Preparation method of large-size thin plate of niobium-containing titanium-aluminum based alloy by powder metallurgy

The invention provides a preparation method of a large-size thin plate of a niobium-containing titanium-aluminum based alloy by powder metallurgy. The alloy comprises the following components in atom percentage: Ti-(44-48)Al-(0.5-3)Cr-(2-7)Nb-(0.1-0.5)W. The preparation method comprises the following steps of: 1, carrying out hot isostatic pressing on spherical alloy powder to prepare an original ingot blank; 2, cutting a blank to be rolled from a hot isostatic pressing ingot blank, covering the cut blank to be rolled by a pure titanium plate and coating an anti-oxidization coating; 3, soaking the covered blank to be rolled at 1200-1250 DEG C, carrying out multi-path rolling, strictly controlling a rolling line speed, a path pressing amount and a rolling piece temperature; when the total deformation amount is more than 70-85%, stopping rolling; and cooling by air and removing a cover to obtain the large-size alloy thin plate. The preparation method disclosed by the invention can be used for solving the problem that the large-size thin plate is difficult to prepare from the niobium-containing titanium-aluminum based alloy through commonly rolling and can provide a large-size sheet material meeting the requirements of the size for the industrial application of the titanium-aluminum based alloy. The preparation method has the advantages of simple process, reasonable parameters and low requirements on rolling equipment; and the surface quality of the obtained sheet material is good and the tissue is uniform and small, so that the preparation method is suitable for industrial production.