CN110408815B - A low elastic modulus, high strength amplitude modulation decomposition type Zr-Nb-Ti alloy material and preparation method thereof - Google Patents

Abstract

The invention discloses an AM decomposition type Zr-Nb-Ti alloy material with low elastic modulus and high strength and a preparation method thereof. The Zr-Nb-Ti alloy material comprises the following components in atomic percentage: 20-50%; nb: 15-45%; the balance being Zr. The preparation method comprises the following steps: preparing a titanium source, a niobium source and a zirconium source according to a designed proportion; the Zr-Nb-Ti alloy material has higher strength and low elastic modulus, wherein the strength can reach 1130.8 +/-8.5 MPa to the maximum, and the elastic modulus is kept between 40 and 50GPa and is close to the elastic modulus of a human body.

Description

A low elastic modulus, high strength amplitude modulation decomposition type Zr-Nb-Ti alloy material and its preparation method

technical field

The invention belongs to the technical field of medical zirconium alloys, and in particular relates to a low elastic modulus and high strength amplitude modulation decomposition type Zr-Nb-Ti alloy material and a preparation method thereof.

technical background

In recent years, with the development of society and the improvement of human living standards, people's demand for safe and reliable biological graft materials is increasing. Therefore, the majority of scientific researchers have conducted in-depth research on implantable biological hard tissue materials. To develop alloys for human implants, it is first required that the alloys have excellent biocompatibility. The biocompatible alloying elements currently used in biomedical metal materials mainly include Ti, Zr, Nb, Ta, Mo, Sn, Mg, Zn, etc. Second, such alloys need to have high strength and excellent corrosion resistance. On this basis, the alloy also needs to have a lower elastic modulus so that it can match the elastic modulus of human bones (15-30 GPa). If the elastic modulus of the implant is too high, it will cause a "stress shielding effect", which will lead to premature failure or fracture of the implant, and ultimately have a serious impact on human health. Therefore, the mismatch of mechanical properties of implant alloy materials is an urgent problem to be solved.

It can be seen that the design and development of safe and reliable metal materials for human transplantation must be based on good biocompatibility and biomechanical compatibility. To make the alloy have good biomechanical compatibility, the alloy should have high strength and low elastic modulus, that is, a high δ (δ=σ _ys /E) value. At present, there are two main ways to achieve this goal: First, reduce the elastic modulus. Scholars at home and abroad have designed and prepared low elastic modulus alloys through alloy composition optimization. In addition, another effective way to reduce the elastic modulus of the alloy is to introduce a pore structure into the alloy to prepare a porous alloy. For example, the patent (CN 109847110A) provides a porous Ti-Nb-Zr composite artificial bone implant material and its preparation method and application. Through the introduction of a large number of holes, the elastic modulus of the alloy can be significantly reduced, but at the same time, it is also greatly reduced. Decreases the strength of the alloy. For dense alloy materials, the method to improve the strength of the alloy is mainly to refine the grains or precipitate the fine second phase through deformation heat treatment, so as to achieve the purpose of fine grain strengthening or second phase strengthening. However, high elastic modulus phases, such as α phase and ω phase, will be precipitated during the heat treatment of the alloy, resulting in the alloy exhibiting high elastic modulus. Therefore, how to solve the contradiction between high strength and low elastic modulus has become a hot issue in this research field.

Amplitude-modulated decomposition refers to a homogeneous phase transition in which a solid solution is destabilized or decomposed into two phases with different compositions and the same structure due to infinitely small composition fluctuations in the infinite/non-local area. From a thermodynamic point of view, when the second derivative of the Gibbs free energy with the composition is negative, phase separation occurs in the alloy system. Compared with the traditional phase transition, when the amplitude modulation decomposition occurs, the nucleation is not formed, and two phases with different components and the same structure are rapidly formed. The unique phase transition method of AM decomposition makes it have many excellent properties compared with the traditional nucleation and growth precipitation strengthening method. The AM structure is uniform and the corrosion resistance of the alloy is high. During the normal aging process, no over-aging or grain growth occurs; during the AM decomposition process, the excessive accumulation of dislocations does not occur, which can reduce the sensitivity of crack generation and prevent the formation of cracks. Delay crack propagation. Therefore, it has become an effective means of strengthening and toughening some engineering materials. More importantly, the amplitude modulation structure with little difference in composition and the same structure can ensure the low elastic modulus of the alloy and the strength is significantly improved.

