1. The low-elastic-modulus zirconium alloy is characterized by comprising, by mass, 0.5-45% of Nb0.5-5% of Hf0.5-5% of Zr and the balance of Zr.

2. The low elastic modulus zirconium alloy according to claim 1, comprising Nb 10-45%, Hf0.5-5%, and the balance Zr.

3. A method of making the low elastic modulus zirconium alloy of claim 1 or 2, comprising the steps of:

smelting the alloy raw materials to obtain an as-cast alloy blank; the composition of the alloy raw material is determined according to the composition of the low-elasticity-modulus zirconium alloy;

carrying out cold rolling deformation on the as-cast alloy blank to obtain a rolled plate;

and carrying out solution treatment on the rolled plate to obtain the low-elasticity-modulus zirconium alloy.

4. The production method according to claim 3, wherein the melting is vacuum arc melting, and the temperature of the vacuum arc melting is 1900-2100 ℃.

5. The preparation method according to claim 3, wherein the number of times of smelting is more than 5, and the time of each smelting is 3-5 min.

6. The production method according to claim 3, wherein the total deformation amount of the cold rolling deformation is 75 to 85%.

7. The method of claim 3, wherein the cold rolling deformation is a multiple pass rolling with a 5% deformation per pass.

8. The method according to claim 3, wherein the temperature of the solution treatment is 850 to 900 ℃.

9. The production method according to claim 3 or 8, wherein the heat-retaining time of the solution treatment is 20 to 40 min.

10. The production method according to claim 3 or 8, wherein the solution treatment is performed by water cooling.

Background

With the development of society and the improvement of living standard of human beings, people increasingly demand safe and reliable biological transplantation materials. Zirconium alloy has great application potential in the aspect of medical metal materials as an alloy material with excellent biocompatibility. In addition to biocompatibility, medical metals require a low elastic modulus to match the elastic modulus of human bones (15-30 GPa). The existing zirconium alloy can not meet the requirement of low elastic modulus.

Disclosure of Invention

The invention aims to provide a zirconium alloy with low elastic modulus and a preparation method thereof.

In order to achieve the above object, the present invention provides the following technical solutions:

the invention provides a low-elasticity-modulus zirconium alloy which comprises, by mass, 0.5-45% of Nb, 0.5-5% of Hf0.5-5% of Zr and the balance of Zr.

Preferably, the alloy comprises 10-45% of Nb, 0.5-5% of Hf0.5 and the balance of Zr.

The invention provides a preparation method of the low-elasticity-modulus zirconium alloy, which comprises the following steps of:

smelting the alloy raw materials to obtain an as-cast alloy blank; the composition of the alloy raw material is determined according to the composition of the low-elasticity-modulus zirconium alloy;

carrying out cold rolling deformation on the as-cast alloy blank to obtain a rolled plate;

and carrying out solution treatment on the rolled plate to obtain the low-elasticity-modulus zirconium alloy.

Preferably, the smelting is vacuum arc smelting, and the temperature of the vacuum arc smelting is 1900-2100 ℃.

Preferably, the smelting times are more than 5 times, and the time of each smelting is 3-5 min.

Preferably, the total deformation of the cold rolling deformation is 75-85%.

Preferably, the cold rolling deformation is multi-pass rolling, and the deformation of each pass of rolling is 5%.

Preferably, the temperature of the solution treatment is 850-900 ℃.

Preferably, the heat preservation time of the solution treatment is 20-40 min.

Preferably, the solution treatment is performed by water cooling.

The invention provides a low-elasticity-modulus zirconium alloy which comprises, by mass, 0.5-45% of Nb, 0.5-5% of Hf0.5-5% of Zr and the balance of Zr. According to the invention, the elasticity modulus of the zirconium alloy can be reduced by adding a proper amount of Nb element into the zirconium alloy.

Further, when the addition amount of Nb element is more than 1%, the zirconium alloy of the present invention is composed of β crystal grains, and the elastic modulus of β phase is lower than that of α phase. The results of the examples show that the elastic modulus of the zirconium alloy prepared by the invention is reduced and can reach 43GPa at the lowest.

