Mapping hierarchical and heterogeneous micromechanics of a transformative high entropy alloy by nanoindentation and machine learning augmented clustering

•Deformation in f.c.c. austenitic grains is slip-dominated and demonstrates orientation dependent incipient plasticity and phase transformation.•Strong dependency of phase, crystal orientation, and interfacial constraints on the nanoindentation response was observed.•A disproportionately high hardness is observed in martensite-rich area due to hierarchical activation various micromechanisms.•Creation of coherent twin boundaries and dislocation activities in the twinned interfaces occurs during nanoindentation in martensitic regions.