Mechanically alloyed high entropy alloys: existing challenges and opportunities

High entropy alloys (HEAs) for the first time were reported in 2004, however, the progress in this field was markedly realized since 2010 when a drastic upsurging demand of HEAs was observed owing to their unique properties and possibilities to form various compositions significantly grabbing the attention of academia and researchers. Initially, the main focus of researchers was on equiatomic HEAs which later paradigm shifted to non-equiatomic alloys. With progress in the research, four core effects were examined as the predominant factors enabling the distinguished properties. Amongst, mechanical alloying (MA) followed by the sintering route grabbed the attention of all the researchers dealing with the processing of HEAs. Therefore, the basic objective of this review is to critically discuss the mechanically alloyed HEAs, functional properties, and their applications. Subsequently, the existing challenges and their opportunities are also discussed which leads this review article towards uniqueness and novelty.