Method for preparing large-size rare earth magnesium alloy high-performance ingots by short process severe plastic deformation

Patent metadata

Field	Value
Publication number	US-11813653-B2
Application number	US-202217944218-A
Country	US
Kind code	B2
Filing date	Sep 14, 2022
Priority date	Apr 12, 2022
Publication date	Nov 14, 2023
Grant date	Nov 14, 2023

Abstract

The present disclosure discloses a method for preparing large-size rare earth magnesium alloy with high-performance ingots by short process severe plastic deformation. When in use, the pushing cylinder moves upward, and the back pressure plate is adjusted to the outlet of the extrusion deformation area. After the male mold stroke is completed, the recoverable discard block fills the extrusion deformation area, and the upsetting extrusion deformation is completed. Then, the pushing cylinder drives the back pressure plate to remove from the lower part of the lower mold cavity downward, and the recoverable discard block has been broken due to the high pressure. Then, the extruded blank and residual block powder are taken out from the lower part of the lower mold cavity, restored into a plate shape for the next use. The present disclosure can solve the tail shrinking phenomenon, save materials and increase the strengthening effect.

First claim

What is claimed is:

1. A method for preparing a rare earth magnesium alloy with ingots by severe plastic deformation, comprising:
S1: providing a cylindrical magnesium alloy bar;
S2: homogenizing the cylindrical magnesium alloy bar to form a cylinder blank;
S3: heating the cylinder blank to a forming temperature and holding the forming temperature, and heating a preparation mold above an experimental temperature and holding the experimental temperature for half an hour, wherein the preparation mold comprises a male mold installed on an upper workbench of a press machine, a female mold installed on a lower workbench of the press machine, a recoverable discard block and a back pressure plate connected with a pushing cylinder of the press machine, the female mold is provided with an upper mold cavity and a lower mold cavity, and an upper part of the upper mold cavity is configured for placing blanks, the recoverable discard block and the male mold, and a lower part of the upper mold cavity is inclined inward to form an extrusion deformation area communicated with the lower mold cavity; the recoverable discard block is separated between the cylinder blank and the male mold, the recoverable discard block is made of deformable material, and the recoverable discard block is configured to be deformed and filled in an extrusion deformation area and restored through deformation; an upper part of the back pressure plate is fitted in the lower mold cavity, so that a molding cavity is formed between the upper part of the back pressure plate and the lower mold cavity, and an upper surface of the back pressure plate is raised in a middle;
S4: installing the preparation mold after preheating and heat preservation on a pressing machine, and evenly spraying organic graphite lubricant on the male mold and the female mold;
S6: putting the cylinder blank after homogenization and heat treatment into the upper mold cavity;
S7: placing the recoverable discard block above the cylinder blank;
S8: adjusting a height of the back pressure plate to an outlet of the extrusion deformation area by an upward movement of the pushing cylinder in an initial stage of extrusion forming; wherein the pressing machine drives the male mold to move downward and gradually extrudes the cylinder blank into the extrusion deformation area; a bottom of the cylinder blank slowly deforms, contracts and fills the extrusion deformation area; as the male mold continues to move downward, the bottom of the cylinder blank contacts the upper surface of the back pressure plate; when a contact width is close to a size of an extruded part, the back pressure plate starts its downward return with the male mold; after a stroke of the male mold is completed, the recoverable discard block fills the extrusion deformation area, and an upsetting deformation is completed; in this process, the back pressure plate always gives an upward back pressure to the cylinder blank;
S9: driving the back pressure plate downward to remove from a lower part of the lower mold cavity by the pushing cylinder, wherein the recoverable discard block has been broken; taking out the cylinder blank after extruded and a powder of the recoverable discard block from the lower part of the lower mold cavity, and restoring the powder into a plate shape for use next time.

2. The method for preparing a rare earth magnesium alloy with ingots by severe plastic deformation according to claim 1 , wherein the recoverable discard block is in a molten state at a first temperature, and the recoverable discard block is a brittle solid at a second temperature and is broken into solid powder when pressed in the extrusion deformation area; the first temperature is higher than the second temperature.

3. The method for preparing a rare earth magnesium alloy with ingots by severe plastic deformation according to claim 1 , wherein the recoverable discard block is made of a mixture of fluorite powder and graphite.

4. The method for preparing a rare earth magnesium alloy with ingots by severe plastic deformation according to claim 1 , wherein the preparation mold further comprises an extrusion restoration mold, the extrusion restoration mold comprises a pressing box and a pressing block, the pressing box is provided with a groove, the recoverable discard block is crushed into solid powder under pressure and placed in the groove, and the pressing block presses the solid powder to restore the solid powder into recoverable discard block under a first temperature.

5. The method for preparing a rare earth magnesium alloy with ingots by severe plastic deformation according to claim 1 , wherein the male mold and the female mold are connected to the upper and lower workbenches through fasteners; the method further comprises S10: after a process for preparing rare the earth magnesium alloy with ingots by severe plastic deformation is completed, molding the male mold and the female mold together to perform a mold closing action, then loosening the fasteners, and then removing the preparation mold.

Assignees

• Univ North China

Inventors

• Zhang Zhimin
• Yu Jianmin
• Wang Zhen
• Cheng Zhe
• Cheng Mei

Classifications

• B21D22/022 Primary

  by heating the blank or stamping associated with heat treatment (C21D takes precedence) · CPC title

• C22F1/06 Primary

  of magnesium or alloys based thereon · CPC title

• B21C25/00 Primary

  Profiling tools for metal extruding · CPC title

• B21C23/02

  Making uncoated products · CPC title

• B21C35/02

  Removing or drawing-off work · CPC title