Long-term stability of 14YT-4Sc alloy at high temperature

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:647

Article

Li, Lulu¹  Xu, Weizong¹  Saber, Mostafa²  Zhu, Yuntian¹  Koch, Carl C.¹  Scattergood, Ronald O.¹ 

[1] N Carolina State Univ, Dept Mat Sci & Engn, Raleigh, NC 27695 USA

[2] Portland State Univ, Dept Mech & Mat Engn, Portland, OR 97207 USA

关键词: Nanocrystalline ODS ferritic alloys;    Grain growth;    Sc stabilization;    long-term stability;   

DOI  :  10.1016/j.msea.2015.09.012

来源: Elsevier

【 摘 要 】

14YT alloy (Fe-14Cr-0.25wt%Y2O3-0.4wt%Ti) with 4 at% Sc addition was previously reported to exhibit a nanoscale microstructure and high strength when annealed at temperatures up to 1000 degrees C (0.65T(m)) for 1 h. Here we report that the microstructure and mechanical behavior of 14YT-4Sc alloy after long-term annealing for up to 60 h at 1000 degrees C. FIB analysis shows abnormal grain growth with annealing time, while a large fraction of the matrix still consists of nanoscale grains. TEM images reveal a slight growth of nano grains, with estimated grain growth exponent, n, to be 0.29. Sc-Ti-Y-O enriched nano oxide particles (< 10 nm) were observed in EDS mapping of the 14YT-4Sc-60h sample. The nano-structure retention at the high temperature of 1000 degrees C for 60 h is attributed to these complex nano oxides. (C) 2015 Elsevier B.V. All rights reserved.

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