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Microstructural refinement and anomalous eutectic structure induced by containerless solidification for high-entropy Fe–Co–Ni–Si–B alloys
- Source :
- Intermetallics. 122:106812
- Publication Year :
- 2020
- Publisher :
- Elsevier BV, 2020.
-
Abstract
- The mechanical properties of high-entropy alloys (HEAs) strongly depend on their microstructural features. In this work, the phase formation and morphologies of Fe26.7Co26.7Ni26.7Si8.9B11.0 HEAs fabricated under different undercooling levels by the drop tube technique together with subsequent quenching were investigated in detail. It was found when the droplet size decreases (i.e. the increase of the undercooling level), the grain refinement is easily achieved without any phase transformation for the present hypoeutectic HEA which is composed of the fcc dendrites and eutectic structure. After quenching under large undercooling levels, the liquid should be deeply undercooled into an asymmetric couple zone, leading to the primary formation of eutectic structure and the subsequent precipitation of the fcc dendrites. The direct product of rapid solidification after deep undercooling and subsequent recalescence may induce the decoupled eutectic growth, resulting in a transition from the regular into anomalous eutectic structures. Furthermore, the volume fractions of the eutectic structures and the fcc dendrites increase and decrease with decreasing droplet size, respectively. As a result, the Vickers hardness gradually increases with decreasing droplet size, which exhibits a linear relationship with the volume fraction of eutectic matrix. The present study may provide a simple way to tailor microstructures and mechanical properties of HEAs.
- Subjects :
- 010302 applied physics
Quenching
Materials science
Mechanical Engineering
Metals and Alloys
Thermodynamics
Recalescence
02 engineering and technology
General Chemistry
021001 nanoscience & nanotechnology
Microstructure
01 natural sciences
Mechanics of Materials
0103 physical sciences
Volume fraction
Vickers hardness test
Materials Chemistry
0210 nano-technology
Supercooling
Drop tube
Eutectic system
Subjects
Details
- ISSN :
- 09669795
- Volume :
- 122
- Database :
- OpenAIRE
- Journal :
- Intermetallics
- Accession number :
- edsair.doi...........e828eef98ab7ecb5c5dda53f967c7cf0