阅读说明：本技术 一种高强度低弹性模量医用植入锆合金及制备方法 (High-strength low-elasticity-modulus medical implanted zirconium alloy and preparation method thereof ) 是由 陈锋 罗聪 武祥为 于 2020-05-20 设计创作，主要内容包括：本发明涉及一种高强度低弹性模量医用植入锆合金及制备方法,所述合金的组份及重量百分比为：Ti：36-40wt％；Nb：14-24wt％；O：0.10-0.30wt％；余量为Zr。合金制备的具体步骤是：采用高真空非自耗电弧炉熔炼获得成分的均匀合金铸锭,经热锻成棒材后在900℃-950℃固溶处理,水冷至室温；随后冷轧变形加工,变形量为80-90％；最后进行时效热处理,其加热温度为500-550℃,保温时间为8-16h。本发明锆合金的抗拉强度与目前应用最广的医用植入钛合金Ti-6Al-4V相当,而弹性模量仅为后者的55-61％,生物相容性和力学相容性更优异,可应用于制备生物医用植入体。(The invention relates to a medical implanted zirconium alloy with high strength and low elastic modulus and a preparation method thereof, wherein the alloy comprises the following components in percentage by weight: ti: 36-40 wt%; nb: 14-24 wt%; o: 0.10-0.30 wt%; the balance being Zr. The preparation method of the alloy comprises the following specific steps: smelting by adopting a high-vacuum non-consumable arc furnace to obtain a uniform alloy ingot with components, carrying out hot forging to obtain a bar, carrying out solution treatment at 900-950 ℃, and cooling to room temperature by water; then cold rolling deformation processing is carried out, and the deformation amount is 80-90%; finally, carrying out aging heat treatment, wherein the heating temperature is 500-550 ℃, and the heat preservation time is 8-16 h. The tensile strength of the zirconium alloy is equivalent to that of the medical implanted titanium alloy Ti-6Al-4V which is most widely applied at present, the elastic modulus is only 55-61% of the latter, the biocompatibility and the mechanical compatibility are more excellent, and the zirconium alloy can be applied to preparing biomedical implants.)

1. The medical implanted zirconium alloy with high strength and low elastic modulus is characterized by comprising the following components in percentage by weight:

Ti：36-40wt％；

Nb：14-24wt％；

O：0.10-0.30wt％；

the balance being Zr.

2. A method for preparing a high strength low elastic modulus medical implant zirconium alloy as claimed in claim 1, comprising the steps of:

the first step is as follows: based on the zirconium alloy composition, Zr, Ti, Nb, TiO₂Preparing the components according to the proportion;

the second step is that: repeatedly smelting the prepared raw materials in a magnetic stirring high-vacuum non-consumable electric arc furnace to obtain an ingot with uniform components;

the third step: hot forging the cast ingot into a bar, putting the bar into water for quenching and cooling after solution treatment;

the fourth step: turning to remove oxide skin on the surface of the bar, and then performing cold deformation processing at room temperature;

the fifth step: and placing the bar material in a quartz tube, vacuumizing and sealing, carrying out aging heat treatment in a heat treatment furnace, and then cooling to room temperature in the air to obtain the high-strength low-elasticity-modulus medical implanted zirconium alloy with the beta matrix and a small amount of submicron alpha precipitated phase.

3. The method for preparing a high-strength low-elastic-modulus medical zirconium-implanting alloy as claimed in claim 2, wherein the Zr, Ti, Nb, TiO is selected from Zr, Ti, Nb, and TiO₂The purity of the raw materials is more than 99.9 wt%.

4. The method for preparing the medical implanted zirconium alloy with high strength and low elastic modulus as claimed in claim 2, wherein the hot forging is carried out in air at a heating temperature of 600-700 ℃ and a deformation amount of 60-80%.

5. The method for preparing the medical implanted zirconium alloy with high strength and low elastic modulus as claimed in claim 2, wherein the solution treatment is performed at a heating temperature of 900-950 ℃ for 30-60 min.

6. The method for preparing a high-strength low-elastic-modulus medical implanted zirconium alloy as claimed in claim 2, wherein the cold deformation processing is carried out, and the deformation amount is 80-90%.

7. The method for preparing the high-strength low-elastic-modulus medical zirconium implantation alloy as claimed in the claim, wherein the aging heat treatment is performed at a heating temperature of 500-550 ℃ for a heat preservation time of 8-16 h.

Technical Field

The invention relates to a high-strength low-elasticity-modulus medical implanted zirconium alloy and a preparation method thereof, belonging to the technical field of zirconium alloy material design and preparation.

