EFFECTS OF ULTRA-HIGH PURIFICATION AND ADDITION OF INTERSTITIAL ELEMENTS ON PROPERTIES OF PURE TITANIUM AND TITANIUM-ALLOY

Various properties of pure titanium and titanium alloys with ultra-hig h purity prepared by melting raw titanium made by improved iodide proc ess have been examined. Effects of oxygen, nitrogen and carbon additio n to pure titanium and SP-700 alloy on tensile properties were investi gated, and strengthening effect and ductility variation due to these e lements were evaluated. The strength of pure titanium and SP-700 alloy markedly decreased with the increase of purity, the yield strength of pure titanium containing oxygen of 40 ppm being reduced to 100 MPa. T he recrystallization temperature of cold rolled ultra-high purity tita nium was extremely low, 553 K, a small amount of oxygen and iron dopin g markedly increased this temperature. (C) 1998 Elsevier Science S.A. All rights reserved.