Improvement in ductility of Ni 3Al by γ former doping

Abstract

Ductility of Ni 3Al macroalloyed with a γ former and a γ′ former has been examined on the basis of the assumption that lowering of ordering energy is responsible for ductility improvement of macroalloyed Ni 3Al. It was found that the addition of γ formers such as palladium, platinium copper and cobalt improves the ductility of Ni 3Al, whereas alloys containing γ′ formers such as tantalum, molybdenum, niobium, zirconium, vanadium, titanium and silicon remain brittle. In addition, observations of antiphase domain (APD) structures in melt-spun ribbons of macroalloyed Ni 3Al revealed that the addition of γ formers effective in ductilizing lowers the ordering energy of Ni 3Al, whereas that of γ′ formers ineffective in ductilizing raises the ordering energy of Ni 3Al. It is concluded that the addition of a ternary element lowering the ordering energy of Ni 3Al is strongly associated with the ductilization of Ni 3Al.