Two-time torsion extrusion device and method with variable-section cavity for grain refining

Abstract

The invention discloses a two-time torsion extrusion device and method with a variable-section cavity for grain refining. The device comprises a male die part, a transmission mechanism, a power mechanism and a female die part, wherein the male die part is matched with the female die part, and the power mechanism is connected with the transmission mechanism; and the male die part comprises an upperdie plate and an upper die, the female die part comprises an upper cylinder, an upper plate and a main die, the upper die plate is arranged on the upper die, the upper die is matched with the upper cylinder and enters the upper cylinder and the main die in a working state under the action of a hydraulic press sliding block, the upper cylinder is arranged on the upper plate, the main die is arranged below the upper plate and connected with the upper cylinder, and the upper die enters the upper cylinder in the working process. According to the two-time torsion extrusion device and method, by changing the shape of the section of the inner cavity of the rotating die, the die with the variable-section cavity is rotated during extrusion, a material has both extrusion deformation and shearing deformation brought by die rotation, severe plastic deformation is realized, forming force is small, deformation efficiency is high, and a good grain refining effect can be achieved.

Description

technical field [0001] The invention relates to a technology in the field of plastic processing for preparing ultra-fine-grained material rods, in particular to a secondary torsion extrusion device and method for a variable-section cavity with fine grains. Background technique [0002] Materials with ultrafine grains not only have good physical and mechanical properties, but can even achieve superplasticity under certain temperature and strain rate conditions when the grain size is less than 10 μm. The superplastic flow deformation resistance of the material is small, the fluidity and filling are excellent, and a large deformation can be obtained. An important condition for materials to be superplastic is to have ultra-fine grains, and a series of ultra-fine-grained materials with superior performance can be obtained by using large plastic deformation technology. [0003] Torsional extrusion is also a large plastic deformation process, but although the material grains produ...

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Problems solved by technology

[0003] Torsional extrusion is also a large plastic deformation process, but although the material grains produced by this process are refined, because the shear deformation is concentrated at the edge, there are differences in the size of the edge and core grains. have an adverse effect on the improvement of the performance of the material

In addition, the shear deformation of the material is mainly realized by the friction between the mold and the material. When the mold rotates at a high speed, there will be slippage and the torsion effect cannot be reflected.

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