SUMMARY OF THE INVENTION

Aiming at the problem that zirconium alloys in the prior art cannot achieve low elastic modulus and high strength at the same time, the purpose of the present invention is to provide a low elastic modulus, high strength amplitude modulation decomposition type Zr-Nb-Ti alloy material and its preparation method .

In order to achieve the above objects, the present invention adopts the following technical solutions. The present invention is an amplitude modulation decomposition type Zr-Nb-Ti alloy material with low elastic modulus and high strength, the composition of which is as follows in atomic percentage: Ti: 20-50%;

Aiming at the problem that the current zirconium alloy cannot achieve low elastic modulus and high strength at the same time, the present invention provides an amplitude modulation decomposition type zirconium alloy: Zr-Nb-Ti alloy material, the alloy has an amplitude modulation decomposition region within the above composition range ; and AM decomposition does not require nucleation, but quickly forms two phases with small uniform organization, the same crystal structure and different compositions. Therefore, the alloy can ensure a low elastic modulus while improving the strength of the alloy.

In a preferred solution, the composition of the Zr-Nb-Ti alloy material is as follows in atomic percentage: Ti: 30-35%; Nb: 30-35%; the balance is Zr.

Within the above preferred ranges, there must be an AM decomposition.

A method for preparing a low elastic modulus and high strength amplitude modulation decomposition type Zr-Nb-Ti alloy material of the present invention comprises the following steps: preparing a titanium source, a niobium source and a zirconium source according to a design ratio; and obtaining a zirconium alloy by smelting multiple times The ingot is cast, and the zirconium alloy ingot is suction-casted to obtain a zirconium alloy rod, and the zirconium alloy rod is sequentially subjected to solution treatment and aging treatment to obtain a Zr-Nb-Ti alloy material.

In the preparation method of the present invention, firstly, a zirconium alloy ingot with prepared and uniform composition is obtained by multiple smelting, but suction casting further increases the uniformity, and then a supersaturated solid solution of a zirconium alloy rod is obtained after solid solution treatment, and then an aging treatment is carried out. The material undergoes a homogeneous phase transformation to obtain an amplitude modulation decomposition phase. Since the solid solution and aging treatment in the present invention will not precipitate other phases with higher elastic modulus, such as α phase and ω equal, but without nucleation, two phases with different compositions and the same structure are quickly formed. . Therefore, in the normal aging process, no over-aging or grain growth will occur, but an amplitude-modulated structure with little difference in composition and the same structure, which can ensure a low elastic modulus of the alloy and a significant increase in strength.

In a preferred solution, the titanium source is selected from titanium particles with a purity of not less than 99.99%; the niobium source is selected from niobium particles with a purity of not less than 99.99%, and the zirconium source is selected from zirconium with a purity of not less than 99.99% grain.

In a preferred solution, the smelting current is 200-250 A, the single smelting suspension time is 60-90 s, and the smelting times are ≥4 times. More preferably, it is 6 times.

A zirconium alloy ingot with accurate and uniform composition can be obtained by smelting multiple times within the above process range.

In the actual operation process, both melting and suction casting are carried out in a vacuum arc melting furnace.

The suction casting process can ensure better uniformity of the zirconium alloy. If the ingot is directly used, there will still be some dendritic materials that make the material composition uneven. In order to solve this unevenness, it is necessary to increase the solution treatment time, which will lead to grain becomes larger and affects the material properties.

In a preferred solution, the temperature of the solution treatment is 850-950° C., and the holding time is 1-10 h.

As a further preference, the temperature of the solution treatment is 860-900° C., and the holding time is 3-6 hours.

In a preferred solution, the solution treatment is performed in a vacuum environment.

In a preferred solution, after the solution treatment and heat preservation are completed, the zirconium alloy rod is quenched in ice brine.

