These crystals can be produced by:
Annealing of deformed wires or rods by secondary recrystallization and extreme crystal growth; thoriated tungsten wires (cross-section, e.g., 100µm) are pulled through a narrow zone at a temperature of above 2000℃ at the same time the crystal grows, forming a single crystal up to several meters long (Pintsch procedure).
Zone melting.
Single crystals, due to their high cost are used only in special cases like basic investigations. The outstanding properties are a lack of grain boundaries and a very small number of lattice defects. They are therefore easy to deform, show great ductility, and possess no embrittlement up to the highest temperature.
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