Novel Frontiers in High-Entropy Alloys

Abstract

There is little doubt that there is significant potential for high-entropy alloys (HEAs) in cryogenic and aerospace applications. However, given the immense design space for HEAs, there is much more to be explored. This review will focus on four areas of application for HEAs that receive less attention. These focus areas include joining technologies, HEA nanomaterial synthesis, catalysis, and marine applications. The performance of HEAs as a filler metal for welding and brazing as well as their performance as a welded/brazed base metal will be discussed. Various methods for synthesizing HEA nanomaterials are reviewed with specifically highlighted applications in catalysis and energy storage. HEA catalysts, in particular, will be discussed in detail regarding their effectiveness, selectiveness, and stability. Marine applications are explored given the inherent corrosion resistance of HEAs as well as superior antifouling properties that make HEAs an intriguing marine-ready material.

Synthesis and Unique Behaviors of High-Purity HEA Nanoparticles Using Femtosecond Laser Ablation

“…The exploration of HEA nanoparticles as electrocatalysts represents a burgeoning field of research with the potential to revolutionize energy conversion and storage technologies [ 2 ]. Figure 10 a presents the LSV plots illustrating the multi-functional catalyst applications of the HEA nanoparticles.…”

“…In nanomaterial science, developing methods for the rapid and reliable synthesis of nanoparticles, especially from complex materials like HEAs, is essential [ 1 , 2 ]. HEAs, with their composition of four or more principal elements in nearly equal molar ratios, have significantly altered the traditional approach to alloy design.…”

“…Developed methods include carbothermal shock (CTS) [23], mechanical alloying [24,25], plasma-spark sintering [24], microwave heating [26], wet chemistry [27], and laser ablation synthesis [28]. Each method offers distinct advantages in process control, scalability, processing time, yield, and property customization, but also includes limitations like potential contamination, excessive energy requirements, and post-processing needs [2]. Using the CTS method, exposure of the carbon substrate can lead to unwanted reactions, which poses challenges for applications such as hydrogen evolution, CO 2 reduction, and N 2 reduction reactions, where high nanoparticle surface coverage is essential [29].…”

Gallium-based liquid metals as reaction media for nanomaterials synthesis

“…(4) HEA NPs can be synthesized by a variety of methods, such as carbothermal shock synthesis, mechanical alloying, microwave heating, wet chemistry, liquid laser ablation, chemical dealloying, etc . 143 However, these methods always require the application of extreme heating temperatures to provide high mixing entropy. 82 The easy alloying property of liquid Ga makes it possible to synthesize HEA NPs at low temperatures.…”