In the present invention, the solution treatment temperature will have a certain influence on the properties of the material. If the solution treatment temperature is too high, the grains will grow rapidly and affect the properties of the material. If the solution treatment temperature is too low, the solution treatment time will be prolonged, and rapid homogenization cannot be achieved. . In addition, rapid cooling and quenching in ice brine can ensure the retention of β phase, if the cooling rate is too slow, α and ω phases with higher elastic modulus will be precipitated.

In a preferred solution, the specific process of the solution treatment is as follows: sealing the zirconium alloy bar with a vacuum quartz tube, placing it in a heat treatment furnace for solution treatment, and then taking out the zirconium alloy bar and placing it in ice brine for quenching.

In the actual operation process, after the solution treatment is completed, the vacuum quartz tube is taken out and quickly smashed, so that the bar is dropped into the ice brine for quenching.

In a preferred solution, the temperature of the aging treatment is 500-600° C., and the holding time is 4-24 h.

As a further preference, the temperature of the aging treatment is 500-560° C., and the holding time is 4-14 hours.

In a preferred solution, the aging treatment is carried out in a vacuum environment.

In a preferred solution, after the aging treatment and heat preservation are completed, the zirconium alloy bar is placed in ice brine for cooling.

In the present invention, the aging treatment temperature will have a great influence on the performance of the material. If the aging temperature is not within the scope of the present invention, the AM decomposition phase cannot be precipitated, and at the same time, it needs to be cooled in ice brine, otherwise the precipitated AM decomposition phase cannot be retained. Mutually.

In a preferred solution, the aging treatment process is as follows: the solution-treated zirconium alloy rod is sealed with a vacuum quartz tube and then placed in a heat treatment furnace for aging treatment, and then the zirconium alloy rod is taken out and cooled in ice brine.

In the actual operation process, after the aging treatment is completed, the vacuum quartz tube is taken out and quickly crushed, so that the bar is dropped into the ice brine for cooling.

Beneficial effects:

The present invention is the first to provide a zirconium alloy material with an amplitude-modulated decomposition phase. On the one hand, through thermodynamic calculations and a large number of experiments, the material composition range with the amplitude-modulated decomposition phase has been obtained. In the process, the AM decomposition phase is formed. Amplitude-modulated decomposition does not require nucleation, but rapidly forms two phases with uniform organization, the same crystal structure and different compositions. Therefore, the alloy material obtained by the present invention can ensure a low elastic modulus while improving the strength of the alloy.

The zirconium alloy material obtained by the invention has higher strength and lower elastic modulus, wherein the maximum strength can reach 1130.8±8.5MPa, and the elastic modulus is maintained between 40-50GPa, which is relatively close to the elastic modulus of the human body.

The zirconium alloy material obtained by the invention is a Zr-Nb-Ti ternary alloy material. Compared with pure titanium, the zirconium alloy has good ductility, wear resistance, lower magnetic susceptibility, and a coordinated elastic modulus. It is expected to replace the currently used titanium-based implants and become a new type of bone replacement material in the next stage.

Description of drawings

Fig. 1 is the XRD pattern of each stage sample in embodiment 1;

Fig. 2 is the TEM bright-field image and the selected area diffraction pattern of the sample after aging in Example 1;

Fig. 3 is the compressive stress-strain curve of each stage sample in Example 1;

Fig. 4 is the TEM bright field image of the sample after aging in Example 2;

Fig. 5 is the compressive stress-strain curve of the sample after the aging treatment of Example 2;

6 is a TEM bright field image of the sample after aging in Example 3;

FIG. 7 is the compressive stress-strain curve of the sample after aging treatment in Example 3. FIG.

Detailed ways

The present invention will be described in further detail below with reference to examples and accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1

(1) Weighing: Weigh the raw materials: 30% Ti, 30% Nb, and Zr as the remainder according to the atomic percentage of the elements. Weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles respectively. The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 220A, and the melting suspension time is 65s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 900℃ for 3h, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. The quartz tube was sealed, placed in a tube furnace, heated to 500 °C for 4 hours, taken out and quickly smashed, and the rod was dropped into ice brine to cool.

