*2.1. Fusion-based Welding of HEAs*

Several studies [53–69] have already been reported on fusion-based welding of HEAs. To date, these works focus mainly on laser-based techniques, although some information is also available on Electron Beam and Gas Tungsten Arc Welding (GTAW) techniques.

In terms of the materials, the most used HEA is the CoCrFeNiMn one. This is probably related to the fact that this alloy system is the most studied within the field of HEAs [22,25,34,70–72]. For this reason, in this section of the paper (2.1.1), we first address the current status on fusion-welding of the CoCrFeNiMn HEA system, and the following one (2.1.2) focuses on the remaining materials that were already welded.
