    2015-01-01

    Ceramic-to-metal joints have been of paramount importance for the nuclear and aeronautic industry since the last century. In this document, two different approaches to the Cu-to-SiC joining are briefly described and discussed. The first approach consists of an intermediate piece of lower Coefficient of Thermal Expansion than copper aiming to reduce the expansion mismatch with the ceramic during the brazing cycle. Soldering is selected as a second attempt, whose lower joining temperature reduces the absolute expansion difference between Cu and SiC. In addition, four SiC metallization processes are proposed and some of them have been also tested and discussed.

  6. Development of high thermal flux components for continuous operation in Tokamaks

    International Nuclear Information System (INIS)

    High heat flux plasma facing components are under development and appropriate experimental evaluations have been carried out in order to operate during cycles of several hundred seconds. In Tore Supra, a large tokamak with a plasma nominal duration in excess of 30 seconds, solutions are tested that could be later applied to the NET/ITER tokamak, where peaked heat flux values of 15 MW/m2 on the divertor plates are foreseen. The proposed concept is a swirl square tube design protected with brazed CFC flat tiles. Development programs and validation tests are presented. The tests results are compared with calculations

  7. A basic design fault in ceramic flat packs

    Science.gov (United States)

    Drotman, B.

    1983-01-01

    Recent moisture resistance tests of various multilayer top brazed ceramic flat packs and leaded and unleaded chip carriers has revealed a serious design defect. These packages, which utilize a tungsten interconnect system, in the presence of high humidity, suffer a galvanic corrosion which anodically consumes the tungsten. This process can continue until the package suffers an open circuit. The test results indicate that the lead plating system does not adequately seal off the interface area where the tungsten strips egresses from the inside of the package.

  8. The structural materials for the first wall and plasma facing components of NET

    International Nuclear Information System (INIS)

    SA 316 and high-strength high-conductivity Cu and Mo based alloys have been selected as structural materials for the first wall and divertor plates of NET, respectively. The effects of irradiation on their bulk properties and behaviour: tensile properties, low-cycle fatigue, fracture toughness, irradiation creep, stress corrosion cracking, H-embrittlement and microstructural stability are discussed in terms of the proposed NET operating conditions with a special emphasis on the possible effect of the neutron spectrum. Finally microstructural instabilities of the intermetallic compounds of the brazed joints due to recoil effects are mentioned. (orig.)

  9. Electromagnetic forming - a potentially viable technique for accelerator technology

    International Nuclear Information System (INIS)

    Modern day accelerator development encompasses a myriad technologies required for their diverse needs. Whereas RF, high voltage, vacuum, cryogenics etc., technologies meet their functional requirements, high finish lapping processes, ceramic-metal joining, oven brazing, spark erosion or wire cutting etc., are a must to meet their fabrication requirements. Electromagnetic (EM) forming technique falls in the latter category and is developed as a special technology. It is currently catering to the development as a nuclear reactor technology, but has the potential to meet accelerator requirements too. This paper highlights the general principle of its working, simple design guidelines, advantages, and suggests some specific areas where this could benefit accelerator technologies

  10. Metals and Ceramics Division annual progress report, October 1, 1978-June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, S. (ed.)

    1979-09-01

    Research is reported concerning: (1) engineering materials including materials compatibility, mechanical properties, nondestructive testing, pressure vessel technology, and welding and brazing; (2) fuels and processes consisting of ceramic technology, fuel cycle technology, fuels evaluation, fuels fabrication and metals processing; and (3) materials science which includes, ceramic studies, physical metallurgy and properties, radiation effects and microstructural analysis, metastable and superconducting materials, structure and properties of surfaces, theoretical research, and x-ray research and applications. Highlights of the work of the metallographic group and the current status of the High-Temperature Materials Laboratory (HTML) and the Materials and Structures Technology Management Center (MSTMC) are presented. (FS)

  11. Study of graphite sealing for the instrumentation feed through part

    International Nuclear Information System (INIS)

