Correlation between Ductility and Ordering Energy of Ni₃Al

Ductility improvement is investigated at room temperature in polycrystalline Ni₃Al macroalloyed with Pd which has been revealed to have a strong tendency to substitute for the Ni site independent of the composition of the host elements. Pd-doped Ni₃Al was successfully rolled by 10∽40% reduction in as-cast condition. It was found that the recrystallized Ni₇₅Al₂₃Pd₂ exhibited elongation to fracture of 11%, whereas recrystallized Ni₇₃Al₂₅Pd₂ did brittle fracture. It can be concluded that the ductility improvement of Ni₃Al by macroalloying with Pd is attributable to degradation of the ordering energy, combined with decrease in Al content.