The possibility of further enhancing the strength of a (CoCrFeNi)(94)Ti2Al4 high-entropy alloy (HEA), which is already strengthened by Ni-3(Ti,Al) second-phase particles, by grain refinement through high-pressure torsion (HPT) is examined. Concomitant with nanograin formation, HPT was found to induce particle dissolution and structural transformation of the remnant particles. Nanoindentation experiments of nanocrystalline HEA, with and without particles in the pre-HPT microstructure, suggests that grain boundary strengthening is the dominant strengthening mechanism. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.