Effect of Mo on the thermal stability of gamma ' precipitate in Inconel 740 alloy

Abstract

The effect of Mo on gamma prime (γ') coarsening kinetics of Ni-25Cr-20Co-1.8Ti-0.9Al-2Nb-0.03C-xMo (x=0.5, 3, 6wt.%) alloys was investigated with respect to the activation energy for γ' precipitate coarsening. The coarsening rates were measured at temperatures of 760 o C, 780 o C, and 810 o C up to 500h. Coarsening rate decreased with increasing Mo, and the activation energies for coarsening were determined to be 245kJ/mol, 261kJ/mol, and 278kJ/mol for 0.5wt.% Mo, 3wt.% Mo, and 6wt.% Mo, respectively.