THE BEHAVIOR OF IMPROVED ELEMENTS IN SWAGING TUNGSTEN BILLET MIXED BY SOLID-LIQUID METHOD

The analysis of the fracture and milling surface of swaging tungsten billets and drawing tungsten wire was made by the scanning electronic microscope. These sample were done by traditional process:making powder doped by Liquid-Solid mixing method, pressing, sintering, swaging, drawing etc. Results indicate that elements of silicon and aluminium are richened in the cavity on grain boundary; except elements of silicon and aluminium, likewise, the element of potassium is also richened in the interior cavity in crystalline grain. The theory of potassium bubble can be used for explaining the creep characteristic under high temperature. Otherwise, the theory of molecular sieve and phase diagram of SiO₂-Al₂O₃ System may also be used for explaining compensation for high temperature properties of tungsten wire.