Fig. 1 is the XRD pattern of the sample after solid solution and solid solution plus aging of Example 1. It can be seen from Fig. 1 that the phases of the alloy after solution treatment and solution treatment plus aging treatment are all β-phase, but it can be seen from the enlarged view that, Sideband peaks appeared after the alloy aging treatment, indicating that the alloy has an amplitude-modulated decomposition structure. Figure 2 is a bright-field image of the TEM image of the sample after solution and aging treatment, and an obvious amplitude modulation structure can be seen, and the size of the structure is nanoscale. From the selected area diffraction of the sample after solid solution and aging treatment in Fig. 2, it can be seen that there are obvious satellite diffraction spots. From Figure 2, it can be shown that there is an AM decomposition phase in the sample after aging treatment in Example 1. Compression tests are carried out on the samples at each stage in this example, and the compressive stress-strain curves are shown in Figure 3. It can be seen from the curve that the compressive yield strength of the sample after solution treatment is 795±8.5MPa, the elastic modulus is 40.8±1.3GPa, and the delta value is 0.019; the compressive yield strength of the sample after solution and aging treatment is 1130.8±8.5 MPa, the elastic modulus is 45.5±2.8GPa, and the delta value is 0.025, which is significantly improved compared with the solution treated sample; it can be seen that the yield strength of the sample after aging treatment increases significantly, while the elastic modulus still remains at lower range.

Example 2

(1) Weigh each component: Weigh the raw materials: 33% Ti, 31% Nb, and Zr as the remainder according to the atomic percentage of the elements, respectively weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles. . The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 200A, and the melting suspension time is 90s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 860°C for 6 hours, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. The quartz tube was sealed, placed in a tube furnace, heated to 560 °C for 14 hours, taken out and quickly smashed, and the rod was dropped into ice brine to cool.

The TEM bright-field image after aging treatment in this example is shown in Figure 4. The figure shows that there is an amplitude modulation structure. The compressive stress-strain curve of the sample after aging treatment is shown in Figure 5. It can be seen from Figure 5 that the compressive yield of the sample after aging treatment is shown in Figure 5. The strength is 998.9±8.5MPa, the elastic modulus is 46.3±2.1GPa, and the delta value is 0.022.

Example 3

(1) Weigh each component: Weigh the raw materials: 30% Ti, 30% Nb, and Zr as the remainder according to the atomic percentage of the elements, respectively weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles. . The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 230A, and the melting suspension time is 85s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 950℃ for 2h, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. In the aging treatment step, the solution-treated sample was The vacuum quartz tube was sealed, placed in a tube furnace, heated to 500 °C for 24 hours, and the quartz tube was taken out and quickly smashed, so that the bar was dropped into ice brine to cool.

The TEM bright-field image after aging treatment in this example is shown in Figure 6. The figure shows that there is an amplitude modulation decomposition phase. The compressive stress-strain curve of the sample after aging treatment is shown in Figure 7. It can be seen from Figure 7 that the compression of the sample after aging treatment The yield is 899.6±8.5MPa, the elastic modulus is 48.4±1.9GPa, and the δ value is 0.018. It may be due to the long-term heat preservation, the structure in the alloy grows and becomes thicker, resulting in a decrease in strength. Therefore, the δ value is relative to the solution treated sample. There is a slight decrease.

Comparative Example 1

(1) Weighing: Weigh the raw materials: according to the atomic percentage of the elements, the composition is made of 10% Ti, 10% Nb, and the balance is Zr. Weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles respectively. The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 220A, and the melting suspension time is 65s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 900℃ for 3h, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. The quartz tube was sealed, placed in a tube furnace, heated to 500 °C for 4 hours, taken out and quickly smashed, and the rod was dropped into ice brine to cool.

The composition of the material in this comparative example 1 is not within the corresponding range, so the zirconium alloy material obtained after solution + aging treatment has no amplitude modulation decomposition phase, its compressive yield is 780.6±5.5MPa, and its elastic modulus is 55.7±2.3GPa , the delta value is 0.014

Comparative Example 2

(1) Weighing: Weigh the raw materials: 30% Ti, 30% Nb, and Zr as the remainder according to the atomic percentage of the elements. Weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles respectively. The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 220A, and the melting suspension time is 65s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 900℃ for 3h, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. The quartz tube is sealed, placed in a tube furnace, heated to 400 °C for 4 hours, and the quartz tube is taken out and quickly smashed, so that the bar is dropped into ice brine to cool.

