阅读说明：本技术 一种可降解生物医用Zn-Al-Mg-Nd锌合金及其制备方法 (Degradable biomedical Zn-Al-Mg-Nd zinc alloy and preparation method thereof ) 是由 刘洋 王兴 朱戴博 李筱萱 华倩 邓晶晶 庄玉春 胡西艳 赵志雅 于 2019-11-11 设计创作，主要内容包括：一种可降解生物医用Zn-Al-Mg-Nd锌合金及其制备方法,它涉及一种可降解生物医用合金及其制备方法。本发明的目的是要解决现有生物医用Zn合金塑性变形能力较差,成材率低和传统金属熔炼铸造方法易产生气孔、缩松、成分偏析,导致变形能力差的问题。方法：一、真空熔炼；二、喷射沉积制坯；三、热挤压；四、热处理；五、酸洗与抛光；六、拉拔定尺；七、磨光；八、裁剪包装,得到可降解生物医用Zn-Al-Mg-Nd锌合金。本发明采用合适的合金元素及配比,提高Zn合金塑性变形能力,获得更优性能生物医用锌基合金。本发明可获得一种可降解生物医用Zn-Al-Mg-Nd锌合金。(A degradable biomedical Zn-Al-Mg-Nd zinc alloy and a preparation method thereof relate to a degradable biomedical alloy and a preparation method thereof. The invention aims to solve the problems that the existing biomedical Zn alloy has poor plastic deformation capability and low yield and the deformation capability is poor due to easy generation of pores, shrinkage porosity and component segregation in the traditional metal smelting and casting method. The method comprises the following steps: firstly, vacuum smelting; secondly, spraying, depositing and blank making; thirdly, hot extrusion; fourthly, heat treatment; fifthly, acid washing and polishing; sixthly, drawing and sizing; seventhly, polishing; eighthly, cutting and packaging to obtain the degradable biomedical Zn-Al-Mg-Nd zinc alloy. The invention adopts proper alloy elements and proportion to improve the plastic deformation capacity of the Zn alloy and obtain the biomedical zinc-based alloy with better performance. The invention can obtain the degradable biomedical Zn-Al-Mg-Nd zinc alloy.)

1. A degradable biomedical Zn-Al-Mg-Nd zinc alloy is characterized in that the degradable biomedical Zn-Al-Mg-Nd zinc alloy consists of the following components in percentage by mass: 1% -4%, Mg: 0.1% -1%, Nd: 0.05-2 percent, less than or equal to 0.43 percent of the sum of impurity elements and the balance of Zn.

2. The degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 1, wherein the degradable biomedical Zn-Al-Mg-Nd zinc alloy consists of, in terms of element mass fraction, Al: 1% -2%, Mg: 0.1% -0.5%, Nd: 0.05 to 0.15 percent, less than or equal to 0.43 percent of impurity element and the balance of Zn.

3. The degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 1, wherein the degradable biomedical Zn-Al-Mg-Nd zinc alloy consists of, in terms of element mass fraction, Al: 2% -4%, Mg: 0.5% -1%, Nd: 0.15 to 0.5 percent, less than or equal to 0.43 percent of impurity element and the balance of Zn.

4. The degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 1, wherein the degradable biomedical Zn-Al-Mg-Nd zinc alloy consists of, in terms of element mass fraction, Al: 4%, Mg: 0.5%, Nd: 0.05 percent, less than or equal to 0.43 percent of impurity element and the balance of Zn.

5. The preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 1, characterized in that the preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy is completed according to the following steps:

firstly, vacuum melting:

①, weighing:

according to the element mass fraction Al: 1% -4%, Mg: 0.1% -1%, Nd: 0.05-2 percent of pure Zn ingot, less than or equal to 0.43 percent of impurity element sum and the balance of Zn, and weighing pure Zn ingot, Mg-Nd intermediate alloy, Al-Mg intermediate alloy and pure Mg ingot;

②, preheating the graphite crucible at 190-210 ℃ for 20-40 min, and cleaning the hearth of the graphite crucible with argon before smelting;

