The　hot　deformation　behavior　of　an　Al-5.7　wt.%Mg　alloy　with　erbium　has　been　investigated.　Compression　tests　are　performed　in　the　temperature　range　of　300-500　degrees　C　and　in　the　strain　rate　ranging　from　0.001　s(-1)　to　50　s(-1)　up　to　a　true　strain　of　0.7.　The　processing　maps　are　developed　at　different　strains　and　the　standard　kinetic　analysis　has　been　applied　to　evaluate　the　rate　controlling　mechanisms.　The　processing　maps　have　exhibited　two　domains　of　350-450　degrees　C　at　0.001-0.03　s(-1)　and　450-500　degrees　C　at　0.01-1　s(-1),　representing　dynamic　recovery　of　Al-5.7　wt.%Mg　with　erbium.　The　apparent　activation　energies　estimated　in　these　two　domains　are　180　kJ/mol　and　163　kJ/mol　respectively,　which　suggests　that　cross-slip　of　dislocation　and　lattice　self-diffusion　are　the　deformation　mechanisms.　At　strain　rates　higher　than　10　s(-1),　the　flow　curves　demonstrate　flow　softening　behavior,　and　the　flow　instability　regions　reveal　mixed　microstructure　of　local　deformation　and　dynamic　recrystallization.　(C)　2009　Elsevier　B.V.　All　rights　reserved.