In　order　to　improve　the　mechanical　properties　of　AZ31　alloys,　the　repeated　plastic　working　process　was　employed　to　fabricate　the　AZ31-based　composites　reinforced　with　stable　icosahedral　quasicrystal　particles.　The　microstructure　of　the　composites　has　been　investigated　by　XRD,　SEM,　TEM　and　HREM,　and　their　mechanical　properties　have　also　been　studied.　The　results　showed　that　the　RPW　process　reduced　the　grain　size　significantly,　and　the　average　grain　size　was　only　about　500　nm　after　200　cycles　of　RPW.　A　good　metallurgical　bond　interface　between　the　quasicrystal　particles　and　the　Mg　matrix　was　found　in　their　crystallographic　orientation　relationship　of　(1　0　(1)　over　bar　0)(mg)//2-f.　The　composites　exhibited　the　maximum　yield　tensile　strength　of　334　MPa　and　the　maximum　ultimate　tensile　strength　of　372　MPa　at　room　temperature,　respectively.　The　enhanced　mechanical　properties　were　attributed　to　the　strengthening　effect　of　quasicrystal　particles　and　the　refined　microstructure.　(C)　2011　Elsevier　B.V.　All　rights　reserved.