EMBRITTLEMENT OF TI3AL-10NB-3V-1MO CAUSED BY SLIGHT OXIDATION

Residual tensile properties at room temperature of Super alpha2 were examined after exposing in air. The elongation in beta-solution treated materials was 2 to 2.5%. The tensile specimens were exposed at 813 or 973 K for 0.9 to 1080 ks. The elongation at room temperature has continuously decreased from 2 to 0.3% with increasing the exposure temperature and time. The ductility was almost completely recovered by mechanically removing oxidation-affected layers. The oxidation at 813 K for a half year is quite mild with a mass gain of 2 g.m-2, while the ductility of the oxidized specimen extrapolated in this work was only 0.3%. Although the detailed mechanism of embrittlement has not been clarified, it was concluded that slight oxidation has enhanced surface cracking and premature failure.