Effect of Al and Ti on precipitation behaviour of gamma' in cast alloy 625

摘要

In the smelting process of large castings, the addition of deoxidiser is bound to introduce other elements, such as Al and Ti. This research investigates the influence of Al and Ti on the precipitation behaviour of the gamma" phase in cast alloy 625. The results showed that Al and Ti can improve the supersaturation of Nb in inter-dendritic zones during long-term aging. Furthermore, Al and Ti atoms replace partial Nb atoms in the gamma" phase and promote the precipitation and growth of gamma", which lead to an increase in strength at high temperatures.