ATOM-PROBE STUDY TI AL BASED ALLOY

Two phase alpha(2) + gamma Ti Al based alloys have a better ductility than single phase alloys. Oxygen seems to have a key role with respect to the ductility properties of these alloys. This paper present an at om probe determination of oxygen concentration in alpha(2) and gamma p hases of two phase alloys and in single phase alloys. The nearly const ant observed oxygen concentration in gamma phase is considered as the oxygen maximum solubility in this phase (similar to 200 at. ppm). The oxygen excess which exists in normal alloys either leads to an oxide p recipitation in single phase alloys or is absorbed in the alpha(2) pha se of two phase alloys. The absence of oxides in two phase alloys coul d explain the better ductility of these alloys.