    Because highly pressurized (15.5 MPa) and highly heated (300 .deg. C) coolant is circulated through the test rig, it needs to seal out the instrumentation feed through part. In this case, general sealing method is brazing and several works have been carried out in nuclear fields. However, because high temperature is induced on the sealing plug and sheaths, it is easy to be broken due to oxidisation of the sheath during brazing process. In addition, because the brazing process is irreversible, if the brazing process fails, the whole inner assembly should be scrapped out. Another approach which uses graphite has been studied to seal out the instrumentation feed through part. In the study, graphite sealing is considered as a sealing method and the improvement of mechanical structure has been studied to improve the workability. To check the sealing performance of the instrumentation feed through part, a hydraulic pressure test and a helium leak test were carried out according to the ASME section III. The criterion of a hydraulic pressure test is 125% of the design pressure. In this study, because the design pressure of the pressure vessel is 17.5 MPa. the sealing criterion should be 21.9 MPa. Also, in a Helium leak test, the criterion is less than 5 Χ 10-9 torr·liter/sec. At first, a Helium leak test was carried out. After eliminating Helium in the pressure vessel by evacuating the internal area of the pressure vessel up to 1 Χ 10-3 torr using ASM 310, Helium detection test was carried out by spraying Helium gas at the top face of the top flange for 5 minutes. Fig. 4 shows the rate of Helium leakage is 2.4 Χ 10-9 torr·liter/sec, and it satisfies the sealing performance criterion. A hydraulic pressure test was also carried out, and there was no leakage or pressure drop when the water in the pressure vessel is pressurized up to 22.5 MPa. The above test results show that graphite powder can seal out the instrumentation feed through part easily with the improved

  12. Magnetron sputter deposition of boron and boron carbide

    International Nuclear Information System (INIS)

    The fabrication of X-ray optical coatings with greater reflectivity required the development of sputter deposition processes for boron and boron carbide. The use of high density boron and boron carbide (B4C) and a vacuum-brazed target design was required to achieve the required sputter process stability and resistance to the thermal stress created by high rate sputtering. Our results include a description of the target fabrication procedures and sputter process parameters necessary to fabricate B4C and boron modulated thin film structures. (orig.)

  13. Progress report; Rapport d'activite

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This 2000 issue of the activity report of the CEREM (CEA) gives a general overview of the CEREM organization, activities and human resources with some budgetary information. The main activities described concern the materials fabrication for the nuclear industry and for the medical field, the powder metallurgy, the surface treatments, the joining (by electron beam welding, laser welding, brazing), the electrochemical storage of the energy (SOFC, PEMFC, lithium batteries), the robots for nuclear, automotive and aeronautic industries, the mechanical properties and the cracks, the corrosion and physico-chemistry of fluids, the non-destructive testing and the applications and metrology of ionizing radiations. (O.M.)

  14. Metals and Ceramics Division. Annual progress report, ending June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-09-01

    Research is reported concerning: (1) engineering materials, including materials compatibility, mechanical properties, nondestructive testing, pressure vessel technology, and welding and brazing; (2) fuels and processes consisting of ceramic technology, fuel cycle technology, fuels evaluation, fuel fabrication and metals processing; and (3) materials science which includes, ceramic studies, physical metallurgy properties, radiation effects and microstructural analysis, metastable and superconducting materials, structure and properties of surfaces, theroretical research and x-ray research and applications. Highlights of the work of the metallographic group and the current state of the High-Temperature Materials Laboratory (HTML) and the Materials and Structures Technology Management Center (MSTMC) are presented. (FS)

  15. Experimental evaluation of an Internal Heat Exchanger in a CO2 subcritical refrigeration cycle with gas-cooler

    OpenAIRE

    Llopis Doménech, Rodrigo; Sanz Kock, Carlos; Cabello López, Ramón; Sánchez García-Vacas, Daniel; Torrella Alcaraz, Enrique

    2015-01-01

    We present the experimental evaluation of an internal heat exchanger or suction-line/liquid-line heat exchanger in a CO2 subcritical refrigeration plant with gas-cooler. The plant, driven by a 1.5kW CO2 semi hermetic compressor, uses brazed plate heat exchangers as condenser, evaporator and internal heat exchanger, an air finned tube gas-cooler and an electronic expansion valves. The evaluation (77 steady- states) covers evaporating temperatures from -40 to -25 oC and condensing temperatures ...

