Superalloys are high tech materials used in aggressive atmospheres in aero-engines and land-base gas turbines. IN738LC is an important superalloy used in gas turbines. Main strengthening ingredient in this superalloy is the Ni3(Al,Ti,Nb) type precipitate phase, which goes through size and morphological changes by the influence of temperature and time. Coarsening features of the precipitate phase in IN738LC are explored. Coarsening of precipitates is via agglomeration of nearby precipitates moving as a whole in the matrix. In contrast to conventionally accepted view of constant activation energy, experimental data in this study suggest varying activation energy which causes coalescence and relates to the precipitate size in the form of an increasing polynomial.