The　FCC-structured　medium　entropy　alloys　(MEAs)　possess　excellent　ductility,　but　their　strength　is　still　insufficient　for　engineering　application.　In　this　work,　the　effects　of　aluminum　alloying　and　thermomechanical　treatment　on　the　microstructures　and　mechanical　properties　of　an　equiatomic　VCoNi　MEA　were　systematically　investigated.　The　results　showed　the　structure　changed　from　a　single　FCC　structure　to　an　FCC　and　BCC　dual-phase　structure　in　the　as-cast　alloys　as　the　Al　content　increased,　and　would　further　evolve　into　a　multiple-phase　structure　after　thermomechanical　treatment.　The　Al　alloying　and　thermomechanical　treatment　led　to　the　formation　of　a　refined　and　heterogeneous　microstructure　with　nanoscaled　precipitates,　and　the　(VCoNi)93Al7　alloy　exhibited　very　comprehensive　properties　of　1.3　GPa　yield　strength,　1.7　GPa　ultimate　tensile　strength　and　22.7%　elongation.　The　strength　increment　was　mainly　due　to　the　enhanced　strengthening　contributions　from　the　dislocation,　solid　solution　and　precipitation　as　compared　with　the　undoped　alloy,　while　the　good　ductility　was　resulted　from　the　optimal　morphology　and　volume　fraction　of　the　second　phases.　This　work　was　useful　for　developing　high-performance　medium　entropy　alloys　by　optimizing　composition　and　treatment.　©　2021　Elsevier　B.V.