A method for recycling waste titanium or titanium alloy powder from additive manufacturing

Abstract

The present invention relates to a method for recycling and processing waste titanium or titanium alloy powder by additive manufacturing. Add sodium amalgam to waste titanium or titanium alloy powder in additive manufacturing to obtain mixed slurry; step 2: perform a mixing operation on the mixed slurry obtained in step 1, so that the mixed slurry reaches a fluidized state; step 3: to step 3 2 Inert gas is introduced into the obtained mixed slurry in a fluidized state, and through the bubbles generated in the mixed slurry and the convection between the slurries, the shear friction between the titanium or titanium alloy powders is driven, and the slurry in the slurry is accelerated. Evaporation of the sodium amalgam to separate solid-phase titanium or titanium alloy powder; Step 4: Wash the titanium or titanium alloy powder obtained in Step 3, and then dry to obtain titanium or titanium alloy powder that can be used again for additive manufacturing.

Description

technical field [0001] The invention belongs to the technical field of metal powder waste treatment, and in particular relates to a recovery and treatment method for waste titanium or titanium alloy powder produced by additive manufacturing. Background technique [0002] Metal additive manufacturing is a manufacturing technology that uses lasers or electron beams as heat sources and metal powders that are preset or synchronously supplied as materials, which are deposited layer by layer on the substrate to form metal parts. Titanium and titanium alloys are the most widely used powders in the field of additive manufacturing. During the additive manufacturing process, titanium or titanium alloy powder that is not directly heated by the heat source will remain in the powder bed and continue to be used as raw materials. However, after repeated use of titanium or titanium alloy powder in the powder bed, due to repeated "heating-cooling", the sphericity decreases, sintering and bo...

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Problems solved by technology

[0005] However, although these powder processing methods, such as ball milling or gas agitation, can improve the hollow defects of the powder, they will inevitably lead to changes in the macroscopic shape of the powder such as collapse and cracking, so that the powder no longer has a spherical shape, which is not conducive to the reuse of the powder ; The gas stirring treatment reduces the fine satellite powder attached to the surface of the powder material without changing the macroscopic shape of the powder, but it cannot achieve the reduction of the powder impurity content, especially the oxygen content; the ultrasonic pickling method treats the titanium powder, although The surface morphology and composition of the powder can be improved at the same time, but due to the huge specific surface area of ​​the powder, it will make the reaction process difficult to control, and the treated titanium or titanium alloy powder will cause serious mass loss, and will also cause the powder Hydrogen absorption causes embrittlement in the pickling environment, and the original physical and chemical properties are lost; the active metal vapor reduction method reduces the oxygen content of the powder, and generally requires maintaining a high-temperature reaction environment, which will lead to sintering between powders and changes in powder morphology. At the same time, the high-temperature reaction environment will also cause the diffusion of active metal elements to the inside of the powder. Finally, the remaining active metals on the surface of the powder still need to be removed by pickling, which will inevitably cause the powder to absorb hydrogen and cause embrittlement.

[0006] From the above analysis, it can be seen that there is no mature recycling treatment method for the waste powder of additive manufacturing in China.

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