Microstructural and Mechanical-Property Manipulation through Rapid Dendrite Growth and Undercooling in an Fe-based Multinary Alloy
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Microstructural and.pdf
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1.53 MB
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Author(s)
Ruan, Ying
Dao, Ming
Mohajerani, Amirhossein
Date Issued
August 2016
Journal
Scientific Reports
Publisher
Nature Publishing Group
Citation
Ruan, Ying, Amirhossein Mohajerani, and Ming Dao. “Microstructural and Mechanical-Property Manipulation through Rapid Dendrite Growth and Undercooling in an Fe-Based Multinary Alloy.” Scientific Reports 6.1 (2016): n. pag.
Version
Final published version
Abstract
Rapid dendrite growth in single- or dual-phase multicomponent alloys can be manipulated to improve the mechanical properties of such metallic materials. Rapid growth of (αFe) dendrites was realized in an undercooled Fe-5Ni-5Mo-5Ge-5Co (wt.%) multinary alloy using the glass fluxing method. The relationship between rapid dendrite growth and the micro-/nano-mechanical properties of the alloy was investigated by analyzing the grain refinement and microstructural evolution resulting from the rapid dendrite growth. It was found that (αFe) dendrites grow sluggishly within a low but wide undercooling range. Once the undercooling exceeds 250 K, the dendritic growth velocity increases steeply until reaching a plateau of 31.8 ms[superscript −1]. The increase in the alloy Vickers microhardness with increasing dendritic growth velocity results from the hardening effects of increased grain/phase boundaries due to the grain refinement, the more homogeneous distribution of the second phase along the boundaries, and the more uniform distribution of solutes with increased contents inside the grain, as verified also by nanohardness maps. Once the dendritic growth velocity exceeds ~8 ms[superscript −1], the rate of Vickers microhardness increase slows down significantly with a further increase in dendritic growth velocity, owing to the microstructural transition of the (αFe) phase from a trunk-dendrite to an equiaxed-grain microstructure.
MIT Department
Massachusetts Institute of Technology. Department of Materials Science and Engineering
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Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1038/srep31684
