Fatigue life of fine-grain Al–Mg–Sc alloys produced by equal-channel angular pressing

The effect of severe plastic deformation through equal-channel angular pressing (ECAP) on the fatigue life of Al–Mg–Sc alloys with different concentration of magnesium is discussed. Both high-cyclic and low-cyclic fatigue properties have been assessed in terms of the fatigue strength, fatigue ductility, cyclic stress–strain curves, etc. It is shown that the addition of Sc significantly increases the thermal stability of the fine-grain structure formed during ECAP. However, only modest improvement of tensile and cyclic mechanical properties have been achieved via ECAP of Al–Mg–Sc alloys in comparison to their ordinarily fabricated counterparts. The results of present investigation show that the grain refinement of precipitation hardenable Al-alloys through severe plastic deformation can not be effective for enhancement of their static or cyclic strength. It is argued that early shear banding play an important role in cyclic degradation of ECAP Al–Mg–Sc alloys.