  16. Stainless steel component with compressed fiber Bragg grating for high temperature sensing applications

    Science.gov (United States)

    Jinesh, Mathew; MacPherson, William N.; Hand, Duncan P.; Maier, Robert R. J.

    2016-05-01

    A smart metal component having the potential for high temperature strain sensing capability is reported. The stainless steel (SS316) structure is made by selective laser melting (SLM). A fiber Bragg grating (FBG) is embedded in to a 3D printed U-groove by high temperature brazing using a silver based alloy, achieving an axial FBG compression of 13 millistrain at room temperature. Initial results shows that the test component can be used for up to 700°C for sensing applications.

  17. Metals and Ceramics Division. Annual progress report, ending June 30, 1980

    International Nuclear Information System (INIS)

    Research is reported concerning: (1) engineering materials, including materials compatibility, mechanical properties, nondestructive testing, pressure vessel technology, and welding and brazing; (2) fuels and processes consisting of ceramic technology, fuel cycle technology, fuels evaluation, fuel fabrication and metals processing; and (3) materials science which includes, ceramic studies, physical metallurgy properties, radiation effects and microstructural analysis, metastable and superconducting materials, structure and properties of surfaces, theroretical research and x-ray research and applications. Highlights of the work of the metallographic group and the current state of the High-Temperature Materials Laboratory (HTML) and the Materials and Structures Technology Management Center (MSTMC) are presented

  18. The installation of the JET pumped divertor systems inside the vacuum vessel

    International Nuclear Information System (INIS)

    The JET Pumped Divertor, designed to study impurity control will be installed during 1992/1993. The related in-vessel components are essentially: four magnetic coils, forty-eight beryllium divertor plate assemblies, one toroidal LHe cryopump, eight ICRH antennae, and poloidal limiters. With the exception of the magnetic coils, which will be would and brazed inside the vessel, all other components will be pre-assembled and prepared before installation. The paper describes the organization and the installation principles to undertake and to accomplish all the activities

  19. High power distributed x-ray source

    Science.gov (United States)

    Frutschy, Kris; Neculaes, Bogdan; Inzinna, Lou; Caiafa, Antonio; Reynolds, Joe; Zou, Yun; Zhang, Xi; Gunturi, Satish; Cao, Yang; Waters, Bill; Wagner, Dave; De Man, Bruno; McDevitt, Dan; Roffers, Rick; Lounsberry, Brian; Pelc, Norbert J.

    2010-04-01

    This paper summarizes the development of a distributed x-ray source with up to 60kW demonstrated instantaneous power. Component integration and test results are shown for the dispenser cathode electron gun, fast switching controls, high voltage stand-off insulator, brazed anode, and vacuum system. The current multisource prototype has been operated for over 100 hours without failure, and additional testing is needed to discover the limiting component. Example focal spot measurements and x-ray radiographs are included. Lastly, future development opportunities are highlighted.

