National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow, Russia:

A. A. Ivannikov, Assistant, e-mail: ivannikov7@rambler.ru
V. A. Tukhbatov, Student
A. N. Suchkov, Assistant Professor
A. L. Ustyuzhaninov, Student
I. A. Bogachev, Engineer

The study of possibility of amorphous alloys application for creation of joints of structural nuclear and aerospace engineering components requires a detailed research of the joints' strength and rigorous study of physical processes, occurring at the border of the brazed seam under mechanical loads and deformation. Inside the brazed seam, obtained using amorphous filler metals, there can be observed the reduction of intermetallic phases and other fragile phases, due to more active diffusion of filler metal doped components into basic material. Thus, application of amorphous filler metals for materials provides higher strength of the joint in comparison with crystalline analogues (with the same composition). The amorphous filler metal STEMET-1301A (Ni – 7% Cr – 4,6% Si – 3% Fe – 2,6% B (% (wt.)) — the BNi-2 analogue) was used in this research for creation of stainless steel 12Kh18N10T (12Х18Н10Т) (Fe – 18% Cr – 10% Ni – 1% Ti (% (wt.))). The brazing was conducted at several temperature modes. The temperature was varied in the range from 1050 to 1160 ^оС with holding time of 15 minutes. General regularities of formation of structural-phase state of obtained joints were identified during the research. Mechanical tests of uniaxial tension of cylindrical specimens (State Standard 5949–75) were carried out. The higher strength was reached during the brazing at 1070 ^оC and holding time of 15 minutes: the tensile stress value σ_b = 500±20 MPa; the relative extension value δ = 20±2% (in comparison with initial steel peculiarities: σ_b = 540±20 MPa, δ = 35±3%). The fracture surface fractography was investigated. Interrelation between structure and strength of brazed joint was determined.

1. Khorunov V. F. Osnovy payki tonkostennykh konstruktsiy iz vysokolegiro vannykh staley (Basis of brazing of thin-wall constructions made of high-alloy steels). Kiev : Naukova Dumka, 2008. 240 p.
2. Petrunin I. E., Bereznikov Yu. I. et al. Spravochnik po payke (Brazing reference book). Under the editorship of I. E. Petrunin. Third edition, revised and enlarged. Moscow : Mashinostroenie, 2003. 480 p.
3. Ponimash I. D., Orlov A. V., Rybkin B. V. Vakuumnaya payka reaktornykh materialov (Vacuum brazing of reactor materials). Moscow : Energoizdat, 1995. 192 p.
4. Hu Chen, Jian-Ming Gong, Shan-Tung Tu. Diffusion-Based Analytical Modeling of Brazing Stainless Steel with BNi-2. Journal of Computational and Theoretical Nanoscience. 2008. Vol. 5. pp. 1746–1752.
5. Arafin M. A., Medraj M., Turner D. P. Effect of alloying elements on the isothermal solidification during TLP bonding of SS 410 and SS 321 using a BNi-2 interlayer. Materials Chemistry and Physics. 2007. Vol. 106. pp. 109–119.
6. Logvenchev I. S., Ivannikov A. A., Volkov A. A. The Brazing of Nickel alloys for Nuclear Reactor with the using of the Rapidly-Quenched filler metals. Inorganic materials: applied research. 2014. Vol. 5, No. 3. pp. 263–267.
7. GOST 5949–75. Stal sortovaya kalibrovannaya korrozionno-stoykaya, zharostoykaya i zharoprochnaya. Tekhnicheskie usloviya (State Standard 5949–75. Section sized corrosion-resistance and heat-resistance steel. Technical requirements). Introduced: January 01, 1977. (in Russian).
8. GOST 28830–90. Soedineniya payanye. Metody ispytaniy na rastyazhenie i dlitelnuyu prochnost (State Standard 28830–90. Brazed joints. Tensile test and stress-durability methods). Introduced: January 01, 1992. (in Russian).
9. Maksimova S. V. Amorfnye pripoi dlya payki nerzhaveyushchey stali i titana i struktura payanykh soedineniy (Amorphous solder for brazing of stainless steel and titanium and structure of brazed joints). Adgeziya rasplavov i payka materialov = Adhesion of melts and materials brazing. 2007. No. 40. pp. 70–81.
10. John A Fellows. Fraktografiya i atlas fraktogram: spravochnoe izdanie (Fractografy and atlas of fracture patterns: reference book). Translated from English by E. A. Shur. Under the editorship of M. L. Bershteyn. Moscow : Metallurgiya, 1982. 489 p.