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This work systematically investigated the influence of the micro-Mn addition on the microstructures and mechanical properties of Mg-Er alloys. To investigate their deformation mechanisms during tensile testing, electron back-scattered diffraction, transmission electron microscopy, slip trace analysis, and visco-plastic self-consistent polycrystal constitutive (VPSC) modeling were used. The study showed that the as-solid solution samples only consist of the α-Mg phase. All samples exhibit a complete dynamic recrystallized (DRXed) microstructure with an average grain size of 2.79 µm after hot extrusion. The ductility first increases from 26.02 % to 35.34 % and then remains unchanged with the increment of Mn content. Meanwhile, the yield strength significantly increases from 95 MPa to 200 MPa. According to VPSC results, the initial slip resistance (τ0) difference between prismatic and basal slips decreases from 109 MPa to 92 MPa and τ0 between pyramidal and basal slip systems from 129 MPa to 112 MPa. Both the VPSC and two-beam diffraction results confirmed that pyramidalslip andslip were activated during tensile deformation. The quantitative analysis of the slip trace line verified that the volume of non-basal slip reached 65 % when the content of Mn was increased to 0.9 wt%. Mn in solid solution increased the activity of pyramidaland prismaticdislocations during deformation, which is beneficial for accommodating c-axis strain. Consequently, the ambient ductility of Mg-2Er alloy with Mn addition is improved.

Ternary magnesium-based alloys with an aluminum content of 0.5 wt.% and a varying manganese content of x = 1, 2, and 3 wt.% (Mg-xMn-0.5Al) were prepared and characterized. The study focused on the effect of Mn addition on the formation of ultrafine grains (UFGs, average grain size

The effect of Mn on the microstructure and mechanical properties of as-extruded Mg-0.5Sr alloy were discussed in this work. The results showed that high Mn alloying (2 wt.%) could significantly improve the mechanical properties of the alloys, namely, the tensile and compressive yield strength. The grain size of as-extruded Mg-0.5Sr alloys significantly was refined from 2.78 &mu, m to 1.15 &mu, m due to the pinning effect by fine &alpha, Mn precipitates during the extrusion. Moreover, it also showed that the tensile yield strength and the compressive yield strength of Mg-0.5Sr-2Mn alloy were 32 and 40 percent age higher than those of Mg-0.5Sr alloy, respectively. Moreover, the strain hardening behaviors of the Mg-0.5Sr-2Mn alloy were discussed, which proved that a large number of small grains and texture have an important role in improving mechanical properties.

Developing high yield strength and ductility in low–cost Mg alloys using conventional plastic forming process is a tremendous challenge. Mg–Mn–based alloys have drawn considerable attention owing to their low–cost, high ductility and good corrosion resistance. However, the strength of Mg–Mn binary alloy is not satisfactory for industrial scale applications. In the present study, low content of Al alloying in Mg–1Mn alloy is the aim to obtain high strength and ductility of Mg–Mn–based alloys with low cost. Experimental results revealed that phase composition of the targeted Mg–1Mn–xAl (x = 0.3 wt%, 0.5 wt%, 1.0 wt%) alloys were composed of α-Mn + Al8Mn5, Al8Mn5 and Al8Mn5+Al11Mn4 phase, respectively. Al–Mn particles significantly refined the dynamically recrystallized (DRXed) grains. Among them, Al8Mn5 particles exhibited the most effective grain refinement. Therefore, Mg–1Mn–0.5Al alloy containing single-phase Al8Mn5 particles possessed the finest microstructure and exhibited the best mechanical properties. The high performance of the alloy was mainly attributed to the fine DRXed grains according to the Hall–Petch effect and to the large amount of fine Al8Mn5 particles through the dispersion strengthening. Meanwhile, the weak texture of fine grains enhanced the ductility. The fine DRXed grains and numerous Al8Mn5 particles effectively suppressed the extension twining, thus substantially enhanced the compression yield strength, and resulted in improved anisotropy.

Highly-uniform ultrafine Mg–3Al–1Zn alloy was successfully fabricated by a simple conventional extrusion method called continuous forging extrusion (CFE). After CFE, the average grain size of Mg–3Al–1Zn alloy was refined to 0.6 μm. The ultra-fine grain (UFG) AZ31 alloy exhibited an excellent combination of yield strength of 307 MPa and ductility of 26.3%. The improved mechanical properties were mainly attributed to grain boundary strengthening and texture weakening. The formation of dynamic recrystallized submicron grain in the CFE was also discussed.