③, heating the graphite crucible to 410-430 ℃, and then vacuumizing to 3 x 10^-3Pa, putting the weighed pure Zn ingot into a graphite crucible, heating the graphite crucible to 450-470 ℃, and then preserving heat for 30min at the temperature of 450-470 ℃;

④, adding the weighed Mg-Nd intermediate alloy, Al-Mg intermediate alloy and pure Mg ingot into a graphite crucible at the temperature of 450-470 ℃, heating the graphite crucible to 810-830 ℃, and then preserving heat at the temperature of 810-830 ℃ for 50-70 min to obtain a metal melt;

⑤, stirring the molten metal for 10min at the stirring speed of 50r/min to obtain a Zn-Al-Mg-Nd alloy melt with uniformly distributed alloy components;

⑥, introducing argon gas with 0.5 atmospheric pressure into the graphite crucible as protective gas;

secondly, spray deposition blank making:

①, the deposition chamber of the spray deposition device is at 10²In a vacuum low-pressure environment of Pa, circularly introducing argon gas of 0.1 Pa-0.5 Pa into the deposition chamber;

②, spraying Zn-Al-Mg-Nd alloy melt with uniformly distributed alloy components to a substrate disc of a water-cooled spray deposition device with the rotating speed of 10 r/min-300 r/min in the form of metal droplets through an atomization device of the spray deposition device;

③, enabling a substrate disc of the water-cooled spray deposition device to rotate at a constant speed at the rotating speed of 10 r/min-300 r/min to obtain a Zn-Al-Mg-Nd alloy round cast ingot with the diameter of 12 mm-20 mm;

thirdly, hot extrusion:

heating a Zn-Al-Mg-Nd alloy round cast ingot with the diameter of 12-20 mm to 250-350 ℃, and then carrying out hot extrusion under the conditions that the extrusion ratio is 40-70, the extrusion temperature is 250-350 ℃ and the extrusion speed is 0.5-2 m/min, so as to obtain a Zn-Al-Mg-Nd alloy capillary tube with the diameter of 3-5 mm and the wall thickness of 0.5-0.8 mm;

fourthly, heat treatment:

placing a Zn-Al-Mg-Nd alloy capillary tube with the diameter of 3-5 mm and the wall thickness of 0.5-0.8 mm in an argon atmosphere, and carrying out heat treatment at the temperature of 150-300 ℃ for 1-4 h to obtain a heat-treated Zn-Al-Mg-Nd alloy capillary tube;

fifthly, acid washing and polishing:

firstly, putting the Zn-Al-Mg-Nd alloy capillary tube subjected to heat treatment into a pickling solution for pickling for 5-30 min, then taking out the Zn-Al-Mg-Nd alloy capillary tube, respectively ultrasonically cleaning the Zn-Al-Mg-Nd alloy capillary tube for 5-10 min by using deionized water and absolute ethyl alcohol in sequence, and finally putting the Zn-Al-Mg-Nd alloy capillary tube into a tubular polishing machine for polishing to obtain the Zn-Al-Mg-Nd alloy capillary tube with the surface oxide layer removed;

sixthly, drawing and sizing:

putting the Zn-Al-Mg-Nd alloy capillary tube with the surface oxide layer removed into a combined drawing machine for cold drawing to obtain the Zn-Al-Mg-Nd alloy capillary tube with the diameter of 1.5-3.5 mm and the wall thickness of 0.2-0.3 mm;

seventhly, polishing:

polishing the Zn-Al-Mg-Nd alloy capillary tube with the diameter of 1.5-3.5 mm and the wall thickness of 0.2-0.3 mm to obtain the Zn-Al-Mg-Nd alloy capillary tube with a smooth surface;

eighthly, cutting and packaging:

cutting the Zn-Al-Mg-Nd alloy capillary tube with a smooth surface into required length by a straightening cutting machine to obtain the degradable biomedical Zn-Al-Mg-Nd zinc alloy, namely completing the preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy.

