Production of Large Monocrystalline Ingots and Discs of

Production of Large Monocrystalline Ingots and Discs of Molybdenum and its Alloys via Crucibleless Zone Melting for Special Application Products Authors: E. G. Kolesnikov, V. A. Stepanov, P. A. Stepanchikov, R. A. Fedoseev, A. N. Shotaev Speakers: P. A. Stepanchikov, V. A. Stepanov

Crucibleless Zone Melting with Electron Beam Heating The operational medium of the crystal growth chamber is high vacuum (< 2· 10 -5 mm. Hg) Maximum length of the grown ingots ≥ 600 mm Diameter of the grown ingots: 13 ÷ 40 mm www. minatom. ru www. sialuch. com 2

Layout of the Crystal Growth Chamber 5 6 2 3, 4 8 1 U = 5 – 18 k. V I = 0. 8 – 2. 0 A N = 5 – 20 k. W 9 7 1 – bottom screen; 2 – top bed; 3 – top screen; 4 – heating cathode; 5 – polycrystalline workpiece; 6 – growth chamber; 7 – seed crystal; 8 – metal spacers; 9 – bottom bed. www. sialuch. com www. minatom. ru 3

Automated Ingot Growing Process Control System (ACS) An automated ingot growing process control system has been developed and integrated into the crucibleless zone melting equipment. 1. For growing crystals whose diameter is ≤ 20 mm, the ACS stabilizes the power yielded in the molten zone with the software control of the high-voltage power source. 2. For growing crystals whose diameter exceeds 20 mm, the ACS stabilizes the diameter of the growing crystal at the crystallization front. www. sialuch. com www. minatom. ru www. luch. podosk. ru 4

Sequence of Long Monocrystalline Ingots Production 1 2 3 4 5 1 – an assembly of two cylindrical fillets produced via powder metallurgy; 2 – a polycrystalline workpiece after fillets remelting; 3 – a workpiece machined to the specified dimensions; 4 – a grown long monocrystalline ingot of a specified orientation; 5 – a monocrystalline ingot – the final product www. sialuch. com www. minatom. ru www. luch. podolsk. ru 5

Layout of the Growth Chamber with the Modified Drive 1 – growth chamber; 2 – bottom rod; 3 – top rod; 4 – bottom drive; 5 – polycrystalline charge; 6 – monocrystalline seed; 7 – horizontal shaft; 8 – top screen; 9 – water-cooled bed; 10 – bottom screen; 11 – heating cathode; 12 – molten zone www. sialuch. com www. minatom. ru 6

Potential of the Technique Employed Grown monocrystalline molybdenum discs Monocrystalline molybdenum plates with dimensions of 100× 4 made of a monocrystalline disc Axle-disc workpiece www. sialuch. com www. minatom. ru www. luch. podolsk. ru 7

Products and Application Geometry of the products made via electric arc crucibleless zone melting: Application: Type Diameter, mm Length, mm Molybdenum Monocrystalline / polycrystalline 12 -48 ≥ 600 Molybdenumniobium-zirconium Monocrystalline / polycrystalline 12 -30 ≥ 600 Molybdenumrhenium (47% Re) Polycrystalline Material (rods) 12 -30 ≥ 400 Monocrystalline / polycrystalline 12 -28 ≥ 400 Tungsten-rhenium (27% Re) Polycrystalline 12 -30 ≥ 300 Titanium-vanadium Polycrystalline 12 -25 ≥ 400 Material (discs) Type Diameter, mm Length, mm Monocrystalline / polycrystalline ≥ 130 ≥ 600 Tungsten Molybdenum ü Work pieces for production of zonerefined refractory roll stock (foils, wires, rods, tubes etc); ü Monocrystalline pipes of hightemperature nuclear power systems; ü Anodes and cathodes of x-ray tubes, electronic tubes; ü Ultra-pure targets for sputtering systems employed in electronics industry; ü Materials for electronic components resources; ü Power mirrors for laser facilities and systems of various applications; ü Materials for fundamental physical research. www. minatom. ru 8

Thank you very much for your attention! www. sialuch. com www. minatom. ru www. luch. podolsk. ru 9