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Precipitation strengthening represents a crucial strengthening approach in the realm of metals, with particular significance for magnesium. In this study, a complex LPSO–precipitate structure, which is constituted of the principal secondary phases in Mg rare earth (RE) alloys, namely the Long-Period Stacking Ordered (LPSO) phase and the aging precipitate, was successfully fabricated within a Mg-11Y-1Al alloy. Subsequently, an in-depth investigation was conducted regarding the interaction between dislocations and this LPSO–precipitate structure under varying temperature conditions. The findings revealed that, at room temperature (RT), the aging precipitates effectively hindered the movement of basal dislocations, and the activation of non-basal dislocations is rather difficult, resulting in the alloy's high strength and low plasticity. When the temperature was elevated to 200 °C, although non-basal slip could be initiated, the LPSO–precipitate structure was capable of blocking both basal and non-basal slips. Consequently, the alloy still demonstrated high strength and low plasticity. As the temperature further increased to 250 °C, dislocations could cut through the aging precipitate particles, and the interior of the grains could provide partial deformation. Hence, the tensile elongation of the alloy was significantly enhanced, increasing from 4% to 12% as the temperature was elevated from 200 °C to 250 °C. These results suggest that the LPSO–precipitate structure still exerts a remarkable strengthening effect at 200 °C. When the temperature reaches 250 °C, the plasticity of the alloy is improved but its strength decreases. The research outcomes presented in this paper offer a novel perspective for the precise tailoring of mechanical properties through precipitation strengthening within Mg-RE alloys. [ABSTRACT FROM AUTHOR]

In this study, in situ synchrotron X-ray experiments with wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) detectors were performed on two pure magnesium materials produced by powder metallurgy. According to SAXS analysis, each of the two materials has a porosity of less than 0.5%. Line broadening analysis was performed on diffraction patterns collected by WAXS to analyze the dislocation evolution during material deformation. In both materials, -type dislocation activities dominate the tensile deformation. The influence of grain size and texture on the different tensile behaviors of these two materials is also discussed. [ABSTRACT FROM AUTHOR]

In this study, the microstructure evolution of solution-treated Mg 9Y alloy during high strain rate deformation was systematically investigated. Abundant deformation bands were formed to subdivide the grain. The crystallographic features of these defomation bands, including the { 11 2 ¯ 1 } twin, twin-like tilt boundaries, { 11 2 ¯ 2 } twin and kink bands, were identified by characteristic misorientation angles along < 1 1 ¯ 00 > axis. The { 11 2 ¯ 2 } twin was observed for the first time in Mg alloys, and probably evolved from { 11 2 ¯ 1 } twin through lattice rotation along < 1 1 ¯ 00 > axis in this case. To accommodate strain in a short time, kink band boundaries with < 1 1 ¯ 00 > rotation axis were formed due to local lattice rotation and interacted with { 11 2 ¯ 1 } twin boundaries, resulting in the the formation of < 1 1 ¯ 00 > axis tilt boundaries with various misorientation angles. The lattice rotation process was attributed to the basal < a > and pyramidal-II < c + a > dislocation slips under high strain rate deformation. These results will offer insight into microstructure evolution during high strain rate deformation and inspire the development of high-performance Mg alloys. [Display omitted] • Multiple < 1 1 ¯ 00 > axis tilt boundaries are formed in the SHPBed Mg 9Y alloy. • The 11 2 ¯ 2 twin boundary can be evolved from the 11 2 ¯ 1 twin boundary via lattice rotation. • The intersection of < 1 1 ¯ 00 > tilt boundaries can subdivide the grain effectively. • The homogeneous strain can be achieved by the twin mesh microstructure. [ABSTRACT FROM AUTHOR]