# Structural Particularities, Prediction, and Synthesis Methods in High-Entropy Alloys
## 3 Synthesis Methods and Their Influence on the Structure and Properties of HEA Alloys  
### Synthesis Methods for HEA Alloys  
The processing methods for developing high-entropy alloys (HEAs) are quite similar to those used for conventional alloys. Various techniques for fabricating HEAs are documented in the literature, with casting, sputtering, spraying, and powder metallurgy being the most commonly employed methods [67]. Additionally, High-Pressure Torsion (HPT) has been utilized to create nanocrystalline materials characterized by high strength and structural stability [68]. Generally, the development of HEAs is categorized into three main groups (Figure 4). The first processing route involves the liquid state, which includes methods such as electric arc melting, electric resistance melting, induction melting, laser melting, laser cladding, and LENS (Laser Engineered Net Shaping) forming. The second route involves the solid-state approach, primarily through mechanical alloying followed by consolidation processes. Additionally, elements can be mixed in the vapor state using tech \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & \multicolumn{4}{c}{**CALPHAD Results**} & \multicolumn{2}{c}{**Experimental**} \\ \cline{2-5}  & **25\({}^{\circ}\)C** & **400\({}^{\circ}\)C** & **600\({}^{\circ}\)C** & **800\({}^{\circ}\)C** & **[Reference]** \\ \hline CoCFeMnNi & FCC + BCC + sigma & FCC & FCC & FCC & FCC [42] \\ \hline CoCFeNi & BCC + sigma + IM & FCC + BCC + sigma & FCC + sigma & FCC & FCC [43] \\ \hline CoCFeNiAl\({}_{25}\) & BCC + sigma + IM & BCC + sigma + IM & FCC + sigma + IM & FCC & FCC [44] \\ \hline CrFeMnCuCo & FCC + BCC + sigma+ IM & FCC + BCC + HCP + sigma & FCC + BCC & FCC + BCC & FCC [42] \\ \hline WMoNbTa & BCC + IM & BCC & BCC & BCC & BCC [45] \\ \hline WMoNbTaV & BCC + IM & BCC & BCC & BCC & BCC [45] \\ \hline NbTaHfZr/Ih & HCP + BCC & BCC + HCP & BCC + HCP & BCC & BCC [46] \\ \hline CrMnFe\({}_{13}\)Nb\({}_{53}\)Al\({}_{53}\) & SIGMA + BCC + IM & SIGMA + BCC + IM & SIGMA + FCC + BCC + & BCC + F FCC + IM & BCC + IM [47] \\ \hline CrMnFe\({}_{13}\)Nb\({}_{53}\)Al\({}_{1.2}\) & SIGMA + BCC + IM & BCC + SIGMA + IM & BCC + IM & BCC + IM & BCC [47] \\ \hline Cr\({}_{13}\)Fe\({}_{13}\)NiAl\({}_{53}\)Al\({}_{53}\)Al\({}_{1.3}\) & SIGMA + BCC + IM & BCC + SIGMA + IM & BCC + IM & BCC + IM & BCC [47] \\ \hline Cr\({}_{13}\)Fe\({}_{13}\)NiAl\({}_{53}\)Al\({}_{53}\)Al\({}_{53}\)Mv & BCC + IM & BCC + IM & BCC + IM & BCC + FCC + IM & BCC [47] \\ \hline CrNiCoMnCuV & FCC + BCC + IM & FCC + BCC & FCC + BCC & FCC + BCC & FCC + IM [42] \\ \hline CrNiMnFeTi & FCC + IM & BCC + IM & BCC + IM & BCC + IM & BCC + FCC + IM [42] \\ \hline Al\({}_{33}\)Cu\({}_{53}\)Si\({}_{22}\)Nb\({}_{53}\)Mg\({}_{21}\) & FCC + HCP + IM & BCC + FCC + IM & LIQUID & LIQUID & FCC + HCP + IM [48] \\ \hline Al\({}_{53}\)Si\({}_{53}\)Zn\({}_{33}\)Mg\({}_{20}\) & FCC + IM & FCC + IM & IM & LIQUID & FCC + IM [48] \\ \hline Al65 CFeCuSiSiSiMnSiTeS & BCC + IM & FCC + BCC + IM & FCC + BCC & LIQUID & IM [50] \\ \hline AlCrFeMnMnTe\({}_{25}\) & BCC + FCC & BCC & BCC & BCC & BCC + La\({}_{21}\)[51] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of CALPHAD simulations versus experimental for selected alloys. niques such as sputtering, pulsed laser deposition (PLD), atomic layer deposition (ALD), molecular beam epitaxy (MBE), and vapor deposition to produce films on substrates [69]. Traditionally, melting and solidification processes have been extensively used for alloy synthesis, with the melting and casting method being employed for HEA production from the beginning. The Vacuum Arc Melting (VAM) technique is particularly effective for achieving the high temperatures required to handle the different melting points of elements in HEAs. Despite its effectiveness, the primary challenge of this method is the evaporation of metals with low boiling points, which makes it challenging to maintain accurate compositional control in HEAs [70].