Abstract:In current research, a novel Al-Mg-Sc-Zr alloy was produced through conventional rolling and annealing process and achieved a high thermal stability, a high ultimate strength (UTS) of 501.7 MPa, a high yield strength (YS) of 320.4 MPa and a high elongation to failure of 21.6%. X-ray diffraction(XRD), electron backscattered diffraction (EBSD) and transmission electron microscope (TEM) were utilized to observe the microstructure of samples. As a result, complex effects of solute Mg atoms and precipitate of Al3(Sc,Zr) precipitation promoted formation of microstructure with large lattice misfit, sub-grain and dispersive distributed Al3(Sc,Zr) precipitation. The main mechanisms for observed high strength were found to be due to the solid solution of Mg and precipitate of Al3(Sc,Zr) precipitation, theoretical strength is in agreement with experimental strength. The presence of bimodal grain structure which was first found in conventional rolling structure and Al3(Sc,Zr) precipitation provided space for dislocation accumulation, improved the dislocation storage capacity of the alloy, and then directly increases the elongation of the alloy.