In　this　study,　we　successfully　developed　a　low　RE　containing　Mg-3Y-2Gd-1Nd-0.5Zr　(wt%)　alloy　with　high　strength-ductility　synergy　by　combined　processes　of　hot　extrusion,　hot　rolling　and　ageing.　This　alloy　exhibits　an　excellent　strength-ductility　balance　(UTS　of　345　&　PLUSMN;　2.0　MPa,　TYS　of　301　&　PLUSMN;　5.0　MPa　and　EL　of　9.2　&　PLUSMN;　1.9%),　which　is　better　than　that　of　many　Mg-RE　wrought　alloys　with　higher　RE　concentration　and　even　comparable　to　that　of　6061　Al　wrought　alloy.　A　long-range　chain-like　structure　consisting　of　&　beta;＇　phase,　&　beta;H　phase,　&　beta;M　phase　and　zig-zag　atomic　columns　is　observed　for　the　first　time　in　the　studied　alloy.　The　combined　process　of　hot　extrusion　and　hot　rolling　boosts　the　formation　of　deformed　grains　and　low　angle　grain　boundaries,　and　makes　the　deformed　grains　dominate　in　the　alloy　strengthening.　Under　this　circumstance,　the　following　ageing　generates　a　novel　heterogeneous　structure　comprising　the　long-range　chain-like　structure　with　broad　interparticle　spacing　and　the　spacious　precipitate-free　zones　in　the　deformed　grains,　which　plays　a　key　role　in　the　concurrent　strengthening　and　toughening　of　the　alloy.　The　present　study　demonstrates　that　the　deformed　grains　with　long-range　chain-like　structures　and　precipitate-free　zones　is　desirable　microstructure　for　the　low　RE　containing　Mg　alloys　to　achieve　high　strength-ductility　synergy.　&　COPY;　2022　Chongqing　University.　Publishing　services　provided　by　Elsevier　B.V.　on　behalf　of　KeAi　Communications　Co.　Ltd.　This　is　an　open　access　article　under　the　CC　BY-NC-ND　license　(　http://creativecommons.org/licenses/by-nc-nd/4.0/　)　Peer　review　under　responsibility　of　Chongqing　University