6. The method for preparing the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 5, wherein the graphite crucible is heated to 420-425 ℃ in the first step ③, and then is vacuumized to 3 x 10^-3Pa, putting the weighed pure Zn ingot into a graphite crucible, heating the graphite crucible to 460-465 ℃, and then preserving heat for 30min at the temperature of 460-465 ℃.

7. The preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 5, characterized in that in the first step ④, the weighed Mg-Nd intermediate alloy, Al-Mg intermediate alloy and pure Mg ingot are added into a graphite crucible with the temperature of 460 ℃ -465 ℃, then the temperature of the graphite crucible is heated to 820 ℃ -825 ℃, and then the temperature is kept at 820 ℃ -825 ℃ for 60 min-65 min, so as to obtain the metal melt.

8. The preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 5, characterized in that the preparation method comprises the third step of heating a round Zn-Al-Mg-Nd alloy ingot with the diameter of 12 mm-20 mm to 280-320 ℃, and then performing hot extrusion under the conditions of extrusion ratio of 40-70, extrusion temperature of 280-320 ℃ and extrusion rate of 0.6 m/min-1.2 m/min to obtain the Zn-Al-Mg-Nd alloy capillary with the diameter of 3.5 mm-4 mm and wall thickness of 0.5 mm.

9. The preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 5, characterized in that in the fourth step, the Zn-Al-Mg-Nd alloy capillary tube with the diameter of 3 mm-5 mm and the wall thickness of 0.5 mm-0.8 mm is placed in argon atmosphere, and is subjected to heat treatment at the temperature of 200 ℃ to 230 ℃ for 2h to 3h to obtain the heat-treated Zn-Al-Mg-Nd alloy capillary tube.

10. The method for preparing the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to claim 5, wherein the pickling solution in the fifth step is a mixed solution of 80 mass percent of phosphoric acid, ammonium bifluoride and deionized water; the concentration of phosphoric acid with the mass fraction of 80% in the pickling solution is 70 mL/L-90 mL/L, and the concentration of ammonium bifluoride is 40 g/L-60 g/L.

Technical Field

The invention relates to a degradable biomedical alloy and a preparation method thereof.

Background

The biological Zn alloy has a far-reaching development prospect as a novel biodegradable medical metal material. In 2015, pure zinc wires are implanted into an aortic cavity of the abdomen of an SD rat by Patrick K.Bowen and the like for 6.5 months, and the result shows that metal Zn has good biocompatibility and great potential for preparing a biomedical degradable vascular stent. Compared with various metal implant materials which are put into clinical use at present, the Zn alloy mainly has the following advantages: (1) the standard electrode potential (-0.76V) of Zn is between Mg (-2.73V) and Fe (-0.44V), and the corrosion degradation rate of Zn is between the standard electrode potential and the Fe (-2.73V), so that the defect of corrosion degradation rate of iron-based alloy and magnesium-based alloy can be effectively overcome. (2) Zn is a trace element necessary for human bodies, plays an important role in catalysis or construction in aspects of nucleic acid metabolism, neurotransmitter, protein synthesis, gene expression and the like, has the function of resisting atherosclerosis, can resist malignant cell proliferation, and prevents restenosis after stent implantation surgery. (3) Compared with Mg, Zn has lower melting point (420 ℃), and has lower reactivity in a molten state, low preparation cost and better mechanical property. However, pure zinc has poor mechanical properties, and cannot meet the current clinical requirements. Therefore, the addition of alloying elements to improve the mechanical property of zinc is very important for promoting the application of zinc alloy in the biomedical field.

At present, common biomedical Zn-Mg, Zn-Al pipes and the like are generally prepared by a metal smelting-processing-heat treatment method, and the main problems are as follows: by adopting the traditional metal smelting and casting method, the defects of air holes, shrinkage porosity, component segregation and the like are easily generated, and the subsequent deformability of the alloy is influenced by the defects. Meanwhile, zinc belongs to a close-packed hexagonal crystal structure, only 3 independent sliding systems exist at room temperature, and the plastic deformation capacity of the zinc alloy ingot is poor, so that the zinc alloy ingot prepared by smelting has poor plastic deformation capacity, the tube has to be prepared by multi-pass repeated extrusion and intermediate annealing, the yield is reduced, and the energy consumption is high. In order to solve the problems, the smelting preparation method is improved to prepare the cast ingot with fine and uniform crystal grains, the processing process flow of the material can be shortened, and the production efficiency is improved.

