Isothermal　hot　compression　experiments　of　homogenized　Al-Mg-Si-Er-Zr　alloy　were　conducted　at　temperatures　ranging　from　350　to　500　degrees　C　and　strain　rates　of　0.01-10　s-1on　a　Gleeble-3500　thermal　simulation　tester.　The　hot　deformation　behavior　and　optimum　pro-cessing　parameters　of　the　alloy　were　determined　by　analyzing　the　flow　curves　and　pro-cessing　maps.　Characterization　of　the　microstructures　of　the　deformed　specimens　was　done　using　electron　backscatter　diffraction　(EBSD)　and　transmission　electron　microscopy　(TEM),　and　the　geometrically　necessary　dislocation　(GND)　density　was　used　based　on　the　kernel　average　misorientation　(KAM).　The　results　showed　that　the　GND　density　decreased　with　a　decrease　in　the　strain　rate　and　with　an　increase　in　the　deformation　temperature.　Dynamic　recovery　and　continuous　dynamic　recrystallization　were　the　main　softening　mechanisms　during　hot　deformation,　and　dynamic　recovery　was　dominant.　It　was　found　that　the　capacity　for　dynamic　recovery　was　reduced,　while　dynamic　recrystallization　was　prevented　in　the　Al-Mg-Si-Er-Zr　alloy.　This　was　a　result　of　hindered　dislocations　and　sub-grain　boundary　movement　caused　by　the　pinning　of　dislocations　and　sub-grain　boundaries　from　the　Mg2Si,　Al(MnFe)Si,　and　Al3(Er,　Zr)　particles.　The　addition　of　Er　and　Zr　resulted　in　an　increase　in　the　activation　energy,　which　can　be　attributed　to　the　formation　of　Al3(Er,　Zr)　particles.(c)　2022　The　Author(s).　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/).