Background

In recent years, with the development of society and the improvement of living standard of human beings, the demand of safe and reliable biomedical implants is increasing. At present, titanium and its alloy are the first choice materials for repairing and replacing human hard tissues such as artificial joints and dental implants due to excellent mechanical properties and high corrosion resistance in body fluid environment. The common titanium-based implant material has Ti-6Al-4V, tensile strength of 895MPa-930MPa and elongation of about 10 percent, and is the most widely used implant material at present. But has problems that: (1) the alloy contains V, Al element harmful to human body, especially V has cytotoxicity, and has potential safety hazard in long-term use. (2) The elastic modulus (110GPa) of the alloy is far higher than the modulus (10-30GPa) of human skeleton, the serious mismatching of the elastic modulus causes the interface of an implant and the skeleton to generate stress shielding effect, and the long-term use causes bone absorption and osteoporosis, so that the implant is aseptically loosened, and the service life is shortened.

Elements with good biocompatibility with the human body include Nb, Ti, Zr, Ta, Mo, Sn, etc., wherein Zr is the most excellent. Relevant studies have shown that (Kuroda D, Niinomi M, Morinaga M, et al, Design and mechanical properties of new β type titanium alloys for implant materials, Mater Sci Eng A,1998,243(1-2):244-249), Zr is superior to Ti in terms of relative cell proliferation rate, and that the biocompatibility of Nb, Ti, Zr gradually increases, indicating that Zr is more favorable for the adhesion growth of bone cells. In addition, zirconium alloys also have superior corrosion resistance over titanium alloys, meaning that zirconium alloy implants have a longer service life in the human body.

Currently, research on biomedical zirconium-based alloys mainly focuses on obtaining high strength and simultaneously making the alloy have low elastic modulus so as to improve mechanical compatibility between an implant and human bones. Through the optimization of alloy components, a plurality of zirconium alloys with low elastic modulus are designed and prepared. The alloy designed by the patent (CN101984114A) has Zr (1-30) Ti (17-26) Nb, the elastic modulus in an as-cast state is 52-66GPa, the elongation is 5-15%, but the tensile strength is only 580-810MPa, and the strength is lower than that of Ti-6 Al-4V. The alloy designed by the patent (CN105274393B) has Zr (20.5-27) Ti (3.5-13.5) Nb (2.5-6.5) Sn, the elastic modulus in an as-cast state is 38-45GPa, the elongation is 6-13%, but the tensile strength is only 580-620MPa, and the alloy also does not meet the practical application requirement in the aspect of strength. Zr37Ti28Nb alloy is cold rolled and solution treated by the university of Membranaceae (regenerative Ozan, Jixing Lin, Yuncang Li, Deformationmechanization and biological properties of thermally processed beta Ti-28 Nb-35.4 Zr alloy, Journal of the Mechanical biology of biological Materials,2018,78:224 234), the alloy has a modulus of elasticity of 63GPa and an elongation of 13%, but has a tensile strength of only 633MPa and still has a low strength.

From the above, it can be seen that it is still difficult to obtain biomedical zirconium alloy with high strength, low elastic modulus and good plasticity.

Disclosure of Invention

The technical problem is as follows: the invention aims to provide a medical implanted zirconium alloy with high strength and low elastic modulus and a preparation method thereof. The zirconium alloy has the strength equivalent to that of the medical implanted titanium alloy Ti-6Al-4V which is most widely applied at present, has good plasticity, has the elastic modulus obviously lower than that of the medical implanted titanium alloy, has more excellent biocompatibility and mechanical compatibility, and can be applied to the preparation of biomedical implants.

The technical scheme is as follows: the invention relates to a high-strength low-elasticity-modulus biological planting zirconium alloy which comprises the following components in percentage by weight:

Ti：36-40wt％；

Nb：14-24wt％；

O：0.10-0.30wt％；

the balance being Zr.

The preparation method of the high-strength low-elasticity-modulus biological planting titanium alloy comprises the following steps of:

the first step is as follows: based on the zirconium alloy composition, Zr, Ti, Nb, TiO₂Preparing alloy for raw materials;

the second step is that: repeatedly smelting the prepared raw materials in a magnetic stirring high-vacuum non-consumable electric arc furnace to obtain an ingot with uniform components;

the third step: hot forging the cast ingot into a bar, putting the bar into water for quenching and cooling after solution treatment;

the fourth step: turning to remove oxide skin on the surface of the bar, and then performing cold deformation processing at room temperature;

the fifth step: and placing the bar material in a quartz tube, vacuumizing and sealing, carrying out aging heat treatment in a heat treatment furnace, and then cooling to room temperature in the air to obtain the high-strength low-elasticity-modulus medical implanted zirconium alloy with the beta matrix and a small amount of submicron alpha precipitated phase.

