New high-modulus and high-strength Mg-Gd-Ag-Mn-Ge alloys

In the field of lightweight metals, it is difficult to develop magnesium (Mg) alloys with both high-modulus and high-strength. In this paper, the results show that adding Ge element to the base Mg-Gd-Ag-Mn alloy can simultaneously improve the elastic modulus and strength of the alloy, and the higher the Ge content is, the higher the modulus and strength will be. After Ge alloying, the average grain size and texture of Mg-Gd-Ag-Mn-Ge alloy are reduced and new high-modulus MgAg and Gd5Ge3 phases are formed compared with the base Mg-Gd-Ag-Mn alloy. In Ge-containing alloys, the Mg-10Gd-1.5Ag-0.2Mn-3.5Ge alloy obtained the best comprehensive mechanical properties, the elastic modulus, strength and ductility are 51 GPa, 423 MPa and 10%, respectively. The high-modulus is due to the formation of high-modulus second phases. The high-strength is the result of dislocation strengthening, grain boundary strengthening and precipitation strengthening.

Automated summary

The study demonstrates that adding Ge element to Mg alloys can improve both the elastic modulus and strength, while refining the grain size and promoting the formation of high-modulus phases. The Mg-10Gd-1.5Ag-0.2Mn-3.5Ge alloy exhibits the best comprehensive mechanical properties with a high modulus, strength, and ductility.