Hits:

Indexed by:期刊论文

Date of Publication:2018-01-01

Journal:RSC ADVANCES

Included Journals:SCIE、EI

Volume:8

Issue:27

Page Number:14936-14946

ISSN No.:2046-2069

Abstract:Mechanical grinding method was employed to prepare FeCoNiSixAl0.4 high entropy alloy powders, which present a simple solid solution structure (FCC and BCC). After annealing at 673 K, a large amount of BCC phase precipitate and a small amount of CoFe2O4 phase generate. The change of crystal structure may lead to an increase in M-s (from 100.3 emu g(-1) to 124.2 emu g(-1)) and a decrease in H-c (from 107 Oe to 59.5 Oe for FeCoNiSi0.3Al0.4). The silica content has a significant effect on the electromagnetic parameters of the as-milled and as-annealed alloy powders, presenting the trend of first increase and then decrease. And the dielectric constant is obviously improved after annealing (e.g. from 8.48 to 11.21 and from 0.15 to 2.84 for the epsilon and epsilon of FeCoNiSi0.3Al0.4 at 18 GHz, respectively), while the permeability is reduced. Compared with those of the as-milled samples, the of as-annealed FeCoNiSixAl0.4 (x = 0.1, 0.3, 0.4) remain unchanged or even increase due to the formation of CoFe2O4. Meanwhile, the relative content of the precipitated BCC to FCC for FeCoNiSi0.3Al0.4 enhance with the annealing temperature increase from 573 K to 773 K, and then reduce. And the epsilon and at 2 GHz present the same trend as the content ratio (A(BCC)/A(FCC)), while the epsilon improve obviously after annealing, corresponding to the elevation of conductivity.