Microstructure evolution and tensile property of deformed Al–Mg–Sc alloy: comparison of ECAP and FSP

In this paper, the effects of two severe plastic deformation (SPD) methods, ECAP and FSP, on the microstructure evolution and tensile strength of an Al–6Mg–0.4Mn–0.25Sc–0.1Zr (wt.%) alloy are comparatively studied. The microstructure was characterized by SEM, EBSD, T-EBSD, TEM and HRTEM, and the tensile strength of the material was tested by uniaxial tensile testing machine. The results show that ECAP has a stronger grain refining effect than FSP. ECAP can refine the average grain size of Al–Mg-Sc alloys to about 1 μm, while the grain size of the FSP samples is mostly 2–3 μm. In addition, the effects of the two SPD methods on the second phase particles in the Al–Mg–Sc alloy are also different, but both methods will change the distribution and morphology of Al3(Sc, Zr) particles, which is due to the different deformation mechanisms of ECAP and FSP. The yield strength of the ECAP sample is higher than that of the FSP sample, but the elongation after fracture is slightly less than that of the FSP sample.