Disclosure of Invention

The invention aims to solve the problems of poor plastic deformation capability and low yield of the existing biomedical Zn alloy and poor deformation capability caused by easy generation of pores, shrinkage porosity and component segregation in the traditional metal smelting and casting method, and provides a degradable biomedical Zn-Al-Mg-Nd zinc alloy and a preparation method thereof.

A degradable biomedical Zn-Al-Mg-Nd zinc alloy is prepared from the following components in percentage by mass: 1% -4%, Mg: 0.1% -1%, Nd: 0.05-2 percent, less than or equal to 0.43 percent of the sum of impurity elements and the balance of Zn.

The preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy is completed according to the following steps:

firstly, vacuum melting:

①, weighing:

according to the element mass fraction Al: 1% -4%, Mg: 0.1% -1%, Nd: 0.05-2 percent of pure Zn ingot, less than or equal to 0.43 percent of impurity element sum and the balance of Zn, and weighing pure Zn ingot, Mg-Nd intermediate alloy, Al-Mg intermediate alloy and pure Mg ingot;

②, preheating the graphite crucible at 190-210 ℃ for 20-40 min, and cleaning the hearth of the graphite crucible with argon before smelting;

③, heating the graphite crucible to 410-430 ℃, and then vacuumizing to 3 x 10^-3Pa, putting the weighed pure Zn ingot into a graphite crucible, heating the graphite crucible to 450-470 ℃, and then preserving heat for 30min at the temperature of 450-470 ℃;

④, adding the weighed Mg-Nd intermediate alloy, Al-Mg intermediate alloy and pure Mg ingot into a graphite crucible at the temperature of 450-470 ℃, heating the graphite crucible to 810-830 ℃, and then preserving heat at the temperature of 810-830 ℃ for 50-70 min to obtain a metal melt;

⑤, stirring the molten metal for 10min at the stirring speed of 50r/min to obtain a Zn-Al-Mg-Nd alloy melt with uniformly distributed alloy components;

⑥, introducing argon gas with 0.5 atmospheric pressure into the graphite crucible as protective gas;

secondly, spray deposition blank making:

①, the deposition chamber of the spray deposition device is at 10²In a vacuum low-pressure environment of Pa, circularly introducing argon gas of 0.1 Pa-0.5 Pa into the deposition chamber;

②, spraying Zn-Al-Mg-Nd alloy melt with uniformly distributed alloy components to a substrate disc of a water-cooled spray deposition device with the rotating speed of 10 r/min-300 r/min in the form of metal droplets through an atomization device of the spray deposition device;

③, enabling a substrate disc of the water-cooled spray deposition device to rotate at a constant speed at the rotating speed of 10 r/min-300 r/min to obtain a Zn-Al-Mg-Nd alloy round cast ingot with the diameter of 12 mm-20 mm;

thirdly, hot extrusion:

heating a Zn-Al-Mg-Nd alloy round cast ingot with the diameter of 12-20 mm to 250-350 ℃, and then carrying out hot extrusion under the conditions that the extrusion ratio is 40-70, the extrusion temperature is 250-350 ℃ and the extrusion speed is 0.5-2 m/min, so as to obtain a Zn-Al-Mg-Nd alloy capillary tube with the diameter of 3-5 mm and the wall thickness of 0.5-0.8 mm;

fourthly, heat treatment:

placing a Zn-Al-Mg-Nd alloy capillary tube with the diameter of 3-5 mm and the wall thickness of 0.5-0.8 mm in an argon atmosphere, and carrying out heat treatment at the temperature of 150-300 ℃ for 1-4 h to obtain a heat-treated Zn-Al-Mg-Nd alloy capillary tube;

fifthly, acid washing and polishing:

