Ultra-fine grain and nanocrystalline material preparation die and method

Abstract

The invention discloses an ultra-fine grain and nanocrystalline material preparation die and method. The ultra-fine grain and nanocrystalline material preparation die comprises an upper die body, a lower die body and a piece ejection device. The upper die body is provided with a male die. The male die and an upper padding plate used for bearing the pressure of the male die are fixed to an upper die holder together through a male die fixing plate via a screw and a pin. The lower die body is provided with a female die. A rectangular cavity with the length and width being in proper proportion isformed in the female die, and the female die and a lower padding plate are fixed to a lower die holder together via a screw and a pin. The piece ejection device comprises a piece ejection block installed inside the female die and an ejection rod used for pushing the piece ejection block to eject a blank out of the female die. The upper die body and the lower die body are guided by a guide sleeve fixed to the upper die body and a guide pillar fixed to the lower die body, and thus the effect that the male die can press the blank into the female die accurately is guaranteed. The male die compresses the blank, the height of the blank is decreased, the female die is filled with the blank, the upper die body returns, and the piece ejection block ejects out the blank; the blank is rotated, the length is rotated to be in the vertical direction, the width corresponds to the length of the die, the height corresponds to the width of the die, and the female die is put in to be compressed again; and due to the fact that the dimensions of the length, width and height are unchanged after compression is completed each time, compressive deformation can be conducted repeatedly and the purpose of refining crystal particles is achieved. The die is reasonable in structure, the method is easy, operation is convenient, the deformation degree can be controlled accurately, the manual material collecting time between working procedures is saved, the dangerousness is effectively lowered, and production efficiency is improved obviously.

Description

technical field [0001] The invention relates to a mold and method for preparing materials, in particular to a mold and method for preparing ultrafine and nanocrystalline materials, which belong to the field of material processing. Background technique [0002] Multidirectional compression is a typical process in the large plastic deformation method. It has a strong ability to refine grains and can directly refine the internal structure of materials to submicron or even nanometer levels. One of the most effective and fastest-growing technologies for crystalline materials, the essence of its deformation is to compress the material sequentially along different axial directions. Since the shape and size of the sample do not change before and after compression, it can be repeatedly compressed, and each deformation The cumulative superposition of the strain amount can reach a very large total deformation amount, and achieve the effect of refining the grain and improving the perfor...

AI Technical Summary

Problems solved by technology

However, this technology does not use a mold for free compression, the amount of deformation is not easy to accurately control and the deformation inside the blank is uneven; even if a mold is used, because the mold is too simple and the structure is unreasonable, it is difficult to remove the blank from the mold, and the mold is usually not fixed to the equipment. After each compression, the mold must be disassembled, and the billet must be taken out manually. The next compression needs to be re-adjusted, which greatly affects the extrusion efficiency and is not safe.

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