scholarly journals Brazing Tungsten/Tantalum/RAFM Steel Joint for DEMO by Fully Reduced Activation Brazing Alloy 48Ti-48Zr-4Be

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1417
Author(s):  
Diana Bachurina ◽  
Alexey Suchkov ◽  
Julia Gurova ◽  
Vladislav Kliucharev ◽  
Vladimir Vorkel ◽  
...  

To create a DEMO reactor, it is necessary to develop high-quality technology to join tungsten with reduced-activation ferritic-martensitic (RAFM) steel (Rusfer, Eurofer, CLF-1, etc.). Difficulties arise in their direct connection due to the large difference in the coefficient of thermal expansion (CTE). To suppress the difference of CTE, intermediate interlayers are usually used, such as vanadium or tantalum, and brazing is a prospective technology to conduct the joining. The vast majority of works represent copper- or nickel-based brazing alloys, but their applicability is under significant discussion due to their activation properties. That is why, in this work, fully reduced activation 48Ti-48Zr-4Be wt.% brazing alloy was used. The following joint was made: Rusfer steel/48Ti-48Zr-4Be/Ta/48Ti-48Zr-4Be/W. The brazing was successfully carried out under a mode providing thermal heat treatment of Rusfer. Through EDS and EBSD analysis, the microstructure of the joint was determined. Shear strength of the as-joined composition was measured as 127 ± 20 MPa. The joint endured 200 thermocycles in the temperature range between 300–600 °C, but the fillet regions degraded.

Alloy Digest ◽  
1990 ◽  
Vol 39 (7) ◽  

Abstract AA 4032 has a comparatively low coefficient of thermal expansion and good forgeability. The alloy takes on an attractive dark gray appearance when anodized which may be desirable in architectural applications. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-305. Producer or source: Various aluminum companies.


2018 ◽  
Vol 52 (27) ◽  
pp. 3745-3758 ◽  
Author(s):  
Amin Bahrami ◽  
Niloofar Soltani ◽  
Martin I Pech-Canul ◽  
Shaghayegh Soltani ◽  
Luis A González ◽  
...  

In this study, wettability behavior of B4C substrate as well as B4C/crystalline rice husk ash and B4C/amorphous rice husk ash substrates with two aluminum alloys were studied. The electrical resistivity, thermal expansion coefficients, and thermal diffusivity of bilayer Al/B4C/rice husk ash composite fabricated by one-step pressureless infiltration were measured and the obtained data were systemically analyzed using the Taguchi method and analysis of variance. Boron carbide substrates after addition of amorphous or crystalline rice husk ash display good wettability with molten aluminum alloys. The results show that, electrical resistivity of Al/B4C/rice husk ash composites is mainly influenced by initial preform porosity, while the coefficient of thermal expansion of composites is determined by the chemical composition of infiltrated alloys. The measured values for coefficient of thermal expansion (10.5 × 10−6/℃) and electrical resistivity (0.60 × 10−5 Ω.m) of Al/B4C/rice husk ash composites, fabricated according to analysis of variance's optimal conditions are in good agreement with those of the projected values (11.02 × 10−6/℃ and 0.65 × 10−5 Ω.m, respectively). The difference between the corresponding values obtained from verification tests and projected values, for electrical resistivity and coefficient of thermal expansion are less than 5%. Finally, as a material selection approach, the strengths and weaknesses of the composites have been graphed in the form of radar diagrams.


2014 ◽  
Vol 3 (2) ◽  
pp. 216 ◽  
Author(s):  
S. Gopinath ◽  
R Sabarish ◽  
R. Sasidharan

This paper reports a finite element study of effect of bonding strength between metal and ceramic. The bonding strength is evaluated with different processing temperature and holding time. The difference between the coefficients of linear thermal expansion (CTEs) of the metal and ceramic induces thermal stress at the interface. The mismatch thermal stress at the interface region plays an important role in improving bonding strength. Hence, it is essential to evaluate the interface bonding in metal-ceramics joints. The Al/SiC bonding was modeled and analyzed using finite element analysis in ANSYS (v.10). Keywords: Bonding Strength, Coefficient of Thermal Expansion, Thermal Stress, Interface, Al/Sic, FEA.


