Multi-criteria decision making for selecting optimal composition under erosive environment using entropy–TOPSIS approach

High-entropy alloy advanced material is gaining lots of attention due to its distinctive atomic arrangements and extraordinary multifunctional characteristics. Application of the high-entropy alloys can be majorly seen in the blades of hydro turbine power generation turbines that have to work in a severe environment, under both dry and slurry erosion conditions. To improve the mechanical characteristics of these blades, chemical coating was used previously. High-entropy alloys have shown better performance, but selection of an optimal composition of the constituents for the blade coating needs more attention. In the present study, Fe 43 Mo 15 Cr 12 Ni 10 B 7 WC 13 , Fe 43 Mo 15 Cr 12 Ni 10 B 11 WC 9 , and Fe 43 Mo 15 Cr 12 Ni 10 B 15 WC 5 compositions have been chosen as coating over SS316L taken as the base material, and the performance was analyzed. An entropy-based TOPSIS approach using a multi-criteria decision-making method has been used to identify the best-performing alloy composition for turbine blades to work effectively under such aggressive conditions. This study aims to identify the optimal high-entropy alloy coating composition, which should be capable of delivering superior mechanical strength and high erosion resistance, thereby extending the operational life of hydro turbine blades.