Drawings

FIG. 1 is a TEM micrograph of a zirconium alloy obtained in example 1;

FIG. 2 is a metallographic optical micrograph of a zirconium alloy obtained in example 2;

FIG. 3 is a metallographic optical micrograph of a zirconium alloy obtained in example 3;

FIG. 4 is a metallographic optical micrograph of a zirconium alloy obtained in example 4;

FIG. 5 is a metallographic optical micrograph of a zirconium alloy obtained in example 5;

FIG. 6 is a TEM micrograph of a zirconium alloy obtained in comparative example 1;

FIG. 7 is a graph of the dimensions of tensile specimens tested for tensile properties in accordance with the present invention.

Detailed Description

The invention provides a low-elasticity-modulus zirconium alloy which comprises, by mass, 0.5-45% of Nb, 0.5-5% of Hf0.5-5% of Zr and the balance of Zr.

The low-elastic-modulus zirconium alloy comprises, by mass, 0.5-45% of Nb, preferably 10-45%, more preferably 15-45%, and even more preferably 20-45%. According to the invention, the elastic modulus of the zirconium alloy can be reduced by adding a proper amount of Nb element.

The low-elasticity-modulus zirconium alloy comprises, by mass, 0.5-5% of Hf0, preferably 1-4%, and more preferably 2-3%.

In the invention, when the Nb content is more than 1% and less than or equal to 45%, the low-elasticity-modulus zirconium alloy consists of equiaxed beta grains, and the grain size of the equiaxed beta grains is preferably 5-25 μm; the beta phase has a lower elastic modulus than the alpha phase.

The invention provides a preparation method of the low-elasticity-modulus zirconium alloy, which comprises the following steps of:

smelting the alloy raw materials to obtain an as-cast alloy blank; the composition of the alloy raw material is determined according to the composition of the low-elasticity-modulus zirconium alloy;

carrying out cold rolling deformation on the as-cast alloy blank to obtain a rolled plate;

and carrying out solution treatment on the rolled plate to obtain the low-elasticity-modulus zirconium alloy.

The invention carries out smelting on alloy raw materials to obtain an as-cast alloy blank.

The invention is not limited to the kind of the alloy raw material, and the alloy raw material well known to those skilled in the art is used to obtain the zirconium alloy with the target composition. In the present invention, the alloy raw material preferably includes sponge zirconium and niobium wire; hf is attached to the sponge zirconium. The invention has no special limit on the proportion of various alloy raw materials, and the final alloy components can meet the requirements.

Before smelting, the alloy raw materials are preferably subjected to ultrasonic cleaning in an alcohol solution; the present invention does not require any particular embodiment of the ultrasonic cleaning, and may be performed in a manner known to those skilled in the art.

In the invention, the smelting is preferably vacuum arc smelting, and the temperature of the vacuum arc smelting is preferably 1900-2100 ℃, and more preferably 2000-2050 ℃. In the invention, the vacuum degree of the vacuum arc melting is preferably 0.04-0.05 MPa, and the vacuum arc melting is preferably carried out in the presence of argon as a shielding gasThe reaction is carried out under bulk conditions. When vacuum arc melting is adopted, the invention preferably firstly pumps the vacuum degree in the furnace chamber to 8 x 10^-3Introducing argon gas below Pa; the introduction amount of the argon is enough to satisfy the amount of the ionized gas for arc melting. In the invention, the current of the vacuum arc melting is preferably 400-450A, and more preferably 420-435A. The present invention does not require special embodiments of the vacuum arc melting process, as will be appreciated by those skilled in the art. The invention adopts the mode of firstly vacuumizing and then introducing argon gas, can firstly avoid a large amount of oxygen absorption and nitrogen absorption of Zr under the condition of high temperature, and can also provide ionized gas for electric arc melting. In the invention, the smelting times are preferably more than 5 times, and more preferably 6-10 times; the time of each smelting is preferably 3-5 min. In the present invention, when the melting is repeatedly performed, the melting is preferably performed in a vacuum arc furnace; specifically, the method comprises the following steps: smelting the alloy raw materials in an electric arc smelting furnace to obtain a smelting solution; and then cooling to obtain a casting blank, turning over the casting blank, smelting, and obtaining a smelting solution again, wherein the process is repeated for more than 5 times to ensure that the obtained as-cast alloy blank has uniform components.

During smelting, the smelting liquid forms a beta-phase blank in the solidification process.

After the as-cast alloy blank is obtained, the as-cast alloy blank is subjected to cold rolling deformation to obtain a rolled plate.

