A hexagonal close-packed high-entropy alloy: The effect of entropy

• Published in: Materials & design 2016-04, Vol.96 (C), p.10-15
• Main Authors: Zhao, Y.J., Qiao, J.W., Ma, S.G., Gao, M.C., Yang, H.J., Chen, M.W., Zhang, Y.
• Format: Article
• Language: English
• Subjects: Close packed lattices; compression; Electronics; Entropy; Fracture strength; hardness; Hexagonal cells; Hexagonal close-packed structure; High-entropy alloys; Lattice distortion; MATERIALS SCIENCE; Mechanical properties; Phase diagram; Rule of mixture; Solid solutions; Strain; yield strength
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2016.01.149

The formation of disordered solid solution in the hexagonal close-packed (hcp) structure in the GdHoLaTbY alloy and its mechanical properties were investigated in this study. The single hcp phase of the alloy in the as-cast state was confirmed by X-ray diffraction and scanning electron microscopy analyses. The compressive yield strength, fracture strength, and plastic strain of the alloy are 108MPa, 880MPa, and 21.8%, respectively, and the Vickers hardness is 96HV. The results show that the yield strength, fracture strength, and hardness of the alloy obey the rule of mixture, which indicates that there is no hardening effect from entropy. Although the high entropy of mixing stabilizes the solid solution against intermetallic compounds, lack of severe lattice distortion from elastic strain or electronic interactions between principal elements impacts little on the mechanical properties. [Display omitted] •The GdHoLaTbY high-entropy alloy forms a hexagonal close-packed solid solution.•The strengthening effect from the configurational entropy is not found in the alloy.•The mechanical properties and Vickers hardness of the alloy obey the rule of mixture.