To the evaluation of structure improvement of heat-resistant metal monocrystal

Vanadium single crystals derived from alumothermic (98.5%) and electrolytic (99.9%) material by growing using electron crucible-free zone melting at different zone travel rates with the growth axis being oriented along < 001 >, < 110 > and < 111 > been analyzed by roetgenographic technique. The < 110 > crystals from alumothermic vanadium have a critical growth rate of 1.5 mm/min, those from electrolytic one, 6-7 mm/min. The experiments indicate that < 001 > ot < 111 > oriented crystals can not be made defect-free even at infinitely low growth rates; the imperfection factor for these crystals approaches 0.007-0.009. Growth rate has the greatest effect on the perfection of crystals grown from alumothermic material. It follows from the present data that the most favourable orientation for manufacturing perfect crystals at slow growth rates is the < 110 > direction