|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Phase Transformations and Microstructural Evolution
||Nano-sized Precipitate Stability and Its Controlling Factors in a NiAl-strengthened Ferritic Alloy
||Zhiqian Sun, Gian Song, Jan Ilavsky, Gautam Ghosh, Peter Liaw
|On-Site Speaker (Planned)
In order to improve thermal efficiency and reduce greenhouse gas emissions, fossil-energy power plants require an increase of the steam temperature and pressure. Coherent B2-ordered NiAl-type precipitates have been used to reinforce solid-solution body-centered-cubic iron for high-temperature application in next-generation fossil-energy power plants. In this study, the stability of nano-sized precipitates in a NiAl-strengthened ferritic alloy was investigated at 700-950 °C using ultra-small angle X-ray scattering and electron microscopies. Here we show that the coarsening kinetics of NiAl-type precipitates is in excellent agreement with the ripening model in multicomponent alloys. We further demonstrate that the interfacial energy between the matrix and NiAl-type precipitates is strongly dependent to differences in the matrix/precipitate compositions. The results profile the ripening process in multicomponent alloys by illustrating controlling factors (i.e., interfacial energy, diffusivities, and element partitioning). The study provides guidelines to design and develop high-temperature alloys with stable microstructures for long-term service.
||Planned: A print-only volume