Formation and growth of complex precipitates in 316L austenitic steel during long-term annealing experiments

摘要

Transmission electron microscopy as well as corresponding analytical techniques, such as energy dispersive X-ray analysis, electron energy loss spectroscopy, and elemental mapping via Gatan imaging filter, have been used to study the growth sequence of complex precipitates with a TiN core formed in a commercial 316L(N) austenitic steel after creep experiments at 600 degrees C. It was found that the TiN precipitates, which originally exist in the as-delivered steel, serve as nucleation sites for intermetallic and Cr-containing carbide precipitates. The evolution of precipitate formation and growth was analyzed based on undeformed sample screw heads after 84, 164, 5,481, 41,000, and 85,000 h annealing.