Beneficial effects of deep cryogenic treatment on mechanical properties of additively manufactured high entropy alloy: cyclic vs single cryogenic cooling

•Cyclic deep cryogenic treatment was utilized to homogenize the residual stress and tune the microstructure of a high entropy alloy fabricated by laser melting deposition, in order to improve its overall mechanical properties.•Cyclic deep cryogenic treatment can induce an increased compressive residual stress and introduce various types of reinforcing defect microstructures into a high entropy alloy, including dense dislocations, intersecting twins, transformed HCP phase and nanograins, thus effectively overcoming the strength-ductility trade-off.•Compared to single-step DCT, cyclic DCT can reduce the residual stress gradients in the LMD-built sample, relieving or removing the tensile residual stress at the top surface.•Transformation to HCP phase can occur during the cyclic DCT process due to the cyclic reverting of the thermal stress to a high level on each cryogenic cooling, which promotes twinning on secondary habit planes and more frequent faulting.