Breaking the stiffness limit of Mg alloys by forming hard AlX particles and activating non-basal slip

Traditionally, Mg alloys suffer from the low Young's modulus, making it uncompetitive to Al alloys in such applications as aerospace components where high stiffness is necessary. In this study, a new Mg-Li-Al-Dy-Nd-Y-Ag-Zn-Er-Zr alloy was performed, which has an ultra-high modulus of 61.73 GPa and excellent ductility of 19.3% after cast, homogenization, cold rolling, and heat treatment. The origin of such a significant increase in modulus is due to the formation of micro- and nano- AlX particles. The increase in plasticity can be explained by the activation of non-basal slips in the α-Mg matrix and dislocation slips in the β-Li phase. In addition, the relationship between the grain orientation (obtained from the EBSD results) and hardness were discovered by using nanoindentation experiments and crystal plasticity finite elements modeling (CPFEM). The high hardness of the alloy is due to the fact that the Schmid factor (SF) range of the slip system is mostly between 0.3 and 0.5.