In-situ formed heterogeneous grain structure in spark-plasma-sintered CoCrFeMnNi high-entropy alloy overcomes the strength-ductility trade-off

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 771; p. 138625
• Main Authors: Jiang, Feilong, Zhao, Cancan, Liang, Dingshan, Zhu, Weiwei, Zhang, Yiwen, Pan, Shuai, Ren, Fuzeng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 13.01.2020
• Subjects: Heterogeneous grain structure; High-entropy alloy; Mechanical properties; Mechanical properties; Heterogeneous grain structure; High-entropy alloy
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.138625

The conflict between strength and ductility has been a longstanding dilemma for metallic alloys. Herein, we present a facile strategy to overcome the strength-ductility trade-off of face-center-cubic high-entropy alloys (HEAs) via the in-situ formation of heterogeneous grain structure, using the high local temperature gradients generated during spark plasma sintering coupled with the ‘sluggish diffusion’ of HEAs. The fabricated CoCrFeMnNi HEA has a heterogeneous structure over a large range of grain size from 140 nm to 5 μm, which enables a gigapascal yield strength and a uniform elongation of 9.5%. The mechanism responsible for the associated mechanical properties was analyzed.