  20. Development of the heat sink structure of a beam dump for the proton accelerator

    International Nuclear Information System (INIS)

    The beam dump is the essential component for the good beam quality and the reliable performance of the proton accelerator. The beam dump for a 20 MeV and 20 mA proton accelerator was designed and manufactured in this study. The high heats deposited, and the large amount of radioactivity produced in beam dump should be reduced by the proper heat sink structure. The heat source by the proton beam of 20 MeV and 20 mA was calculated. The radioactivity assessments of the beam dump were carried out for the economic shielding design with safety. The radioactivity by the protons and secondary neutrons in designed beam dump were calculated in this sturdy. The effective engineering design for the beam dump cooling was performed, considering the mitigation methods of the deposited heats with small angle, the power densities with the stopping ranges in the materials and the heat distributions in the beam dump. The heat sink structure of the beam dump was designed to meet the accelerator characteristics by placing two plates of 30 cm by 60 cm at an angle of 12 degree. The highest temperatures of the graphite, copper, and copper faced by cooling water were designed to be 223 degree, 146 degree, and 85 degree, respectively when the velocity of cooling water was 3 m/s. The heat sink structure was manufactured by the brazing graphite tiles to a copper plate with the filler alloy of Ti-Cu-Ag. The brazing procedure was developed. The tensile stress of the graphite was less than 75% of a maximum tensile stress during the accelerator operation based on the analysis. The safety analyses for the commissioning of the accelerator operation were also performed. The specimens from the brazed parts of beam dump structure were made to identify manufacturing problems. The soundness of the heat sink structure of the beam dump was confirmed by the fatigue tests of the brazed specimens of the graphite-copper tile components with the repetitive heating and cooling. The heat sink structure developed

  1. New plates for different types of plate heat exchangers

    OpenAIRE

    Fernandes, Carla S.; Dias, Ricardo P.; João M. Maia

    2008-01-01

    The first patent for a plate heat exchanger was granted in 1878 to Albretch Dracke, a German inventor. The commercial embodiment of these equipments has become available in 1923. However, the plate heat exchanger development race began in the 1930’s and these gasketed plate and frame heat exchangers were mainly used as pasteurizers (e.g. for milk and beer). Industrial plate heat exchangers were introduced in the 1950’s and initially they were converted dairy models. Brazed plate heat exchange...

  2. Technology handbook of vacuum physics

    CERN Document Server

    Beck, A H

    2013-01-01

    Handbook of Vacuum Physics, Volume 3: Technology is part of a series of publications that presents articles featuring the whole spectrum of vacuum physics. This particular volume presents materials that deal with technology concerns in vacuum mechanics. The first material talks about the utilization of ceramic materials in the construction of vacuum devices. The next paper details the application of vacuum physics in soldering and brazing process. The last article deals with the utilization of vacuum technology in high frequency heating. The book will be of great use to professionals involved

  3. RF-driven Proton Source with a Back-streaming Electron Dump

    International Nuclear Information System (INIS)

    This article describes an RF ion source with a back-streaming electron dump. A quartz tube, brazed to a metal plug at one end, is fused in the center of a flat quartz plate. RF power (at 13.6 MHz) is coupled to generate hydrogen plasma using a planar external antenna bonded to the window. Bonding the water-cooled rf antenna to the quartz window significantly lowers its temperature. The water-cooled metal plug serves as the backstreaming electron dump. At 1800W, the current density of extracted hydrogen ions reaches approximately 125 mA/cm2.

  4. Ceramic Technology Project database: September 1990 summary report. [SiC, SiN, whisker-reinforced SiN, ZrO-toughened aluminas, zirconias, joints

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.L.P.

    1992-06-01

    Data generated within the Ceramic Technology Project (CTP) represent a valuable resource for both research and industry. The CTP database was created to provide easy access to this information in electronic and hardcopy forms by using a computerized database and by issuing periodic hardcopy reports on the database contents. This report is the sixth in a series of semiannual database summaries and covers recent additions to the database, including joined brazed specimen test data. It covers 1 SiC, 34 SiN, 10 whisker-reinforced SiN, 2 zirconia-toughened aluminas, 8 zirconias, and 34 joints.

  5. Ceramic Technology Project database: September 1990 summary report

    Energy Technology Data Exchange (ETDEWEB)

    Keyes, B.L.P.

