Microstructural　evolution　and　its　effect　on　microhardness　and　Young＇s　modulus　of　Ti-6Zr-4Fe　alloy　solution　and　aging　treated　at　different　temperatures　were　studied.　The　a　phase　transformed　into　b　phase　completely　at　860　degrees　C,　meanwhile,　the　athermal　u　phase　was　found　at　860　degrees　C　and　it　resulted　in　a　higher　Young＇s　modulus.　The　u　phase　content　increased　from　250　degrees　C　to　400　degrees　C,　and　the　content　decreased　with　further　increase　of　aging　temperature,　there　were　only　a　phase　and　b　phase　at　600　degrees　C.　The　phase　transformation　sequence　was　b-＞　u　+　b-＞　u+a+b-＞　a+b　during　aging　treatment.　The　microhardness　increased　from　315　HV　to　492　HV　due　to　the　element　solution　strengthening　and　phase　transformation　strengthening.　The　peak　microhardness　of　Ti-6Zr-4Fe　alloy　aged　at　400　degrees　C　reached　652　HV.　The　formation　of　u　phase　resulted　in　the　increase　of　microhardness　and　Young＇s　modulus　in　Ti-6Zr-4Fe　alloy.　(c)　2022　The　Authors.　Published　by　Elsevier　B.V.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(http://creativecommons.org/licenses/by-nc-nd/4.0/).