Fabrication structure and properties of monocrystal molybdenum wire

The aim of the work was to obtain monocrystalline molybdenum wire of a great length (20-50 cm) and to investigate the effect of various impurities upon grain growth and formation of a monocrystalline structure. The monocrystalline wire was obtained by recrystallization while continuously passing a wire blank 0.1-0.2 mm in diameter from molybdenum of various grades through a hot zone in vacuum. The best results were obtained with the use of a wire from sintered molybdenum with silicon-alkali additives under the following conditions: temperature of the hot zone, 2000-2100 deg C; length of zone, 5 cm; wire speed 40 cm/h. The orientation of the monocrystalline wire coincided with the crystallographic direction [110], maximum deviation being 6-7 deg, the ultimate strength of the wire being 42-45 kgf/mm2, and relative elongation, 35-36%. It was shown that silicon-alkali additives were promoters of a monocrystalline structure