    1992-06-01

    Data generated within the Ceramic Technology Project (CTP) represent a valuable resource for both research and industry. The CTP database was created to provide easy access to this information in electronic and hardcopy forms by using a computerized database and by issuing periodic hardcopy reports on the database contents. This report is the sixth in a series of semiannual database summaries and covers recent additions to the database, including joined brazed specimen test data. It covers 1 SiC, 34 SiN, 10 whisker-reinforced SiN, 2 zirconia-toughened aluminas, 8 zirconias, and 34 joints.

  6. Development of C-band RF pulse compressor

    International Nuclear Information System (INIS)

    C-band RF compressor is a device that generates high peak RF-power by saving, and compressing the RF-power output from the klystron. In SCSS: The SPring-8 Compact SASE Source, Q-factor of C-band RF compressor is lower than theoretical figure. To improve Q-factor of C-band RF compressor, we changed the production method of C-band RF compressor from Electron Beam Welding (EBW) to the brazing in XFEL: X-ray Free Electron Lasers. As a result, Q-factor of C-band RF compressor has been improved, and it succeeded in the work improvement. (author)

  7. Preprototype nitrogen supply subsystem development

    Science.gov (United States)

    Heppner, D. B.; Fort, J. H.; Schubert, F. H.

    1982-01-01

    The design and development of a test stand for the Nitrogen Generation Module (NGM) and a series of tests which verified its operation and performance capability are described. Over 900 hours of parametric testing were achieved. The results from this testing were then used to design an advanced NGM and a self contained, preprototype Nitrogen Supply Subsystem. The NGM consists of three major components: nitrogen generation module, pressure controller and hydrazine storage tank and ancillary components. The most important improvement is the elimination of all sealing surfaces, achieved with a total welded or brazed construction. Additionally, performance was improved by increasing hydrogen separating capability by 20% with no increase in overall packaging size.

  8. RF-driven Proton Source with a Back-streaming Electron Dump

    Energy Technology Data Exchange (ETDEWEB)

    Ji, Q.; Sy, A.; Kwan, J.W.

    2009-09-20

    This article describes an RF ion source with a back-streaming electron dump. A quartz tube, brazed to a metal plug at one end, is fused in the center of a flat quartz plate. RF power (at 13.6 MHz) is coupled to generate hydrogen plasma using a planar external antenna bonded to the window. Bonding the water-cooled rf antenna to the quartz window significantly lowers its temperature. The water-cooled metal plug serves as the backstreaming electron dump. At 1800W, the current density of extracted hydrogen ions reaches approximately 125 mA/cm{sup 2}.

  9. Structural Characteristics and Properties of Precious Metal Powders and Copper Powder Prepared by High-speed Centrifugal Atomization Technique

    Institute of Scientific and Technical Information of China (English)

    XIE Ming; YANG You-cai; LI Yu-shen; ZHANG Jian-kan; FU Shi-ji; SHI Qing-nan

    2007-01-01

    The principle and characteristics of the rapidly solidified centrifugal atomization technique are studied in present paper. It has been widely used to make fine, rapidly solidified precious metal powders for application as the electrical engineering materials, conductive coatings for electromagnetic shielding and brazing alloys. The silver powder, copper powder and some precious metal alloys powders are prepared by the new method. A comparative analysis is carried out with the conventional electrolytic silver powder and chemical deposition silver powder. The results show that rapidly solidified powders are fine and have higher solid solubility of the alloying elements, and their alloys have excellent properties in various aspects.

