Mg alloys, the lightest structural metal, generally suffer from low strength and poor deformability, and therefore severely restrict their widespread applications in automotive, aircraft, and aerospace industries. [1] The underlying reason for such mechanical behaviors is the anisotropic response inherent in the hexagonal close-packed (hcp) lattice of Mg. [2-3] Therefore, the key of advancing their applications is reducing the anisotropic behavior of different deformation modes, through regulating the relative activities of (easy) basal slips, (hard) non-basal slips, and twinning.
Herein, we demonstrate the new microstructure, the self-assembled hexagonal 1-nm Gd nano-fibers pattern within binary Mg-Gd alloys. [4] As shown in Fig.1, such hexagonal patterns are typically a few hundred nanometers in width and a few microns in length. These patterns are associated with dislocation templates. Such patterns include Gd-segregated dislocations with approximately 1 nm in diameter, which have a c-rod shape, and these in turn become effective inhibitors for basal slips since they have to cut these nano-fibers. On the other hand, non-basal slips suffer much less effect because the glide of non-basal dislocations has much less chances of cutting these Gd-segregations. Thus, these patterns can strengthen Mg alloys mainly through pinning basal dislocations; more importantly, tune the relative activities of basal and non-basal slips, and thus improve the deformability of Mg alloys. It is also worth mentioning that such patterning structure can be synthesized through a generally economical hot extrusion approach.
In summary, 1-nm Gd nano-fibers, with c-rod shape, are self-assembled into hexagonal patterns in Mg matrix, which can tune the relative activities of deformation modes and thus improve mechanical properties of Mg alloys. Our results open up a new path of engineering advanced Mg alloys though manipulating their microstructure.
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Figures:
Figure 1. Gd nano-fiber patterns in Mg. (A) The TEM-BF image. White arrows indicate the Gd nano-fiber patterns. (B) The STEM-HAADF image. Gd shows as bright contrast due to the large atomic number differences between Gd and Mg. These Gd-segregations are patterned in a hexagonal shape with identical interspacing.
To cite this abstract:
Guo-zhen Zhu, Yangxin Li; Hexagonal patterning of 1-nm Gd nano-fibers based on dislocation templates in Mg-Gd alloys. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/hexagonal-patterning-of-1-nm-gd-nano-fibers-based-on-dislocation-templates-in-mg-gd-alloys/. Accessed: December 3, 2023« Back to The 16th European Microscopy Congress 2016
EMC Abstracts - https://emc-proceedings.com/abstract/hexagonal-patterning-of-1-nm-gd-nano-fibers-based-on-dislocation-templates-in-mg-gd-alloys/