firstly, putting the Zn-Al-Mg-Nd alloy capillary tube subjected to heat treatment into a pickling solution for pickling for 5-30 min, then taking out the Zn-Al-Mg-Nd alloy capillary tube, respectively ultrasonically cleaning the Zn-Al-Mg-Nd alloy capillary tube for 5-10 min by using deionized water and absolute ethyl alcohol in sequence, and finally putting the Zn-Al-Mg-Nd alloy capillary tube into a tubular polishing machine for polishing to obtain the Zn-Al-Mg-Nd alloy capillary tube with the surface oxide layer removed;

sixthly, drawing and sizing:

putting the Zn-Al-Mg-Nd alloy capillary tube with the surface oxide layer removed into a combined drawing machine for cold drawing to obtain the Zn-Al-Mg-Nd alloy capillary tube with the diameter of 1.5-3.5 mm and the wall thickness of 0.2-0.3 mm;

seventhly, polishing:

polishing the Zn-Al-Mg-Nd alloy capillary tube with the diameter of 1.5-3.5 mm and the wall thickness of 0.2-0.3 mm to obtain the Zn-Al-Mg-Nd alloy capillary tube with a smooth surface;

eighthly, cutting and packaging:

cutting the Zn-Al-Mg-Nd alloy capillary tube with a smooth surface into required length by a straightening cutting machine to obtain the degradable biomedical Zn-Al-Mg-Nd zinc alloy, namely completing the preparation method of the degradable biomedical Zn-Al-Mg-Nd zinc alloy.

The principle and the advantages of the invention are as follows:

the invention provides a degradable biomedical Zn-Al-Mg-Nd zinc alloy which is prepared from the following components in percentage by mass: 1% -4%, Mg: 0.1% -1%, Nd: 0.05-2 percent of the alloy, less than or equal to 0.43 percent of the sum of impurity elements and the balance of Zn, wherein the addition of Al can improve the casting performance of the alloy, increase the fluidity of the alloy, refine crystal grains, cause solid solution strengthening and improve the mechanical performance, and the introduction of Mg can improve the mechanical performance of zinc-based alloy to a great extent;

secondly, the invention adopts proper alloy elements and proportion, improves the microstructure of the Zn alloy by adding Al, Mg, Nd and other elements, improves the plastic deformation capacity of the Zn alloy, and can regulate the corrosion rate by controlling the content of the added elements to obtain the biomedical zinc-based alloy with better performance;

the preparation method of the alloy is improved, the cooling speed is increased, the defects of alloy segregation and the like caused by the traditional casting process are reduced, the ductility and toughness of the Zn alloy are improved, and the material yield is improved;

the method adopts the spray deposition to prepare the ingot blank, can reduce the problems of alloy segregation and the like caused by the traditional casting process compared with the traditional metal casting method, and obtains the ingot blank with fine crystal grains, uniform tissue and near isotropy, thereby enabling the adoption of a large extrusion ratio in the subsequent extrusion deformation process, reducing the extrusion deformation times, improving the processing and hardening effects of alloy materials, obtaining the pipe with fine crystal grains and uniform tissue, improving the production efficiency, and saving the preparation cost and loss;

by improving the quality of the cast ingot, the extrusion ratio of subsequent extrusion deformation can be improved, the preparation process is shortened, and the production efficiency is improved;

sixthly, the drawing strength of the degradable biomedical Zn-Al-Mg-Nd zinc alloy prepared by the invention is 320-385 MPa, the yield strength is 273-350 MPa, the elongation is 22-32%, and the corrosion rate (Hank's solution) is 0.00010 g-cm^-2·d^-1～0.00022g·cm^-2·d^-1。

The invention can obtain the degradable biomedical Zn-Al-Mg-Nd zinc alloy.

Drawings

FIG. 1 is a schematic view of a spray deposition apparatus according to the second step of the embodiment, in which FIG. 1 is a graphite crucible, FIG. 2 is an atomizing apparatus, FIG. 3 is a deposition chamber, FIG. 4 is a base disk, FIG. 5 is a water cooling apparatus, and FIG. 6 is an exhaust port;

fig. 2 is a flow chart of the preparation process of the degradable biomedical Zn-Al-Mg-Nd zinc alloy according to the first embodiment.

Detailed Description