Synergistic　micro-alloying　with　Ti–Zr　effectively　enhances　the　mechanical　properties　of　cast　Al–Cu–Mn　alloys.　In　this　study,　the　connection　between　microstructure　evolution　and　mechanical　properties　of　Al–Cu–Mn　alloy　through　gravity　casting　was　investigated　with　synergistic　addition　of　Ti　and　Zr　elements,　aiming　to　promote　the　strength　and　toughness　of　Al–Cu–Mn　alloy.　The　results　showed　that　synergistic　addition　of　0.15　wt%Ti　and　0.2　wt%Zr　refined　grains　owing　to　the　constitutional　supercooling　caused　by　Ti　and　Zr.　A　large　number　of　Al3(Ti,Zr)-L12　dispersoids　with　core–shell　structure　uniformly　precipitated　within　the　grains　during　the　solution　process.　The　Al3(Ti,Zr)　dispersoids　served　as　heterogeneous　nucleation　sites　for　θ′(Al2Cu)　precipitates　during　aging.　As　confirmed　by　quantitative　analysis,　Ti–Zr-modified　alloys　(with　0.15　wt%Ti　and　0.2　wt%Zr)　exhibited　finer　and　more　densely　populated　θ′　precipitates　than　unmodified　alloys,　resulting　in　superior　mechanical　properties.　In　the　peak-aged　state,　the　ultimate　tensile　strength,　yield　strength　and　elongation　of　Ti–Zr-modified　alloy　were　530.5　MPa,　462.8　MPa　and　7.6%,　respectively,　which　were　mainly　ascribed　to　grain　boundaries　strengthening,　solution　strengthening　and　precipitation　strengthening.　This　work　is　expected　to　provide　reliable　theoretical　guidance　for　the　successful　preparation　of　high-strength　and　high　toughness　Ti–Zr-modified　aluminum　alloys.　©　2024,　American　Foundry　Society.