Design of Multiphase Compositionally Complex Alloys for Enhanced Hardness at Elevated Temperatures and Machinability: Comparative Study with Inconel 718

Abstract

Inconel 718 alloy is used for high‐temperature industrial applications in its optimized multiphase metallurgical state. Nevertheless, the machining of Inconel 718 alloy becomes problematic and challenging. One alternative consists of developing a new material design strategy based on the metallurgy of high‐entropy alloys (HEAs). These alloys have become a hotspot in the field of innovative high‐temperature metallurgy toward the improvement of the alloy's manufacturability and thermomechanical properties. This study aims at designing, elaborating, and characterizing a new class of alloys with increased entropy, referred to as: “Inco‐like.” The mechanical responses of the alloys, in terms of hardness, have been analyzed using an indentation test at a wide range of temperatures. The dry machinability of the developed alloys has been performed and compared with that characterizing the Inconel 718 in terms of several machining features. Finally, the phases of the studied alloys have been analyzed using metallurgical investigations. The experimental findings and comparisons underscore the advantages of the high‐entropy strategy in terms of tool wear reduction and cutting tool durability. The results demonstrate that the Inco‐like HEA retains a significantly higher hardness of 291 Hv at 800 °C, compared to 160 Hv for Inconel 718 at the same temperature.