In this comparative example 2, since the aging treatment is not carried out in the corresponding temperature range, the amplitude modulation decomposition phase transformation cannot occur. The zirconium alloy material obtained after solid solution + aging treatment does not have the amplitude modulation decomposition phase, and the aging effect is small at a lower temperature. The precipitation of α phase and ω phase with higher elastic modulus increases the elastic modulus significantly. Its compressive yield is 950.9±7.3MPa, its elastic modulus is 77.6±1.2GPa, and its delta value is 0.012

Comparative Example 3

(1) Weighing: Weigh the raw materials: 30% Ti, 30% Nb, and Zr as the remainder according to the atomic percentage of the elements. Weigh high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles respectively. The purity of high-purity titanium particles, high-purity niobium particles, and high-purity zirconium particles is not less than 99.99%.

(2) Smelting: put the raw materials weighed in step (1) into a vacuum arc melting furnace for melting, the melting current is 220A, and the melting suspension time is 65s. In order to improve the accuracy and uniformity of the composition, the ingot needs to be smelted six times repeatedly to obtain the ingot.

(3) Suction casting: put the ingot obtained in step (2) into a vacuum arc melting furnace for suction casting to obtain a zirconium alloy rod.

(4) Microstructure control: carry out solution treatment on the suction-casting rod obtained in step (3), and in the solution-treatment step, the rod obtained by suction-casting is sealed with a vacuum quartz tube, and placed in a tubular heat treatment furnace, Heating to 900℃ for 3h, taking out the quartz tube and breaking it quickly, dropping the bar into ice brine for quenching, and then subjecting the solution-treated sample to aging treatment. The quartz tube was sealed, placed in a tube furnace, heated to 500 °C for 4 hours, and the quartz tube was taken out and crushed to cool the bar in air.

In this comparative example 3, the material is air-cooled after the aging treatment. During the air-cooling process, α phase and ω phase with higher elastic modulus will also be precipitated, but some amplitude modulation decomposition phases will remain in the material, so that the elastic modulus is not high. will increase more, its compressive yield is 966.9±7.3MPa, its elastic modulus is 64.6±1.2GPa, and its delta value is 0.014.

Claims (4)

1. a low elastic modulus, high-strength amplitude modulation decomposition type Zr-Nb-Ti alloy material, is characterized in that: its composition is as follows by atomic percentage: Ti: 30～35%; Nb: 30～35%; The amount of the zirconium alloy is Zr; the preparation method includes the following steps: preparing a titanium source, a niobium source and a zirconium source according to the designed proportion; obtaining a zirconium alloy ingot by smelting multiple times, performing suction casting of the zirconium alloy ingot to obtain a zirconium alloy rod; Zr-Nb-Ti alloy material is obtained by successively performing solution treatment and aging treatment on the zirconium alloy rod; the temperature of the solution treatment is 860~900°C, and the holding time is 3~6h. , the zirconium alloy bar is quenched in ice brine; the temperature of the aging treatment is 500~600℃, and the holding time is 4~24h; after the aging treatment is completed, the zirconium alloy bar is placed in the ice brine cool down. 2. The preparation method of Zr-Nb-Ti alloy material according to claim 1, is characterized in that: described smelting current is 200～250A, single smelting suspension time is 60～90s, and smelting times is ≥ 4 times. 3. the preparation method of Zr-Nb-Ti alloy material according to claim 1 is characterized in that: the concrete process of solution treatment is: the zirconium alloy bar is placed in a heat treatment furnace after being sealed by a vacuum quartz tube to carry out solidification. solution treatment, and then take out the zirconium alloy rod and place it in ice brine for quenching. 4. the preparation method of Zr-Nb-Ti alloy material according to claim 1, is characterized in that: described aging treatment process is, the zirconium alloy bar material after solution treatment adopts vacuum quartz tube to seal and is placed in heat treatment The aging treatment is carried out in the furnace, and then the zirconium alloy bars are taken out and cooled in ice brine.

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