Hits:

Indexed by:Journal Papers

Date of Publication:2020-02-01

Journal:INTERMETALLICS

Included Journals:EI、SCIE

Volume:117

ISSN No.:0966-9795

Key Words:High entropy alloy; FeCoNiSiAl; Nano-crystal and nano-amorphous; Milling; Phase transition; Magnetic properties

Abstract:The idea of adjusting the crystallinity of powders via controlling the phase composition of milling precursor (ribbons) has been used to prepare FeCoNiSi0.4Al0.4 high entropy alloy powders (HEAPs) with dual-phase nano-crystal (NC) and nano-amorphous (NA) microstructure. The crystallinity of HEAPs are related to the FCC phase proportion of milling precursor: within 60%, positive correlation; beyond 60%, negative correlation. Different phase structure for ribbons can be obtained by taking advantage of the difference in phase stability, as an extension of annealing time induces the increment of FCC phase content. The introduction of nano-scale phase separation in HEA ribbons provides a prerequisite. Multiphase NCs distribute randomly in matrix, while NCs with FCC phase are aggregated into about 50 run regions embedded in matrix. Three kinds of phase transition are coexisted during the dry-milling process, generating the coexistence of NCs and NM. Due to the unique microstructure, in especial NCs doped by NM, and the skillful preparation technology, a small H-c, varying from 12.97 Oe (C-0) to 28.33 Oe (C-50), and a large complex permeability (mu'), varying from 2.60 (C-0) to 2.30 (C-50), can be obtained.