阅读说明：本技术 一种Ti6Al4V合金多孔材料的制备方法 (Preparation method of Ti6Al4V alloy porous material ) 是由 李安 马宽 唐洪奎 朱振 黄椿森 瞿宗宏 赖运金 王庆相 梁书锦 张平祥 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种Ti6Al4V合金多孔材料的制备方法,步骤为：步骤1对经PREP得到的Ti6Al4V粉末经过筛分进行分级,得到粘结或团聚的Ti6Al4V粉末；步骤2将步骤1得到粘结或团聚的Ti6Al4V粉末与细颗粒Ti6Al4V粉末进行混合；步骤3将步骤2所得混合后的粉末分批置于模具中。步骤4对步骤3中每一批粉末进行超声振实,直至填满整个模具：步骤5将模具置于真空烧结炉中进行烧结,得到多孔Ti6Al4V烧结件；步骤6将步骤5所得多孔Ti6Al4V烧结件进行喷砂处理获得Ti6Al4V多孔件成品。细颗粒粉末具有更高的活化能,烧结后会与粘结团聚粉末间在晶界扩散及表面扩散等效应下,孔隙缩小球化成规则球形及近球形孔隙,该类孔隙结构分布更规则性能更优。(The invention discloses a preparation method of a Ti6Al4V alloy porous material, which comprises the following steps: step 1, screening and grading the Ti6Al4V powder obtained by PREP to obtain bonded or agglomerated Ti6Al4V powder; step 2, mixing the bonded or agglomerated Ti6Al4V powder obtained in the step 1 with fine-particle Ti6Al4V powder; and 3, placing the mixed powder obtained in the step 2 in batches in a mould. And 4, performing ultrasonic compaction on each batch of powder in the step 3 until the whole die is filled: step 5, placing the die in a vacuum sintering furnace for sintering to obtain a porous Ti6Al4V sintered part; and 6, carrying out sand blasting treatment on the porous Ti6Al4V sintered piece obtained in the step 5 to obtain a finished Ti6Al4V porous piece. The fine particle powder has higher activation energy, and pores are shrunk and formed into regular spherical and nearly spherical pores with the sintering agglomerated powder under the effects of grain boundary diffusion, surface diffusion and the like, so that the pore structure distribution is more regular and the performance is better.)

1. A preparation method of a Ti6Al4V alloy porous material is characterized by comprising the following steps:

step 1, screening and grading the Ti6Al4V powder obtained by PREP to obtain bonded or agglomerated Ti6Al4V powder;

step 2, mixing the bonded or agglomerated Ti6Al4V powder obtained in the step 1 with fine-particle Ti6Al4V powder;

and 3, placing the mixed powder obtained in the step 2 in a mould in batches.

Step 4, performing ultrasonic compaction on each batch of powder in the step 3 until the whole die is filled;

step 5, placing the die in a vacuum sintering furnace for sintering to obtain a porous Ti6Al4V sintered part;

and 6, carrying out sand blasting on the porous Ti6Al4V sintered piece obtained in the step 5 to obtain a finished Ti6Al4V porous piece.

2. The preparation method of the Ti6Al4V alloy porous material, according to claim 1, characterized in that the powder obtained by classification in step 1 has a particle size of 75-180 μm, and argon is introduced for protection during the process.

3. The method for preparing the Ti6Al4V alloy porous material, according to claim 1, wherein the grain size of the fine Ti6Al4V powder in step 2 is 15-53 μm.

4. The method for preparing the Ti6Al4V alloy porous material, according to claim 1, wherein the mass ratio of the Ti6Al4V powder bonded or agglomerated in the step 2 to the fine Ti6Al4V powder is (70-90%): (10-30%) and the total amount is 100%, and uniformly mixing for 0.5-2 h in a mixer.

5. The method for preparing the Ti6Al4V alloy porous material, according to claim 1, wherein the laser particle size D50 of the powder mixed in the step 2 is 70-150 μm.

6. The preparation method of the Ti6Al4V alloy porous material according to claim 1, wherein the mold in the step 3 is selected according to specific needs and is divided into 5-10 batches, preferably a graphite mold with phi (10-30) x 30 mm.

7. The preparation method of the Ti6Al4V alloy porous material according to claim 1, wherein the ultrasonic frequency for tapping in the step 4 is 5-20 Hz, and the single vibration time is 3 min.

8. The preparation method of the Ti6Al4V alloy porous material according to claim 1, wherein the sintering temperature adopted in the step 5 is 900-1300 ℃, and the vacuum degree is lower than 10^-2And Pa, keeping the temperature for 1 hour, and then cooling along with the furnace.

Technical Field

The invention belongs to the technical field of metal material preparation, and relates to a preparation method of a Ti6Al4V alloy porous material.

