High Entropy Alloys for Aerospace Applications

Abstract

In the aerospace industry, materials used as modern engine components must be able to withstand extreme operating temperatures, creep, fatigue crack growth and translational movements of parts at high speed. Therefore, the parts produced must be lightweight and have good elevated-temperature strength, fatigue, resistant to chemical degradation, wear and oxidation resistance. High entropy alloys (HEAs) characterize the cutting edge of high-performance materials. These alloys are materials with complex compositions of multiple elements and striking characteristics in contrast to conventional alloys; their high configuration entropy mixing is more stable at elevated temperatures. This attribute allows suitable alloying elements to increase the properties of the materials based on four core effects , which gives tremendous possibilities as potential structural materials in jet engine applications. Researchers fabricate most of these materials using formative manufacturing technologies; arc melting. However, the challenges of heating the elements together have the tendency to form hypoeutectic that separates itself from the rest of the elements and defects reported are introduced during the casting process. Nevertheless, Laser Engineering Net Shaping (LENS™) and Selective Laser Melting (SLM); a powderbased laser additive manufacturing process offers versatility, accuracy in geometry and fabrication of three-dimensional dense structures layer by layer avoiding production errors.

Exploring the Compositional Space of High-Entropy Alloys for Cost-Effective High-Temperature Applications

“…Non-equimolar HEAs provide a broad compositional space for multi-objective materials design for diverse engineering applications for extreme conditions such as aerospace (Dada et al, 2021a), nuclear reactors (Tong et al, 2005), and biomedical (Varalakshmi et al, 2010) applications. In such applications, conventional alloys commonly have severe limitations to achieve more cost-effective, long-living, and more green designs (Dada et al, 2021b).…”

Critical Raw Materials Saving by Protective Coatings under Extreme Conditions: A Review of Last Trends in Alloys and Coatings for Aerospace Engine Applications

“…), allowing an increased yield strength at the highest temperatures. As a consequence, high entropy alloys are excellent materials candidates for compressors, combustion chambers, exhaust nozzle and gas turbine case applications within the gas turbine engine [ 61 ].…”

Prospects for the Implementation of New Materials and Technologies in the Aerospace Industry

“…In view of such properties, HeAs can be used as a refractory, fatigue-resistant material. In the form of films and coatings resistant to corrosion surface layers, such materials can prevent destructive diffusion for various structural elements of jet engines [12].…”