EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Studies on high-entropy alloys (HEAs) mainly set off to tune the substitutional elements in the single-, dual- or multi-phase matrix, yet, the resultant mechanical properties are often not substantially improved compared to that of the traditional “low-entropy” alloys such as high-strength steels or Ti alloys. In this work, we present how we further tune the phase stability and enhance the mechanical properties of HEAs of CoCrFeMnNi family via the doping of interstitials, e.g., carbon and nitrogen. Thermo-mechanical processing was also employed to refine the matrix grains as well as trigger precipitation of nano-sized particles. The approach enables the synthesis of alloys that show a combination of multiple mechanisms such as significant interstitial solid solution strengthening and twinning-induced plasticity upon deformation. Owing to the multiple strain hardening mechanisms that are jointly active, the combination of tensile strength and ductility of the interstitial HEAs can be significantly better than that of the interstitial-free counterpart, which is strongly related to the phase stabilities affected by interstitials.