CN-116038092-B - Low-cost short-process preparation method of large complex component

Abstract

The invention discloses a low-cost short-process preparation method of a large complex component, and belongs to the technical field of material processing. The method takes an as-cast alloy plate as an initial material, adopts friction stir welding to weld the as-cast alloy plate, then carries out multi-pass friction stir processing (namely single-plate friction stir welding) on the welded large-size plate to obtain a large-size component with integral superplastic forming capability, adopts superplastic forming to prepare a large-size complex component, and the preparation process is shown in figure 1. The method can convert a small cast alloy plate with as-cast defects and coarse structure into a large-size fine-grain plate with integral superplastic forming capability, and finally form a large-scale complex component. The method has the advantages of short preparation flow, high material utilization rate, low cost and no limitation of the size of the initial plate, can be suitable for titanium alloy, steel, aluminum alloy, magnesium alloy, high-entropy alloy and other various alloys with superplasticity, and is beneficial to industrial production and application of large-scale complex components.

Inventors

• WU LIHUI
• LI NING
• NI DINGRUI
• ZHAO HONGBO
• XUE PENG
• WANG BEIBEI
• MA ZONGYI
• XIAO BOLV

Assignees

• 中国科学院金属研究所

Dates

Publication Date

20260512

Application Date

20230118

Claims (8)

1. 1. A low-cost short-process preparation method of a large complex component is characterized by comprising the following steps: (1) A plurality of as-cast alloy plates are connected by friction stir welding to form a large-size alloy welding plate; (2) Carrying out multi-pass friction stir processing on the large-size alloy welding plate obtained in the step (1) to eliminate the defects of the whole cast plate, improve the component segregation and the structure non-uniformity, and prepare a large-size superplastic plate with uniform and fine structures on the whole plate; (3) Carrying out overall superplastic forming on the large-size superplastic plate prepared in the step (2) to prepare a large-size complex member; in the welding process of the steps (1) - (2), the shaft shoulder size of the stirring tool is 8-15 mm, the stirring needle size is 3-8 mm, the rotation speed of the stirring tool is 200-1000 rpm, and the welding speed is 25-300 mm/min.
2. 2. The method for preparing the large complex member with low cost and short process according to claim 1, wherein the large-size plate obtained in the steps (1) - (2) has an equiaxed structure, a grain size of 0.01-5 microns and a high-angle grain boundary ratio of more than 80%, and the high-angle grain boundary is a grain boundary with a mismatch angle of not less than 15 o .
3. 3. The method of low-cost short-process manufacturing a large complex component according to claim 1, wherein the friction stir welding in step (1) is performed with the same parameters as the multi-pass friction stir processing in step (2).
4. 4. The method of low cost short process for manufacturing large complex components according to claim 1, wherein the welding is performed in atmosphere, vacuum, water or even dry ice, liquid nitrogen, liquid helium and organic solvent medium.
5. 5. The method of claim 1, wherein in the step (2), the width of the lap joint area between the former and later passes is 1/5~4/5 of the width of the friction stir processing area of each pass when the friction stir processing is performed for multiple passes.
6. 6. The method of claim 1, wherein in the step (3), the superplastic deformation temperature is 175-1000 ℃, the strain rate is 1X 10 -4 ~1×10 -1 s -1 , and the gas pressure of superplastic forming is 0.1-5 MPa.
7. 7. The method for preparing the large complex component with low cost and short process according to claim 1, wherein the alloy is titanium alloy, aluminum alloy, magnesium alloy or steel.
8. 8. The method for preparing a large complex component with low cost and short process according to claim 1, wherein the alloy is a high entropy alloy.

Description

Low-cost short-process preparation method of large complex component Technical Field The invention relates to the technical field of material processing, in particular to a low-cost short-process preparation method of a large complex component. Background Superplastic forming is a process capable of forming parts with complex structures, and has the characteristics of small deformation resistance, near net forming, great weight reduction of formed components, one-time forming and the like which are superior to the traditional plastic processing method, so that the superplastic forming is outstanding in a plurality of plastic processing processes, and the superplastic forming on a superplastic alloy plate to prepare the complex components, such as aircraft wall panels, flaps, cabin doors and the like, is widely applied at present. However, for large complex components with oversized dimensions, such as large satellite skins, large aircraft air inlet lips, etc., the plates are limited in size by the existing plate preparation technology and cannot be prepared by superplastic forming of a single plate. The fine equiaxed fine grain/superfine grain structure and the high-proportion high-angle grain boundary are important conditions for obtaining superplastic performance of the material, so that the fine grain/superfine grain superplastic plate is prepared, and the high-angle proportion is improved, which is a precondition for realizing superplasticity of the material and carrying out superplastic forming. At present, the existing fine grain preparation technology is difficult to prepare ultra-large-size fine grain/ultra-fine grain superplastic plates. For large complex components, the components can be welded together after superplastic forming, but the welding damages the overall performance of the components, so that great residual stress and deformation are caused, the assembly precision of the components is affected, and the practical application of the large complex components is greatly limited. In order to prepare a large-size titanium alloy plate with superplastic forming capability, wu et al patent 202111282326.4 discloses a superplastic forming process for preparing a large-size titanium alloy member, namely, firstly, carrying out friction stir welding on a commercial titanium alloy superplastic rolled plate to obtain fine equiaxed crystals in a weld core area, annealing the whole welded plate, and finally realizing similar structures of the whole plate through the difference of structure coarsening rates in the annealing process of the weld core and a base metal, thereby enabling each area of the large-size welded plate to have similar superplastic forming capability. However, the method requires that the original titanium alloy plate must be a rolled plate and the rolled plate must be a fine grain structure with superplasticity, so that the fine grain structure can be maintained after subsequent annealing to enable the whole plate to have superplasticity, but the method requires the commercial titanium alloy superplastic fine grain plate as a raw material, but the preparation of the raw material plate still has the problems of long process flow, multiple equipment coordination, complex and complicated process, low material yield and the like of the traditional rolled plate preparation, which greatly limits the engineering application of the method. In addition, the long-time annealing of the method also causes coarsening of the structure of the whole plate, thereby reducing the mechanical properties of the whole plate. Therefore, there is a need to invent a low-cost short-process preparation method for large-scale complex components, namely, a short-process preparation method is adopted to prepare large-size superplastic alloy plates with uniform and fine tissues from as-cast alloy raw materials, and superplastic forming is adopted to prepare the large-scale complex components on the basis. Disclosure of Invention The invention aims to provide a low-cost short-process preparation method of a large complex component. The method can obtain the large-size superplastic plate with uniform fine grain/superfine grain structure from the small-size as-cast alloy raw material, and finally realize the preparation of the high-performance large-size component, and the original plate size of the large-size complex structural component is not limited by a processing method, and the process is simple and efficient and has low cost. In order to achieve the above purpose, the technical scheme of the invention is as follows: a low-cost short-process preparation method of a large complex component comprises the following steps: (1) The cast alloy plates are used as raw materials, so that the cost of the raw materials can be greatly reduced, and the plates with small sizes are connected into the plates with large sizes by welding, so that the limitation of the sizes of the raw material plates can be broken through. (2) A