  10. Testing of cermet fuel pins in the MIR reactor (intermediate results)

    International Nuclear Information System (INIS)

    Fuel elements with cermet fuel are designed and the technology for their manufacturing is developed. The fuel elements of two types are tested in the MIR reactor: 1) the elements with metallurgical provision of a cermet fuel pin-cladding contact (brazing); 2) the elements with a cladding tightly pressed to a cermet pin (rolling). The test results show successful operation of the first type fuel elements with the fuel consisting of uranium dioxide powder, dispersed in a matrix of zirconium base or aluminium base alloy. All fuel elements of the second type appear to be leaking

  11. Commissioning Status of the 3 MeV RFQ for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University

    CERN Document Server

    Xing, QZ; Stovall, J; He, Y; Guan, WQ; Du, L; Cheng, C; Cai, JC; Bin, DT; Bai, YJ; Wang, XW; Wang, D; Jiang, C; Du, Q; Billen, JH; Li, J; Xiong, ZF; Xing, QZ; Zheng, SX; Zhang, HY; Yang, SY; Qiang, Q; Guan, XL; Du, TB

    2012-01-01

    The 3 MeV Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) is in its initial stage for the commissioning at Tsinghua University. Braze of the flanges was completed in January, 2012. The RFQ cavity has been delivered to Tsinghua University after the final field tuning. In 2012 the 3-meter-long RFQ is expected to deliver 3 MeV protons to the downstream High Energy Beam Transport (HEBT) with the peak current of 50 mA, pulse length of 0.5 ms and beam duty factor of 2.5%. The initial commissioning is now underway.

  12. PARAMETRIC SENSITIVITY STUDY OF A FUSION REACTOR DIVERTOR COOLING FINGER

    OpenAIRE

    Martin, Oliver; SIMONOVSKI IGOR

    2012-01-01

    In this paper the results of coupled thermal-mechanical Finite Element (FE) analysis on the design of a fusion reactor divertor cooling finger are presented. Beside its main purpose, to remove alpha particles, helium and other impurities from the plasma stream, a divertor has to remove approximately 15% of the total thermal power of the fusion reactor. The aim of the analysis is to assess the influence of a number of physical properties of the brazing layer (BL) of the cooling finger on the o...

  13. Repair technology for steam generator tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seung Ho; Jung, Hyun Kyu; Jung, Seung Ho; Kim, Chang Hoi; Jung, Young Moo; Seo, Yong Chil; Kim, Jung Su; Seo, Moo Hong

    2001-02-01

    The most commonly used sleeving materials are thermally treated Alloy 600 and thermally treated Alloy 690 Alloy. Currently, thermally treated Alloy 690 and Alloy 800 are being offered although Alloy 800 has not been licensed in the US. To install sleeve, joint strength, leak tightness, PWSCC resistance, evaluation on process parameter range and the effect of equipments and procedures on repair plan and radiation damage have to be investigated before sleeving. ABB CE provides three type of leak tight Alloy 690 TIG welded and PLUSS sleeve. Currently, Direct Tube Repair technique using Nd:YAG laser has been developed by ABB CE and Westinghouse. FTI has brazed and kinetic sleeve designs for recirculating steam generator and hydraulic and rolled sleeve designs for one-through steam generators. Westinghouse provides HEJ, brazed and laser welded sleeve design. When sleeve is installed in order to repair the damaged S/G tubes, it is certain that defects can be occurred due to the plastic induced stress and thermal stress. Therefore it is important to minimize the residual stress. FTI provides the electrosleeve technique as a future repair candidate using electroplating.

  14. A Study of Deposition Coatings Formed by Electroformed Metallic Materials.

    Science.gov (United States)

