A　novel　three-stage　heat　treatment　method　was　applied　to　study　the　microstructural　evolution　and　properties　of　additive-manufactured　Ti-6Al-4 V　alloys.　An　ultrafine　α　phase　was　obtained　via　the　αʹ　→α　+　β　hase　transformation　after　the　three-stage　heat　treatment.　The　distribution　of　low-angle　grain　boundaries　near　the　secondary　phase　was　highly　uniform.　After　the　three-stage　heat　treatment,　the　density　of　geometrically　necessary　dislocation　increased,　while　the　maximum　texture　intensities　of　the　α　phase　decreased.　The　nanoindentation　load–displacement　curve　analysis　revealed　that　the　load　value　increased　from　511.3　to　579.0　mN　after　the　three-stage　heat　treatment.　Tensile　tests　revealed　that　the　three-stage　heat　treatment　sample　has　the　highest　stain　of　11.86%.　All　the　samples　fracture　mode　was　ductile　fracture.　Additionally,　an　increase　in　the　secondary　α　phase　content　could　improve　the　corrosion　performance.　©　ASM　International　2024.