Microstructure and Corrosion Performance of Aluminium Matrix Composites Reinforced with Refractory High-Entropy Alloy Particulates  
[PERSON]  
1 Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; [EMAIL_ADDRESS] (E.A. ); [EMAIL_ADDRESS] (K.T.A. ); [EMAIL_ADDRESS] (A.E.K.) Karantzakis  
1 Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; [EMAIL_ADDRESS] (E.A. ); [EMAIL_ADDRESS] (K.T.A. ); [EMAIL_ADDRESS] (A.E.K.) [PERSON]  
1 Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; [EMAIL_ADDRESS] (E.A. ); [EMAIL_ADDRESS] (K.T.A. ); [EMAIL_ADDRESS] (A.E.K.) [PERSON]  
1 Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; [EMAIL_ADDRESS] (E.A. ); [EMAIL_ADDRESS] (K.T.A. ); [EMAIL_ADDRESS] (A.E.K.) Karantzakis  
1 Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece; [EMAIL_ADDRESS] (E.A. ); [EMAIL_ADDRESS] (K.T.A. ); [EMAIL_ADDRESS] (A.E.K.) products that may act as barriers, interrupting the continuity of the matrix channels within the matrix [12], and matrix/reinforcement decoupling [29]. In other research efforts, AMCs exhibited comparable corrosion resistance with the monolithic alloy [14; 15]. The effect of the reinforcement on the corrosion performance of AMCs may vary and depends on the environmental conditions and processing route [31]. Furthermore, other factors that may modify corrosion behaviour include primary interfacial reaction products between matrix/reinforcement [32], secondary precipitates in the as-cast states [33; 34] and heat-treated states [34], aging kinetics [35], and electrolyte type [36]. High-entropy alloys (HEAs) have attracted a lot of attention. A high-entropy alloy contains at least five principal elements with concentrations of each element from 5 to 35 at%, with exceptional physical and anti-corrosive properties deriving from four core effects: (a) high entropy, (b) sluggish diffusion, (c) severe lattice distortion, and (d) cocktail effect [37; 38]. Due to their sluggish diffusion behaviour, less reactive nature, and attractive properties, HEAs are an outstanding choice for reinforcement in AMCs [39; 40]. Various researchers studied these novel MMCs reinforced with HEA particulates using different types of matrixes, HEA reinforcement, and manufacturing routes [4; 40; 41; 42; 43; 44; 45; 46]. Al-5083 matrix composites reinforced with CoCrFeNiI and AlCoCrFeNiI HEAs, have been fabricated by additive manufacturing and submerged friction stir processing, respectively [39; 40]. The produced composites exhibited improved tensile properties, compressive strength, ultimate tensile strength, yield strength compared to the monolithic alloys. AlCoCrFeNiI HEA, in equiatomic and non-equiatomic compositions, has been employed as the reinforcement in spark plasma sintered AMCs. The fabricated composites exhibited improved yield strength, high strength, increased fracture surface energy, but low plasticity [41; 42]. Composites based on Al-7075 and commercially pure Al have been fabricated with the addition of AlCoCrFeNiTiI HEA particulates (equiatomic and non-equiatomic). The produced composites manifested improved strength, plasticity, and extreme improvement in ultimate tensile strength compared to the monolithic alloys [43; 44]. Al-based composites reinforced by various HEA particulates exhibited improved hardness, Young modulus, and strength compared to conventional Al alloys [4; 45; 46]. The aim of the current investigation is to evaluate the feasibility of fabricating novel AMCs reinforced by MoTaNbVW refractory HEA particulates via a powder metallurgy route. Furthermore, to study the microstructure and the corrosion behaviour of the composites in 3.5 wt.% NaCl solution. To the best of the authors' knowledge, this is the first effort to fabricate and study Al-based composites with the employment of refractory HEA particulates.