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Effect of Zr additions on microstructure evolution and phase formation of Nb−Si based ultrahigh temperature alloys
M. Sankar, , Vajinder Singh, V. V. Satya Prasad
Published in Elsevier Ltd
2018
Volume: 101
   
Pages: 123 - 132
Abstract
In the present work, the role of Zr addition on the microstructure and phase formation of hypoeutectic Nb−16 at. % Si alloy has been investigated. The results showed that both binary and alloy with 2 at. % Zr resulted in two phase microstructures composed of Nbss and Nb3Si phases. In contrast, the alloys with 4 at. % Zr and 6 at. % Zr revealed two phase microstructures composed of Nbss and α−Nb5Si3 phases. The orientation relationship (OR) obtained between eutectoid lamellar structure comprising of Nbss and α−Nb5Si3 phases is (110) Nb//(110) Nb5Si3. The equilibrium microstructures consisting of Nb and α−Nb5Si3 phases were obtained in as cast condition when the Zr concentration is above 2 at.%. The addition of Zr accelerated the dissociation kinetics of Nb3Si phase in to Nbss and α−Nb5Si3 phases during solidification. The formation of α−Nb5Si3 phase in the as cast condition eliminates heat treatment required for decomposition of Nb3Si phase in Nb-Si alloys. © 2018 Elsevier Ltd
About the journal
JournalData powered by TypesetIntermetallics
PublisherData powered by TypesetElsevier Ltd
ISSN09669795
Open AccessNo
Concepts (14)
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