Influence of Solution Treatment on Microstructure of AEREX350 Alloy

The microstructure of hot rolled AEREX350 alloy under various solution treatments was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). It was found that with increasing solution temperature, η phase precipitated firstly at grain boundaries in parallel at 800 °C and then within grains at about 980 °C The η phase precipitated at grain boundaries played a role in preventing the migration of grain boundaries, and the η phase precipitated within grains would form Widmannstätten structure with further increasing solution temperature, η phase precipitated at grain boundaries was dissolved at temperature ranging from 1 080 °C to 1 095 °C, resulting in grain growth promptly owing to release of the pinning effect on grain boundaries. γ phase precipitated during the process of air cooling after hot rolling and dissolved at temperature ranging between 1010 °C and 1020 °C.