Abstract
Sigma phase (σ) precipitation in a stabilized 316Ti austenitic stainless steel (ASS) was studied during isothermal aging at 800 °C by using experimental investigations, thermodynamic and thermokinetic calculations. Microstructural analysis revealed that σ phase directly nucleated from the γ phase on the highly energetic γ/γ grain boundaries, on the triple junctions and on the compositional bands. Kinetics parameters of the σ phase precipitation obtained by using the Kolmogorov-Johnson-Mehl-Avrami (KJMA) model and the MatCalc software agreed well with the experimental results. Thermodynamic calculations predicted the apparition of TiCN carbonitride and the absence of Cr23C6, which enhanced the σ phase precipitation directly from the γ phase. Thermokinetics calculations performed using MatCalc showed that σ phase precipitation was sluggish in comparison to its precipitation in duplex stainless steels and that its formation mechanism did not change during the isothermal aging and was mainly controlled by the diffusion of chromium through the grain boundaries. Both experimental and simulated results indicated that the σ phase precipitation is accompanied by its enrichment in Cr and Mo and depletion in Ni.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
