Precipitation　of　Sm/Cu-enriched　cell　boundary　phase　during　isothermal　aging　plays　a　crucial　role　on　the　hard　magnetic　properties　of　the　cellular　nanostructured　2:17-type　Sm-Co-Fe-Cu-Zr　permanent　magnets.　However,　this　method　offers　only　limited　magnetic　hardening　effect　in　Fe-rich　magnets　as　conventional　thermal　aging　usually　leads　to　decreased　density　of　cell　boundary　precipitates.　Here　we　report　a　stress-aging　approach　to　rectify　this　limitation.　As　exhibited　by　a　model　magnet　Sm25Co44.9Fe21.5Cu5.6Zr3.0　(wt.%),　aging　under　50　MPa　uniaxial　compressive　stress　for　the　same　time　at　the　same　temperature　can　simultaneously　enhance　the　intrinsic　coercivity　from　17.51　to　25.68　kOe　and　maximum　energy　product　from　28.39　to　31.39　MGOe　when　compared　with　conventional　isothermal　aging.　Detailed　microstructural　and　microchemical　investigations　revealed　that　the　magnetic　performance　enhancement　stems　from　the　retained　[001]　texture,　the　increased　number　density　of　Cu-enriched　cell　boundary　precipitates,　and　the　reduced　stacking　faults　density　at　cell　edges,　which　can　significantly　strengthen　the　magnetic　domain　wall　pinning.　Such　microstructural　improvements　are　contributed　from　the　increased　density　of　defects　that　promote　the　precipitate　nucleation　at　early　stage　and　the　stress-induced　dislocation　re-arrangements　that　accelerate　defects　dissociation　and　atomic　diffusion　at　the　following　stage,　i.e.　optimizing　the　thermodynamic-kinetic　compromise　of　precipitation.　Further　study　revealed　that　aging　under　higher　stress　leads　to　abnormal　cell　growth　and　weakened　[001]　texture　due　to　the　dynamic　recrystallization　effect,　deteriorating　the　magnetic　properties.　Consequently,　stress-aging　provides　a　fresh　freedom　to　manipulate　the　microstructure　of　Sm-Co-Fe-Cu-Zr　magnets,　but　the　stress　magnitude　should　be　carefully　controlled　to　improve　the　magnetic　performance.　©　2021　Acta　Materialia　Inc.