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The Mg–8Li dual phase alloy was deformed by multi-directional compression with different passes. Microstructure evolution of deformed Mg–8Li alloy was analyzed by electron backscatter diffraction. X-ray diffraction profile was used to calculate the dislocation density in α-Mg and β-Li phase to reveal the quantitively change trend under different compression passes. The mechanical properties were assessed through tensile and compressive tests. The Mg–8Li alloy exhibited optimal mechanical properties when compressed with 12 passes (sample 12MDC), with a compression yield strength of 183.1 MPa and a tensile yield strength of 124.2 MPa. The improved mechanical properties in sample 12MDC were attributed to an increase in {10 1‾ 2} twin and {101‾ 3}-{101‾ 2} double twin boundaries, along with the presence of sub-grain boundaries and a reduced grain size in the α-Mg phase. Additionally, the inconsistent results between microhardness and dislocation density calculation manifests the uneven distribution of dislocations in β-Li phase. Broken α-Mg phase brings more phase interface to relieve the strain in β-Li phase, which results to a decreased dislocation density in sample 12MDC (1.19 × 1011/m2). Results show that weaken tension-compression yield asymmetry and more even distribution of dislocation in both phases could be achieved when the compression passes increases to 12.

The orientation (including the c axis orientation and crystal direction parallel to rolling direction) evolution of grown recrystallization grains during annealing at 250 °C for 45–180 min in Mg–Zn-Gd alloy was characterized by quasi-in-situ electron backscatter diffraction method. An unusual grain orientation rotation during the process of static recrystallization grain growth, rather than common plastic deformation or recrystallization nucleation process, was observed. Due to the higher storage energy, the growth size in the early stage of annealing (1.41 μm) is larger than that in the late stage of annealing (0.73 μm) for most (∼76%) grains, and corresponding average c-axis rotation angles are 3.65° and 1.39°, respectively, indicating that the larger the increase in grain size, the greater the changing degree in grain orientation. It is speculated that the orientation rotation during grain growth process is mediated by the interaction between dislocations and grain boundaries. The results reported in the current paper can provide a new insight into the study on the relationship between preferential grain growth and non-basal texture formation in rare earth contained Mg alloys.

The study utilizes a multi-directional compression (MDC) process on a basal-textured ZK60 alloy with the aim of inducing extensive twinning, which is followed by an aging treatment on the pre-deformed sample. The mechanical response and corrosion behavior of the deformed and aged samples are systematically investigated. The MDC process effectively generates numerous {10 1‾ 2} twins with increased compression passes, resulting in the enhanced grain refinement. The interplay between twins and numerous dislocations formed during pre-deformation plays a crucial role in altering both the distribution and morphology of the second phase precipitated during aging. During the aging process, the alloy exhibits a higher concentration of dense rod-like β′ phase and disk-like β″ phase. Remarkably, the compressive yield strength and ultimate strength of aged ZK60 alloy along the rolling direction are significantly improved without obvious compromise of ductility by pre-compression. Notably, the yield strength of the sample after 12-passes compression and aging (APD-12) is approximately 45 % higher than that of the sample without pre-compression (APD-0). Furthermore, the corrosion resistance of ZK60 alloy displays notable improvement upon pre-compression treatment. Specifically, the hydrogen evolution in the APD-12 sample is halved compared to the APD-0 sample. Electrochemical assessments were conducted on both pre-compressed and non-pre-compressed samples, revealing their distinct behaviors. Furthermore, an in-depth exploration has also been undertaken into the underlying mechanisms contributing to the enhancement of mechanical properties and corrosion resistance resulting from the pre-compression.

In this work, the dynamic, quasi-static response and twinning behavior of bimodal textured Mg–3Al–1Zn alloy is comparatively investigated at room temperature. The relationship between yield stress and bimodal texture is quantified and characterized as an increase of the yield stress with the increasing of the percentage of ⊥ED (extrusion direction) component; the ultimate strength under high strain rate (103 s−1) was quite higher than that under quasi-static condition (10−3 s−1); but, the yield stress was just the reverse. The competition between twin nucleation and growth is significantly affected by a coupled effect of strain rate and texture. Twin nucleation shows positive strain rate sensitivity and is largely enhanced by dynamic deformation. However, the twin growth tendency is bimodal texture and strain rate dependent: it is favorable under quasi-static condition for samples with more soft orientations, while for samples with more hard orientations, dynamic deformation promotes twin growth. It is also found that a higher strain rate can stimulate the activation of more twin variant types in bimodal textured magnesium alloys.