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Toughened (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2–SiC composites fabricated by one-step reactive sintering with a unique SiB6 additive

Authors :
Wei Hao
Xinzhe Lu
Ling Li
Tao Wang
Guoliang Ren
Huangyue Cai
Xiaofeng Zhao
Dongyun Wang
Na Ni
Source :
Journal of Advanced Ceramics, Vol 13, Iss 1, Pp 86-100 (2024)
Publication Year :
2024
Publisher :
Tsinghua University Press, 2024.

Abstract

High-entropy diboride has been arousing considerable interest in recent years. However, the low toughness and damage tolerance limit its applications as ultra-high-temperature structural materials. Here we report that a unique SiB6 additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2–SiC composite though one-step boro/carbothermal reduction reactive sintering. A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2–51SiC composites. The small grain size was beneficial to shorten the diffusion path for mass transport, thereby enhancing the relative density to ~99.3%. These results in an increase of fracture toughness from ~5.2 in HEBS-1900 to ~7.7 MPa·m1/2 in HEBS-2000, which corresponded to a large improvement of 48%. The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation, resulting from balanced grain boundary strength collectively affected by improved densification, solid solution strengthening, and incorporation of SiC secondary phase.

Details

Language :
English
ISSN :
22264108 and 22278508
Volume :
13
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Journal of Advanced Ceramics
Publication Type :
Academic Journal
Accession number :
edsdoj.b5fe3589aaa24dd1b01050c9ba8dd5ce
Document Type :
article
Full Text :
https://doi.org/10.26599/JAC.2024.9220838