ASSESSMENT OF GAS SATURATION OF TITANIUM ALLOYS SYNTHESIZED FROM POWDERS USING SCREW EXTRUSION

Abstract

The gas saturation of semi-finished titanium alloys produced from metal powder using the technique comprising cold pressing, vacuum sintering, and subsequent severe plastic deformation by twist extrusion is analyzed. Main sources and quantitative analysis of the contamination of sintered alloys with nitrogen and oxygen impurities contained in the powder particles, on their surface, and in the pore spaces of the billet are considered. It is established that the quality of titanium powder has the biggest impact on the contamination of alloys. It is shown that the use of titanium powder with low content of impurities allows keeping the oxygen and nitrogen content of the synthesized semi-finished products at the level meeting the requirements of the reference documentation for VT1-0 titanium and heat-resistant titanium alloys. It is shown that the percentage of impurities entering the synthesized alloy from (i) the oxides on the powder particle surface and (ii) the air filling the closed pore space of the billet is insignificant.