Characterization of alloy 718 subjected to different thermomechanical treatments

Chemical phase and microstructural investigations of alloy 718 solution-annealed and age-hardened were performed in this study. Focus was made in the effects of solution annealing temperature, aging temperature and holding time, and the amount of intermediate cold work on the alloy. The formation of secondary phases such as γ'-phase, γ”-phase, and δ-phase, grain sizes, and any deformations of the microstructure with respect to the processed conditions have been studied. Statistics such as size and number densities of these precipitates with respect to the processing conditions were evaluated and a discussion on optimum conditions in obtaining finer and higher density of γ'- and γ”-phase precipitates is also presented.