Lanthana-bearing nanostructured ferritic steels via spark plasma sintering

JOURNAL OF NUCLEAR MATERIALS

卷:470

Article

Pasebani, Somayeh^1,4  Charit, Indrajit^1,4  Wu, Yaqiao^2,4  Burns, Jatuporn^2,4  Allahar, Kerry N.^2,4  Butt, Darryl P.^2,4  Cole, James I.^3,4  Alsagabi, Sultan F.^1,4 

[1] Univ Idaho, Dept Chem & Mat Engn, Moscow, ID 83844 USA

[2] Boise State Univ, Dept Mat Sci & Engn, Boise, ID 83725 USA

[3] Idaho Natl Lab, Idaho Falls, ID 83401 USA

[4] Ctr Adv Energy Studies, Idaho Falls, ID 83401 USA

关键词: Mechanical alloying;    Powder metallurgy;    Sintering;    Steels;    Nanostructured materials;    Atom probe;   

DOI  :  10.1016/j.jnucmat.2015.12.035

来源: Elsevier

【 摘 要 】

A lanthana-containing nanostructured ferritic steel (NFS) was processed via mechanical alloying (MA) of Fe-14Cr-1Ti-0.3Mo-0.5La(2)O(3) (wt.%) and consolidated via spark plasma sintering (SPS). In order to study the consolidation behavior via SPS, sintering temperature and dwell time were correlated with microstructure, density, microhardness and shear yield strength of the sintered specimens. A bimodal grain size distribution including both micron-sized and nano-sized grains was observed in the microstructure of specimens sintered at 850, 950 and 1050 degrees C for 45 min. Significant densification occurred at temperatures greater than 950 degrees C with a relative density higher than 98%. A variety of nanoparticles, some enriched in Fe and Cr oxides and copious nanoparticles smaller than 10 nm with faceted morphology and enriched in La and Ti oxides were observed. After SPS at 950 degrees C, the number density of Cr-Ti-La-O-enriched nanoclusters with an average radius of 1.5 nmwas estimated to be 1.2 x 10(24)m(-3). The La + Ti:O ratio was close to 1 after SPS at 950 and 1050 degrees C; however, the number density of nanoclusters decreased at 1050 degrees C. With SPS above 950 degrees C, the density improved but the microhardness and shear yield strength decreased due to partial coarsening of the grains and nanoparticles. (C) 2016 Elsevier B.V. All rights reserved.

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