Effect of Friction Stir Processing on Microstructure and Mechanical Properties of Mg-9Li-Zn Alloy

The modification process of Mg-9Li-Zn alloy material by friction stir processing（FSP） technology was carried out. The microstructure, hardness, tensile strength and fracture morphology of processing improvement zone of the alloy were studied. The results show that because of the thermal and mechanical effects, the texture of magnesium lithium alloy gradually disappears after the friction stir treatment, and there are more and more acicular α phase appearing. The grain size is refined,the hardness and tensile strength of the alloy improve, however, due to the uneven distribution of the mixing zone, the elongation of the material decreases, the tensile fracture morphology in the vertical direction of friction stir is composed of the region of the central ductile failure and the region of the edge of the brittle zone, the tensile surface of parallel mixing zone is characterized by uniform ductile fracture.