Directed　Energy　Deposition-Arc　(DED-Arc)　was　utilized　to　fabricate　Inconel-copper　bimetallic　structures,　with　the　aim　of　improving　manufacturing　modes　and　reducing　costs　for　rocket　engine　thrust　chambers.　In　this　paper,　bimetallic　Inconel　superalloy　(GH4169)　and　copper　alloy　(C18150)　structures　were　deposited　using　different　deposition　strategies.　The　formation　mechanisms　of　grain-size　gradients　and　heterogeneous　interfacial　microstructural　evolution　were　comprehensive　investigated　and　further　discussed.　Both　strategies　produced　high-quality　bimetallic　samples　with　tensile　strength　exceeding　260.2　MPa.　Fractures　occurred　within　the　C18150　metal　rather　than　at　the　interface,　indicating　successful　interface　strengthening　of　the　bimetallic　samples.　Gradual　gradients　in　grain　size　distribution　and　nano-hardness　were　observed　across　the　interface.　The　crystal　structures　of　C18150　were　unaffected　by　GH4169,　and　no　new　phases　were　generated　in　the　interfacial　region.　The　crystallographic　orientation　relationship　between　Ni　and　Cu　was　determined　to　be　[011]Cu//[011]Ni　and　(111)Cu//(111)Ni,　and　interfaces　were　strengthened　by　grain　boundary　and　dislocation　strengthening　through.　This　work　demonstrates　an　approach　for　fabricating　large,　high-performance　bimetallic　structures　with　tailored　grain-size　gradients　and　heterogeneous　microstructures,　suitable　for　rocket　engine　thrust　chamber　applications.　©　2024　Elsevier　B.V.