The microstructure of the solutionized and aged superalloy was examined after additional aging at 982 degree C for 72, 250, and 1000 hours. Alloy compositions that were examined contained the normal 1. 34 at. pct (4. 3 wt pct) Ta as well as 0. 67 at. pct and zero Ta levels. The gamma prime phase agglomerated, became plate-like in morphology, and decreased in volume fraction for all three alloys. Changes which occurred in the gamma and gamma prime phase compositions were nearly complete after 72 hours of aging while changes in the MC carbide composition continued throughout the aging. Blocky M//6C carbides precipitated along the grain boundaries in the first 72 hours of aging. In addition, an acicular form of this Mo/Cr/Ni-rich carbide developed in the intragranular regions.