High entropy alloys – Tunability of deformation mechanisms through integration of compositional and microstructural domains

The paradigm shift of alloying approach that led to high entropy alloys (HEAs) is now well established. Although the initial years were dominated by equiatomic approach, recent have seen expansion in non-equiatomic compositional space can be termed as complex concentrated (CCAs). These HEAs/CCAs provide opportunities for tunable performance manipulating deformation mechanisms. Understanding has advanced point certain aspects core effects (entropy mixing, lattice distortion, sluggish diffusion, and cocktail effect) critically examined. In addition, new metastability engineering emergence a wide range processing strategies put this field on an exponential growth path. review, we categorize microstructural approaches exhibit potential combination shear induced phase transformation twinning, thereby expanding beyond slip based emerging HEAs give greater flexibility tailoring transformation-induced plasticity (TRIP) twinning-induced (TWIP), which guided design next-generation steels over last 20 level. For TRIP HEAs, ductility extended 50% while maintaining strength exceeding 1 GPa. On other hand, hierarchical AlxCoCrFeNi lead 2 GPa >10% ductility. Observations evolving c/a ratio HCP hint at possibility micromechanisms. While crack tip twin-bridging been shown key mechanism extend toughness, concurrent push fatigue endurance limit. Tunability mechanisms unprecedented compared conventional metallic materials, particularly compositions transformation. further enhanced integrating microstructure domains, these are highlighted review. take advantage enthalpy states metastable with low stacking fault energy values < 40 mJ m−2. include, heterogeneous grain structure, duplex triplex microstructures intermetallic phases, twinning engineered microstructure, coherent boundary dual-phase triple-phase solid solution phases.