Solid-solution aging heat treatment method of aluminum-lithium alloy large plate

The invention discloses a solid-solution aging heat treatment method of an aluminum-lithium alloy 5A90 large plate. The method comprises a preparation step, a solid solution step and an aging step. The preparation step comprises drilling holes on each of two opposite sides of the plate, allowing an aluminum wire to pass through each drilled hole on each side to fix the plate on a tooling; and adding a nitrate solution, setting the temperature of a nitrate furnace to 450 DEG C-465 DEG C, keeping the temperature for at least 30 min, and stirring the nitrate solution with compressed air. The solid solution step comprises vertically hanging the tooling provided with the plate into the nitrate furnace, and after solid solution, hanging out of the nitrate furnace, wherein the transferring time of transferring the tooling to room temperature air from the nitrate furnace is not greater than 15 s. The aging step comprises levelling in 1 h after the plate is hung out of the nitrate furnace is quenched, and aging, wherein the aging temperature is 120+/-5 DEG C, and the aging time is 5 h-12 h. The method not only can ensure the strength of the aluminum-lithium alloy 5A90, but also can well control the deformation degree of the plate.