فهرست نشریات علمی دسترسی آزاد ایران

In this study, the effect of homogenization time on the microstructural evolution and mechanical properties of the cast AD730 superalloy at 1100 °C was investigated. The as-cast microstructure consisted of a dendritic structure along with interdendritic phases, including η phase, Laves phase, γ/γ′ eutectic, and MC carbides. Microscopic examinations and localized analyses revealed that the eutectic and Laves phases were completely dissolved during the early stages of homogenization, while the η phase disappeared after 10 hours of treatment. Prolonging the homogenization time promoted chemical uniformity and gradual elimination of the dendritic structure, resulting in a nearly uniform microstructure after 25 hours. However, at this stage, the formation of voids was detected, indicating adverse effects due to over-homogenization. Hardness measurements showed a continuous decrease in hardness with increasing homogenization time, attributed to the gradual dissolution of the strengthening γ′ precipitates. Based on these results, an optimal homogenization duration of 15 to 20 hours at 1100 °C is suggested, which can eliminate undesirable phases and enhance compositional uniformity while avoiding structural defects.