Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

0509918 - ÚFP 2020 RIV CH eng J - Journal Article
Zýka, J. - Málek, J. - Veselý, J. - Lukáč, František - Čížek, J. - Kuriplach, J. - Melikhova, O.
Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System.
Entropy. Roč. 21, č. 2 (2019), č. článku 114. E-ISSN 1099-4300
R&D Projects: GA ČR GA17-17016S
Institutional support: RVO:61389021
Keywords : design * refractory high entropy alloys * medium entropy alloys * mechanical properties * microstructure
OECD category: Materials engineering
Impact factor: 2.494, year: 2019
Method of publishing: Open access
https://www.mdpi.com/1099-4300/21/2/114

Refractory high entropy alloys (HEA) are promising materials for high temperature applications. This work presents investigations of the room temperature tensile mechanical properties of selected 3 and 4 elements medium entropy alloys (MEA) derived from the HfNbTaTiZr system. Tensile testing was combined with fractographic and microstructure analysis, using scanning electron microscope (SEM), wavelength dispersive spectroscope (WDS) and X-Ray powder diffraction (XRD). The 5 element HEA alloy HfNbTaTiZr exhibits the best combination of strength and elongation while 4 and 3 element MEAs have lower strength. Some of them are ductile, some of them brittle, depending on microstructure. Simultaneous presence of Ta and Zr in the alloy resulted in a significant reduction of ductility caused by reduction of the BCC phase content. Precipitation of Ta rich particles on grain boundaries reduces further the maximum elongation to failure down to zero values.
Permanent Link: http://hdl.handle.net/11104/0300509