A strong and ductile NiCoCr-based medium-entropy alloy strengthened by coherent nanoparticles with superb thermal-stability

•A novel strong yet ductile (NiCoCr)92Al6Ta2 MEA strengthened by nanoscale coherent L12-precipitate was designed.•The multi-strengthening in particular the pronounced precipitate-hardening confers a good strength-ductility balance in this alloy.•A unique particle-features-dependent plastic mechanism of the matrix in this alloy was revealed.•This alloy displayed an extraordinarily superior coarsening resistance of nanoparticles as compared to typical superalloys and reported M/HEAs.