Solid solution strengthening and damping capacity of Mg-Ga binary alloys
(1. School of Materials Science and Engineering, Hunan University, Changsha 410082, China;
2. Hunan Provincial Key Laboratory of Spray Deposition Technology & Application, Hunan University, Changsha 410082, China;
3. Beijing Institute of Space Long March Vehicle, Beijing 100076, China)
2. Hunan Provincial Key Laboratory of Spray Deposition Technology & Application, Hunan University, Changsha 410082, China;
3. Beijing Institute of Space Long March Vehicle, Beijing 100076, China)
Abstract: The mechanical behaviors and damping capacities of the binary Mg-Ga alloys with the Ga content ranging from 1 to 5 wt.% were investigated by means of optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), hardness test, tensile test and dynamic mechanical analyzer (DMA). The hardness (HV0.5) increases with the increase of Ga content, which can be described as HV0.5=41.61+10.35c, and the solid solution strengthening effect ？σs of the alloy has a linear relationship with cn, where c is the molar fraction of solute atoms and n=1/2 or 2/3. Ga exhibits a stronger solid solution strengthening effect than Al, Zn or Sn due to the large atomic radius difference and the modulus mismatch between Ga and Mg atoms. The addition of Ga makes the Mg-Ga alloys have better damping capacity, and this phenomenon can be explained by the Granato-Lücke dislocation model. The lattice distortion and the modulus mismatch generated because of the addition of Ga increase the resistance to motion of the dislocation in the process of swinging or moving, and thus the better damping capacity is acquired.
Key words: Mg-Ga alloys; solid solution strengthening; damping capacity; Granato-Lücke model