Recent advances of high entropy alloys for aerospace applications: a review

Abstract

Purpose This study aims to review the recent advancements in high entropy alloys (HEAs) called high entropy materials, including high entropy superalloys which are current potential alternatives to nickel superalloys for gas turbine applications. Understandings of the laser surface modification techniques of the HEA are discussed whilst future recommendations and remedies to manufacturing challenges via laser are outlined. Design/methodology/approach Materials used for high-pressure gas turbine engine applications must be able to withstand severe environmentally induced degradation, mechanical, thermal loads and general extreme conditions caused by hot corrosive gases, high-temperature oxidation and stress. Over the years, Nickel-based superalloys with elevated temperature rupture and creep resistance, excellent lifetime expectancy and solution strengthening L12 and γ´ precipitate used for turbine engine applications. However, the superalloy’s density, low creep strength, poor thermal conductivity, difficulty in machining and low fatigue resistance demands the innovation of new advanced materials. Findings HEAs is one of the most frequently investigated advanced materials, attributed to their configurational complexity and properties reported to exceed conventional materials. Thus, owing to their characteristic feature of the high entropy effect, several other materials have emerged to become potential solutions for several functional and structural applications in the aerospace industry. In a previous study, research contributions show that defects are associated with conventional manufacturing processes of HEAs; therefore, this study investigates new advances in the laser-based manufacturing and surface modification techniques of HEA. Research limitations/implications The AlxCoCrCuFeNi HEA system, particularly the Al0.5CoCrCuFeNi HEA has been extensively studied, attributed to its mechanical and physical properties exceeding that of pure metals for aerospace turbine engine applications and the advances in the fabrication and surface modification processes of the alloy was outlined to show the latest developments focusing only on laser-based manufacturing processing due to its many advantages. Originality/value It is evident that high entropy materials are a potential innovative alternative to conventional superalloys for turbine engine applications via laser additive manufacturing.

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). In particular, low Co non-equimolar HEAs are an appealing system for diverse applications and the replacement of high-strength steel components (Li et al, 2022).…”

Synthesis of High Entropy Alloy Nanoparticles by Pulsed Laser Ablation in Liquids: Influence of Target Preparation on Stoichiometry and Productivity

“…[4,5] Industries such as aerospace employ HEAs extensively for components like compressors, combustion chambers, exhaust nozzles, and gas turbine parts, where properties such as strength-to-weight ratio, oxidation resistance, fatigue resistance, and elevated temperature strength are crucial. [6,7] Moreover, HEAs have emerged as potential replacements for conventional alloys in biomedical applications due to their exceptional corrosion resistance, low degradation in physiological environments, biocompatibility, wear resistance, and bacterial infection prevention. [8,9] Additionally, HEAs have been proposed as replacements for traditional materials in nuclear reactors, thanks to their high resistance to irradiation damage and excellent stability at high temperatures, making them suitable for use in harsh nuclear environments.…”

Influence of microstructure of CoCrNi medium entropy alloy on its corrosion behavior

“…With the development of industry in recent years, the increasing requirements have been put forward for the performance of engineering materials such as higher strength, better plasticity and superior corrosion resistance (Dada et al , 2021). High entropy alloys (HEA) have attracted much attention and experienced rapid development due to their unique phase structure and outstanding properties (Lu et al , 2017; Miracle and Senkov, 2017; Xu et al , 2018; Zhang et al , 2014; Xia et al , 2022).…”