In the invention, the total deformation amount of the cold rolling deformation is preferably 75-85%, and more preferably 78-82%. In the invention, the cold rolling deformation is preferably multi-pass rolling, and the deformation amount of each pass of rolling is preferably 5%.

The invention has no special requirement on the rolling times of the multi-pass rolling so as to finish the target deformation. The present invention does not require special embodiments of the rolling deformation, and can be implemented as is well known to those skilled in the art.

The cold rolling deformation can deform and elongate the original beta grains, accumulate dislocation and provide storage energy for the next solid solution treatment.

After the rolled plate is obtained, the invention carries out solution treatment on the rolled plate to obtain the low-elasticity-modulus zirconium alloy.

In the invention, the temperature of the solution treatment is preferably 850-900 ℃, and more preferably 860-880 ℃; the heat preservation time is preferably 20-40 min, and more preferably 25-35 min. In the present invention, the solution treatment is preferably performed under a protective atmosphere, and the protective atmosphere is preferably an argon protective atmosphere. In the present invention, the solution treatment is preferably performed by water cooling.

According to the invention, the alloy in a cold rolling state can be effectively recovered and recrystallized through solution treatment, and an equiaxial beta-phase structure with fine grain size is obtained.

After the solution treatment, the invention preferably further comprises removing the surface scale from the obtained cold alloy to obtain the low elastic modulus zirconium alloy. The invention preferably adopts a grinding mode to remove the surface scale.

The low elastic modulus zirconium alloy provided by the present invention, the preparation method and the application thereof are described in detail with reference to the following examples, but they should not be construed as limiting the scope of the present invention.

Example 1

Preparing materials according to the mass percent of Zr-1Nb, soaking industrial-grade sponge zirconium (Zr and Hf are not separated) and niobium wire (the purity is 99.9%) in absolute ethyl alcohol, ultrasonically cleaning, air-drying, placing into a water-cooled copper crucible of non-consumable vacuum arc melting, and pumping the vacuum degree in a furnace chamber to 8 x 10^-3Pa or less. Introducing high-purity argon as a protective gas (the vacuum degree is 0.04-0.05 MPa) before arc melting, wherein the arc temperature is 2000 ℃ during each melting, the time for each melting is 4 minutes, the uniformity of the components is ensured, cooling is carried out after each melting to obtain an ingot, then the ingot is subjected to turnover treatment for melting, and the ingot is repeatedly melted by the melting-casting and is turned over for 6 times to ensure the uniformity of the components of the finally obtained as-cast alloy blank.

The obtained as-cast alloy slab having a thickness of 15mm was cold-rolled on a rolling mill at a rolling reduction of 0.75mm per pass to finally obtain a rolled sheet having a thickness of 3mm (corresponding to a strain of 5% per pass and a total strain of 80%).

And putting the obtained rolled plate into a vacuum tube furnace (SK-G06143 Zhonghuan experimental electric furnace Co., Ltd. in Tianjin), carrying out solution treatment in an argon atmosphere, controlling the heat preservation temperature of the solution treatment to be 870 ℃ and the heat preservation time to be 30min, then cooling the rolled plate to room temperature by water, taking the cooled rolled plate out, polishing the oxide skin on the surface of the prepared alloy thin plate, cleaning the oxide skin, and air-drying the oxide skin to finally obtain the zirconium alloy.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and found to be Zr-0.98Nb-3.2 Hf.

The zirconium alloy obtained in this example was subjected to TEM microstructure observation, and as a result, as shown in FIG. 1, the zirconium alloy obtained in this example had a typical martensite structure and had a lath size of about 0.2. mu.m.

Example 2

Preparing materials according to the mass percent of Zr-10Nb, soaking industrial-grade sponge zirconium (Zr and Hf are not separated) and niobium wire (99.9%) in absolute ethyl alcohol, ultrasonically cleaning, air-drying, placing into a water-cooled copper crucible of non-consumable vacuum arc melting, and pumping the vacuum degree in a furnace chamber to 8 x 10^-3Pa or less. Introducing high-purity argon as a protective gas (the vacuum degree is 0.04-0.05 MPa) before arc melting, wherein the arc temperature is 2000 ℃ during each melting, the time for each melting is 4 minutes, the uniformity of the components is ensured, cooling is carried out after each melting to obtain an ingot, then the ingot is subjected to turnover treatment for melting, and the ingot is repeatedly melted by the melting-casting and is turned over for 6 times to ensure the uniformity of the components of the finally obtained as-cast alloy blank.

