Designing a low-alloyed Mg–Al–Sn–Ca alloy with high strength and extraordinary formability by regulating fine grains and unique texture

Abstract

Since the strategies used for improving formability usually result in a degradation of strength, evading the formability-strength tradeoff is a severe challenge for magnesium (Mg) alloys. Here, we developed a fine-grained (∼3.1 μm) Mg-2.0Al-0.8Sn-0.5Ca (wt.%) alloy that owns a satisfactory compatibility of formability and strength (Index Erichsen (I.E.) value: ∼7.8 mm, yield strength: ∼189 MPa), by a subtly designed processing scheme, i.e., multidirectional rolling followed by annealing treatment. The large I.E. value arises from the unique ring-characterized weak texture, which promotes the activation of dislocation slips and the formation of low-angle grain boundaries during the stretch forming. The high strength can be related to the fine grain structure and a high dispersion of nano-sized particles. Such a high-performance dilute Mg alloy sheet provides reference for broadening the application of Mg alloys in industries.