Alloy Digest ◽  
1988 ◽  
Vol 37 (2) ◽  

Abstract INCOLOY alloy 907 is a high-strength alloy having a low coefficient of thermal expansion. It is a precipitation hardening alloy. INCOLOY alloy 907 is useful for gas-turbine components where it provides for closer control of clearances and tolerances. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and shear strength. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Fe-83. Producer or source: Inco Alloys International Inc..


2016 ◽  
Vol 879 ◽  
pp. 1258-1264
Author(s):  
Michiya Matsushima ◽  
Noriyasu Nakashima ◽  
Satoshi Nishioka ◽  
Shinji Fukumoto ◽  
Kozo Fujimoto

Electronics devices consist of silicon chips, copper leads, resin or ceramics substrates and which are jointed to each other with solder, conductive adhesive or other materials. Each coefficient of thermal expansion is different and it causes strain concentration and cracks. The solder easily deformed by the difference of the thermal expansion and it relieved the stress on the devices however the epoxy resin of the conductive adhesives are harder. So we suggested the composed joint including the relaxation layers of low elastic material. The shear strength and elongation of the epoxy resin joint, silicone rubber joint and the composite joint of the two materials were investigated. The analytical study was carried out to clarify the stress reduction effect of the design of the relaxation layer in the composite joints. The parameters such as the width, height, pitch and the distance of the relaxation layer from the joint edge are investigated. The high relaxation layer close to the joint edge effectively reduced the stress of the joint. The stress reduction effect appeared in the different pitch of the layers.


2011 ◽  
Vol 66-68 ◽  
pp. 1522-1527
Author(s):  
Li Na Sui ◽  
Li Yan Yu ◽  
Li Feng Dong

Leucite crystal was prepared using SiO2-Al2O3-K2CO3-Na2CO3as raw materials and adopting melt quenching and appropriate heat treatment temperatures. The crystal was characterized and analyzed by X-ray powder diffraction, the coefficient of thermal expansion, and biocompatibility. The results showed that appropriate Na2O could advance the growth of leucite, but high concentration facilitates the formation of KAlSiO4crystal. The coefficient of thermal expansion was 24.52×10-6/°C at 600 °C, and thereby the coefficient could be adjusted by adding appropriate amount of leucite. The biocompatibility of leucite was almost the same as the Songfeng powder for clinical applications.


2016 ◽  
Vol 368 ◽  
pp. 41-44 ◽  
Author(s):  
Martin Švec

The iron aluminides seem to be very perspective materials for high temperature structural application. They have many advantages, but unfortunately also some negative properties – e.g. sharp drop in strength above 600°C or limited ductility at room temperature. These disadvantages can be reduced by alloying of binary alloy by other elements.Present work deals with a study of coefficient of thermal expansion (CTE). It was investigated the influence of microstructure and heat-treatment on the values of CTE. Secondary, it was studied the possibilities, how to determine phase transition temperatures from CTE curves. Influence of type of iron aluminides lattice on CTE values was also examined as well as the influence of addition of alloying elements into binary iron aluminides.


Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 401
Author(s):  
Haiyan Chen ◽  
Xin Nai ◽  
Shuai Zhao ◽  
Decai Lu ◽  
Zhikang Shen ◽  
...  

Ti3SiC2 ceramic and copper were successfully vacuum brazed using Ag-Cu-Ti filler and Ag-Cu-Ti filler with copper mesh, respectively. In this study, the effects of copper mesh and brazing parameters on the interface microstructure and mechanical properties of the joints were systematically studied. The results revealed that the typical interfacial microstructure of joint was Ti3SiC2 ceramic/Ti5Si3 + TiC + Ti2Cu + Ti3Cu/Ag (s, s) + Cu (s, s)/eutectic Ag-Cu + TiSiCu/Cu. A maximum shear strength of joint obtained at a brazing temperature of 870 °C and a holding time of 10 min can reached up to 66.3 ± 1.2 MPa, which was 34.7% higher than that without copper mesh. The improvement of mechanical property was attributed to the extraordinary plasticity of copper mesh, which reduced the residual stress caused by the difference in the coefficient of thermal expansion at the interface of joints. As the brazing temperature and holding time further increased, the shear strength of joints decreased due to the excessively thick reaction layer of intermetallic compounds.


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