The obtained as-cast alloy slab having a thickness of 15mm was cold-rolled on a rolling mill at a reduction of 0.75mm per pass to finally obtain a rolled sheet having a thickness of 3mm (corresponding to a strain of 5% per pass and a total strain of 80%).

And putting the obtained rolled plate into a vacuum tube furnace (SK-G06143 Zhonghuan experimental electric furnace Co., Ltd. in Tianjin), carrying out solution treatment in an argon atmosphere, controlling the heat preservation temperature of the solution treatment to be 870 ℃ and the heat preservation time to be 30min, then cooling the rolled plate to room temperature by water, taking the cooled rolled plate out, polishing the oxide skin on the surface of the prepared alloy thin plate, cleaning the oxide skin, and air-drying the oxide skin to finally obtain the zirconium alloy.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and was Zr-10.04Nb-2.6 Hf.

Metallographic structure observation of the zirconium alloy obtained in this example showed that the zirconium alloy obtained in this example had a typical equiaxed β -phase structure and a grain size of 20 μm, as shown in fig. 2.

Example 3

Preparing materials according to the mass percent of Zr-20Nb, soaking industrial-grade sponge zirconium (Zr and Hf are not separated) and niobium wire (99.9%) in absolute ethyl alcohol, ultrasonically cleaning, air-drying, placing into a water-cooled copper crucible of non-consumable vacuum arc melting, and pumping the vacuum degree in a furnace chamber to 8 x 10^-3Pa or less. Introducing high-purity argon as a protective gas (the vacuum degree is 0.04-0.05 MPa) before arc melting, wherein the arc temperature is 2000 ℃ during each melting, the time for each melting is 4 minutes, the uniformity of the components is ensured, cooling is carried out after each melting to obtain an ingot, then the ingot is subjected to turnover treatment for melting, and the ingot is repeatedly melted by the melting-casting and is turned over for 6 times to ensure the uniformity of the components of the finally obtained as-cast alloy blank.

The obtained as-cast alloy slab having a thickness of 15mm was cold-rolled on a rolling mill at a reduction of 0.75mm per pass to finally obtain a rolled sheet having a thickness of 3mm (corresponding to a strain of 5% per pass and a total strain of 80%).

And putting the obtained rolled plate into a vacuum tube furnace (SK-G06143 Zhonghuan experimental electric furnace Co., Ltd. in Tianjin), carrying out solution treatment in an argon atmosphere, controlling the heat preservation temperature of the solution treatment to be 870 ℃ and the heat preservation time to be 30min, then cooling the rolled plate to room temperature by water, taking the cooled rolled plate out, polishing the oxide skin on the surface of the prepared alloy thin plate, cleaning the oxide skin, and air-drying the oxide skin to finally obtain the zirconium alloy.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and was Zr-20.1Nb-2.1 Hf.

Metallographic structure observation of the zirconium alloy obtained in this example showed that the zirconium alloy obtained in this example had a typical equiaxed β -phase structure and a grain size of 16 μm, as shown in fig. 3.

Example 4

Preparing materials according to the mass percent of Zr-30Nb, soaking industrial-grade sponge zirconium (Zr and Hf are not separated) and niobium wire (99.9%) in absolute ethyl alcohol, ultrasonically cleaning, air-drying, placing into a water-cooled copper crucible of non-consumable vacuum arc melting, and pumping the vacuum degree in a furnace chamber to 8 x 10^-3Pa or less. Introducing high-purity argon as a protective gas (the vacuum degree is 0.04-0.05 MPa) before arc melting, wherein the arc temperature is 2000 ℃ during each melting, the time for each melting is 4 minutes, the uniformity of the components is ensured, cooling is carried out after each melting to obtain an ingot, then the ingot is subjected to turnover treatment for melting, and the ingot is repeatedly melted by the melting-casting and is turned over for 6 times to ensure the uniformity of the components of the finally obtained as-cast alloy blank.

The obtained as-cast alloy slab having a thickness of 15mm was cold-rolled on a rolling mill at a reduction of 0.75mm per pass to finally obtain a rolled sheet having a thickness of 3mm (corresponding to a strain of 5% per pass and a total strain of 80%).

