**Acknowledgements**

*Engineering Steels and High Entropy-Alloys*

use of melt spinning method, or coating.

*High-entropy alloy ribbons by vacuum suspension quenching.*

extrusion deformation, drawing deformation, etc., which can be made into foils, ribbon filaments, etc.; such materials tend to have the characteristics of flexible materials. In addition, further methods to obtain an alloy of a flexible material is the

Ma et al. made the single-crystal structure the Al0.3CoCrFeNi alloy with the Bridgman solidification which found that the elongation of this alloy ~80%, the alloy shows an excellent plastic deformation capacity [32]. Li et al. found that Al0.3CoCrFeNi alloy shows the elongation more than ~60% with forging [33]. Based on these studies the Li et al. formed the fibers with this alloy [34]. In addition, the high-entropy alloy ribbons and fibers can also be prepared by vacuum suspension quenching system, which Zhao et al. [35] use this technology prepared the CoFeNi(AlBSi)*x* ribbons. High entropy alloy films can be prepared by chemical vapor deposition and physical vapor deposition, the thickness of these films tend to be 0.5 μm to 2 μm, which become two-dimensional materials [37], also such films after separation from the substrate will be a flexible materials. Xing et al. [38] corrected the phase formation of the film materials with the concept of cooling rate. **Figure 7** shows the CoFeNi(AlBSi)*x* high-entropy alloy ribbons by vacuum suspen-

Summaries of the relevant properties and specificities of lightweight high-

1.Lightweight high-entropy alloys are often limited by the addition of elements, and these elements tend to have high electronegativity. They are easy to form intermetallic compounds rather than solid solutions and it has been found that high mixing entropy does not promote the formation of solid solution phases.

2.Therefore, the concept of lightweight high-entropy alloy needs to be broad-

3.Due to the excellent comprehensive mechanical properties of traditional highentropy alloys, the lightweight high-entropy alloys are also supposed to have

ened, for which the mixing entropy ΔS*mix* > 1R is a good choice.

**134**

sion quenching.

**Figure 7.**

**4. Conclusions**

entropy alloys are as follows:

Y. Zhang would like to thank the financial support from National Natural Science Foundation of China (NSFC), Grant No. 51671020, and Yasong Li would like to thank Dongyue Li, Weiran Zhang, and Xuehui Yan for their help with accessing references.
