The field has stimulated new ideas and has inspired the exploration of the vast composition space offered by multi-principal element alloys MPEAs. Here we present a critical review of this field, with the intent of summarizing key findings, uncovering major trends and providing guidance for future efforts. Major themes in this assessment include definition of terms; thermodynamic analysis of complex, concentrated alloys CCAs ; taxonomy of current alloy families; microstructures; mechanical properties; potential applications; and future efforts.
High-entropy alloys are materials that consist of five or more metals in approximately equal amounts. These alloys are currently the focus of significant attention in materials science and engineering because they can have desirable properties. The NC State research team combined lithium, magnesium, titanium, aluminum and scandium to make a nanocrystalline high-entropy alloy that has low density, but very high strength.
At this point, the primary problem with the alloy is that it is made of 20 percent scandium, which is extremely expensive. Lead author of the paper is Dr. Khaled Youssef of Qatar University. The study abstract follows.
Youssef, Qatar University; Alexander J. Zaddach, Changning Niu, Douglas L. Irving, and Carl C.
A low density, nanocrystalline high-entropy alloy, Al20Li20Mg10Sc20Ti30 was produced by mechanical alloying. It formed a single-phase fcc structure during ball milling and transformed to single-phase hcp upon annealing.
The alloy has an estimated strength-to-weight ratio that is significantly higher than other nanocrystalline alloys and is comparable to ceramics.
High hardness is retained after annealing.Hence, high entropy alloys are a novel material. Furthermore, research indicates that some HEAs have considerably better strength-to-weight ratios, with a higher degree of fracture resistance, tensile strength, as well as corrosion and oxidation resistance than conventional alloys.
These alloys are expected to have high configurational entropy and hence were termed as "high entropy alloys." HEAs have a broad range of structures and properties, and may find applications in structural, electrical, magnetic, high-temperature, wear-resistant, corrosion-resistant, and .
High Entropy Alloys (HEAs) are among the new and promising material groups, alloys, that have been attracting attention since the beginning of the 21st Century. Historically, alloys have consisted of one, sometimes two, or even three, major elements, together with minor ones.
From High-Entropy Alloys to High-Entropy Steels steel research int.
This book provides a systematic and comprehensive description of high-entropy alloys (HEAs). The authors summarize key properties of HEAs from the perspective of both fundamental understanding and applications, which are supported by in-depth analyses. The book also contains computational modeling. Dislocation avalanche in a high entropy nanopillar. Focused ion beam is used to fabricated the nanopillar (left) for compression test. Transmission electron microscope is used to image dislocation. High-entropy alloys (HEAs) are alloys with five or more principal elements. Due to the distinct design concept, these alloys often exhibit unusual properties. Thus, there has been significant interest in these materials, leading to an emerging yet exciting new field.
86 () No. steel research int. 86 () Raabe High[ ] PDF-Dokument [ KB] Inspired by high-entropy alloys, we study the design of steels that are based on high configurational entropy for stabilizing a .
About 70% of all innovations in Europe are associated with progress in the fields of materials science and engineering. In the grand challenges that modern societies face, metallic materials occupy key roles.
High-entropy alloys (HEAs) concept has opened up an entirely new alloy field, which encompasses a wide range of microstructure and properties, and thus provides many opportunities to replace traditional materials and create new applications.