And putting the obtained rolled plate into a vacuum tube furnace (SK-G06143 Zhonghuan experimental electric furnace Co., Ltd. in Tianjin), carrying out solution treatment in an argon atmosphere, controlling the heat preservation temperature of the solution treatment to be 870 ℃ and the heat preservation time to be 30min, then cooling the rolled plate to room temperature by water, taking the cooled rolled plate out, polishing the oxide skin on the surface of the prepared alloy thin plate, cleaning the oxide skin, and air-drying the oxide skin to finally obtain the zirconium alloy.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and was Zr-29.94Nb-1.8 Hf.

Metallographic structure observation of the zirconium alloy obtained in this example showed that the zirconium alloy obtained in this example had a typical equiaxed β -phase structure and a grain size of 14 μm, as shown in fig. 4.

Example 5

Preparing materials according to the mass percent of Zr-45Nb, soaking industrial-grade sponge zirconium (Zr and Hf are not separated) and niobium wire (99.9%) in absolute ethyl alcohol, ultrasonically cleaning, air-drying, placing into a water-cooled copper crucible of non-consumable vacuum arc melting, and pumping the vacuum degree in a furnace chamber to 8 x 10^-3Pa or less. Introducing high-purity argon as protective gas before arc meltingThe vacancy is 0.04-0.05 MPa), the arc temperature is 2000 ℃ during each smelting, the time for each smelting is 4 minutes, the uniformity of the components is ensured, the ingot is obtained by cooling after each smelting, the ingot is smelted by turning over, and the finally obtained as-cast alloy blank is ensured to have uniform components by repeatedly smelting-casting the ingot and turning over the ingot for 6 times.

The obtained as-cast alloy slab having a thickness of 15mm was cold-rolled on a rolling mill at a rolling reduction of 0.75mm per pass to finally obtain a rolled sheet having a thickness of 3 mm.

And putting the obtained rolled plate into a vacuum tube furnace (SK-G06143 Zhonghuan experimental electric furnace Co., Ltd., Tianjin) for solution treatment in an argon atmosphere, controlling the heat preservation temperature of the solution treatment to be 870 ℃ and the heat preservation time to be 30min, then cooling the rolled plate to room temperature by water, taking the rolled plate out, polishing the oxide skin on the surface of the prepared alloy thin plate, cleaning the oxide skin, and air-drying the oxide skin to finally obtain the zirconium alloy.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and found to be Zr-44.8Nb-1.1 Hf.

Metallographic structure observation of the zirconium alloy obtained in this example showed that the zirconium alloy obtained in this example had a typical equiaxed β -phase structure and a grain size of 10 μm, as shown in fig. 5.

Comparative example 1

The alloy composition was prepared as a pure Zr alloy in the manner of example 1.

The composition of the obtained zirconium alloy was measured by sampling (ICP-OES method) and was Zr-3.48 Hf.

As a result of TEM observation of the zirconium alloy obtained in comparative example 1, the zirconium alloy obtained in this example had a typical martensite structure and had a martensite lath width of about 0.7. mu.m, as shown in FIG. 6.

Tensile specimens (national standard: GBT228-2002) such as those shown in FIG. 7 (in FIG. 7, each dimension is in mm) were cut out by wire cutting from the zirconium alloys of examples 1 to 5 and comparative example 1. At least 5 tensile specimens were cut out of each sample, ensuring reproducibility of the data. The measurements were carried out using room temperature uniaxial tensile testing with an Instron5982 universal materials tester (manufacturer:instron, usa), the tensile displacement of the sample was monitored all the way with an extensometer, the tensile rate was set at 5 x 10^-3s^-1And performing a tensile test to obtain data related to the mechanical properties, wherein the test results are shown in table 1.

TABLE 1 mechanical Properties of zirconium alloys obtained in examples 1 to 5 and comparative example 1

In the invention, as the Nb element in the zirconium alloy is increased and the beta transformation temperature of the alloy is reduced, under the same solid solution cooling condition, the nucleation number of original beta crystal grains is increased, the size of the generated original beta crystal grains is smaller, the number of crystal boundaries is larger, and meanwhile, the beta phase is also kept at room temperature. Under the combined action of solid solution strengthening (Nb element can enter a Zr matrix to form an infinite solid solution) and grain boundary strengthening, the strength of the alloy is greatly improved, and meanwhile, the elastic modulus is reduced, and the lowest elastic modulus can reach 43 GPa.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.