    Hayashi, Shoji; Sugiyama, Shuta; Shimura, Kojiro; Tobayama, Go; Togashi, Toshio

    2016-01-01

    Major joining methods of dental casting metal include brazing and laser welding. However, brazing cannot be applied for electroformed metals since heat treatment could affect the fit, and, therefore, laser welding is used for such metals. New methods of joining metals that do not impair the characteristics of electroformed metals should be developed. When new coating is performed on the surface of the base metal, surface treatment is usually performed before re-coating. The effect of surface treatment is clinically evaluated by peeling and flex tests. However, these testing methods are not ideal for deposition coating strength measurement of electroformed metals. There have been no studies on the deposition coating strength and methods to test electroformed metals. We developed a new deposition coating strength test for electroformed metals. The influence of the negative electrolytic method, which is one of the electrochemical surface treatments, on the strength of the deposition coating of electroformed metals was investigated, and the following conclusions were drawn: 1. This process makes it possible to remove residual deposits on the electrodeposited metal surface layer. 2. Cathode electrolysis is a simple and safe method that is capable of improving the surface treatment by adjustments to the current supply method and current intensity. 3. Electrochemical treatment can improve the deposition coating strength compared to the physical or chemical treatment methods. 4. Electro-deposition coating is an innovative technique for the deposition coating of electroformed metal. PMID:27326757

  15. Material and design considerations for the carbon armored ITER divertor

    International Nuclear Information System (INIS)

    The properties of materials for the carbon armored ITER divertor were evaluated from literature and manufacturers' documentation. Most of these data, however, have been not known or not published yet. We have evaluated an optimum data set of the candidate materials of the ITER divertor, which were needed for finite element analyses (FEM). The materials evaluated are as follows; MFC-1, CX2002U, SEP-N112, P-130, IG-430U for the carbon based materials, and Oxygen Free Copper (OFCu), Dispersion Strengthened Copper (DSCu), TZM, W5Re and W-Cu as a heat sink material. It should be noted that W-Cu is first proposed for a heat sink application of the ITER divertor plate. The finite element analyses were performed for the residual stress induced by brazing, thermal response and thermal stresses under a uniform heat flux of 15 MW/m2 to the plasma facing surface. The stress free temperature of 750degC is assumed for the residual stress by brazing. Ten different geometries of the divertor were considered in the analyses including possible material combinations. The FEM results show that the material combinations of MFC-1 and W-30Cu or DSUc in the flat-plate geometry satisfy the presently accepted ITER requirements. The combinations of CX2002U and TZM or W5Re is considered a good choice in terms of residual and thermal stresses, whereas the surface temperature exceeds the ITER requirements. (author) 106 refs

  16. Effect of joining parameters on microstructure of dissimilar metal joints between aluminum and galvanized steel

    International Nuclear Information System (INIS)

    Highlights: • Weld joints obtained with different welding parameters were investigated. • The phases of the intermetallic compound layer at the interface were studied. • Effect of heat input in base metal on the intermetallic phases was discussed. • Thermodynamic calculation was carried out for the Fe2Al5 and FeAl3 phases. • The formation process of the intermetallic compound layer was analyzed. - Abstract: The interfacial microstructures of aluminum and galvanized steel dissimilar joint formed by pulsed double electrode gas metal arc (Pulsed DE-GMA) welding–brazing were characterized. Electron probe microanalyzer (EPMA) analysis revealed that the intermetallic compound layer of the welding–brazing joint consisted of Fe2Al5 and FeAl3. Comprehensive analysis of the effect of the heat input parameters showed that, at a constant total welding current (Itotal), the thickness of intermetallic compound at the interface of aluminum and steel decreased with the increase of bypass current. Thermodynamic calculations were carried out to derive the Gibbs free energy diagram for Fe2Al5 and FeAl3. These calculations presented that Fe2Al5 firstly formed, subsequently FeAl3 precipitated during welding process. Further model of the Fe2Al5 and FeAl3 intermetallic compounds formation process was proposed

  17. Science & Technology Review October 2005

    Energy Technology Data Exchange (ETDEWEB)

