Formation, thermal stability and mechanical properties of high-entropy (Fe0.25Co0.25Ni0.25Cr0.125Mo0.0625Nb0.0625)(100-x)B-x (x=7-14) amorphous alloys

Autor(es)

Wang, F. ^[1] ; Inoue, A. ^{[1, 2, 3, 4, 5]} ; Kong, F. L. ^[2] ; Zhao, C. C. ^[5] ; Zhang, J. Y. ^[5] ; Zhu, S. L. ^[1] ; Botta, W. J. ^[6] ; Kiminami, C. S. ^[6] ; Ivanov, Yu P. ^[7] ; Greer, A. L. ^[7]

Afiliação do(s) autor(es)

^[1] Tianjin Univ, Sch Mat Sci & Engn, Tianjin 300072 - Peoples R China

^[2] Josai Int Univ, Int Inst Green Mat, Togane 2838555 - Japan

^[3] King Abdulaziz Univ, Dept Phys, Jeddah 22254 - Saudi Arabia

^[4] Natl Univ Sci & Technol, MISiS, Moscow 119049 - Russia

^[5] China Univ Min Technol, Inst Mass Amorphous Met Sci, Xuzhou 221116, Jiangsu - Peoples R China

^[6] Univ Fed Sao Carlos, Dept Mat Engn, BR-13565905 Sao Carlos - Brazil

^[7] Univ Cambridge, Dept Mat Sci & Met, Cambridge CB3 0FS - England

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 825, JUN 5 2020.
• Citações Web of Science: 0

Resumo

High-entropy (Fe0.25Co0.25Ni0.25Cr0.125Mo0.0625Nb0.0625)(100-x)B-x amorphous alloys are formed with low (8 - 14 at%) boron contents by melt spinning. With increasing boron, the broad halo in X-ray diffraction shifts to indicate a decreasing average spacing of nearest-neighbor atoms. The crystallization onset temperature and the Vickers hardness increase with boron content. The glass transition is observed even for a low-boron (13 at%) alloy. The 8-11 at% B alloys crystallize in stages: {[}am] {[}am' + bcc] -> {[}am `' + bcc + fcc] -> {[}bcc + fcc + borides]. The bcc precipitates, diameter similar to 10 nm enriched in (Fe,Co) and the fcc precipitates, diameter similar to 15 nm enriched in (Ni,Fe), are stable on annealing over a wide range (900 - 1060 K) below the temperature at which borides form. The bcc phase shows no internal defects, while the fcc phase has defects such as twin boundaries. The microhardness (Hv) of the {[}am `' + bcc + fcc] nanostructure reaches a high maximum of 1460-1560 kgf.mm(-2 ), before decreasing rapidly when the formation of borides marks the disappearance of the residual amorphous phase. The high thermal stability of the three-phase nanostructure is attributed to the residual amorphous phase enriched in B, Cr, Mo and Nb. These low-boron metastable alloys with novel three-phase nanostructures are attractive as potential amorphous coatings or ultrahard structural alloys with high thermal stability. (C) 2020 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 13/05987-8 - Processamento e caracterização de ligas metálicas amorfas, metaestáveis e nano-estruturadas
• Beneficiário: Claudio Shyinti Kiminami
• Modalidade de apoio: Auxílio à Pesquisa - Temático