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

10th International School-Conference on Materials for Extreme Environment: Development, Production and Application

Kalin, B.A.^1 ; Suchkov, A.N.^1

National Research Nuclear University MEPhI, Moscow Engineering Physics Institute, Kashirskoe Highway 31, Moscow

115409, Russia^1

关键词: Brazing filler alloys;    Brazing temperature;    Experimental alloys;    Experimental materials;    High temperature brazing;    Production methods;    Structural-phase state;    X-ray investigations;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/130/1/012038/pdf
DOI  :  10.1088/1757-899X/130/1/012038

来源: IOP

【 摘 要 】

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.