Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7880901 | Acta Materialia | 2015 | 12 Pages |
Abstract
The ferritic superalloy Fe-10Ni-6.5Al-10Cr-3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923Â K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature deformation mechanisms at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing mechanisms during tensile deformation of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the deformation mechanisms change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873Â K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.
Keywords
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Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Shenyan Huang, Yanfei Gao, Ke An, Lili Zheng, Wei Wu, Zhenke Teng, Peter K. Liaw,