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A method for promoting the densification of metal bodies by utilizing metal hydrogen absorption expansion

A metal blank and densification technology, applied in the direction of process efficiency improvement, additive manufacturing, additive processing, etc., can solve the problems of production efficiency and product size limitation, product anisotropy, product size limitation, etc., to achieve Simple production equipment and molds, uniform structure, and the effect of inhibiting grain growth

Active Publication Date: 2021-09-07
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Hot pressing and sintering can easily lead to anisotropy of the product, and the production efficiency and product size are limited
Spark plasma sintering increases the pulse current on the basis of hot pressing sintering, promotes sintering densification, and can complete the sintering of fully dense materials in a short period of time. The disadvantage is that the size of the product is limited and it is difficult to scale up.
Therefore, the above technologies all have disadvantages such as high cost, low efficiency, and limited product size.

Method used

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  • A method for promoting the densification of metal bodies by utilizing metal hydrogen absorption expansion

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046]1. Put a titanium product with a density of 98% (industrial pure titanium, titanium content > 98%) into a stainless steel mold, and fill the space between the product and the mold with titanium powder with an average particle size of 45 microns (the filling volume of titanium powder accounts for 40% of the inner cavity volume), the mold is packaged and fastened. (due to the gaps left between the mold modules; these gaps are good ventilation holes)

[0047] 2. Put the assembled mold into a hydrogen furnace, heat it to 600 degrees Celsius in a vacuum, feed hydrogen (hydrogen pressure 1 bar), keep feeding hydrogen and keep it warm for 10 hours.

[0048] 3. Stop the hydrogen gas flow in the hydrogen furnace, and vacuumize (vacuum degree is less than 10 -3 Pa), the temperature was increased to 750 degrees Celsius, and the furnace was shut down to cool after keeping for 10 hours.

[0049] 4. Turn on the hydrogen furnace, take out and open the mold, and take out the titanium ...

Embodiment 2

[0053] 1. Put a titanium alloy product with a density of 95% (titanium content > 20%) into a stainless steel mold, the fit between the product and the mold is less than 0.1mm, and then seal and fasten the mold. (due to the gaps left between the mold modules; these gaps are good ventilation holes)

[0054] 2. Put the assembled mold into a hydrogen furnace, heat it to 600 degrees Celsius in a vacuum, feed hydrogen (hydrogen pressure 10 bar), keep feeding hydrogen and keep it warm for 10 hours.

[0055] 3. Stop the hydrogen gas flow in the hydrogen furnace, and vacuumize (vacuum degree is less than 10 -3 Pa), the temperature was increased to 750 degrees Celsius, and the furnace was shut down to cool after keeping for 10 hours.

[0056] 4. Turn on the hydrogen furnace, take out and open the mold, and take out the titanium alloy product with a density greater than 99.5%.

Embodiment 3

[0060] 1. Put the copper alloy (copper content > 60%) product with a density of 95% into a stainless steel mold, and fill the space between the product and the mold with titanium powder with an average particle size of 45 microns (the filling volume of titanium powder accounts for 30% of the inner cavity volume of the mold. %), package and fasten the mold (because there are gaps between the mold modules; these gaps are good ventilation holes).

[0061] 2. Put the assembled mold into a hydrogen furnace, heat it to 600 degrees Celsius in a vacuum, feed hydrogen (hydrogen pressure 1 bar), keep feeding hydrogen and keep it warm for 10 hours.

[0062] 3. Stop the hydrogen flow in the hydrogen furnace, vacuumize (vacuum degree is less than 10-3Pa), raise the temperature to 750 degrees Celsius, keep the furnace for 10 hours, and then stop the furnace to cool.

[0063] 4. Turn on the hydrogen furnace, take out and open the mold, and take out the copper alloy product with a density gre...

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Abstract

The invention relates to a method for promoting the densification of metal blanks by utilizing the hydrogen absorption and expansion effect of metals. The hydrogen absorption expansion effect refers to that some metal blocks or metal powders absorb hydrogen to produce a volume expansion effect under a hydrogen atmosphere and a certain temperature. Under the constraints of a rigid die sleeve, the metal blanks to be densified are filled with hydrogen-absorbing metal. The volume expansion effect is produced by the hydrogen absorption of the metal, so that the internal pressure is applied to close the internal pores of the metal body, thereby increasing the density. The present invention provides a method for preparing high-density or fully-dense metal materials under medium and low temperature and hydrogen atmosphere. The method can be used as a new type of powder metallurgy densification technology, and can also be used to eliminate residual pores in metal materials to improve various properties of materials.

Description

technical field [0001] The invention relates to a method for densification of metals, alloys and metal-based composite materials; in particular, it relates to a method for increasing the densification of metal blanks by using the expansion effect of metal hydrogenation. Background technique [0002] During the processing of metal materials, certain pores are often generated inside the material. Shrinkage cavities and pores often exist in cast alloys. For powder metallurgy materials, there are residual pores in the sintered body of many material systems. According to reports, metal materials manufactured by additives will have tiny pores due to the influence of raw materials and processes. In the process of metal welding, micropores or air bubbles generated at the weld are serious defects. In addition, interfacial reactions may lead to porosity during the fabrication of metal composites. Pores in metal materials are one of the main defects that affect the performance of p...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/15
CPCB22F3/156Y02P10/25B33Y40/20B22F2999/00B22F2998/10B22F10/60B22F10/62B22F10/64B22F2201/013B22F2203/05B22F3/005B22F10/66B33Y10/00B22F10/00B22F2003/153
Inventor 周承商刘咏孙沛刘彬
Owner CENT SOUTH UNIV