Zýka Jiří, Málek Jaroslav, Veselý Jaroslav, Lukáč František, Čížek Jakub, Kuriplach Jan, Melikhova Oksana
UJP PRAHA a.s., Nad Kamínkou 1345, 156 10 Praha 5-Zbraslav, Czech Republic.
Department of Materials Engineering, Institute of Plasma Physics CAS, Za Slovankou 1782, 1820 Praha 8, Czech Republic.
Entropy (Basel). 2019 Jan 26;21(2):114. doi: 10.3390/e21020114.
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.
难熔高熵合金（HEA）是用于高温应用的有前途的材料。这项工作展示了对源自HfNbTaTiZr体系的选定3元和4元中熵合金（MEA）室温拉伸力学性能的研究。拉伸试验与断口分析和微观结构分析相结合，使用扫描电子显微镜（SEM）、波长色散光谱仪（WDS）和X射线粉末衍射（XRD）。5元HEA合金HfNbTaTiZr表现出强度和伸长率的最佳组合，而4元和3元MEA的强度较低。其中一些是韧性的，一些是脆性的，这取决于微观结构。合金中Ta和Zr的同时存在导致由于体心立方（BCC）相含量的减少而使延展性显著降低。富Ta颗粒在晶界上的析出进一步将最大断裂伸长率降低至零值。
