High-performance Nd-Fe-B sintered magnets via co-doping high-melting-point Zr and low-melting-point Dy71.5Fe28.5

•Synergistic effects of co-doped Zr/Dy71.5Fe28.5 on magnetic properties of NdFeB are proposed.•Single Zr addition refines the 2:14:1 grains whereas causes insufficient densification.•Low-melting-point Dy71.5Fe28.5 offsets the adverse effect of Zr and leads to continuous GBs.•Dy-enriched shell surrounding the 2:14:1 grain also forms upon Dy71.5Fe28.5 addition.•Co-doping Zr and Dy71.5Fe28.5 can greatly enhance Hcj with a slight Br reduction.