High-strength and high-toughness magnesium-lithium alloy capable of achieving rapid age hardening and preparation method thereof

The invention discloses a high-strength and high-toughness magnesium-lithium alloy capable of achieving rapid age hardening and a preparation method thereof, and belongs to the technical field of metal materials. 0.1-3 wt% of element Li is added into a Mg-Gd alloy. An alloy matrix comprises an alpha-Mg phase, and a large amount of dense and discretely distributed nanoprecipitates exist in the alpha-Mg matrix. Under the aging condition of 200 DEG C, the peak aging time of the alloy is less than or equal to 12 hours. During peak aging, the yield strength of the alloy reaches 302 MPa; the tensile strength reaches 343 MPa; and the elongation reaches 17.5%. The preparation process of the magnesium-lithium alloy comprises the steps of casting under the protection of molten salt and inert atmosphere, and performing solution treatment, extrusion forming and aging heat treatment to obtain the magnesium-lithium alloy. Compared with the prior art, by simply controlling the content of element Li, the high-strength and hi