Background

Sintered metal porous materials are generally prepared by pressing, high-temperature sintering and other processes based on metal powder, metal wire mesh or metal fibers. During powder sintering and forming, under the action of high temperature, atom vibration is aggravated and diffusion is accelerated, particles which are mainly in a point contact form are gradually transited to be in surface contact, bonding occurs among the particles, and then a sintering neck is formed. In the traditional sintering process, the sintering necks among the powders are often not well combined under the comprehensive action of factors such as temperature, pressure, friction force, arch bridge force and the like, and measures such as increasing the temperature, increasing the sintering pressure and the like are often adopted for good combination among the powders, but the porous piece is often densified.

Plasma Rotation Electrode Process (PREP) is one of the important preparation methods for high quality powder in the fields of current 3D printing, hot isostatic pressing, etc. Plasma arc is used as heat source to melt the alloy rod locally, and the molten liquid drop overcomes the melt viscosity under the action of centrifugal force and surface tension, separates from the Electrode rod and finally cools and solidifies into spherical alloy powder. However, in the process of powder preparation, because of the difference of energy and cooling speed among different powders, metal liquid drops can be mutually adsorbed, contacted, bonded or agglomerated under the impact of external force, and the liquid drops are in a conjoined or satellite shape after being cooled and solidified. The existence of this type of powder often causes the overall sphericity, fluidity, apparent density, tap density and other properties of the powder to be deteriorated, and further affects the properties and forming effect of the product.

Disclosure of Invention

The invention aims to provide a preparation method of a Ti6Al4V alloy porous material, which is characterized in that bonding or agglomeration-shaped Ti6Al4V alloy powder is used as a raw material to prepare the Ti6Al4V alloy porous material, so that the bonding or agglomeration-shaped powder is well utilized, and the material has the characteristics of good powder combination, high strength and the like.

The technical scheme adopted by the invention is a preparation method of a Ti6Al4V alloy porous material, which is implemented according to the following steps:

step 1, screening and grading the Ti6Al4V powder obtained by PREP to obtain bonded or agglomerated Ti6Al4V powder;

step 2, mixing the bonded or agglomerated Ti6Al4V powder obtained in the step 1 with fine-particle Ti6Al4V powder;

and 3, placing the mixed powder obtained in the step 2 in a mould in batches.

Step 4, performing ultrasonic compaction on each batch of powder in the step 3 until the whole die is filled;

step 5, placing the die in a vacuum sintering furnace for sintering to obtain a porous Ti6Al4V sintered part;

and 6, carrying out sand blasting on the porous Ti6Al4V sintered piece obtained in the step 5 to obtain a finished Ti6Al4V porous piece.

The invention is also characterized in that:

the powder obtained by grading in the step 1 has a particle size of 75-180 mu m, and argon is introduced for protection in the process.

In the step 2, the particle size of the fine Ti6Al4V powder is 15-53 mu m.

The mass ratio of the Ti6Al4V powder bonded or agglomerated in the step 2 to the fine-particle Ti6Al4V powder is (70-90%): (10-30%) and the total amount is 100%, and uniformly mixing for 0.5-2 h in a mixer.

The laser granularity D50 of the powder mixed in the step 2 is 70-150 μm.

And 3, selecting the mold according to specific requirements, and putting the mold into 5-10 batches, preferably selecting a graphite mold with phi (10-30) multiplied by 30 mm.

And 4, the ultrasonic frequency for compacting in the step 4 is 5-20 Hz, and the single vibration time is 3 min.

In the step 5, the sintering temperature is 900-1300 ℃, and the vacuum degree is lower than 10^-2And Pa, keeping the temperature for 1 hour, and then cooling along with the furnace.

The invention has the beneficial effects that:

the invention takes the bonding and agglomeration powder obtained by screening as the raw material, the powder has a certain degree of bonding necks preliminarily before sintering, further sintering is favorable for further growth of excellent sintering necks, and the porous piece prepared by the method has better mechanical property;

(2) adding a certain proportion of fine-grained particles for mixing and filling, so that excessive size pores between large-size bonded agglomerated powder are prevented from being left, and finally, the mechanical property of the finished piece is prevented from being deteriorated;

(3) the fine particle powder has higher activation energy, and pores are shrunk and formed into regular spherical and nearly spherical pores with the sintering agglomerated powder under the effects of grain boundary diffusion, surface diffusion and the like, so that the pore structure distribution is more regular and the performance is better.

Drawings

FIG. 1 is a SEM photograph of a normal PREP powder;

FIG. 2 is an SEM photograph of an agglomerated powder of PREP selected for use in the present invention;

FIG. 3 is a 20 μm surface metallographic structure photograph of the Ti6Al4V alloy porous material of the present invention;

FIG. 4 is a 50 μm surface metallographic structure photograph of the porous Ti6Al4V alloy material of the present invention.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.