Brazed joints between tungsten and steel are the essential part of the divertor armor block. Meanwhile, liquid Li is considered as a prospective coolant and plasma facing material. Therefore, it is important to estimate the corrosion rate of the brazed seam. Corrosion mechanism in liquid Li at 600 °C after 100 h exposure investigated on two types of brazed joints: with Cu and with TiZrBe filler metals. Severe corrosion damage and corrosion failure occur on the brazed seam with Cu filler. Corrosion primarily affects Cu phases in brazed seam. The brazed joint with TiZrBe filler metal shows high corrosion resistance. Results of chemical analysis indicates that corrosion products deposited on specimen surface contain high Fe and Cr content. The corrosion mechanism is similar to corrosion of steel. Corrosion in liquid Li causes preliminary dissolution of Cr-containing phases.

The combination of reduced-activation ferritic–martensitic steels (RAFM) and tungsten is suggested for plasma-facing components in future fusion reactors, but joining these materials is challenging. One promising method is a brazing technique that uses a Ta interlayer and a fully reduced activation brazing alloy, TiZr4Be. The initial microstructure of the Rusfer/TiZr4Be/Ta/TiZr4Be/W joint and transformations caused by exposure to D2 gas at elevated temperatures and a pressure of 1 Pa were assessed using electron backscatter diffraction (EBSD), synchrotron X-ray diffraction analysis and secondary ion mass spectrometry. The joining layer was the main center of deuterium accumulation, but there were no changes in the microstructure after D2 exposure at 300 °C. The total D retention after D2 exposure at 600 °C was lower, but it was concentrated in the W/TiZr4Be/Ta seam, and the formation of an additional ZrFe2D2.66 phase was observed.

The fully reduced activation brazing alloy TiZr4Be and a tantalum intermediate layer are considered to be used for joining tungsten (W) to reduced-activation ferritic-martensitic steel (RAFM) for future DEMO reactor application. Deuterium retention in the W-Rusfer joints and separate elements was investigated with the focus on the intermediate brazing layer. The samples were exposed in deuterium gas ( p = 1- 10 4 Pa, T = 30 0-60 0 C) and plasma discharge ( T = 600 C). An acceptable deuterium concentration was observed after gas exposure at the pressure of 1 Pa, that is relevant to operating conditions of future fusion devices, however the brazing alloy and tantalum accumulate a large amount of deuterium in the case of the pressure above 100 Pa that leads to failure of the joint. The D retention after D plasma irra-diation was substantial, but nearly independent on the fluence and the thickness of the W layer due to absorption from surrounding D 2 gas. (C) 2022 Elsevier B.V. All rights reserved.

The work presents the results of high temperature brazing of reduced activated ferritic martensitic steel EK-181 with pure tungsten, which is essential for DEMO fusion reactor. Vanadium interlayer was used to reduce thermal stresses. Brazing alloys to be used were rapidly quenched into ribbons Cu-12Sn, Cu-20Sn, Cu-12Sn-0,4P for EK-181/V, Cu-50Ti for V/W. Microstructure investigations, mechanical and thermocycling test were carried out.

Nanocrystalline ribbon filler metal-alloys of system Ni-Cr-Si-Be are produced by the rapidly quenching of the melt method. By these filler metals carried out hight temperature vacuum brazing of austenitic steels (12Kh18N10T and Kh18N8G2) and austenitic-ferritic class EI-811 (12Kh21N5T). The basic laws of structure-phase state foundation of brazed joints are determined, features of the interaction of the molten filler metal to the brazed materials are identified, the optimal temperature and time parameters of the brazing process are determined.

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.

This work presents results on erosion of mono-and polycrystalline tungsten and its brazed joints with bronze substrates under irradiation by high-temperature pulsed (tau(p) similar to 20 mu s) deuterium plasma flows, with a power density q = 19-66 GW/m(2) and pulses numbering from 2 to 10, simulating the expected plasma disruptions and ELMs in fusion reactors. The surface erosion and heat resistance of tungsten and brazed joints were investigated by scanning electron microscopy, and erosion coefficients were determined by target mass loss.It is found that for both types of tungsten the surface starts to significantly crack even under relatively weak irradiation regimes (q = 19 GW/m(2), N = 2), at which point surface melting is not observed. Local melting becomes visible with an increase of q up to 25 GW/m(2). In addition, there is formation of blisters with a typical size of 1-2 mu m on the surface of monocrystalline samples and craters up to 2 mu m in diameter on polycrystalline samples. In addition, craters similar to 10-30 mu m in diameter are formed on defects similar to those observed under unipolar arcs. At that point, the erosion coefficients change to within ranges of 0.2-0.7 x 10(-5) kg/J m(2).It is found that at q = 50 GW/m(2), the brazed joints of monocrystalline tungsten with bronze of Cu-0.6% Cr-0.08% Zr have the highest heat resistance. (C) 2013 Elsevier B.V. All rights reserved.