    Aufderheide III, M B

    2005-08-22

    This month's issue has the following articles: (1) Important Missions, Great Science, and Innovative Technology--Commentary by Cherry A. Murray; (2) NanoFoil{reg_sign} Solders with Less Heat--Soldering and brazing to join an array of materials are now Soldering and brazing to join an array of materials are now possible without furnaces, torches, or lead; (3) Detecting Radiation on the Move--An award-winning technology can detect even small amounts An award-winning technology can detect even small amounts of radioactive material in transit; (4) Identifying Airborne Pathogens in Time to Respond--A mass spectrometer identifies airborne spores in less than A mass spectrometer identifies airborne spores in less than a minute with no false positives; (5) Picture Perfect with VisIt--The Livermore-developed software tool VisIt helps scientists The Livermore-developed software tool VisIt helps scientists visualize and analyze large data sets; (6) Revealing the Mysteries of Water--Scientists are using Livermore's Thunder supercomputer and new algorithms to understand the phases of water; and (7) Lightweight Target Generates Bright, Energetic X Rays--Livermore scientists are producing aerogel targets for use in inertial Livermore scientists are producing aerogel targets for use in inertial confinement fusion experiments and radiation-effects testing.

  18. Flexible metallic ultrasonic transducers for structural health monitoring of pipes at high temperatures.

    Science.gov (United States)

    Shih, Jeanne-Louise; Kobayashi, Makiko; Jen, Cheng-Kuei

    2010-09-01

    Piezoelectric films have been deposited by a sol-gel spray technique onto 75-μm-thick titanium and stainless steel (SS) membranes and have been fabricated into flexible ultrasonic transducers (FUTs). FUTs using titanium membranes were glued and those using SS membranes brazed onto steel pipes, procedures that serve as on-site installation techniques for the purpose of offering continuous thickness monitoring capabilities at up to 490 °C. At 150 °C, the thickness measurement accuracy of a pipe with an outer diameter of 26.6 mm and a wall thickness of 2.5 mm was estimated to be 26 μm and the center frequency of the FUT was 10.8 MHz. It is demonstrated that the frequency bandwidth of the FUTs and SNR of signals using glue or brazing materials as high-temperature couplant for FUTs are sufficient to inspect the steel pipes even with a 2.5 mm wall thickness. PMID:20876000

  19. Probe for an ultrasonic flaw detector welded to a support

    International Nuclear Information System (INIS)

    A probe for ultrasonic flaw detectors is described that includes a transducer sandwiched between electrodes and either a protective plate to protect the transducer or a metal body by which the transducer is directly attached to the object to be tested, these two parts being bonded to each other with a heat-resisting brazing or soldering material, which also serves as one of the electrodes of the transducer. Owing to its high bonding strength, the probe thus constituted is not only capable of serving both in the high temperature range and in the low temperature range, but also may be used in a mobile role or in a stationary mode in testing the object. Where a metal body is used for the mounting, this may be cylindrical or wedge-shaped. The transducer may be a single lithium niobate crystal and the brazing material and electrodes may be a Al-Si-Mg alloy or a silver alloy. A coupling medium may be of silicone oil, molten lead or liquid sodium and the object may be a space station or a nuclear reactor pressure vessel. (author)

  20. A New High-Temperature Ultrasonic Transducer for Continuous Inspection.

    Science.gov (United States)

    Amini, Mohammad Hossein; Sinclair, Anthony N; Coyle, Thomas W

    2016-03-01

    A novel design of piezoelectric ultrasonic transducer is introduced, suitable for operation at temperatures of up to 700 °C-800 °C. Lithium niobate single crystal is chosen as the piezoelectric element primarily due to the high Curie temperature of 1200 °C. A backing element based on a porous ceramic is designed for which the pore volume fraction and average pore diameter in the ceramic matrix can be controlled in the manufacturing process; this enables the acoustic impedance and attenuation to be selected to match their optimal values as predicted by a one-dimensional transducer model of the entire transducer. Porous zirconia is selected as the ceramic matrix material of the backing element to obtain an ultrasonic signal with center frequency of 2.7-3 MHz, and 3-dB bandwidth of 90%-95% at the targeted operating temperature. Acoustic coupling of the piezocrystal to the backing element and matching layer is investigated using commercially available high-temperature adhesives and brazing alloys. The performance of the transducer as a function of temperature is studied. Stable bonding and clear signals were obtained using an aluminum brazing alloy as the bonding agent. PMID:26829787