The Zr, Ti, Nb and TiO₂The purity of the raw materials is more than 99.9 wt%.

The hot forging is carried out in the air at the heating temperature of 600-700 ℃ and the deformation amount of 60-80%.

The solution treatment is carried out at the heating temperature of 900-950 ℃ and the heat preservation time of 30-60 min.

And the deformation amount of the cold deformation processing is 80-90%.

The aging heat treatment is carried out at the heating temperature of 500-550 ℃ and the heat preservation time of 8-16 h.

Has the advantages that:

1. according to the invention, by reasonably combining the contents of Zr, Ti and Nb, the alloy is ensured to be a single beta phase in a cold rolling state, and the beta phase has a lower elastic modulus. The beta matrix can be further strengthened by adding a proper amount of oxygen element (0.10-0.30 wt%) and precipitating a small amount of submicron alpha phase by aging heat treatment at the temperature of 500-550 ℃, and the influence on the elastic modulus is not great.

2. The obtained zirconium alloy has high tensile strength (1043-1137MPa) and yield strength (983-1073MPa), low elastic modulus (60-67GPa), good elongation (10.1-11.9%), tensile strength equivalent to that of the medical implanted titanium alloy Ti-6Al-4V which is most widely applied at present, elastic modulus of only 55-61% of the latter, excellent biocompatibility and mechanical compatibility, and can be applied to the preparation of biomedical implants.

3. The alloy of the invention can precipitate submicron alpha phase by aging heat treatment at 500-550 ℃, effectively eliminate internal stress and micro defects and obtain high strength and good plasticity. Compared with the existing as-cast or cold-rolled zirconium-based alloy, the implant of the alloy has higher fatigue strength or longer service life under the condition of the same tensile strength.

Drawings

FIG. 1 shows the XRD pattern of Zr14Nb40Ti0.2O alloy after aging for 8h at 550 ℃, and the alloy is mainly composed of beta phase, and the precipitation amount of alpha phase is very small (the height of alpha peak is very low).

FIG. 2 shows the microstructure of Zr14Nb40Ti0.2O alloy in a Scanning Electron Microscope (SEM) after aging at 550 ℃ for 8h, and a small amount of needle-like alpha phase with a size of less than 500nm is precipitated on the beta phase matrix.

FIG. 3 is a tensile stress-strain curve of Zr14Nb40Ti0.2O alloy after aging for 8h at 550 ℃.

Detailed Description

The invention designs and prepares the medical implanted zirconium alloy with high strength and low elastic modulus based on the following thought:

the invention relates to a high-strength low-elasticity-modulus biological planting zirconium alloy which comprises the following components in percentage by weight:

Ti：36-40wt％；

Nb：14-24wt％；

O：0.10-0.30wt％；

the balance being Zr.

O content in the O alloy. TiO 2₂Is a raw material, wherein 40 wt% of the raw material is O, 60 wt% of the raw material is Ti, O, Ti elements of the raw material enter the alloy during smelting, and the calculation is good during batching.

(1) The elastic modulus of beta-zirconium is low, and the elastic modulus of alpha-zirconium is high, so that a proper amount of beta stabilizing element Nb must be added to ensure that the alloy is a single beta phase in a cold rolling state, and a large amount of alpha phase can be inhibited from being precipitated when the alloy is aged at 500-550 ℃. The precipitation of a small amount of submicron alpha phase has obvious dispersion strengthening effect, and has little influence on the elastic modulus.

(2) Oxygen is an essential element for human body, and has good biocompatibility. In zirconium alloys, oxygen, as an interstitial element, can distort the lattice of beta zirconium and also refine the beta and alpha structure. The addition of a small amount of oxygen can improve the strength of the alloy, and has little influence on the elastic modulus.

(3) The fatigue strength of the implant is critical since it is to be in service in the human body for at least 20 years. By matching the cold rolling and high-temperature aging processes, the microstructure can be refined, the dispersed alpha phase (inhibiting crack propagation) can be separated out, the residual stress and the micro defects can be eliminated, the strength and the plasticity of the alloy can be improved, and the improvement of the fatigue strength of implantation or the service life of the implantation can be obviously facilitated.

For a further understanding of the invention, reference will now be made to the embodiments illustrated in the drawings, but it is to be understood that the description is intended to illustrate and describe further features and advantages of the invention, rather than to limit the scope of the appended claims.