Forging process for preparing isotropic ultrahigh-strength heat-resistant magnesium alloy structural member

Abstract

The invention discloses a forging process for preparing an isotropic ultrahigh-strength heat-resistant magnesium alloy structural member. Firstly, a cast ingot prepared through semi-continuous electromagnetic casting is subjected to homogenizing annealing, an ingot blank is formed through machining, the height direction of the cylindrical ingot blank and any two mutually perpendicular radial directions are used as the Z direction, the Y direction and the X direction correspondingly, 3-6 passes of heading are performed in the Z direction, the Y direction and the X direction, and the pass deformation amount is 20-40%; then the X direction or the Y direction is used as the axis, 2-6 passes of corner angle rolling compressing are performed, the pass deformation amount is 10-20%, intermediate annealing is performed, and the forging process is performed repeatedly once or twice; a forge piece is subjected to T6 treatment after forging is finished, and a final forge piece with the diameter being 450-650 mm and the height being 300-700 mm is obtained; as for both the height direction and the radial directions of the T6 state at the room temperature, the tensile strength is larger than or equal to 460 MPa, the yield strength is larger than or equal to 400 MPa, the ductility is larger than or equal to 4%, and the strength difference between the height direction and the radial directions is smaller than or equal to 10 MPa, and the ductility difference between the height direction and the radial direction is smaller than or equal to 0.5%; and as for both the height direction and the radial directions at the temperature of 200 DEG C, the tensile strength is larger than or equal to 350 MPa, and the ductility is larger than or equal to 6%.

Description

technical field [0001] The invention relates to the field of thermal deformation of high-strength heat-resistant magnesium alloys, in particular to multidirectional forging deformation of Mg-Gd-Y-Zr series magnesium alloys. Background technique [0002] Magnesium alloy has the advantages of large reserves, low density, high specific strength and specific stiffness, and is known as "green material in the 21st century". Compared with die castings, wrought magnesium alloys have gained more and more applications due to their special advantages. Deformed magnesium alloys can obtain ideal shapes and sizes through deformation, and can also use deformation to eliminate casting defects, refine grains, and improve mechanical properties. As a typical wrought magnesium alloy, Mg-Gd-Y-Zr alloy has attracted wide attention for its excellent mechanical properties and heat resistance. At present, the application of Mg-Gd-Y-Zr alloy is still mainly extruded profiles and rolled plates, and ...

AI Technical Summary

Problems solved by technology

The reasons are as follows: first, the addition of rare earths such as Gd and Y increases the deformation resistance of the magnesium alloy and narrows the processing window; second, due to factors such as friction, the sample has a difficult and easy deformation zone during free forging, and the deformation is not stable. Uniform and difficult to penetrate, resulting in uneven structure and mechanical properties; third, magnesium alloy has a special hexagonal close-packed structure, and the deformation process is very easy to produce texture, resulting in obvious anisotropy of mechanical properties

These three reasons make it difficult to prepare large-scale Mg-Gd-Y-Zr forgings with uniform structure, up-to-standard performance and small anisotropy

Images