Modeling thermally-driven microstructure evolution in nanocrystalline materials
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Authors
Chen, Zhanyang
Issue Date
2018-08
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Materials engineering
Alternative Title
Abstract
Solute mobility is limited in the W-based system (W-Zn for a grain boundary segregated system and W-Cr for a duplex alloy) and is relatively high in the Fe based system (Fe-Zn for a grain boundary segregated system and Fe-Au for a duplex alloy). Advanced thermal stability is observed through grain boundary segregation, where the low solute mobility system exhibits better stabilization. A pinning-depinning process is observed in the W-Zn system at low temperature, leading to a discontinuous grain growth phenomenon. Spatial grain size gradient is reduced in a pure metallic system, and the addition of solutes helps stabilize the spatial grain size gradient. In duplex alloys, the mixing enthalpy, , plays an important role in the microstructure evolution. In W-Cr system where is low, the dissolution of solutes into W matrix leads to weak solute stabilization. In Fe-Au system, a dual-phase nanocrystalline structure showing great stability against grain growth is observed.
Description
August 2018
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY