Effect of Ta and Pd Addition on Mechanical Properties of Inconel 718

Tantalum and palladium were added to Inconel 718 at the expense of Nb content to study resultant microstructure and mechanical properties in hot-worked and annealed condition. An increase in {100} peak intensity along with a concomitant decrease in {111} peak intensity was observed with decreasing Nb content. Ta-containing alloys exhibited annealing twins and annealing twin density showed a direct relationship with Ta content. Overall, alloying additions improved strength as well as ductility except the alloy containing only Ta which was less strong than Inconel 718. The alloy containing Ta as well as Pd exhibited highest toughness and lowest Rockwell hardness value.